from flask import Flask, render_template, request, redirect, send_file, make_response, jsonify
from db import get_db_connection
from utils import generate_client_code, generate_service_code
from datetime import datetime, timezone
from zoneinfo import ZoneInfo
from decimal import Decimal, InvalidOperation
from email.message import EmailMessage

from io import BytesIO, StringIO
import csv
import zipfile
import json
import smtplib
from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas
from reportlab.lib.utils import ImageReader

app = Flask(
    __name__,
    template_folder="../templates",
    static_folder="../static",
)

LOCAL_TZ = ZoneInfo("America/Toronto")

def load_version():
    try:
        with open("/home/def/otb_billing/VERSION", "r") as f:
            return f.read().strip()
    except Exception:
        return "unknown"

APP_VERSION = load_version()

@app.context_processor
def inject_version():
    return {"app_version": APP_VERSION}

@app.context_processor
def inject_app_settings():
    return {"app_settings": get_app_settings()}

def fmt_local(dt_value):
    if not dt_value:
        return ""
    if isinstance(dt_value, str):
        try:
            dt_value = datetime.fromisoformat(dt_value)
        except ValueError:
            return str(dt_value)
    if dt_value.tzinfo is None:
        dt_value = dt_value.replace(tzinfo=timezone.utc)
    return dt_value.astimezone(LOCAL_TZ).strftime("%Y-%m-%d %I:%M:%S %p")

def to_decimal(value):
    if value is None or value == "":
        return Decimal("0")
    try:
        return Decimal(str(value))
    except (InvalidOperation, ValueError):
        return Decimal("0")

def fmt_money(value, currency_code="CAD"):
    amount = to_decimal(value)
    if currency_code == "CAD":
        return f"{amount:.2f}"
    return f"{amount:.8f}"

def refresh_overdue_invoices():
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("""
        UPDATE invoices
        SET status = 'overdue'
        WHERE due_at IS NOT NULL
          AND due_at < UTC_TIMESTAMP()
          AND status IN ('pending', 'partial')
    """)
    conn.commit()
    conn.close()

def recalc_invoice_totals(invoice_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT id, total_amount, due_at, status
        FROM invoices
        WHERE id = %s
    """, (invoice_id,))
    invoice = cursor.fetchone()

    if not invoice:
        conn.close()
        return

    cursor.execute("""
        SELECT COALESCE(SUM(payment_amount), 0) AS total_paid
        FROM payments
        WHERE invoice_id = %s
          AND payment_status = 'confirmed'
    """, (invoice_id,))
    row = cursor.fetchone()

    total_paid = to_decimal(row["total_paid"])
    total_amount = to_decimal(invoice["total_amount"])

    if invoice["status"] == "cancelled":
        update_cursor = conn.cursor()
        update_cursor.execute("""
            UPDATE invoices
            SET amount_paid = %s,
                paid_at = NULL
            WHERE id = %s
        """, (
            str(total_paid),
            invoice_id
        ))
        conn.commit()
        conn.close()
        return

    if total_paid >= total_amount and total_amount > 0:
        new_status = "paid"
        paid_at_value = "UTC_TIMESTAMP()"
    elif total_paid > 0:
        new_status = "partial"
        paid_at_value = "NULL"
    else:
        if invoice["due_at"] and invoice["due_at"] < datetime.utcnow():
            new_status = "overdue"
        else:
            new_status = "pending"
        paid_at_value = "NULL"

    update_cursor = conn.cursor()
    update_cursor.execute(f"""
        UPDATE invoices
        SET amount_paid = %s,
            status = %s,
            paid_at = {paid_at_value}
        WHERE id = %s
    """, (
        str(total_paid),
        new_status,
        invoice_id
    ))

    conn.commit()
    conn.close()

def get_client_credit_balance(client_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT COALESCE(SUM(amount), 0) AS balance
        FROM credit_ledger
        WHERE client_id = %s
    """, (client_id,))
    row = cursor.fetchone()
    conn.close()
    return to_decimal(row["balance"])


def generate_invoice_number():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT invoice_number
        FROM invoices
        WHERE invoice_number IS NOT NULL
          AND invoice_number LIKE 'INV-%'
        ORDER BY id DESC
        LIMIT 1
    """)
    row = cursor.fetchone()
    conn.close()

    if not row or not row.get("invoice_number"):
        return "INV-0001"

    invoice_number = str(row["invoice_number"]).strip()

    try:
        number = int(invoice_number.split("-")[1])
    except (IndexError, ValueError):
        return "INV-0001"

    return f"INV-{number + 1:04d}"


APP_SETTINGS_DEFAULTS = {
    "business_name": "OTB Billing",
    "business_tagline": "By a contractor, for contractors",
    "business_logo_url": "",
    "business_email": "",
    "business_phone": "",
    "business_address": "",
    "business_website": "",
    "tax_label": "HST",
    "tax_rate": "13.00",
    "tax_number": "",
    "business_number": "",
    "default_currency": "CAD",
    "report_frequency": "monthly",
    "invoice_footer": "",
    "payment_terms": "",
    "local_country": "Canada",
    "apply_local_tax_only": "1",
    "smtp_host": "",
    "smtp_port": "587",
    "smtp_user": "",
    "smtp_pass": "",
    "smtp_from_email": "",
    "smtp_from_name": "",
    "smtp_use_tls": "1",
    "smtp_use_ssl": "0",
    "report_delivery_email": "",
}

def ensure_app_settings_table():
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("""
        CREATE TABLE IF NOT EXISTS app_settings (
            setting_key VARCHAR(100) NOT NULL PRIMARY KEY,
            setting_value TEXT NULL,
            updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
        )
    """)
    conn.commit()
    conn.close()

def get_app_settings():
    ensure_app_settings_table()
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT setting_key, setting_value
        FROM app_settings
    """)
    rows = cursor.fetchall()
    conn.close()

    settings = dict(APP_SETTINGS_DEFAULTS)
    for row in rows:
        settings[row["setting_key"]] = row["setting_value"] if row["setting_value"] is not None else ""

    return settings

def save_app_settings(form_data):
    ensure_app_settings_table()
    conn = get_db_connection()
    cursor = conn.cursor()

    for key in APP_SETTINGS_DEFAULTS.keys():
        if key in {"apply_local_tax_only", "smtp_use_tls", "smtp_use_ssl"}:
            value = "1" if form_data.get(key) else "0"
        else:
            value = (form_data.get(key) or "").strip()

        cursor.execute("""
            INSERT INTO app_settings (setting_key, setting_value)
            VALUES (%s, %s)
            ON DUPLICATE KEY UPDATE setting_value = VALUES(setting_value)
        """, (key, value))

    conn.commit()
    conn.close()


@app.template_filter("localtime")
def localtime_filter(value):
    return fmt_local(value)

@app.template_filter("money")
def money_filter(value, currency_code="CAD"):
    return fmt_money(value, currency_code)




def get_report_period_bounds(frequency):
    now_local = datetime.now(LOCAL_TZ)

    if frequency == "yearly":
        start_local = now_local.replace(month=1, day=1, hour=0, minute=0, second=0, microsecond=0)
        label = f"{now_local.year}"
    elif frequency == "quarterly":
        quarter = ((now_local.month - 1) // 3) + 1
        start_month = (quarter - 1) * 3 + 1
        start_local = now_local.replace(month=start_month, day=1, hour=0, minute=0, second=0, microsecond=0)
        label = f"Q{quarter} {now_local.year}"
    else:
        start_local = now_local.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
        label = now_local.strftime("%B %Y")

    start_utc = start_local.astimezone(timezone.utc).replace(tzinfo=None)
    end_utc = now_local.astimezone(timezone.utc).replace(tzinfo=None)

    return start_utc, end_utc, label

def get_revenue_report_data():
    settings = get_app_settings()
    frequency = (settings.get("report_frequency") or "monthly").strip().lower()
    if frequency not in {"monthly", "quarterly", "yearly"}:
        frequency = "monthly"

    start_utc, end_utc, label = get_report_period_bounds(frequency)

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT COALESCE(SUM(cad_value_at_payment), 0) AS collected
        FROM payments
        WHERE payment_status = 'confirmed'
          AND received_at >= %s
          AND received_at <= %s
    """, (start_utc, end_utc))
    collected_row = cursor.fetchone()

    cursor.execute("""
        SELECT COUNT(*) AS invoice_count,
               COALESCE(SUM(total_amount), 0) AS invoiced
        FROM invoices
        WHERE issued_at >= %s
          AND issued_at <= %s
    """, (start_utc, end_utc))
    invoiced_row = cursor.fetchone()

    cursor.execute("""
        SELECT COUNT(*) AS overdue_count,
               COALESCE(SUM(total_amount - amount_paid), 0) AS overdue_balance
        FROM invoices
        WHERE status = 'overdue'
    """)
    overdue_row = cursor.fetchone()

    cursor.execute("""
        SELECT COUNT(*) AS outstanding_count,
               COALESCE(SUM(total_amount - amount_paid), 0) AS outstanding_balance
        FROM invoices
        WHERE status IN ('pending', 'partial', 'overdue')
    """)
    outstanding_row = cursor.fetchone()

    conn.close()

    return {
        "frequency": frequency,
        "period_label": label,
        "period_start": start_utc.isoformat(sep=" "),
        "period_end": end_utc.isoformat(sep=" "),
        "collected_cad": str(to_decimal(collected_row["collected"])),
        "invoice_count": int(invoiced_row["invoice_count"] or 0),
        "invoiced_total": str(to_decimal(invoiced_row["invoiced"])),
        "overdue_count": int(overdue_row["overdue_count"] or 0),
        "overdue_balance": str(to_decimal(overdue_row["overdue_balance"])),
        "outstanding_count": int(outstanding_row["outstanding_count"] or 0),
        "outstanding_balance": str(to_decimal(outstanding_row["outstanding_balance"])),
    }



def send_configured_email(to_email, subject, body, attachments=None):
    settings = get_app_settings()

    smtp_host = (settings.get("smtp_host") or "").strip()
    smtp_port = int((settings.get("smtp_port") or "587").strip() or "587")
    smtp_user = (settings.get("smtp_user") or "").strip()
    smtp_pass = (settings.get("smtp_pass") or "").strip()
    from_email = (settings.get("smtp_from_email") or settings.get("business_email") or "").strip()
    from_name = (settings.get("smtp_from_name") or settings.get("business_name") or "").strip()
    use_tls = (settings.get("smtp_use_tls") or "0") == "1"
    use_ssl = (settings.get("smtp_use_ssl") or "0") == "1"

    if not smtp_host:
        raise ValueError("SMTP host is not configured.")
    if not from_email:
        raise ValueError("From email is not configured.")
    if not to_email:
        raise ValueError("Recipient email is missing.")

    msg = EmailMessage()
    msg["Subject"] = subject
    msg["From"] = f"{from_name} <{from_email}>" if from_name else from_email
    msg["To"] = to_email
    msg.set_content(body)

    for attachment in attachments or []:
        filename = attachment["filename"]
        mime_type = attachment["mime_type"]
        data = attachment["data"]
        maintype, subtype = mime_type.split("/", 1)
        msg.add_attachment(data, maintype=maintype, subtype=subtype, filename=filename)

    if use_ssl:
        with smtplib.SMTP_SSL(smtp_host, smtp_port, timeout=30) as server:
            if smtp_user:
                server.login(smtp_user, smtp_pass)
            server.send_message(msg)
    else:
        with smtplib.SMTP(smtp_host, smtp_port, timeout=30) as server:
            server.ehlo()
            if use_tls:
                server.starttls()
                server.ehlo()
            if smtp_user:
                server.login(smtp_user, smtp_pass)
            server.send_message(msg)

def build_invoice_pdf_bytes(invoice, settings):
    buffer = BytesIO()
    pdf = canvas.Canvas(buffer, pagesize=letter)
    width, height = letter

    left = 50
    right = 560
    y = height - 50

    def money(value, currency="CAD"):
        return f"{to_decimal(value):.2f} {currency}"

    pdf.setTitle(f"Invoice {invoice['invoice_number']}")

    logo_url = (settings.get("business_logo_url") or "").strip()
    if logo_url.startswith("/static/"):
        local_logo_path = "/home/def/otb_billing" + logo_url
        try:
            pdf.drawImage(ImageReader(local_logo_path), left, y - 35, width=42, height=42, preserveAspectRatio=True, mask='auto')
        except Exception:
            pass

    pdf.setFont("Helvetica-Bold", 22)
    pdf.drawString(left + 60, y, f"Invoice {invoice['invoice_number']}")

    pdf.setFont("Helvetica-Bold", 14)
    pdf.drawRightString(right, y, settings.get("business_name") or "OTB Billing")
    y -= 18
    pdf.setFont("Helvetica", 12)
    pdf.drawRightString(right, y, settings.get("business_tagline") or "")
    y -= 15

    right_lines = [
        settings.get("business_address", ""),
        settings.get("business_email", ""),
        settings.get("business_phone", ""),
        settings.get("business_website", ""),
    ]
    for item in right_lines:
        if item:
            pdf.drawRightString(right, y, item[:80])
            y -= 14

    y -= 10

    pdf.setFont("Helvetica-Bold", 12)
    pdf.drawString(left, y, "Status:")
    pdf.setFont("Helvetica", 12)
    pdf.drawString(left + 45, y, str(invoice["status"]).upper())
    y -= 28

    pdf.setFont("Helvetica-Bold", 13)
    pdf.drawString(left, y, "Bill To")
    y -= 20
    pdf.setFont("Helvetica-Bold", 12)
    pdf.drawString(left, y, invoice["company_name"] or "")
    y -= 16
    pdf.setFont("Helvetica", 11)
    if invoice.get("contact_name"):
        pdf.drawString(left, y, str(invoice["contact_name"]))
        y -= 15
    if invoice.get("email"):
        pdf.drawString(left, y, str(invoice["email"]))
        y -= 15
    if invoice.get("phone"):
        pdf.drawString(left, y, str(invoice["phone"]))
        y -= 15
    pdf.drawString(left, y, f"Client Code: {invoice.get('client_code', '')}")
    y -= 28

    pdf.setFont("Helvetica-Bold", 13)
    pdf.drawString(left, y, "Invoice Details")
    y -= 20
    pdf.setFont("Helvetica", 11)
    pdf.drawString(left, y, f"Invoice #: {invoice['invoice_number']}")
    y -= 15
    pdf.drawString(left, y, f"Issued: {fmt_local(invoice.get('issued_at'))}")
    y -= 15
    pdf.drawString(left, y, f"Due: {fmt_local(invoice.get('due_at'))}")
    y -= 15
    if invoice.get("paid_at"):
        pdf.drawString(left, y, f"Paid: {fmt_local(invoice.get('paid_at'))}")
        y -= 15
    pdf.drawString(left, y, f"Currency: {invoice.get('currency_code', 'CAD')}")
    y -= 28

    pdf.setFont("Helvetica-Bold", 11)
    pdf.drawString(left, y, "Service Code")
    pdf.drawString(180, y, "Service")
    pdf.drawString(330, y, "Description")
    pdf.drawRightString(right, y, "Total")
    y -= 14
    pdf.line(left, y, right, y)
    y -= 18

    pdf.setFont("Helvetica", 11)
    pdf.drawString(left, y, str(invoice.get("service_code") or "-"))
    pdf.drawString(180, y, str(invoice.get("service_name") or "-"))
    pdf.drawString(330, y, str(invoice.get("notes") or "-")[:28])
    pdf.drawRightString(right, y, money(invoice.get("total_amount"), invoice.get("currency_code", "CAD")))
    y -= 28

    totals_x_label = 360
    totals_x_value = right

    totals = [
        ("Subtotal", money(invoice.get("subtotal_amount"), invoice.get("currency_code", "CAD"))),
        ((settings.get("tax_label") or "Tax"), money(invoice.get("tax_amount"), invoice.get("currency_code", "CAD"))),
        ("Total", money(invoice.get("total_amount"), invoice.get("currency_code", "CAD"))),
        ("Paid", money(invoice.get("amount_paid"), invoice.get("currency_code", "CAD"))),
    ]

    remaining = to_decimal(invoice.get("total_amount")) - to_decimal(invoice.get("amount_paid"))

    for label, value in totals:
        pdf.setFont("Helvetica-Bold", 11)
        pdf.drawString(totals_x_label, y, label)
        pdf.setFont("Helvetica", 11)
        pdf.drawRightString(totals_x_value, y, value)
        y -= 18

    pdf.setFont("Helvetica-Bold", 11)
    pdf.drawString(totals_x_label, y, "Remaining")
    pdf.drawRightString(totals_x_value, y, f"{remaining:.2f} {invoice.get('currency_code', 'CAD')}")
    y -= 25

    if settings.get("tax_number"):
        pdf.setFont("Helvetica", 10)
        pdf.drawString(left, y, f"{settings.get('tax_label') or 'Tax'} Number: {settings.get('tax_number')}")
        y -= 14

    if settings.get("business_number"):
        pdf.setFont("Helvetica", 10)
        pdf.drawString(left, y, f"Business Number: {settings.get('business_number')}")
        y -= 14

    if settings.get("payment_terms"):
        y -= 8
        pdf.setFont("Helvetica-Bold", 11)
        pdf.drawString(left, y, "Payment Terms")
        y -= 15
        pdf.setFont("Helvetica", 10)
        terms = settings.get("payment_terms", "")
        for chunk_start in range(0, len(terms), 90):
            line_text = terms[chunk_start:chunk_start+90]
            pdf.drawString(left, y, line_text)
            y -= 13

    if settings.get("invoice_footer"):
        y -= 8
        pdf.setFont("Helvetica-Bold", 11)
        pdf.drawString(left, y, "Footer")
        y -= 15
        pdf.setFont("Helvetica", 10)
        footer = settings.get("invoice_footer", "")
        for chunk_start in range(0, len(footer), 90):
            line_text = footer[chunk_start:chunk_start+90]
            pdf.drawString(left, y, line_text)
            y -= 13

    pdf.showPage()
    pdf.save()
    buffer.seek(0)
    return buffer.getvalue()

def build_accounting_package_bytes():
    settings = get_app_settings()
    frequency = (settings.get("report_frequency") or "monthly").strip().lower()
    if frequency not in {"monthly", "quarterly", "yearly"}:
        frequency = "monthly"

    start_utc, end_utc, label = get_report_period_bounds(frequency)

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            id,
            client_code,
            company_name,
            contact_name,
            email,
            phone,
            status,
            created_at,
            updated_at
        FROM clients
        ORDER BY id ASC
    """)
    clients = cursor.fetchall()

    cursor.execute("""
        SELECT
            i.id,
            i.invoice_number,
            i.client_id,
            c.client_code,
            c.company_name,
            i.service_id,
            i.currency_code,
            i.subtotal_amount,
            i.tax_amount,
            i.total_amount,
            i.amount_paid,
            i.status,
            i.issued_at,
            i.due_at,
            i.paid_at,
            i.notes,
            i.created_at,
            i.updated_at
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        WHERE i.issued_at >= %s
          AND i.issued_at <= %s
        ORDER BY i.id ASC
    """, (start_utc, end_utc))
    invoices_csv_rows = cursor.fetchall()

    cursor.execute("""
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE i.issued_at >= %s
          AND i.issued_at <= %s
        ORDER BY i.id ASC
    """, (start_utc, end_utc))
    invoices_pdf_rows = cursor.fetchall()

    cursor.execute("""
        SELECT
            p.id,
            p.invoice_id,
            i.invoice_number,
            p.client_id,
            c.client_code,
            c.company_name,
            p.payment_method,
            p.payment_currency,
            p.payment_amount,
            p.cad_value_at_payment,
            p.reference,
            p.sender_name,
            p.txid,
            p.wallet_address,
            p.payment_status,
            p.received_at,
            p.notes
        FROM payments p
        JOIN invoices i ON p.invoice_id = i.id
        JOIN clients c ON p.client_id = c.id
        WHERE p.received_at >= %s
          AND p.received_at <= %s
        ORDER BY p.id ASC
    """, (start_utc, end_utc))
    payments = cursor.fetchall()

    conn.close()

    report = get_revenue_report_data()

    zip_buffer = BytesIO()
    with zipfile.ZipFile(zip_buffer, "w", zipfile.ZIP_DEFLATED) as zipf:
        clients_io = StringIO()
        writer = csv.writer(clients_io)
        writer.writerow([
            "id", "client_code", "company_name", "contact_name", "email", "phone", "status", "created_at", "updated_at"
        ])
        for r in clients:
            writer.writerow([
                r.get("id", ""),
                r.get("client_code", ""),
                r.get("company_name", ""),
                r.get("contact_name", ""),
                r.get("email", ""),
                r.get("phone", ""),
                r.get("status", ""),
                r.get("created_at", ""),
                r.get("updated_at", ""),
            ])
        zipf.writestr("csv/clients.csv", clients_io.getvalue())

        invoices_io = StringIO()
        writer = csv.writer(invoices_io)
        writer.writerow([
            "id", "invoice_number", "client_id", "client_code", "company_name", "service_id",
            "currency_code", "subtotal_amount", "tax_amount", "total_amount", "amount_paid",
            "status", "issued_at", "due_at", "paid_at", "notes", "created_at", "updated_at"
        ])
        for r in invoices_csv_rows:
            writer.writerow([
                r.get("id", ""),
                r.get("invoice_number", ""),
                r.get("client_id", ""),
                r.get("client_code", ""),
                r.get("company_name", ""),
                r.get("service_id", ""),
                r.get("currency_code", ""),
                r.get("subtotal_amount", ""),
                r.get("tax_amount", ""),
                r.get("total_amount", ""),
                r.get("amount_paid", ""),
                r.get("status", ""),
                r.get("issued_at", ""),
                r.get("due_at", ""),
                r.get("paid_at", ""),
                r.get("notes", ""),
                r.get("created_at", ""),
                r.get("updated_at", ""),
            ])
        zipf.writestr("csv/invoices.csv", invoices_io.getvalue())

        payments_io = StringIO()
        writer = csv.writer(payments_io)
        writer.writerow([
            "id", "invoice_id", "invoice_number", "client_id", "client_code", "company_name",
            "payment_method", "payment_currency", "payment_amount", "cad_value_at_payment",
            "reference", "sender_name", "txid", "wallet_address", "payment_status", "received_at", "notes"
        ])
        for r in payments:
            writer.writerow([
                r.get("id", ""),
                r.get("invoice_id", ""),
                r.get("invoice_number", ""),
                r.get("client_id", ""),
                r.get("client_code", ""),
                r.get("company_name", ""),
                r.get("payment_method", ""),
                r.get("payment_currency", ""),
                r.get("payment_amount", ""),
                r.get("cad_value_at_payment", ""),
                r.get("reference", ""),
                r.get("sender_name", ""),
                r.get("txid", ""),
                r.get("wallet_address", ""),
                r.get("payment_status", ""),
                r.get("received_at", ""),
                r.get("notes", ""),
            ])
        zipf.writestr("csv/payments.csv", payments_io.getvalue())

        zipf.writestr("json/revenue_report.json", json.dumps(report, indent=2))

        for invoice in invoices_pdf_rows:
            pdf_bytes = build_invoice_pdf_bytes(invoice, settings)
            zipf.writestr(f"pdf/{invoice['invoice_number']}.pdf", pdf_bytes)

    zip_buffer.seek(0)
    safe_label = label.replace(" ", "_")
    filename = f"accounting_package_{safe_label}.zip"
    return zip_buffer.getvalue(), filename




def ensure_email_log_table():
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("""
        CREATE TABLE IF NOT EXISTS email_log (
            id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
            email_type VARCHAR(50) NOT NULL,
            invoice_id INT UNSIGNED NULL,
            recipient_email VARCHAR(255) NOT NULL,
            subject VARCHAR(255) NOT NULL,
            status VARCHAR(50) NOT NULL,
            error_message TEXT NULL,
            sent_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
            KEY idx_email_log_invoice_id (invoice_id),
            KEY idx_email_log_type (email_type),
            KEY idx_email_log_sent_at (sent_at)
        )
    """)
    conn.commit()
    conn.close()

def log_email_event(email_type, recipient_email, subject, status, invoice_id=None, error_message=None):
    ensure_email_log_table()
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("""
        INSERT INTO email_log
        (
            email_type,
            invoice_id,
            recipient_email,
            subject,
            status,
            error_message
        )
        VALUES (%s, %s, %s, %s, %s, %s)
    """, (
        email_type,
        invoice_id,
        recipient_email,
        subject,
        status,
        error_message
    ))
    conn.commit()
    conn.close()

@app.route("/settings", methods=["GET", "POST"])
def settings():
    ensure_app_settings_table()

    if request.method == "POST":
        save_app_settings(request.form)
        return redirect("/settings")

    settings = get_app_settings()
    return render_template("settings.html", settings=settings)



@app.route("/reports/accounting-package.zip")
def accounting_package_zip():
    package_bytes, filename = build_accounting_package_bytes()
    return send_file(
        BytesIO(package_bytes),
        mimetype="application/zip",
        as_attachment=True,
        download_name=filename
    )


@app.route("/reports/revenue")
def revenue_report():
    report = get_revenue_report_data()
    return render_template("reports/revenue.html", report=report)

@app.route("/reports/revenue.json")
def revenue_report_json():
    report = get_revenue_report_data()
    return jsonify(report)

@app.route("/reports/revenue/print")
def revenue_report_print():
    report = get_revenue_report_data()
    return render_template("reports/revenue_print.html", report=report)


@app.route("/invoices/email/<int:invoice_id>", methods=["POST"])
def email_invoice(invoice_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE i.id = %s
    """, (invoice_id,))
    invoice = cursor.fetchone()

    if not invoice:
        conn.close()
        return "Invoice not found", 404

    conn.close()

    recipient = (invoice.get("email") or "").strip()
    if not recipient:
        return "Client email is missing for this invoice.", 400

    settings = get_app_settings()
    pdf_bytes = build_invoice_pdf_bytes(invoice, settings)

    subject = f"Invoice {invoice['invoice_number']} from {settings.get('business_name') or 'OTB Billing'}"
    remaining = to_decimal(invoice.get("total_amount")) - to_decimal(invoice.get("amount_paid"))
    body = (
        f"Hello {invoice.get('contact_name') or invoice.get('company_name') or ''},

"
        f"Please find attached invoice {invoice['invoice_number']}.
"
        f"Total: {to_decimal(invoice.get('total_amount')):.2f} {invoice.get('currency_code', 'CAD')}
"
        f"Remaining: {remaining:.2f} {invoice.get('currency_code', 'CAD')}
"
        f"Due: {fmt_local(invoice.get('due_at'))}

"
        f"Thank you,
"
        f"{settings.get('business_name') or 'OTB Billing'}"
    )

    try:
        send_configured_email(
            recipient,
            subject,
            body,
            attachments=[{
                "filename": f"{invoice['invoice_number']}.pdf",
                "mime_type": "application/pdf",
                "data": pdf_bytes,
            }]
        )
        log_email_event("invoice", recipient, subject, "sent", invoice_id=invoice_id, error_message=None)
        return redirect(f"/invoices/view/{invoice_id}?email_sent=1")
    except Exception as e:
        log_email_event("invoice", recipient, subject, "failed", invoice_id=invoice_id, error_message=str(e))
        return redirect(f"/invoices/view/{invoice_id}?email_failed=1")

@app.route("/reports/revenue/email", methods=["POST"])
def email_revenue_report_json():
    settings = get_app_settings()
    recipient = (settings.get("report_delivery_email") or settings.get("business_email") or "").strip()
    if not recipient:
        return "Report delivery email is not configured.", 400

    report = get_revenue_report_data()
    report_json = json.dumps(report, indent=2).encode("utf-8")

    subject = f"Revenue Report {report.get('period_label', '')} from {settings.get('business_name') or 'OTB Billing'}"
    body = (
        f"Attached is the revenue report JSON for {report.get('period_label', '')}.

"
        f"Frequency: {report.get('frequency', '')}
"
        f"Collected CAD: {report.get('collected_cad', '')}
"
        f"Invoices Issued: {report.get('invoice_count', '')}
"
    )

    try:
        send_configured_email(
            recipient,
            subject,
            body,
            attachments=[{
                "filename": "revenue_report.json",
                "mime_type": "application/json",
                "data": report_json,
            }]
        )
        log_email_event("revenue_report", recipient, subject, "sent", invoice_id=None, error_message=None)
        return redirect("/reports/revenue?email_sent=1")
    except Exception as e:
        log_email_event("revenue_report", recipient, subject, "failed", invoice_id=None, error_message=str(e))
        return redirect("/reports/revenue?email_failed=1")

@app.route("/reports/accounting-package/email", methods=["POST"])
def email_accounting_package():
    settings = get_app_settings()
    recipient = (settings.get("report_delivery_email") or settings.get("business_email") or "").strip()
    if not recipient:
        return "Report delivery email is not configured.", 400

    package_bytes, filename = build_accounting_package_bytes()

    subject = f"Accounting Package from {settings.get('business_name') or 'OTB Billing'}"
    body = "Attached is the latest accounting package export."

    try:
        send_configured_email(
            recipient,
            subject,
            body,
            attachments=[{
                "filename": filename,
                "mime_type": "application/zip",
                "data": package_bytes,
            }]
        )
        log_email_event("accounting_package", recipient, subject, "sent", invoice_id=None, error_message=None)
        return redirect("/?pkg_email=1")
    except Exception as e:
        log_email_event("accounting_package", recipient, subject, "failed", invoice_id=None, error_message=str(e))
        return redirect("/?pkg_email_failed=1")

@app.route("/")
def index():
    refresh_overdue_invoices()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("SELECT COUNT(*) AS total_clients FROM clients")
    total_clients = cursor.fetchone()["total_clients"]

    cursor.execute("SELECT COUNT(*) AS active_services FROM services WHERE status = 'active'")
    active_services = cursor.fetchone()["active_services"]

    cursor.execute("""
        SELECT COUNT(*) AS outstanding_invoices
        FROM invoices
        WHERE status IN ('pending', 'partial', 'overdue')
    """)
    outstanding_invoices = cursor.fetchone()["outstanding_invoices"]

    cursor.execute("""
        SELECT COALESCE(SUM(cad_value_at_payment), 0) AS revenue_received
        FROM payments
        WHERE payment_status = 'confirmed'
    """)
    revenue_received = cursor.fetchone()["revenue_received"]

    conn.close()

    return render_template(
        "dashboard.html",
        total_clients=total_clients,
        active_services=active_services,
        outstanding_invoices=outstanding_invoices,
        revenue_received=revenue_received,
    )

@app.route("/dbtest")
def dbtest():
    try:
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute("SELECT NOW()")
        result = cursor.fetchone()
        conn.close()
        return f"""
        <h1>OTB Billing v{APP_VERSION}</h1>
        <h2>Database OK</h2>
        <p><a href="/">Home</a></p>
        <p>DB server time (UTC): {result[0]}</p>
        <p>Displayed local time: {fmt_local(result[0])}</p>
        """
    except Exception as e:
        return f"<h1>Database FAILED</h1><pre>{e}</pre>"



@app.route("/clients/export.csv")
def export_clients_csv():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT
            id,
            client_code,
            company_name,
            contact_name,
            email,
            phone,
            status,
            created_at,
            updated_at
        FROM clients
        ORDER BY id ASC
    """)
    rows = cursor.fetchall()
    conn.close()

    output = StringIO()
    writer = csv.writer(output)
    writer.writerow([
        "id",
        "client_code",
        "company_name",
        "contact_name",
        "email",
        "phone",
        "status",
        "created_at",
        "updated_at",
    ])

    for r in rows:
        writer.writerow([
            r.get("id", ""),
            r.get("client_code", ""),
            r.get("company_name", ""),
            r.get("contact_name", ""),
            r.get("email", ""),
            r.get("phone", ""),
            r.get("status", ""),
            r.get("created_at", ""),
            r.get("updated_at", ""),
        ])

    response = make_response(output.getvalue())
    response.headers["Content-Type"] = "text/csv; charset=utf-8"
    response.headers["Content-Disposition"] = "attachment; filename=clients.csv"
    return response

@app.route("/clients")
def clients():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("SELECT * FROM clients ORDER BY id DESC")
    clients = cursor.fetchall()
    conn.close()

    for client in clients:
        client["credit_balance"] = get_client_credit_balance(client["id"])

    return render_template("clients/list.html", clients=clients)

@app.route("/clients/new", methods=["GET", "POST"])
def new_client():
    if request.method == "POST":
        company_name = request.form["company_name"]
        contact_name = request.form["contact_name"]
        email = request.form["email"]
        phone = request.form["phone"]

        conn = get_db_connection()
        cursor = conn.cursor(dictionary=True)
        cursor.execute("SELECT MAX(id) AS last_id FROM clients")
        result = cursor.fetchone()
        last_number = result["last_id"] if result["last_id"] else 0

        client_code = generate_client_code(company_name, last_number)

        insert_cursor = conn.cursor()
        insert_cursor.execute(
            """
            INSERT INTO clients
            (client_code, company_name, contact_name, email, phone)
            VALUES (%s, %s, %s, %s, %s)
            """,
            (client_code, company_name, contact_name, email, phone)
        )
        conn.commit()
        conn.close()

        return redirect("/clients")

    return render_template("clients/new.html")

@app.route("/clients/edit/<int:client_id>", methods=["GET", "POST"])
def edit_client(client_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    if request.method == "POST":
        company_name = request.form.get("company_name", "").strip()
        contact_name = request.form.get("contact_name", "").strip()
        email = request.form.get("email", "").strip()
        phone = request.form.get("phone", "").strip()
        status = request.form.get("status", "").strip()
        notes = request.form.get("notes", "").strip()

        errors = []

        if not company_name:
            errors.append("Company name is required.")
        if not status:
            errors.append("Status is required.")

        if errors:
            cursor.execute("SELECT * FROM clients WHERE id = %s", (client_id,))
            client = cursor.fetchone()
            client["credit_balance"] = get_client_credit_balance(client_id)
            conn.close()
            return render_template("clients/edit.html", client=client, errors=errors)

        update_cursor = conn.cursor()
        update_cursor.execute("""
            UPDATE clients
            SET company_name = %s,
                contact_name = %s,
                email = %s,
                phone = %s,
                status = %s,
                notes = %s
            WHERE id = %s
        """, (
            company_name,
            contact_name or None,
            email or None,
            phone or None,
            status,
            notes or None,
            client_id
        ))
        conn.commit()
        conn.close()
        return redirect("/clients")

    cursor.execute("SELECT * FROM clients WHERE id = %s", (client_id,))
    client = cursor.fetchone()
    conn.close()

    if not client:
        return "Client not found", 404

    client["credit_balance"] = get_client_credit_balance(client_id)

    return render_template("clients/edit.html", client=client, errors=[])

@app.route("/credits/<int:client_id>")
def client_credits(client_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT id, client_code, company_name
        FROM clients
        WHERE id = %s
    """, (client_id,))
    client = cursor.fetchone()

    if not client:
        conn.close()
        return "Client not found", 404

    cursor.execute("""
        SELECT *
        FROM credit_ledger
        WHERE client_id = %s
        ORDER BY id DESC
    """, (client_id,))
    entries = cursor.fetchall()

    conn.close()

    balance = get_client_credit_balance(client_id)

    return render_template(
        "credits/list.html",
        client=client,
        entries=entries,
        balance=balance,
    )

@app.route("/credits/add/<int:client_id>", methods=["GET", "POST"])
def add_credit(client_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT id, client_code, company_name
        FROM clients
        WHERE id = %s
    """, (client_id,))
    client = cursor.fetchone()

    if not client:
        conn.close()
        return "Client not found", 404

    if request.method == "POST":
        entry_type = request.form.get("entry_type", "").strip()
        amount = request.form.get("amount", "").strip()
        currency_code = request.form.get("currency_code", "").strip()
        notes = request.form.get("notes", "").strip()

        errors = []

        if not entry_type:
            errors.append("Entry type is required.")
        if not amount:
            errors.append("Amount is required.")
        if not currency_code:
            errors.append("Currency code is required.")

        if not errors:
            try:
                amount_value = Decimal(str(amount))
                if amount_value == 0:
                    errors.append("Amount cannot be zero.")
            except Exception:
                errors.append("Amount must be a valid number.")

        if errors:
            conn.close()
            return render_template("credits/add.html", client=client, errors=errors)

        insert_cursor = conn.cursor()
        insert_cursor.execute("""
            INSERT INTO credit_ledger
            (
                client_id,
                entry_type,
                amount,
                currency_code,
                notes
            )
            VALUES (%s, %s, %s, %s, %s)
        """, (
            client_id,
            entry_type,
            amount,
            currency_code,
            notes or None
        ))
        conn.commit()
        conn.close()

        return redirect(f"/credits/{client_id}")

    conn.close()
    return render_template("credits/add.html", client=client, errors=[])

@app.route("/services")
def services():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT s.*, c.client_code, c.company_name
        FROM services s
        JOIN clients c ON s.client_id = c.id
        ORDER BY s.id DESC
    """)
    services = cursor.fetchall()
    conn.close()
    return render_template("services/list.html", services=services)

@app.route("/services/new", methods=["GET", "POST"])
def new_service():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    if request.method == "POST":
        client_id = request.form["client_id"]
        service_name = request.form["service_name"]
        service_type = request.form["service_type"]
        billing_cycle = request.form["billing_cycle"]
        currency_code = request.form["currency_code"]
        recurring_amount = request.form["recurring_amount"]
        status = request.form["status"]
        start_date = request.form["start_date"] or None
        description = request.form["description"]

        cursor.execute("SELECT MAX(id) AS last_id FROM services")
        result = cursor.fetchone()
        last_number = result["last_id"] if result["last_id"] else 0
        service_code = generate_service_code(service_name, last_number)

        insert_cursor = conn.cursor()
        insert_cursor.execute(
            """
            INSERT INTO services
            (
                client_id,
                service_code,
                service_name,
                service_type,
                billing_cycle,
                status,
                currency_code,
                recurring_amount,
                start_date,
                description
            )
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
            """,
            (
                client_id,
                service_code,
                service_name,
                service_type,
                billing_cycle,
                status,
                currency_code,
                recurring_amount,
                start_date,
                description
            )
        )
        conn.commit()
        conn.close()

        return redirect("/services")

    cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name ASC")
    clients = cursor.fetchall()
    conn.close()
    return render_template("services/new.html", clients=clients)

@app.route("/services/edit/<int:service_id>", methods=["GET", "POST"])
def edit_service(service_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    if request.method == "POST":
        client_id = request.form.get("client_id", "").strip()
        service_name = request.form.get("service_name", "").strip()
        service_type = request.form.get("service_type", "").strip()
        billing_cycle = request.form.get("billing_cycle", "").strip()
        currency_code = request.form.get("currency_code", "").strip()
        recurring_amount = request.form.get("recurring_amount", "").strip()
        status = request.form.get("status", "").strip()
        start_date = request.form.get("start_date", "").strip()
        description = request.form.get("description", "").strip()

        errors = []

        if not client_id:
            errors.append("Client is required.")
        if not service_name:
            errors.append("Service name is required.")
        if not service_type:
            errors.append("Service type is required.")
        if not billing_cycle:
            errors.append("Billing cycle is required.")
        if not currency_code:
            errors.append("Currency code is required.")
        if not recurring_amount:
            errors.append("Recurring amount is required.")
        if not status:
            errors.append("Status is required.")

        if not errors:
            try:
                recurring_amount_value = float(recurring_amount)
                if recurring_amount_value < 0:
                    errors.append("Recurring amount cannot be negative.")
            except ValueError:
                errors.append("Recurring amount must be a valid number.")

        if errors:
            cursor.execute("""
                SELECT s.*, c.company_name
                FROM services s
                LEFT JOIN clients c ON s.client_id = c.id
                WHERE s.id = %s
            """, (service_id,))
            service = cursor.fetchone()

            cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name ASC")
            clients = cursor.fetchall()

            conn.close()
            return render_template("services/edit.html", service=service, clients=clients, errors=errors)

        update_cursor = conn.cursor()
        update_cursor.execute("""
            UPDATE services
            SET client_id = %s,
                service_name = %s,
                service_type = %s,
                billing_cycle = %s,
                status = %s,
                currency_code = %s,
                recurring_amount = %s,
                start_date = %s,
                description = %s
            WHERE id = %s
        """, (
            client_id,
            service_name,
            service_type,
            billing_cycle,
            status,
            currency_code,
            recurring_amount,
            start_date or None,
            description or None,
            service_id
        ))
        conn.commit()
        conn.close()
        return redirect("/services")

    cursor.execute("""
        SELECT s.*, c.company_name
        FROM services s
        LEFT JOIN clients c ON s.client_id = c.id
        WHERE s.id = %s
    """, (service_id,))
    service = cursor.fetchone()

    cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name ASC")
    clients = cursor.fetchall()
    conn.close()

    if not service:
        return "Service not found", 404

    return render_template("services/edit.html", service=service, clients=clients, errors=[])






@app.route("/invoices/export.csv")
def export_invoices_csv():
    start_date = (request.args.get("start_date") or "").strip()
    end_date = (request.args.get("end_date") or "").strip()
    status = (request.args.get("status") or "").strip()
    client_id = (request.args.get("client_id") or "").strip()
    limit_count = (request.args.get("limit") or "").strip()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    query = """
        SELECT
            i.id,
            i.invoice_number,
            i.client_id,
            c.client_code,
            c.company_name,
            i.service_id,
            i.currency_code,
            i.subtotal_amount,
            i.tax_amount,
            i.total_amount,
            i.amount_paid,
            i.status,
            i.issued_at,
            i.due_at,
            i.paid_at,
            i.notes,
            i.created_at,
            i.updated_at
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        WHERE 1=1
    """
    params = []

    if start_date:
        query += " AND DATE(i.issued_at) >= %s"
        params.append(start_date)

    if end_date:
        query += " AND DATE(i.issued_at) <= %s"
        params.append(end_date)

    if status:
        query += " AND i.status = %s"
        params.append(status)

    if client_id:
        query += " AND i.client_id = %s"
        params.append(client_id)

    query += " ORDER BY i.id ASC"

    if limit_count:
        try:
            limit_int = int(limit_count)
            if limit_int > 0:
                query += " LIMIT %s"
                params.append(limit_int)
        except ValueError:
            pass

    cursor.execute(query, tuple(params))
    rows = cursor.fetchall()
    conn.close()

    output = StringIO()
    writer = csv.writer(output)
    writer.writerow([
        "id",
        "invoice_number",
        "client_id",
        "client_code",
        "company_name",
        "service_id",
        "currency_code",
        "subtotal_amount",
        "tax_amount",
        "total_amount",
        "amount_paid",
        "status",
        "issued_at",
        "due_at",
        "paid_at",
        "notes",
        "created_at",
        "updated_at",
    ])

    for r in rows:
        writer.writerow([
            r.get("id", ""),
            r.get("invoice_number", ""),
            r.get("client_id", ""),
            r.get("client_code", ""),
            r.get("company_name", ""),
            r.get("service_id", ""),
            r.get("currency_code", ""),
            r.get("subtotal_amount", ""),
            r.get("tax_amount", ""),
            r.get("total_amount", ""),
            r.get("amount_paid", ""),
            r.get("status", ""),
            r.get("issued_at", ""),
            r.get("due_at", ""),
            r.get("paid_at", ""),
            r.get("notes", ""),
            r.get("created_at", ""),
            r.get("updated_at", ""),
        ])

    filename = "invoices"
    if start_date or end_date or status or client_id or limit_count:
        filename += "_filtered"
    filename += ".csv"

    response = make_response(output.getvalue())
    response.headers["Content-Type"] = "text/csv; charset=utf-8"
    response.headers["Content-Disposition"] = f"attachment; filename={filename}"
    return response


@app.route("/invoices/export-pdf.zip")
def export_invoices_pdf_zip():
    start_date = (request.args.get("start_date") or "").strip()
    end_date = (request.args.get("end_date") or "").strip()
    status = (request.args.get("status") or "").strip()
    client_id = (request.args.get("client_id") or "").strip()
    limit_count = (request.args.get("limit") or "").strip()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    query = """
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE 1=1
    """
    params = []

    if start_date:
        query += " AND DATE(i.issued_at) >= %s"
        params.append(start_date)

    if end_date:
        query += " AND DATE(i.issued_at) <= %s"
        params.append(end_date)

    if status:
        query += " AND i.status = %s"
        params.append(status)

    if client_id:
        query += " AND i.client_id = %s"
        params.append(client_id)

    query += " ORDER BY i.id ASC"

    if limit_count:
        try:
            limit_int = int(limit_count)
            if limit_int > 0:
                query += " LIMIT %s"
                params.append(limit_int)
        except ValueError:
            pass

    cursor.execute(query, tuple(params))
    invoices = cursor.fetchall()
    conn.close()

    settings = get_app_settings()

    def build_invoice_pdf_bytes(invoice, settings):
        buffer = BytesIO()
        pdf = canvas.Canvas(buffer, pagesize=letter)
        width, height = letter

        left = 50
        right = 560
        y = height - 50

        def money(value, currency="CAD"):
            return f"{to_decimal(value):.2f} {currency}"

        pdf.setTitle(f"Invoice {invoice['invoice_number']}")

        logo_url = (settings.get("business_logo_url") or "").strip()
        if logo_url.startswith("/static/"):
            local_logo_path = "/home/def/otb_billing" + logo_url
            try:
                pdf.drawImage(ImageReader(local_logo_path), left, y - 35, width=42, height=42, preserveAspectRatio=True, mask='auto')
            except Exception:
                pass

        pdf.setFont("Helvetica-Bold", 22)
        pdf.drawString(left + 60, y, f"Invoice {invoice['invoice_number']}")

        pdf.setFont("Helvetica-Bold", 14)
        pdf.drawRightString(right, y, settings.get("business_name") or "OTB Billing")
        y -= 18
        pdf.setFont("Helvetica", 12)
        pdf.drawRightString(right, y, settings.get("business_tagline") or "")
        y -= 15

        right_lines = [
            settings.get("business_address", ""),
            settings.get("business_email", ""),
            settings.get("business_phone", ""),
            settings.get("business_website", ""),
        ]
        for item in right_lines:
            if item:
                pdf.drawRightString(right, y, item[:80])
                y -= 14

        y -= 10

        pdf.setFont("Helvetica-Bold", 12)
        pdf.drawString(left, y, "Status:")
        pdf.setFont("Helvetica", 12)
        pdf.drawString(left + 45, y, str(invoice["status"]).upper())
        y -= 28

        pdf.setFont("Helvetica-Bold", 13)
        pdf.drawString(left, y, "Bill To")
        y -= 20
        pdf.setFont("Helvetica-Bold", 12)
        pdf.drawString(left, y, invoice["company_name"] or "")
        y -= 16
        pdf.setFont("Helvetica", 11)
        if invoice.get("contact_name"):
            pdf.drawString(left, y, str(invoice["contact_name"]))
            y -= 15
        if invoice.get("email"):
            pdf.drawString(left, y, str(invoice["email"]))
            y -= 15
        if invoice.get("phone"):
            pdf.drawString(left, y, str(invoice["phone"]))
            y -= 15
        pdf.drawString(left, y, f"Client Code: {invoice.get('client_code', '')}")
        y -= 28

        pdf.setFont("Helvetica-Bold", 13)
        pdf.drawString(left, y, "Invoice Details")
        y -= 20
        pdf.setFont("Helvetica", 11)
        pdf.drawString(left, y, f"Invoice #: {invoice['invoice_number']}")
        y -= 15
        pdf.drawString(left, y, f"Issued: {fmt_local(invoice.get('issued_at'))}")
        y -= 15
        pdf.drawString(left, y, f"Due: {fmt_local(invoice.get('due_at'))}")
        y -= 15
        if invoice.get("paid_at"):
            pdf.drawString(left, y, f"Paid: {fmt_local(invoice.get('paid_at'))}")
            y -= 15
        pdf.drawString(left, y, f"Currency: {invoice.get('currency_code', 'CAD')}")
        y -= 28

        pdf.setFont("Helvetica-Bold", 11)
        pdf.drawString(left, y, "Service Code")
        pdf.drawString(180, y, "Service")
        pdf.drawString(330, y, "Description")
        pdf.drawRightString(right, y, "Total")
        y -= 14
        pdf.line(left, y, right, y)
        y -= 18

        pdf.setFont("Helvetica", 11)
        pdf.drawString(left, y, str(invoice.get("service_code") or "-"))
        pdf.drawString(180, y, str(invoice.get("service_name") or "-"))
        pdf.drawString(330, y, str(invoice.get("notes") or "-")[:28])
        pdf.drawRightString(right, y, money(invoice.get("total_amount"), invoice.get("currency_code", "CAD")))
        y -= 28

        totals_x_label = 360
        totals_x_value = right

        totals = [
            ("Subtotal", money(invoice.get("subtotal_amount"), invoice.get("currency_code", "CAD"))),
            ((settings.get("tax_label") or "Tax"), money(invoice.get("tax_amount"), invoice.get("currency_code", "CAD"))),
            ("Total", money(invoice.get("total_amount"), invoice.get("currency_code", "CAD"))),
            ("Paid", money(invoice.get("amount_paid"), invoice.get("currency_code", "CAD"))),
        ]

        remaining = to_decimal(invoice.get("total_amount")) - to_decimal(invoice.get("amount_paid"))

        for label, value in totals:
            pdf.setFont("Helvetica-Bold", 11)
            pdf.drawString(totals_x_label, y, label)
            pdf.setFont("Helvetica", 11)
            pdf.drawRightString(totals_x_value, y, value)
            y -= 18

        pdf.setFont("Helvetica-Bold", 11)
        pdf.drawString(totals_x_label, y, "Remaining")
        pdf.drawRightString(totals_x_value, y, f"{remaining:.2f} {invoice.get('currency_code', 'CAD')}")
        y -= 25

        if settings.get("tax_number"):
            pdf.setFont("Helvetica", 10)
            pdf.drawString(left, y, f"{settings.get('tax_label') or 'Tax'} Number: {settings.get('tax_number')}")
            y -= 14

        if settings.get("business_number"):
            pdf.setFont("Helvetica", 10)
            pdf.drawString(left, y, f"Business Number: {settings.get('business_number')}")
            y -= 14

        if settings.get("payment_terms"):
            y -= 8
            pdf.setFont("Helvetica-Bold", 11)
            pdf.drawString(left, y, "Payment Terms")
            y -= 15
            pdf.setFont("Helvetica", 10)
            terms = settings.get("payment_terms", "")
            for chunk_start in range(0, len(terms), 90):
                line_text = terms[chunk_start:chunk_start+90]
                pdf.drawString(left, y, line_text)
                y -= 13

        if settings.get("invoice_footer"):
            y -= 8
            pdf.setFont("Helvetica-Bold", 11)
            pdf.drawString(left, y, "Footer")
            y -= 15
            pdf.setFont("Helvetica", 10)
            footer = settings.get("invoice_footer", "")
            for chunk_start in range(0, len(footer), 90):
                line_text = footer[chunk_start:chunk_start+90]
                pdf.drawString(left, y, line_text)
                y -= 13

        pdf.showPage()
        pdf.save()
        buffer.seek(0)
        return buffer.getvalue()

    zip_buffer = BytesIO()
    with zipfile.ZipFile(zip_buffer, "w", zipfile.ZIP_DEFLATED) as zipf:
        for invoice in invoices:
            pdf_bytes = build_invoice_pdf_bytes(invoice, settings)
            zipf.writestr(f"{invoice['invoice_number']}.pdf", pdf_bytes)

    zip_buffer.seek(0)

    filename = "invoices_export"
    if start_date:
        filename += f"_{start_date}"
    if end_date:
        filename += f"_to_{end_date}"
    if status:
        filename += f"_{status}"
    if client_id:
        filename += f"_client_{client_id}"
    if limit_count:
        filename += f"_limit_{limit_count}"
    filename += ".zip"

    return send_file(
        zip_buffer,
        mimetype="application/zip",
        as_attachment=True,
        download_name=filename
    )


@app.route("/invoices/print")
def print_invoices():
    refresh_overdue_invoices()

    start_date = (request.args.get("start_date") or "").strip()
    end_date = (request.args.get("end_date") or "").strip()
    status = (request.args.get("status") or "").strip()
    client_id = (request.args.get("client_id") or "").strip()
    limit_count = (request.args.get("limit") or "").strip()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    query = """
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE 1=1
    """
    params = []

    if start_date:
        query += " AND DATE(i.issued_at) >= %s"
        params.append(start_date)

    if end_date:
        query += " AND DATE(i.issued_at) <= %s"
        params.append(end_date)

    if status:
        query += " AND i.status = %s"
        params.append(status)

    if client_id:
        query += " AND i.client_id = %s"
        params.append(client_id)

    query += " ORDER BY i.id ASC"

    if limit_count:
        try:
            limit_int = int(limit_count)
            if limit_int > 0:
                query += " LIMIT %s"
                params.append(limit_int)
        except ValueError:
            pass

    cursor.execute(query, tuple(params))
    invoices = cursor.fetchall()
    conn.close()

    settings = get_app_settings()

    filters = {
        "start_date": start_date,
        "end_date": end_date,
        "status": status,
        "client_id": client_id,
        "limit": limit_count,
    }

    return render_template("invoices/print_batch.html", invoices=invoices, settings=settings, filters=filters)

@app.route("/invoices")
def invoices():
    refresh_overdue_invoices()

    start_date = (request.args.get("start_date") or "").strip()
    end_date = (request.args.get("end_date") or "").strip()
    status = (request.args.get("status") or "").strip()
    client_id = (request.args.get("client_id") or "").strip()
    limit_count = (request.args.get("limit") or "").strip()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    query = """
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            COALESCE((SELECT COUNT(*) FROM payments p WHERE p.invoice_id = i.id AND p.payment_status = 'confirmed'), 0) AS payment_count
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        WHERE 1=1
    """
    params = []

    if start_date:
        query += " AND DATE(i.issued_at) >= %s"
        params.append(start_date)

    if end_date:
        query += " AND DATE(i.issued_at) <= %s"
        params.append(end_date)

    if status:
        query += " AND i.status = %s"
        params.append(status)

    if client_id:
        query += " AND i.client_id = %s"
        params.append(client_id)

    query += " ORDER BY i.id DESC"

    if limit_count:
        try:
            limit_int = int(limit_count)
            if limit_int > 0:
                query += " LIMIT %s"
                params.append(limit_int)
        except ValueError:
            pass

    cursor.execute(query, tuple(params))
    invoices = cursor.fetchall()

    cursor.execute("""
        SELECT id, client_code, company_name
        FROM clients
        ORDER BY company_name ASC
    """)
    clients = cursor.fetchall()

    conn.close()

    filters = {
        "start_date": start_date,
        "end_date": end_date,
        "status": status,
        "client_id": client_id,
        "limit": limit_count,
    }

    return render_template("invoices/list.html", invoices=invoices, filters=filters, clients=clients)

@app.route("/invoices/new", methods=["GET", "POST"])
def new_invoice():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    if request.method == "POST":
        client_id = request.form.get("client_id", "").strip()
        service_id = request.form.get("service_id", "").strip()
        currency_code = request.form.get("currency_code", "").strip()
        total_amount = request.form.get("total_amount", "").strip()
        due_at = request.form.get("due_at", "").strip()
        notes = request.form.get("notes", "").strip()

        errors = []

        if not client_id:
            errors.append("Client is required.")
        if not service_id:
            errors.append("Service is required.")
        if not currency_code:
            errors.append("Currency is required.")
        if not total_amount:
            errors.append("Total amount is required.")
        if not due_at:
            errors.append("Due date is required.")

        if not errors:
            try:
                amount_value = float(total_amount)
                if amount_value <= 0:
                    errors.append("Total amount must be greater than zero.")
            except ValueError:
                errors.append("Total amount must be a valid number.")

        if errors:
            cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name")
            clients = cursor.fetchall()

            cursor.execute("SELECT id, service_code, service_name FROM services ORDER BY service_name")
            services = cursor.fetchall()

            conn.close()

            form_data = {
                "client_id": client_id,
                "service_id": service_id,
                "currency_code": currency_code,
                "total_amount": total_amount,
                "due_at": due_at,
                "notes": notes,
            }

            return render_template(
                "invoices/new.html",
                clients=clients,
                services=services,
                errors=errors,
                form_data=form_data,
            )

        invoice_number = generate_invoice_number()

        insert_cursor = conn.cursor()
        insert_cursor.execute("""
            INSERT INTO invoices
            (
                client_id,
                service_id,
                invoice_number,
                currency_code,
                total_amount,
                subtotal_amount,
                issued_at,
                due_at,
                status,
                notes
            )
            VALUES (%s, %s, %s, %s, %s, %s, UTC_TIMESTAMP(), %s, 'pending', %s)
        """, (
            client_id,
            service_id,
            invoice_number,
            currency_code,
            total_amount,
            total_amount,
            due_at,
            notes
        ))

        conn.commit()
        conn.close()

        return redirect("/invoices")

    cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name")
    clients = cursor.fetchall()

    cursor.execute("SELECT id, service_code, service_name FROM services ORDER BY service_name")
    services = cursor.fetchall()

    conn.close()

    return render_template(
        "invoices/new.html",
        clients=clients,
        services=services,
        errors=[],
        form_data={},
    )





@app.route("/invoices/pdf/<int:invoice_id>")
def invoice_pdf(invoice_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE i.id = %s
    """, (invoice_id,))
    invoice = cursor.fetchone()

    if not invoice:
        conn.close()
        return "Invoice not found", 404

    conn.close()

    settings = get_app_settings()
    pdf_bytes = build_invoice_pdf_bytes(invoice, settings)

    return send_file(
        BytesIO(pdf_bytes),
        mimetype="application/pdf",
        as_attachment=True,
        download_name=f"{invoice['invoice_number']}.pdf"
    )


@app.route("/invoices/view/<int:invoice_id>")
def view_invoice(invoice_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            i.*,
            c.client_code,
            c.company_name,
            c.contact_name,
            c.email,
            c.phone,
            s.service_code,
            s.service_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        LEFT JOIN services s ON i.service_id = s.id
        WHERE i.id = %s
    """, (invoice_id,))
    invoice = cursor.fetchone()

    if not invoice:
        conn.close()
        return "Invoice not found", 404

    ensure_email_log_table()
    cursor.execute("""
        SELECT *
        FROM email_log
        WHERE invoice_id = %s
          AND email_type = 'invoice'
        ORDER BY sent_at DESC, id DESC
        LIMIT 1
    """, (invoice_id,))
    latest_email_log = cursor.fetchone()

    conn.close()
    settings = get_app_settings()
    return render_template("invoices/view.html", invoice=invoice, settings=settings, latest_email_log=latest_email_log)


@app.route("/invoices/edit/<int:invoice_id>", methods=["GET", "POST"])
def edit_invoice(invoice_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT i.*,
               COALESCE((SELECT COUNT(*) FROM payments p WHERE p.invoice_id = i.id), 0) AS payment_count
        FROM invoices i
        WHERE i.id = %s
    """, (invoice_id,))
    invoice = cursor.fetchone()

    if not invoice:
        conn.close()
        return "Invoice not found", 404

    locked = invoice["payment_count"] > 0 or float(invoice["amount_paid"]) > 0

    if request.method == "POST":
        due_at = request.form.get("due_at", "").strip()
        notes = request.form.get("notes", "").strip()

        if locked:
            update_cursor = conn.cursor()
            update_cursor.execute("""
                UPDATE invoices
                SET due_at = %s,
                    notes = %s
                WHERE id = %s
            """, (
                due_at or None,
                notes or None,
                invoice_id
            ))
            conn.commit()
            conn.close()
            return redirect("/invoices")

        client_id = request.form.get("client_id", "").strip()
        service_id = request.form.get("service_id", "").strip()
        currency_code = request.form.get("currency_code", "").strip()
        total_amount = request.form.get("total_amount", "").strip()
        status = request.form.get("status", "").strip()

        errors = []

        if not client_id:
            errors.append("Client is required.")
        if not service_id:
            errors.append("Service is required.")
        if not currency_code:
            errors.append("Currency is required.")
        if not total_amount:
            errors.append("Total amount is required.")
        if not due_at:
            errors.append("Due date is required.")
        if not status:
            errors.append("Status is required.")

        manual_statuses = {"draft", "pending", "cancelled"}
        if status and status not in manual_statuses:
            errors.append("Manual invoice status must be draft, pending, or cancelled.")

        if not errors:
            try:
                amount_value = float(total_amount)
                if amount_value < 0:
                    errors.append("Total amount cannot be negative.")
            except ValueError:
                errors.append("Total amount must be a valid number.")

        cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name")
        clients = cursor.fetchall()

        cursor.execute("SELECT id, service_code, service_name FROM services ORDER BY service_name")
        services = cursor.fetchall()

        if errors:
            invoice["client_id"] = int(client_id) if client_id else invoice["client_id"]
            invoice["service_id"] = int(service_id) if service_id else invoice["service_id"]
            invoice["currency_code"] = currency_code or invoice["currency_code"]
            invoice["total_amount"] = total_amount or invoice["total_amount"]
            invoice["due_at"] = due_at or invoice["due_at"]
            invoice["status"] = status or invoice["status"]
            invoice["notes"] = notes
            conn.close()
            return render_template("invoices/edit.html", invoice=invoice, clients=clients, services=services, errors=errors, locked=locked)

        update_cursor = conn.cursor()
        update_cursor.execute("""
            UPDATE invoices
            SET client_id = %s,
                service_id = %s,
                currency_code = %s,
                total_amount = %s,
                subtotal_amount = %s,
                due_at = %s,
                status = %s,
                notes = %s
            WHERE id = %s
        """, (
            client_id,
            service_id,
            currency_code,
            total_amount,
            total_amount,
            due_at,
            status,
            notes or None,
            invoice_id
        ))
        conn.commit()
        conn.close()
        return redirect("/invoices")

    clients = []
    services = []

    if not locked:
        cursor.execute("SELECT id, client_code, company_name FROM clients ORDER BY company_name")
        clients = cursor.fetchall()

        cursor.execute("SELECT id, service_code, service_name FROM services ORDER BY service_name")
        services = cursor.fetchall()

    conn.close()
    return render_template("invoices/edit.html", invoice=invoice, clients=clients, services=services, errors=[], locked=locked)



@app.route("/payments/export.csv")
def export_payments_csv():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT
            p.id,
            p.invoice_id,
            i.invoice_number,
            p.client_id,
            c.client_code,
            c.company_name,
            p.payment_method,
            p.payment_currency,
            p.payment_amount,
            p.cad_value_at_payment,
            p.reference,
            p.sender_name,
            p.txid,
            p.wallet_address,
            p.payment_status,
            p.received_at,
            p.notes
        FROM payments p
        JOIN invoices i ON p.invoice_id = i.id
        JOIN clients c ON p.client_id = c.id
        ORDER BY p.id ASC
    """)
    rows = cursor.fetchall()
    conn.close()

    output = StringIO()
    writer = csv.writer(output)
    writer.writerow([
        "id",
        "invoice_id",
        "invoice_number",
        "client_id",
        "client_code",
        "company_name",
        "payment_method",
        "payment_currency",
        "payment_amount",
        "cad_value_at_payment",
        "reference",
        "sender_name",
        "txid",
        "wallet_address",
        "payment_status",
        "received_at",
        "notes",
    ])

    for r in rows:
        writer.writerow([
            r.get("id", ""),
            r.get("invoice_id", ""),
            r.get("invoice_number", ""),
            r.get("client_id", ""),
            r.get("client_code", ""),
            r.get("company_name", ""),
            r.get("payment_method", ""),
            r.get("payment_currency", ""),
            r.get("payment_amount", ""),
            r.get("cad_value_at_payment", ""),
            r.get("reference", ""),
            r.get("sender_name", ""),
            r.get("txid", ""),
            r.get("wallet_address", ""),
            r.get("payment_status", ""),
            r.get("received_at", ""),
            r.get("notes", ""),
        ])

    response = make_response(output.getvalue())
    response.headers["Content-Type"] = "text/csv; charset=utf-8"
    response.headers["Content-Disposition"] = "attachment; filename=payments.csv"
    return response

@app.route("/payments")
def payments():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            p.*,
            i.invoice_number,
            i.status AS invoice_status,
            i.total_amount,
            i.amount_paid,
            i.currency_code AS invoice_currency_code,
            c.client_code,
            c.company_name
        FROM payments p
        JOIN invoices i ON p.invoice_id = i.id
        JOIN clients c ON p.client_id = c.id
        ORDER BY p.id DESC
    """)
    payments = cursor.fetchall()

    conn.close()
    return render_template("payments/list.html", payments=payments)

@app.route("/payments/new", methods=["GET", "POST"])
def new_payment():
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    if request.method == "POST":
        invoice_id = request.form.get("invoice_id", "").strip()
        payment_method = request.form.get("payment_method", "").strip()
        payment_currency = request.form.get("payment_currency", "").strip()
        payment_amount = request.form.get("payment_amount", "").strip()
        cad_value_at_payment = request.form.get("cad_value_at_payment", "").strip()
        reference = request.form.get("reference", "").strip()
        sender_name = request.form.get("sender_name", "").strip()
        txid = request.form.get("txid", "").strip()
        wallet_address = request.form.get("wallet_address", "").strip()
        notes = request.form.get("notes", "").strip()

        errors = []

        if not invoice_id:
            errors.append("Invoice is required.")
        if not payment_method:
            errors.append("Payment method is required.")
        if not payment_currency:
            errors.append("Payment currency is required.")
        if not payment_amount:
            errors.append("Payment amount is required.")
        if not cad_value_at_payment:
            errors.append("CAD value at payment is required.")

        if not errors:
            try:
                payment_amount_value = Decimal(str(payment_amount))
                if payment_amount_value <= Decimal("0"):
                    errors.append("Payment amount must be greater than zero.")
            except Exception:
                errors.append("Payment amount must be a valid number.")

        if not errors:
            try:
                cad_value_value = Decimal(str(cad_value_at_payment))
                if cad_value_value < Decimal("0"):
                    errors.append("CAD value at payment cannot be negative.")
            except Exception:
                errors.append("CAD value at payment must be a valid number.")

        invoice_row = None

        if not errors:
            cursor.execute("""
                SELECT
                    i.id,
                    i.client_id,
                    i.invoice_number,
                    i.currency_code,
                    i.total_amount,
                    i.amount_paid,
                    i.status,
                    c.client_code,
                    c.company_name
                FROM invoices i
                JOIN clients c ON i.client_id = c.id
                WHERE i.id = %s
            """, (invoice_id,))
            invoice_row = cursor.fetchone()

            if not invoice_row:
                errors.append("Selected invoice was not found.")
            else:
                allowed_statuses = {"pending", "partial", "overdue"}
                if invoice_row["status"] not in allowed_statuses:
                    errors.append("Payments can only be recorded against pending, partial, or overdue invoices.")
                else:
                    remaining_balance = to_decimal(invoice_row["total_amount"]) - to_decimal(invoice_row["amount_paid"])
                    entered_amount = to_decimal(payment_amount)

                    if remaining_balance <= Decimal("0"):
                        errors.append("This invoice has no remaining balance.")
                    elif entered_amount > remaining_balance:
                        errors.append(
                            f"Payment amount exceeds remaining balance. Remaining balance is {fmt_money(remaining_balance, invoice_row['currency_code'])} {invoice_row['currency_code']}."
                        )

        if errors:
            cursor.execute("""
                SELECT
                    i.id,
                    i.invoice_number,
                    i.currency_code,
                    i.total_amount,
                    i.amount_paid,
                    i.status,
                    c.client_code,
                    c.company_name
                FROM invoices i
                JOIN clients c ON i.client_id = c.id
                WHERE i.status IN ('pending', 'partial', 'overdue')
                  AND (i.total_amount - i.amount_paid) > 0
                ORDER BY i.id DESC
            """)
            invoices = cursor.fetchall()
            conn.close()

            form_data = {
                "invoice_id": invoice_id,
                "payment_method": payment_method,
                "payment_currency": payment_currency,
                "payment_amount": payment_amount,
                "cad_value_at_payment": cad_value_at_payment,
                "reference": reference,
                "sender_name": sender_name,
                "txid": txid,
                "wallet_address": wallet_address,
                "notes": notes,
            }

            return render_template(
                "payments/new.html",
                invoices=invoices,
                errors=errors,
                form_data=form_data,
            )

        client_id = invoice_row["client_id"]

        insert_cursor = conn.cursor()
        insert_cursor.execute("""
            INSERT INTO payments
            (
                invoice_id,
                client_id,
                payment_method,
                payment_currency,
                payment_amount,
                cad_value_at_payment,
                reference,
                sender_name,
                txid,
                wallet_address,
                payment_status,
                received_at,
                notes
            )
            VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, 'confirmed', UTC_TIMESTAMP(), %s)
        """, (
            invoice_id,
            client_id,
            payment_method,
            payment_currency,
            payment_amount,
            cad_value_at_payment,
            reference or None,
            sender_name or None,
            txid or None,
            wallet_address or None,
            notes or None
        ))

        conn.commit()
        conn.close()

        recalc_invoice_totals(invoice_id)

        return redirect("/payments")

    cursor.execute("""
        SELECT
            i.id,
            i.invoice_number,
            i.currency_code,
            i.total_amount,
            i.amount_paid,
            i.status,
            c.client_code,
            c.company_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        WHERE i.status IN ('pending', 'partial', 'overdue')
          AND (i.total_amount - i.amount_paid) > 0
        ORDER BY i.id DESC
    """)
    invoices = cursor.fetchall()
    conn.close()

    return render_template(
        "payments/new.html",
        invoices=invoices,
        errors=[],
        form_data={},
    )



@app.route("/payments/void/<int:payment_id>", methods=["POST"])
def void_payment(payment_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT id, invoice_id, payment_status
        FROM payments
        WHERE id = %s
    """, (payment_id,))
    payment = cursor.fetchone()

    if not payment:
        conn.close()
        return "Payment not found", 404

    if payment["payment_status"] != "confirmed":
        conn.close()
        return redirect("/payments")

    update_cursor = conn.cursor()
    update_cursor.execute("""
        UPDATE payments
        SET payment_status = 'reversed'
        WHERE id = %s
    """, (payment_id,))

    conn.commit()
    conn.close()

    recalc_invoice_totals(payment["invoice_id"])

    return redirect("/payments")

    recalc_invoice_totals(payment["invoice_id"])

    return redirect("/payments")

@app.route("/payments/edit/<int:payment_id>", methods=["GET", "POST"])
def edit_payment(payment_id):
    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)

    cursor.execute("""
        SELECT
            p.*,
            i.invoice_number,
            c.client_code,
            c.company_name
        FROM payments p
        JOIN invoices i ON p.invoice_id = i.id
        JOIN clients c ON p.client_id = c.id
        WHERE p.id = %s
    """, (payment_id,))
    payment = cursor.fetchone()

    if not payment:
        conn.close()
        return "Payment not found", 404

    if request.method == "POST":
        payment_method = request.form.get("payment_method", "").strip()
        payment_currency = request.form.get("payment_currency", "").strip()
        payment_amount = request.form.get("payment_amount", "").strip()
        cad_value_at_payment = request.form.get("cad_value_at_payment", "").strip()
        reference = request.form.get("reference", "").strip()
        sender_name = request.form.get("sender_name", "").strip()
        txid = request.form.get("txid", "").strip()
        wallet_address = request.form.get("wallet_address", "").strip()
        notes = request.form.get("notes", "").strip()

        errors = []

        if not payment_method:
            errors.append("Payment method is required.")
        if not payment_currency:
            errors.append("Payment currency is required.")
        if not payment_amount:
            errors.append("Payment amount is required.")
        if not cad_value_at_payment:
            errors.append("CAD value at payment is required.")

        if not errors:
            try:
                amount_value = float(payment_amount)
                if amount_value <= 0:
                    errors.append("Payment amount must be greater than zero.")
            except ValueError:
                errors.append("Payment amount must be a valid number.")

            try:
                cad_value = float(cad_value_at_payment)
                if cad_value < 0:
                    errors.append("CAD value at payment cannot be negative.")
            except ValueError:
                errors.append("CAD value at payment must be a valid number.")

        if errors:
            payment["payment_method"] = payment_method or payment["payment_method"]
            payment["payment_currency"] = payment_currency or payment["payment_currency"]
            payment["payment_amount"] = payment_amount or payment["payment_amount"]
            payment["cad_value_at_payment"] = cad_value_at_payment or payment["cad_value_at_payment"]
            payment["reference"] = reference
            payment["sender_name"] = sender_name
            payment["txid"] = txid
            payment["wallet_address"] = wallet_address
            payment["notes"] = notes
            conn.close()
            return render_template("payments/edit.html", payment=payment, errors=errors)

        update_cursor = conn.cursor()
        update_cursor.execute("""
            UPDATE payments
            SET payment_method = %s,
                payment_currency = %s,
                payment_amount = %s,
                cad_value_at_payment = %s,
                reference = %s,
                sender_name = %s,
                txid = %s,
                wallet_address = %s,
                notes = %s
            WHERE id = %s
        """, (
            payment_method,
            payment_currency,
            payment_amount,
            cad_value_at_payment,
            reference or None,
            sender_name or None,
            txid or None,
            wallet_address or None,
            notes or None,
            payment_id
        ))
        conn.commit()
        invoice_id = payment["invoice_id"]
        conn.close()

        recalc_invoice_totals(invoice_id)

        return redirect("/payments")

    conn.close()
    return render_template("payments/edit.html", payment=payment, errors=[])

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5050, debug=True)