from flask import Flask, render_template, request, redirect
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

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}

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()

@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)

@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")
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()
    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()
            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

    return render_template("clients/edit.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("/invoices")
def invoices():
    refresh_overdue_invoices()

    conn = get_db_connection()
    cursor = conn.cursor(dictionary=True)
    cursor.execute("""
        SELECT
            i.*,
            c.client_code,
            c.company_name
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        ORDER BY i.id DESC
    """)
    invoices = cursor.fetchall()
    conn.close()
    return render_template("invoices/list.html", invoices=invoices)

@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,
            )

        cursor.execute("SELECT MAX(id) AS last_id FROM invoices")
        result = cursor.fetchone()
        number = (result["last_id"] or 0) + 1
        invoice_number = f"INV-{number:04d}"

        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("/payments")
def payments():
    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
        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.")

        amount_value = None

        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:
            cursor.execute("""
                SELECT
                    i.id,
                    i.invoice_number,
                    c.client_code,
                    c.company_name,
                    i.total_amount,
                    i.amount_paid,
                    i.currency_code
                FROM invoices i
                JOIN clients c ON i.client_id = c.id
                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,
            )

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

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

        client_id = invoice["client_id"]
        new_amount_paid = float(invoice["amount_paid"]) + amount_value

        if new_amount_paid >= float(invoice["total_amount"]):
            new_status = "paid"
        elif new_amount_paid > 0:
            new_status = "partial"
        else:
            new_status = "pending"

        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
        ))

        update_cursor = conn.cursor()
        if new_status == "paid":
            update_cursor.execute("""
                UPDATE invoices
                SET amount_paid = %s,
                    status = %s,
                    paid_at = UTC_TIMESTAMP()
                WHERE id = %s
            """, (new_amount_paid, new_status, invoice_id))
        else:
            update_cursor.execute("""
                UPDATE invoices
                SET amount_paid = %s,
                    status = %s
                WHERE id = %s
            """, (new_amount_paid, new_status, invoice_id))

        conn.commit()
        conn.close()

        return redirect("/payments")

    cursor.execute("""
        SELECT
            i.id,
            i.invoice_number,
            c.client_code,
            c.company_name,
            i.total_amount,
            i.amount_paid,
            i.currency_code
        FROM invoices i
        JOIN clients c ON i.client_id = c.id
        ORDER BY i.id DESC
    """)
    invoices = cursor.fetchall()
    conn.close()

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

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