import time
import subprocess
import json
import threading
import re
from datetime import datetime
from pathlib import Path

from app import create_app
from app.db import get_db

INTEL_DEV = "/dev/dri/renderD129"
AMD_DEV = "/dev/dri/renderD128"

def run_ffprobe_json(src):
    cmd = [
        "ffprobe",
        "-v", "error",
        "-select_streams", "v:0",
        "-show_entries", "stream=duration:stream_tags=rotate",
        "-of", "json",
        src,
    ]
    result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
    if result.returncode != 0:
        return {}
    try:
        return json.loads(result.stdout or "{}")
    except Exception:
        return {}

def get_rotation_degrees(src):
    data = run_ffprobe_json(src)
    streams = data.get("streams", [])
    if not streams:
        return 0
    tags = streams[0].get("tags", {}) or {}
    rotate_tag = tags.get("rotate")
    if rotate_tag is not None:
        try:
            return int(rotate_tag) % 360
        except Exception:
            pass
    return 0

def get_duration_seconds(src):
    data = run_ffprobe_json(src)
    streams = data.get("streams", [])
    if not streams:
        return None
    duration = streams[0].get("duration")
    try:
        return float(duration)
    except Exception:
        return None

def build_absolute_source_path(db, job):
    with db.cursor() as cur:
        cur.execute(
            "SELECT storage_root FROM tenants WHERE id = %s",
            (job["tenant_id"],)
        )
        tenant_row = cur.fetchone()

    if not tenant_row:
        raise RuntimeError(f"Tenant id {job['tenant_id']} not found")

    return str(Path(tenant_row["storage_root"]) / job["source_relative_path"])

def build_absolute_output_path(db, job, src):
    with db.cursor() as cur:
        cur.execute(
            "SELECT storage_root FROM tenants WHERE id = %s",
            (job["tenant_id"],)
        )
        tenant_row = cur.fetchone()

        cur.execute(
            "SELECT relative_path FROM devices WHERE id = %s",
            (job["device_id"],)
        )
        device_row = cur.fetchone()

    if not tenant_row:
        raise RuntimeError(f"Tenant id {job['tenant_id']} not found")
    if not device_row:
        raise RuntimeError(f"Device id {job['device_id']} not found")

    storage_root = Path(tenant_row["storage_root"])
    device_relative_path = Path(device_row["relative_path"])
    out_dir = storage_root / device_relative_path / "video"
    out_dir.mkdir(parents=True, exist_ok=True)

    profile = (job.get("requested_profile") or "default").lower()
    out_name = Path(src).stem + f"_{profile}_processed.mp4"
    return str(out_dir / out_name)

def to_relative_output_path(db, job, absolute_output):
    with db.cursor() as cur:
        cur.execute(
            "SELECT storage_root FROM tenants WHERE id = %s",
            (job["tenant_id"],)
        )
        tenant_row = cur.fetchone()

    if not tenant_row:
        return absolute_output

    try:
        return str(Path(absolute_output).relative_to(Path(tenant_row["storage_root"])))
    except Exception:
        return absolute_output

def build_profile_settings(profile):
    profile = (profile or "default").lower()

    if profile == "compress":
        return {"width": 720, "height": 1280, "va_bitrate": "1200k", "va_maxrate": "1400k", "va_bufsize": "2400k", "crf": "30"}
    elif profile == "hq":
        return {"width": 1080, "height": 1920, "va_bitrate": "4500k", "va_maxrate": "5000k", "va_bufsize": "9000k", "crf": "18"}
    else:
        return {"width": 900, "height": 1600, "va_bitrate": "2500k", "va_maxrate": "3000k", "va_bufsize": "5000k", "crf": "23"}

def build_filter_chain(src, settings, rotation_override=None, use_vaapi=True):
    rotation = rotation_override if rotation_override in (90, 180, 270) else get_rotation_degrees(src)
    filters = []

    if rotation == 90:
        filters.append("transpose=1")
    elif rotation == 270:
        filters.append("transpose=2")
    elif rotation == 180:
        filters.append("hflip,vflip")

    if use_vaapi:
        filters.append("format=nv12")
        filters.append("hwupload")
        filters.append(f"scale_vaapi=w={settings['width']}:h={settings['height']}:force_original_aspect_ratio=decrease")
    else:
        filters.append(f"scale={settings['width']}:{settings['height']}:force_original_aspect_ratio=decrease")

    return ",".join(filters)

def ensure_metrics_row(db, tenant_id):
    with db.cursor() as cur:
        cur.execute(
            """
            INSERT INTO tenant_usage_metrics (tenant_id)
            VALUES (%s)
            ON DUPLICATE KEY UPDATE tenant_id = tenant_id
            """,
            (tenant_id,)
        )
    db.commit()

def bump_metrics(db, tenant_id, complete=False, failed=False, gpu_seconds=0):
    ensure_metrics_row(db, tenant_id)

    with db.cursor() as cur:
        cur.execute(
            """
            UPDATE tenant_usage_metrics
            SET video_jobs_total = video_jobs_total + 1,
                video_jobs_complete = video_jobs_complete + %s,
                video_jobs_failed = video_jobs_failed + %s,
                gpu_seconds_total = gpu_seconds_total + %s
            WHERE tenant_id = %s
            """,
            (
                1 if complete else 0,
                1 if failed else 0,
                int(gpu_seconds or 0),
                tenant_id,
            ),
        )
    db.commit()

def update_progress(db, job_id, percent):
    percent = max(5, min(99, int(percent)))
    with db.cursor() as cur:
        cur.execute(
            "UPDATE video_jobs SET progress_percent = %s WHERE id = %s",
            (percent, job_id),
        )
    db.commit()

def run_ffmpeg_with_progress(db, job_id, cmd, duration_seconds):
    process = subprocess.Popen(
        cmd,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        text=True,
        bufsize=1,
    )

    log_lines = []
    time_re = re.compile(r"time=(\d{2}):(\d{2}):(\d{2}(?:\.\d+)?)")

    for line in process.stdout:
        log_lines.append(line.rstrip())
        if len(log_lines) > 200:
            log_lines = log_lines[-200:]

        if duration_seconds and duration_seconds > 0:
            m = time_re.search(line)
            if m:
                hh = int(m.group(1))
                mm = int(m.group(2))
                ss = float(m.group(3))
                current = hh * 3600 + mm * 60 + ss
                percent = (current / duration_seconds) * 100.0
                update_progress(db, job_id, percent)

    process.wait()
    return process.returncode, "\n".join(log_lines[-120:])

def process_job(db, job, processor):
    job_id = job["id"]
    src = build_absolute_source_path(db, job)
    profile = job["requested_profile"]
    rotation_override = job.get("requested_rotation_degrees")

    device = INTEL_DEV if processor == "intel" else AMD_DEV
    output = build_absolute_output_path(db, job, src)
    settings = build_profile_settings(profile)
    duration_seconds = get_duration_seconds(src)

    if processor in ("intel", "amd"):
        vf = build_filter_chain(src, settings, rotation_override=rotation_override, use_vaapi=True)
        cmd = [
            "ffmpeg", "-hide_banner", "-y",
            "-noautorotate",
            "-fflags", "+genpts",
            "-vaapi_device", device,
            "-i", src,
            "-vf", vf,
            "-c:v", "h264_vaapi",
            "-b:v", settings["va_bitrate"],
            "-maxrate", settings["va_maxrate"],
            "-bufsize", settings["va_bufsize"],
            "-c:a", "aac",
            "-b:a", "160k",
            "-ac", "2",
            "-ar", "48000",
            "-movflags", "+faststart",
            "-metadata:s:v:0", "rotate=0",
            "-metadata:s:v:0", "rotate=0",
            output
        ]
    else:
        vf = build_filter_chain(src, settings, rotation_override=rotation_override, use_vaapi=False)
        cmd = [
            "ffmpeg", "-hide_banner", "-y",
            "-noautorotate",
            "-fflags", "+genpts",
            "-i", src,
            "-vf", vf,
            "-c:v", "libx264",
            "-preset", "medium",
            "-crf", settings["crf"],
            "-c:a", "aac",
            "-b:a", "160k",
            "-ac", "2",
            "-ar", "48000",
            "-movflags", "+faststart",
            "-metadata:s:v:0", "rotate=0",
            "-metadata:s:v:0", "rotate=0",
            output
        ]

    start = datetime.utcnow()

    try:
        returncode, log_excerpt = run_ffmpeg_with_progress(db, job_id, cmd, duration_seconds)
        end = datetime.utcnow()
        gpu_seconds = max(0, int((end - start).total_seconds()))

        with db.cursor() as cur:
            if returncode == 0:
                rel_output = to_relative_output_path(db, job, output)
                cur.execute(
                    """
                    UPDATE video_jobs
                    SET status='complete',
                        assigned_processor=%s,
                        output_relative_path=%s,
                        progress_percent=100,
                        gpu_seconds=%s,
                        started_at=COALESCE(started_at, %s),
                        completed_at=%s,
                        log_excerpt=%s,
                        error_message=NULL
                    WHERE id=%s
                    """,
                    (
                        processor,
                        rel_output,
                        gpu_seconds,
                        start,
                        end,
                        log_excerpt[:4000],
                        job_id,
                    ),
                )
                db.commit()
                bump_metrics(db, job["tenant_id"], complete=True, failed=False, gpu_seconds=gpu_seconds)
            else:
                with db.cursor() as cur2:
                    cur2.execute(
                        """
                        UPDATE video_jobs
                        SET status='failed',
                            assigned_processor=%s,
                            gpu_seconds=%s,
                            error_message=%s,
                            log_excerpt=%s,
                            completed_at=%s
                        WHERE id=%s
                        """,
                        (
                            processor,
                            gpu_seconds,
                            "ffmpeg failed",
                            log_excerpt[:4000],
                            end,
                            job_id,
                        ),
                    )
                db.commit()
                bump_metrics(db, job["tenant_id"], complete=False, failed=True, gpu_seconds=gpu_seconds)

    except Exception as e:
        with db.cursor() as cur:
            cur.execute(
                """
                UPDATE video_jobs
                SET status='failed',
                    assigned_processor=%s,
                    error_message=%s,
                    completed_at=UTC_TIMESTAMP()
                WHERE id=%s
                """,
                (processor, str(e)[:1000], job_id),
            )
        db.commit()
        bump_metrics(db, job["tenant_id"], complete=False, failed=True, gpu_seconds=0)

def _claim_from_query(cur, processor, where_sql="", args=()):
    """
    Scheduling policy:
    - Intel prefers default/compress and can fall back to any queued job.
    - AMD prefers HQ.
    - AMD may help with default/compress only when there is light-job backlog
      or Intel is already processing a job. This avoids AMD stealing single
      default/compress jobs when Intel is free.
    """
    job = None

    if processor == "amd":
        # 1) AMD always prefers HQ first.
        cur.execute(
            f"""
            SELECT *
            FROM video_jobs
            WHERE status='queued' {where_sql} AND requested_profile = %s
            ORDER BY id ASC
            LIMIT 1
            FOR UPDATE
            """,
            tuple(args) + ("hq",),
        )
        job = cur.fetchone()

        if job:
            return job

        # 2) Only let AMD help with light jobs if there is backlog
        #    or Intel is already busy.
        cur.execute(
            f"""
            SELECT COUNT(*) AS c
            FROM video_jobs
            WHERE status='queued' {where_sql}
              AND requested_profile IN ('default','compress')
            """,
            tuple(args),
        )
        row = cur.fetchone()
        light_backlog = row["c"] if isinstance(row, dict) else row[0]

        cur.execute(
            """
            SELECT COUNT(*) AS c
            FROM video_jobs
            WHERE status='processing'
              AND assigned_processor = 'intel'
            """
        )
        row = cur.fetchone()
        intel_busy = (row["c"] if isinstance(row, dict) else row[0]) > 0

        if light_backlog >= 2 or intel_busy:
            cur.execute(
                f"""
                SELECT *
                FROM video_jobs
                WHERE status='queued' {where_sql}
                  AND requested_profile IN ('default','compress')
                ORDER BY id ASC
                LIMIT 1
                FOR UPDATE
                """,
                tuple(args),
            )
            job = cur.fetchone()

        return job

    # Intel path: default/compress first.
    cur.execute(
        f"""
        SELECT *
        FROM video_jobs
        WHERE status='queued' {where_sql} AND requested_profile IN ('default','compress')
        ORDER BY id ASC
        LIMIT 1
        FOR UPDATE
        """,
        tuple(args),
    )
    job = cur.fetchone()

    # Intel may fall back to HQ/anything if no light work exists.
    if not job:
        cur.execute(
            f"""
            SELECT *
            FROM video_jobs
            WHERE status='queued' {where_sql}
            ORDER BY id ASC
            LIMIT 1
            FOR UPDATE
            """,
            tuple(args),
        )
        job = cur.fetchone()

    return job

def claim_next_job(db, processor, current_batch_id=None, current_tenant_id=None):
    with db.cursor() as cur:
        cur.execute("START TRANSACTION")

        # 1) Keep this worker on its current batch until the batch is finished.
        if current_batch_id:
            job = _claim_from_query(cur, processor, "AND batch_id = %s", (current_batch_id,))
            if job:
                cur.execute(
                    """
                    UPDATE video_jobs
                    SET status='processing',
                        assigned_processor=%s,
                        started_at=COALESCE(started_at, UTC_TIMESTAMP()),
                        progress_percent=5
                    WHERE id=%s
                    """,
                    (processor, job["id"]),
                )
                db.commit()
                job["assigned_processor"] = processor
                return job, current_batch_id, job["tenant_id"]

        # 2) Count active tenants. If only one tenant is active, let them use all GPUs.
        cur.execute("""
            SELECT COUNT(DISTINCT tenant_id) AS c
            FROM video_jobs
            WHERE status IN ('queued','processing')
        """)
        row = cur.fetchone()
        active_tenants = row["c"] if isinstance(row, dict) else row[0]

        if active_tenants <= 1:
            job = _claim_from_query(cur, processor)
            if not job:
                db.rollback()
                return None, None, None

            cur.execute(
                """
                UPDATE video_jobs
                SET status='processing',
                    assigned_processor=%s,
                    started_at=COALESCE(started_at, UTC_TIMESTAMP()),
                    progress_percent=5
                WHERE id=%s
                """,
                (processor, job["id"]),
            )
            db.commit()
            job["assigned_processor"] = processor
            return job, job.get("batch_id"), job["tenant_id"]

        # 3) Multiple active tenants:
        #    only allow a tenant without an already-processing job to get a GPU slot.
        cur.execute("""
            SELECT DISTINCT tenant_id
            FROM video_jobs
            WHERE status='processing'
        """)
        busy_rows = cur.fetchall()
        busy_tenants = {r["tenant_id"] if isinstance(r, dict) else r[0] for r in busy_rows}

        if busy_tenants:
            placeholders = ",".join(["%s"] * len(busy_tenants))
            cur.execute(
                f"""
                SELECT tenant_id
                FROM video_jobs
                WHERE status='queued'
                  AND tenant_id NOT IN ({placeholders})
                ORDER BY id ASC
                LIMIT 1
                FOR UPDATE
                """,
                tuple(busy_tenants),
            )
        else:
            cur.execute(
                """
                SELECT tenant_id
                FROM video_jobs
                WHERE status='queued'
                ORDER BY id ASC
                LIMIT 1
                FOR UPDATE
                """
            )

        tenant_row = cur.fetchone()
        if not tenant_row:
            db.rollback()
            return None, None, None

        tenant_id = tenant_row["tenant_id"] if isinstance(tenant_row, dict) else tenant_row[0]

        job = _claim_from_query(cur, processor, "AND tenant_id = %s", (tenant_id,))
        if not job:
            db.rollback()
            return None, None, None

        cur.execute(
            """
            UPDATE video_jobs
            SET status='processing',
                assigned_processor=%s,
                started_at=COALESCE(started_at, UTC_TIMESTAMP()),
                progress_percent=5
            WHERE id=%s
            """,
            (processor, job["id"]),
        )
        db.commit()
        job["assigned_processor"] = processor
        return job, job.get("batch_id"), job["tenant_id"]

def worker_loop(app, processor):
    current_batch_id = None
    current_tenant_id = None

    with app.app_context():
        print(f"{processor} worker started", flush=True)

        while True:
            try:
                db = get_db()
                try:
                    db.rollback()
                except Exception:
                    pass

                job, new_batch_id, new_tenant_id = claim_next_job(
                    db,
                    processor,
                    current_batch_id=current_batch_id,
                    current_tenant_id=current_tenant_id,
                )

                if job:
                    current_batch_id = new_batch_id
                    current_tenant_id = new_tenant_id
                    print(f"{processor} worker picked job id={job['id']} batch={job.get('batch_id')} tenant={job['tenant_id']} source={job['source_relative_path']}", flush=True)
                    process_job(db, job, processor)
                else:
                    current_batch_id = None
                    current_tenant_id = None
                    time.sleep(2)

            except Exception as e:
                print(f"{processor} worker loop error: {e}", flush=True)
                time.sleep(2)

def run_worker():
    app = create_app()

    threads = [
        threading.Thread(target=worker_loop, args=(app, "intel"), daemon=True),
        threading.Thread(target=worker_loop, args=(app, "amd"), daemon=True),
    ]

    for t in threads:
        t.start()

    while True:
        time.sleep(60)