"""ElevenClip AI — FastAPI Backend.

Endpoints:
  POST /api/video-info          — get YouTube metadata (no download)
  POST /api/process             — full pipeline (download/upload → clips)
  WS   /ws/progress/{session}   — real-time pipeline progress
  GET  /api/clips/{session}     — list generated clips
  PATCH /api/clips/{session}/{index}/subtitles — update subtitle event
  PATCH /api/clips/{session}/{index}/style     — apply global style override
  POST /api/clips/{session}/{index}/render     — burn-in subtitles → download
  GET  /downloads/{session}/{filename}         — serve output files
"""
import asyncio
import json
import os
import uuid
from pathlib import Path
from typing import Optional

from fastapi import FastAPI, UploadFile, File, Form, Header, Response, WebSocket, WebSocketDisconnect, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from pydantic import BaseModel
from loguru import logger
import httpx

from src.gpu.rocm_utils import get_device, log_gpu_status
from src.gpu.vllm_manager import ensure_vllm_running, vllm_stop, vllm_status
from src.ingestion.youtube import download_video_async, get_video_info
from src.transcription.whisper import transcribe_async, extract_audio
from src.analysis.scene_detector import detect_scenes, sample_frames
from src.analysis.vision import analyze_scenes_batch_async
from src.analysis.highlight_scorer import score_scenes, select_top_clips
from src.processing.clip_extractor import extract_all_clips_async, burn_subtitles
from src.processing.subtitle import generate_subtitles, update_subtitle_event, apply_global_style_override
from src.processing.high_retention import apply_hre

app = FastAPI(title="ElevenClip AI", version="1.0.0")

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

WORK_DIR = Path(os.getenv("WORK_DIR", "/tmp/elevnclip"))
WORK_DIR.mkdir(parents=True, exist_ok=True)

DEMO_ACCESS_CODE = os.getenv("DEMO_ACCESS_CODE", "").strip()
MAX_CONCURRENT_JOBS = int(os.getenv("MAX_CONCURRENT_JOBS", "1"))
MAX_UPLOAD_MB = int(os.getenv("MAX_UPLOAD_MB", "500"))
REMOTE_BACKEND_URL = os.getenv("REMOTE_BACKEND_URL", "").rstrip("/")

# In-memory session store + WebSocket registry
sessions: dict[str, dict] = {}
ws_connections: dict[str, WebSocket] = {}
ws_queues: dict[str, list[dict]] = {}  # buffer progress messages until WS connects
active_jobs: set[str] = set()


def _require_access(x_demo_key: Optional[str]) -> None:
    """Optional public-demo guard for expensive GPU endpoints."""
    if DEMO_ACCESS_CODE and (x_demo_key or "").strip() != DEMO_ACCESS_CODE:
        raise HTTPException(403, "Access code required for generation")


def _demo_headers(x_demo_key: Optional[str]) -> dict[str, str]:
    return {"X-Demo-Key": x_demo_key.strip()} if x_demo_key and x_demo_key.strip() else {}


def _proxy_response(resp: httpx.Response) -> Response:
    content_type = resp.headers.get("content-type", "application/octet-stream")
    headers = {}
    if disposition := resp.headers.get("content-disposition"):
        headers["Content-Disposition"] = disposition
    return Response(content=resp.content, status_code=resp.status_code, media_type=content_type, headers=headers)


# ─── Startup ──────────────────────────────────────────────────────────────

@app.on_event("startup")
async def startup():
    log_gpu_status()
    # Pre-populate demo session so /editor?session=demo always works
    sessions["demo"] = {"status": "done", "clips": _build_demo_clips()}


def _build_demo_clips() -> list[dict]:
    return [
        {
            "index": 1, "start": 0.0, "end": 45.0, "duration": 45.0, "score": 0.91,
            "clip_path": None, "final_path": None, "ass_path": None,
            "download_url": None, "raw_url": None,
            "highlight_reason": "High-energy moment with peak audience reaction",
            "vision_analysis": {"excitement_score": 0.92, "tiktok_potential": 0.89, "emotion": "excited", "action_type": "gaming"},
        },
        {
            "index": 2, "start": 90.0, "end": 150.0, "duration": 60.0, "score": 0.83,
            "clip_path": None, "final_path": None, "ass_path": None,
            "download_url": None, "raw_url": None,
            "highlight_reason": "Funny reaction — peak humor level detected",
            "vision_analysis": {"excitement_score": 0.78, "tiktok_potential": 0.85, "emotion": "funny", "action_type": "reaction"},
        },
        {
            "index": 3, "start": 210.0, "end": 270.0, "duration": 60.0, "score": 0.76,
            "clip_path": None, "final_path": None, "ass_path": None,
            "download_url": None, "raw_url": None,
            "highlight_reason": "Educational highlight with strong engagement signal",
            "vision_analysis": {"excitement_score": 0.70, "tiktok_potential": 0.80, "emotion": "happy", "action_type": "tutorial"},
        },
    ]


# ─── WebSocket Progress ────────────────────────────────────────────────────

@app.websocket("/ws/progress/{session_id}")
async def ws_progress(websocket: WebSocket, session_id: str):
    await websocket.accept()
    ws_connections[session_id] = websocket

    # Flush messages that were sent before the WS connected
    for msg in ws_queues.pop(session_id, []):
        try:
            await websocket.send_json(msg)
        except Exception:
            break

    try:
        while True:
            await asyncio.sleep(30)  # keep-alive
    except WebSocketDisconnect:
        ws_connections.pop(session_id, None)


async def send_progress(session_id: str, stage: str, pct: int, message: str = ""):
    payload = {"stage": stage, "pct": pct, "message": message}
    sessions.setdefault(session_id, {})["last_progress"] = payload

    ws = ws_connections.get(session_id)
    if ws:
        try:
            await ws.send_json(payload)
            return
        except Exception:
            ws_connections.pop(session_id, None)

    # WS not yet connected — buffer for flush on connect
    ws_queues.setdefault(session_id, []).append(payload)


# ─── Models ───────────────────────────────────────────────────────────────

class VideoInfoRequest(BaseModel):
    url: str

DEMO_VIDEO_DIR = Path("/root/ElevenClip-AI/demo_videos")
_DEMO_CANDIDATES = ["demo1.mp4", "demo2.mp4", "demo.mp4"]

def _get_demo_video() -> Path | None:
    import random
    available = [DEMO_VIDEO_DIR / f for f in _DEMO_CANDIDATES if (DEMO_VIDEO_DIR / f).exists()]
    return random.choice(available) if available else None

class ProcessSettings(BaseModel):
    youtube_url: Optional[str] = None
    use_demo_video: bool = False
    channel_description: str = ""
    clip_style: str = "entertaining"
    target_duration: int = 60
    clip_count: int = 3
    clip_language: str = "auto"
    subtitle_language: str = "en"
    mode: str = "normal"  # "normal" | "hre"
    aspect_mode: str = "crop"  # "crop" | "letterbox"
    style_config: dict = {}

class SubtitlePatch(BaseModel):
    event_index: int
    updates: dict  # {text, start, end}

class GlobalStylePatch(BaseModel):
    style_config: dict


# ─── Routes ───────────────────────────────────────────────────────────────

@app.get("/health")
async def health():
    return {"status": "ok", "device": get_device()}


@app.post("/api/video-info")
async def video_info(req: VideoInfoRequest, x_demo_key: Optional[str] = Header(None, alias="X-Demo-Key")):
    _require_access(x_demo_key)
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=120.0) as client:
            resp = await client.post(
                f"{REMOTE_BACKEND_URL}/api/video-info",
                json=req.model_dump(),
                headers=_demo_headers(x_demo_key),
            )
        return _proxy_response(resp)
    try:
        return get_video_info(req.url)
    except Exception as e:
        raise HTTPException(400, str(e))


@app.post("/api/process")
async def process(
    settings_json: str = Form(...),
    file: Optional[UploadFile] = File(None),
    x_demo_key: Optional[str] = Header(None, alias="X-Demo-Key"),
):
    """Main pipeline endpoint. Returns session_id immediately; progress via WebSocket."""
    _require_access(x_demo_key)
    if REMOTE_BACKEND_URL:
        file_bytes: Optional[bytes] = None
        file_name: Optional[str] = None
        file_type = "application/octet-stream"
        if file:
            file_bytes = await file.read()
            file_name = file.filename or "upload.mp4"
            file_type = file.content_type or file_type
            if len(file_bytes) > MAX_UPLOAD_MB * 1024 * 1024:
                raise HTTPException(413, f"File too large. Max upload size is {MAX_UPLOAD_MB} MB.")

        files = {"file": (file_name, file_bytes, file_type)} if file_bytes and file_name else None
        async with httpx.AsyncClient(timeout=900.0) as client:
            resp = await client.post(
                f"{REMOTE_BACKEND_URL}/api/process",
                data={"settings_json": settings_json},
                files=files,
                headers=_demo_headers(x_demo_key),
            )
        return _proxy_response(resp)

    if len(active_jobs) >= MAX_CONCURRENT_JOBS:
        raise HTTPException(429, "GPU is busy. Please try again in a few minutes.")

    settings = ProcessSettings(**json.loads(settings_json))
    session_id = str(uuid.uuid4())
    session_dir = WORK_DIR / session_id
    session_dir.mkdir(parents=True, exist_ok=True)

    sessions[session_id] = {"status": "starting", "clips": []}

    # Read file bytes NOW — UploadFile becomes invalid once the response is sent
    file_bytes: Optional[bytes] = None
    file_name: Optional[str] = None
    if file:
        file_bytes = await file.read()
        file_name = file.filename or "upload.mp4"
        if len(file_bytes) > MAX_UPLOAD_MB * 1024 * 1024:
            raise HTTPException(413, f"File too large. Max upload size is {MAX_UPLOAD_MB} MB.")

    active_jobs.add(session_id)
    asyncio.create_task(_run_pipeline(session_id, session_dir, settings, file_bytes, file_name))
    return {"session_id": session_id}


# ─── Pipeline ─────────────────────────────────────────────────────────────

async def _run_pipeline(
    session_id: str,
    session_dir: Path,
    settings: ProcessSettings,
    file_bytes: Optional[bytes],
    file_name: Optional[str],
):
    loop = asyncio.get_running_loop()
    frames_dir = session_dir / "frames"

    try:
        # ── 1. Acquire video ──────────────────────────────────────────────
        await send_progress(session_id, "download", 5, "Acquiring video...")

        if settings.use_demo_video and (demo_vid := _get_demo_video()):
            video_path = demo_vid
            await send_progress(session_id, "download", 30, f"Using demo video: {demo_vid.name}")
        elif settings.youtube_url:
            def pct_cb(p):
                asyncio.run_coroutine_threadsafe(
                    send_progress(session_id, "download", max(5, int(p * 0.28)), f"Downloading {p:.0f}%"),
                    loop,
                )
            video_path = await download_video_async(
                settings.youtube_url, session_dir, session_id, pct_cb
            )
        elif file_bytes:
            suffix = Path(file_name).suffix if file_name else ".mp4"
            video_path = session_dir / f"{session_id}_input{suffix}"
            await loop.run_in_executor(None, video_path.write_bytes, file_bytes)
        else:
            raise ValueError("No video source provided")

        await send_progress(session_id, "download", 30, "Video ready")

        # ── 2. Extract audio ─────────────────────────────────────────────
        await send_progress(session_id, "audio", 32, "Extracting audio (16kHz mono)...")
        audio_path = session_dir / f"{session_id}_audio.wav"
        await loop.run_in_executor(None, lambda: extract_audio(video_path, audio_path))

        # ── 3+4. Scene detection AND Whisper transcription IN PARALLEL ───
        # Scene detection runs on CPU; Whisper runs on AMD GPU. True concurrency.
        await send_progress(session_id, "scenes", 35, "Scene detection + Whisper transcription (parallel on AMD ROCm)...")
        device = get_device()

        scenes_future = loop.run_in_executor(None, lambda: detect_scenes(video_path))
        transcript_task = transcribe_async(
            audio_path,
            clip_language=settings.clip_language,
            subtitle_language=settings.subtitle_language,
            device=device,
        )
        scenes, transcript = await asyncio.gather(scenes_future, transcript_task)

        await send_progress(
            session_id, "transcribe", 58,
            f"Whisper: {len(transcript.get('segments', []))} segments | SceneDetect: {len(scenes)} scenes"
        )

        # Frame sampling (after scenes list is known)
        scenes_with_frames = await loop.run_in_executor(
            None, lambda: sample_frames(video_path, scenes, frames_dir)
        )

        # ── 5. Qwen2.5-VL multimodal analysis (concurrent requests to vLLM) ─
        n_scenes = len(scenes_with_frames)
        await send_progress(session_id, "vision", 58, "Ensuring AI model is running...")
        await loop.run_in_executor(
            None,
            lambda: ensure_vllm_running(
                progress_cb=lambda msg: asyncio.run_coroutine_threadsafe(
                    send_progress(session_id, "vision", 59, msg), loop
                )
            ),
        )
        await send_progress(session_id, "vision", 60, f"Qwen2.5-VL analyzing {n_scenes} scenes (vision + audio + text fusion)...")
        scenes_analyzed = await analyze_scenes_batch_async(
            scenes_with_frames,
            transcript.get("segments", []),
            channel_description=settings.channel_description,
            clip_style=settings.clip_style,
        )
        await send_progress(session_id, "vision", 76, f"Multimodal analysis complete: {n_scenes} scenes scored")

        # ── 6. Multi-signal scoring ─────────────────────────────────────
        await send_progress(session_id, "scoring", 77, "Scoring: 0.40×vision + 0.35×audio_energy + 0.25×text_keywords")
        scored = score_scenes(scenes_analyzed, audio_path, settings.clip_style, settings.target_duration)
        selected = select_top_clips(scored, settings.clip_count, settings.target_duration)

        # ── 7. Extract clips (AMD AMF hardware encoder) ─────────────────
        await send_progress(session_id, "cutting", 81, f"Cutting {len(selected)} clips (h264_amf)...")
        # HRE needs a true TikTok crop, not a shrunken fit/letterbox frame.
        # The crop extractor centers on Qwen's face/person bbox when available.
        extract_aspect_mode = "crop" if settings.mode == "hre" else settings.aspect_mode
        clips = await extract_all_clips_async(video_path, selected, session_dir, session_id, aspect_mode=extract_aspect_mode)

        # ── 8. Subtitles / HRE (all clips in parallel) ─────────────────
        await send_progress(session_id, "subtitles", 86, "Generating subtitles (parallel)...")

        subtitle_tasks = []
        final_clips = []

        for clip in clips:
            if not clip.get("clip_path"):
                continue
            clip_path = Path(clip["clip_path"])
            i = clip["clip_index"]

            clip_transcript = {
                **transcript,
                "segments": [
                    s for s in transcript.get("segments", [])
                    if s["start"] < clip["end"] and s["end"] > clip["start"]
                ],
            }

            ass_path = session_dir / f"{session_id}_clip_{i:02d}.ass"
            final_path = session_dir / f"{session_id}_clip_{i:02d}_final.mp4"

            if settings.mode == "hre":
                subtitle_tasks.append(loop.run_in_executor(
                    None,
                    lambda cp=clip_path, cd=clip, tr=clip_transcript, fp=final_path:
                        apply_hre(cp, cd, tr, fp)
                ))
            else:
                def _gen_and_burn(cp=clip_path, ap=ass_path, tr=clip_transcript, cs=clip["start"], fp=final_path):
                    generate_subtitles(tr, ap, settings.style_config, clip_start_offset=cs)
                    burn_subtitles(cp, ap, fp)
                subtitle_tasks.append(loop.run_in_executor(None, _gen_and_burn))

            final_clips.append({
                "index": i,
                "start": clip["start"],
                "end": clip["end"],
                "duration": clip["end"] - clip["start"],
                "score": clip.get("final_score", 0),
                "clip_path": str(clip_path),
                "final_path": str(final_path),
                "ass_path": str(ass_path) if settings.mode == "normal" else None,
                "download_url": f"/downloads/{session_id}/{final_path.name}",
                "raw_url": f"/downloads/{session_id}/{clip_path.name}",
                "vision_analysis": clip.get("vision_analysis", {}),
                "highlight_reason": clip.get("vision_analysis", {}).get("highlight_reason", ""),
            })

        if subtitle_tasks:
            await asyncio.gather(*subtitle_tasks)

        sessions[session_id] = {"status": "done", "clips": final_clips}
        await send_progress(session_id, "done", 100, f"Done! {len(final_clips)} clips ready for download.")

    except Exception as e:
        logger.exception(f"Pipeline failed [{session_id}]")
        sessions[session_id] = {"status": "error", "error": str(e), "clips": []}
        await send_progress(session_id, "error", 0, f"Pipeline error: {e}")
    finally:
        active_jobs.discard(session_id)


# ─── Editor API ───────────────────────────────────────────────────────────

@app.get("/api/clips/{session_id}")
async def get_clips(session_id: str):
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=120.0) as client:
            resp = await client.get(f"{REMOTE_BACKEND_URL}/api/clips/{session_id}")
        return _proxy_response(resp)

    session = sessions.get(session_id)
    if not session:
        raise HTTPException(404, "Session not found")
    return session


@app.patch("/api/clips/{session_id}/{clip_index}/subtitles")
async def patch_subtitle(session_id: str, clip_index: int, patch: SubtitlePatch):
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=120.0) as client:
            resp = await client.patch(
                f"{REMOTE_BACKEND_URL}/api/clips/{session_id}/{clip_index}/subtitles",
                json=patch.model_dump(),
            )
        return _proxy_response(resp)

    clip = _get_clip_or_404(session_id, clip_index)
    if not clip.get("ass_path"):
        raise HTTPException(404, "No subtitle file for this clip")
    update_subtitle_event(Path(clip["ass_path"]), patch.event_index, patch.updates)
    return {"ok": True}


@app.patch("/api/clips/{session_id}/{clip_index}/style")
async def patch_global_style(session_id: str, clip_index: int, patch: GlobalStylePatch):
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=120.0) as client:
            resp = await client.patch(
                f"{REMOTE_BACKEND_URL}/api/clips/{session_id}/{clip_index}/style",
                json=patch.model_dump(),
            )
        return _proxy_response(resp)

    clip = _get_clip_or_404(session_id, clip_index)
    if not clip.get("ass_path"):
        raise HTTPException(404, "No subtitle file for this clip")
    apply_global_style_override(Path(clip["ass_path"]), patch.style_config)
    return {"ok": True}


@app.post("/api/clips/{session_id}/{clip_index}/render")
async def render_clip(session_id: str, clip_index: int):
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=600.0) as client:
            resp = await client.post(f"{REMOTE_BACKEND_URL}/api/clips/{session_id}/{clip_index}/render")
        return _proxy_response(resp)

    clip = _get_clip_or_404(session_id, clip_index)

    clip_path = Path(clip["clip_path"])
    ass_path = Path(clip["ass_path"]) if clip.get("ass_path") else None
    final_path = clip_path.parent / f"{clip_path.stem}_edited.mp4"

    if ass_path and ass_path.exists():
        loop = asyncio.get_running_loop()
        await loop.run_in_executor(None, lambda: burn_subtitles(clip_path, ass_path, final_path))
    else:
        final_path = Path(clip["final_path"])

    download_url = f"/downloads/{session_id}/{final_path.name}"
    clip["download_url"] = download_url
    clip["final_path"] = str(final_path)
    return {"download_url": download_url}


def _get_clip_or_404(session_id: str, clip_index: int) -> dict:
    session = sessions.get(session_id)
    if not session:
        raise HTTPException(404, "Session not found")
    clip = next((c for c in session.get("clips", []) if c["index"] == clip_index), None)
    if not clip:
        raise HTTPException(404, f"Clip {clip_index} not found")
    return clip


# ─── vLLM management endpoints ────────────────────────────────────────────────

@app.get("/downloads/{file_path:path}")
async def download_file(file_path: str):
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=600.0) as client:
            resp = await client.get(f"{REMOTE_BACKEND_URL}/downloads/{file_path}")
        return _proxy_response(resp)

    target = (WORK_DIR / file_path).resolve()
    work_root = WORK_DIR.resolve()
    try:
        target.relative_to(work_root)
    except ValueError:
        raise HTTPException(404, "File not found")
    if not target.is_file():
        raise HTTPException(404, "File not found")
    return FileResponse(
        path=str(target),
        filename=target.name,
        media_type="application/octet-stream",
    )


@app.get("/api/vllm/status")
async def get_vllm_status():
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=30.0) as client:
            resp = await client.get(f"{REMOTE_BACKEND_URL}/api/vllm/status")
        return _proxy_response(resp)
    return vllm_status()


@app.post("/api/vllm/stop")
async def stop_vllm(x_demo_key: Optional[str] = Header(None, alias="X-Demo-Key")):
    _require_access(x_demo_key)
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=120.0) as client:
            resp = await client.post(
                f"{REMOTE_BACKEND_URL}/api/vllm/stop",
                headers=_demo_headers(x_demo_key),
            )
        return _proxy_response(resp)

    loop = asyncio.get_running_loop()
    await loop.run_in_executor(None, vllm_stop)
    return {"ok": True, "message": "vLLM stopped — will restart automatically on next job"}


@app.post("/api/vllm/start")
async def start_vllm(x_demo_key: Optional[str] = Header(None, alias="X-Demo-Key")):
    _require_access(x_demo_key)
    if REMOTE_BACKEND_URL:
        async with httpx.AsyncClient(timeout=240.0) as client:
            resp = await client.post(
                f"{REMOTE_BACKEND_URL}/api/vllm/start",
                headers=_demo_headers(x_demo_key),
            )
        return _proxy_response(resp)

    loop = asyncio.get_running_loop()
    await loop.run_in_executor(None, ensure_vllm_running)
    return {"ok": True, "status": vllm_status()}


if __name__ == "__main__":
    import uvicorn
    log_gpu_status()
    uvicorn.run(app, host="0.0.0.0", port=8000, reload=False)