"""
ManaCore STT API Service
Speech-to-Text with Whisper (MLX), WhisperX (CUDA), Voxtral (vLLM), and Mistral API (fallback)

Run with: uvicorn app.main:app --host 0.0.0.0 --port 3020
"""

import os
import logging
import time
from typing import Optional
from contextlib import asynccontextmanager

from fastapi import FastAPI, File, UploadFile, Form, HTTPException, Depends, Response
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from pydantic import BaseModel

from app.auth import verify_api_key, AuthResult, get_api_key_stats, REQUIRE_AUTH

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
)
logger = logging.getLogger(__name__)

# Environment
PORT = int(os.getenv("PORT", "3020"))
DEFAULT_WHISPER_MODEL = os.getenv("WHISPER_MODEL", "large-v3")
PRELOAD_MODELS = os.getenv("PRELOAD_MODELS", "false").lower() == "true"
CORS_ORIGINS = os.getenv(
    "CORS_ORIGINS",
    "https://mana.how,https://chat.mana.how,http://localhost:5173"
).split(",")

# vLLM configuration (disabled by default - has issues on macOS CPU)
VLLM_URL = os.getenv("VLLM_URL", "http://localhost:8100")
USE_VLLM = os.getenv("USE_VLLM", "false").lower() == "true"

# WhisperX configuration (CUDA GPU server)
USE_WHISPERX = os.getenv("USE_WHISPERX", "false").lower() == "true"


# Response models
class TranscriptionResponse(BaseModel):
    text: str
    language: Optional[str] = None
    model: str
    latency_ms: Optional[float] = None
    duration_seconds: Optional[float] = None


class WordTimestampResponse(BaseModel):
    word: str
    start: float
    end: float
    score: float = 0.0
    speaker: Optional[str] = None


class SegmentResponse(BaseModel):
    start: float
    end: float
    text: str
    speaker: Optional[str] = None
    words: list[WordTimestampResponse] = []


class UtteranceResponse(BaseModel):
    speaker: int
    text: str
    offset: int  # milliseconds
    duration: int  # milliseconds


class RichTranscriptionResponse(BaseModel):
    """Extended response with segments, utterances, and speaker diarization."""
    text: str
    language: Optional[str] = None
    model: str
    latency_ms: Optional[float] = None
    duration_seconds: Optional[float] = None
    segments: list[SegmentResponse] = []
    utterances: list[UtteranceResponse] = []
    speakers: dict[str, str] = {}
    speaker_map: dict[str, int] = {}
    languages: list[str] = []
    primary_language: Optional[str] = None
    words: list[WordTimestampResponse] = []


class HealthResponse(BaseModel):
    status: str
    whisper_loaded: bool
    whisperx_available: bool
    vllm_available: bool
    vllm_url: Optional[str] = None
    mistral_api_available: bool
    auth_required: bool
    models: dict


class ModelsResponse(BaseModel):
    whisper: list
    whisperx: list
    voxtral_vllm: list
    default_whisper: str


# Track loaded models
models_status = {
    "whisper_loaded": False,
    "whisperx_available": False,
    "vllm_available": False,
}


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Startup and shutdown events."""
    logger.info("Starting ManaCore STT Service...")

    # Check vLLM availability
    if USE_VLLM:
        from app.vllm_service import check_health
        health = await check_health()
        models_status["vllm_available"] = health.get("status") == "healthy"
        if models_status["vllm_available"]:
            logger.info(f"vLLM server available at {VLLM_URL}")
        else:
            logger.warning(f"vLLM server not available: {health}")

    # Check WhisperX availability
    if USE_WHISPERX:
        try:
            from app.whisperx_service import is_available as whisperx_available
            models_status["whisperx_available"] = whisperx_available()
            if models_status["whisperx_available"]:
                logger.info("WhisperX (CUDA) available")
            else:
                logger.warning("WhisperX not available (whisperx package not installed)")
        except Exception as e:
            logger.warning(f"WhisperX check failed: {e}")

    # Check Mistral API
    from app.voxtral_api_service import is_available as api_available
    if api_available():
        logger.info("Mistral API fallback configured")

    # Optionally preload Whisper
    if PRELOAD_MODELS:
        logger.info("Preloading Whisper model...")
        try:
            from app.whisper_service import get_whisper_model
            get_whisper_model(DEFAULT_WHISPER_MODEL)
            models_status["whisper_loaded"] = True
            logger.info("Whisper model preloaded")
        except Exception as e:
            logger.warning(f"Failed to preload Whisper: {e}")

    logger.info(f"STT Service ready on port {PORT}")
    yield
    logger.info("Shutting down STT Service...")


# Create FastAPI app
app = FastAPI(
    title="ManaCore STT Service",
    description="Speech-to-Text API with Whisper (MLX), Voxtral (vLLM), and Mistral API",
    version="2.0.0",
    lifespan=lifespan,
)

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


@app.get("/health", response_model=HealthResponse)
async def health_check():
    """Health check endpoint."""
    from app.voxtral_api_service import is_available as api_available
    from app.vllm_service import check_health

    vllm_health = await check_health()

    return HealthResponse(
        status="healthy",
        whisper_loaded=models_status["whisper_loaded"],
        whisperx_available=models_status["whisperx_available"],
        vllm_available=vllm_health.get("status") == "healthy",
        vllm_url=VLLM_URL if USE_VLLM else None,
        mistral_api_available=api_available(),
        auth_required=REQUIRE_AUTH,
        models={
            "default_whisper": DEFAULT_WHISPER_MODEL,
        },
    )


@app.get("/models", response_model=ModelsResponse)
async def list_models(auth: AuthResult = Depends(verify_api_key)):
    """List available models."""
    from app.whisper_service import AVAILABLE_MODELS as whisper_models
    from app.vllm_service import get_models

    vllm_models = await get_models()

    whisperx_models = []
    if USE_WHISPERX:
        try:
            from app.whisperx_service import AVAILABLE_MODELS as wx_models
            whisperx_models = wx_models
        except ImportError:
            pass

    return ModelsResponse(
        whisper=whisper_models,
        whisperx=whisperx_models,
        voxtral_vllm=vllm_models,
        default_whisper=DEFAULT_WHISPER_MODEL,
    )


@app.post("/transcribe", response_model=TranscriptionResponse)
async def transcribe_whisper(
    response: Response,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    language: Optional[str] = Form(None, description="Language code (auto-detect if not provided)"),
    model: Optional[str] = Form(None, description="Whisper model to use"),
    auth: AuthResult = Depends(verify_api_key),
):
    """
    Transcribe audio using Whisper (Lightning MLX).

    Best for: General transcription, many languages
    Supported formats: mp3, wav, m4a, flac, ogg, webm
    Max file size: 100MB
    """
    # Add rate limit headers
    if auth.rate_limit_remaining is not None:
        response.headers["X-RateLimit-Remaining"] = str(auth.rate_limit_remaining)

    if not file.filename:
        raise HTTPException(status_code=400, detail="No file provided")

    allowed_extensions = {".mp3", ".wav", ".m4a", ".flac", ".ogg", ".webm", ".mp4"}
    ext = os.path.splitext(file.filename)[1].lower()
    if ext not in allowed_extensions:
        raise HTTPException(
            status_code=400,
            detail=f"Unsupported file type: {ext}. Allowed: {allowed_extensions}"
        )

    start_time = time.time()

    try:
        from app.whisper_service import transcribe_audio_bytes

        audio_bytes = await file.read()
        if len(audio_bytes) > 100 * 1024 * 1024:
            raise HTTPException(status_code=400, detail="File too large (max 100MB)")

        model_name = model or DEFAULT_WHISPER_MODEL

        result = await transcribe_audio_bytes(
            audio_bytes=audio_bytes,
            filename=file.filename,
            language=language,
            model_name=model_name,
        )

        models_status["whisper_loaded"] = True
        latency_ms = (time.time() - start_time) * 1000

        return TranscriptionResponse(
            text=result.text,
            language=result.language,
            model=f"whisper-{model_name}",
            latency_ms=latency_ms,
        )

    except Exception as e:
        logger.error(f"Whisper transcription error: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@app.post("/transcribe/voxtral", response_model=TranscriptionResponse)
async def transcribe_voxtral(
    response: Response,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    language: str = Form("de", description="Language code"),
    use_realtime: bool = Form(False, description="Use Realtime 4B model for lower latency"),
    auth: AuthResult = Depends(verify_api_key),
):
    """
    Transcribe audio using Voxtral via vLLM server.

    Models:
    - Voxtral Mini 3B (default): Best quality
    - Voxtral Realtime 4B: Lower latency (<500ms)

    Falls back to Mistral API if vLLM is unavailable.

    Supported formats: mp3, wav, m4a, flac, ogg, webm
    Max file size: 100MB
    """
    # Add rate limit headers
    if auth.rate_limit_remaining is not None:
        response.headers["X-RateLimit-Remaining"] = str(auth.rate_limit_remaining)

    if not file.filename:
        raise HTTPException(status_code=400, detail="No file provided")

    from app.vllm_service import (
        SUPPORTED_LANGUAGES,
        is_available as vllm_available,
        transcribe_audio_bytes as vllm_transcribe,
        transcribe_with_realtime,
        check_health,
    )
    from app.voxtral_api_service import (
        is_available as api_available,
        transcribe_audio_bytes as api_transcribe,
    )

    if language not in SUPPORTED_LANGUAGES:
        raise HTTPException(
            status_code=400,
            detail=f"Unsupported language: {language}. Supported: {SUPPORTED_LANGUAGES}"
        )

    try:
        audio_bytes = await file.read()
        if len(audio_bytes) > 100 * 1024 * 1024:
            raise HTTPException(status_code=400, detail="File too large (max 100MB)")

        # Try vLLM first
        if USE_VLLM:
            health = await check_health()
            if health.get("status") == "healthy":
                logger.info("Using vLLM for Voxtral transcription")
                if use_realtime:
                    result = await transcribe_with_realtime(
                        audio_bytes=audio_bytes,
                        filename=file.filename,
                        language=language,
                    )
                else:
                    result = await vllm_transcribe(
                        audio_bytes=audio_bytes,
                        filename=file.filename,
                        language=language,
                    )

                return TranscriptionResponse(
                    text=result.text,
                    language=result.language,
                    model=result.model,
                    latency_ms=result.latency_ms,
                    duration_seconds=result.duration_seconds,
                )

        # Fallback to Mistral API
        if api_available():
            logger.info("Falling back to Mistral API")
            result = await api_transcribe(
                audio_bytes=audio_bytes,
                filename=file.filename,
                language=language,
            )

            return TranscriptionResponse(
                text=result.text,
                language=result.language,
                model=result.model,
                latency_ms=None,
                duration_seconds=result.duration_seconds,
            )

        raise HTTPException(
            status_code=503,
            detail="Voxtral not available. Start vLLM server or configure MISTRAL_API_KEY."
        )

    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Voxtral transcription error: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@app.post("/transcribe/voxtral/api", response_model=TranscriptionResponse)
async def transcribe_voxtral_api(
    response: Response,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    language: Optional[str] = Form(None, description="Language code (auto-detect if not provided)"),
    diarization: bool = Form(False, description="Enable speaker diarization"),
    auth: AuthResult = Depends(verify_api_key),
):
    """
    Transcribe audio using Mistral's Voxtral API directly.

    Features:
    - Speaker diarization
    - Auto language detection
    - High quality (~4% WER)

    Requires MISTRAL_API_KEY environment variable.
    """
    # Add rate limit headers
    if auth.rate_limit_remaining is not None:
        response.headers["X-RateLimit-Remaining"] = str(auth.rate_limit_remaining)

    from app.voxtral_api_service import is_available, transcribe_audio_bytes

    if not is_available():
        raise HTTPException(
            status_code=503,
            detail="Mistral API not configured. Set MISTRAL_API_KEY environment variable."
        )

    if not file.filename:
        raise HTTPException(status_code=400, detail="No file provided")

    try:
        audio_bytes = await file.read()
        if len(audio_bytes) > 100 * 1024 * 1024:
            raise HTTPException(status_code=400, detail="File too large (max 100MB)")

        result = await transcribe_audio_bytes(
            audio_bytes=audio_bytes,
            filename=file.filename,
            language=language,
            diarization=diarization,
        )

        return TranscriptionResponse(
            text=result.text,
            language=result.language,
            model=result.model,
            duration_seconds=result.duration_seconds,
        )

    except Exception as e:
        logger.error(f"Mistral API error: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@app.post("/transcribe/whisperx", response_model=RichTranscriptionResponse)
async def transcribe_whisperx(
    response: Response,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    language: Optional[str] = Form(None, description="Language code (auto-detect if not provided)"),
    model: Optional[str] = Form(None, description="Whisper model to use"),
    diarization: bool = Form(True, description="Enable speaker diarization"),
    alignment: bool = Form(True, description="Enable word-level alignment"),
    min_speakers: Optional[int] = Form(None, description="Minimum expected speakers"),
    max_speakers: Optional[int] = Form(None, description="Maximum expected speakers"),
    auth: AuthResult = Depends(verify_api_key),
):
    """
    Transcribe audio using WhisperX (CUDA GPU).

    Returns rich transcription with:
    - Word-level timestamps (via forced alignment)
    - Speaker diarization (via pyannote.audio)
    - Memoro-compatible utterances with speaker IDs

    Requires NVIDIA GPU with CUDA and USE_WHISPERX=true.
    Diarization requires HF_TOKEN with pyannote model access.

    Supported formats: mp3, wav, m4a, flac, ogg, webm, mp4
    Max file size: 100MB
    """
    if auth.rate_limit_remaining is not None:
        response.headers["X-RateLimit-Remaining"] = str(auth.rate_limit_remaining)

    if not USE_WHISPERX:
        raise HTTPException(
            status_code=503,
            detail="WhisperX not enabled. Set USE_WHISPERX=true on a CUDA-capable server."
        )

    if not file.filename:
        raise HTTPException(status_code=400, detail="No file provided")

    allowed_extensions = {".mp3", ".wav", ".m4a", ".flac", ".ogg", ".webm", ".mp4"}
    ext = os.path.splitext(file.filename)[1].lower()
    if ext not in allowed_extensions:
        raise HTTPException(
            status_code=400,
            detail=f"Unsupported file type: {ext}. Allowed: {allowed_extensions}"
        )

    start_time = time.time()

    try:
        from app.whisperx_service import transcribe_audio_bytes

        audio_bytes = await file.read()
        if len(audio_bytes) > 100 * 1024 * 1024:
            raise HTTPException(status_code=400, detail="File too large (max 100MB)")

        model_name = model or DEFAULT_WHISPER_MODEL

        result = await transcribe_audio_bytes(
            audio_bytes=audio_bytes,
            filename=file.filename,
            language=language,
            model_name=model_name,
            enable_diarization=diarization,
            enable_alignment=alignment,
            min_speakers=min_speakers,
            max_speakers=max_speakers,
        )

        latency_ms = (time.time() - start_time) * 1000

        return RichTranscriptionResponse(
            text=result.text,
            language=result.language,
            model=f"whisperx-{model_name}",
            latency_ms=latency_ms,
            duration_seconds=result.duration_seconds,
            segments=[
                SegmentResponse(
                    start=s.start,
                    end=s.end,
                    text=s.text,
                    speaker=s.speaker,
                    words=[
                        WordTimestampResponse(
                            word=w.word,
                            start=w.start,
                            end=w.end,
                            score=w.score,
                            speaker=w.speaker,
                        )
                        for w in s.words
                    ],
                )
                for s in result.segments
            ],
            utterances=[
                UtteranceResponse(
                    speaker=u.speaker,
                    text=u.text,
                    offset=u.offset,
                    duration=u.duration,
                )
                for u in result.utterances
            ],
            speakers=result.speakers,
            speaker_map={k: v for k, v in result.speaker_map.items()},
            languages=result.languages,
            primary_language=result.primary_language,
            words=[
                WordTimestampResponse(
                    word=w.word,
                    start=w.start,
                    end=w.end,
                    score=w.score,
                    speaker=w.speaker,
                )
                for w in result.words
            ],
        )

    except HTTPException:
        raise
    except ImportError:
        raise HTTPException(
            status_code=503,
            detail="WhisperX not installed. Install with: pip install -r requirements-cuda.txt"
        )
    except Exception as e:
        logger.error(f"WhisperX transcription error: {e}")
        raise HTTPException(status_code=500, detail=str(e))


@app.post("/transcribe/auto", response_model=TranscriptionResponse)
async def transcribe_auto(
    response: Response,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    language: Optional[str] = Form(None, description="Language hint"),
    prefer: str = Form("whisper", description="Preferred: 'whisper', 'whisperx', or 'voxtral'"),
    auth: AuthResult = Depends(verify_api_key),
):
    """
    Transcribe with automatic model selection and fallback.

    Fallback chain:
    - whisper: Whisper → WhisperX → Voxtral → Mistral API
    - whisperx: WhisperX → Whisper → Voxtral → Mistral API
    - voxtral: Voxtral → WhisperX → Whisper → Mistral API
    """
    # Add rate limit headers
    if auth.rate_limit_remaining is not None:
        response.headers["X-RateLimit-Remaining"] = str(auth.rate_limit_remaining)

    async def try_whisperx_simple():
        """Try WhisperX and return as simple TranscriptionResponse."""
        if not USE_WHISPERX:
            raise RuntimeError("WhisperX not enabled")
        from app.whisperx_service import transcribe_audio_bytes as wx_transcribe
        audio_bytes = await file.read()
        result = await wx_transcribe(
            audio_bytes=audio_bytes,
            filename=file.filename or "audio.wav",
            language=language,
            enable_diarization=False,
            enable_alignment=False,
        )
        return TranscriptionResponse(
            text=result.text,
            language=result.language,
            model=f"whisperx-{DEFAULT_WHISPER_MODEL}",
            latency_ms=None,
            duration_seconds=result.duration_seconds,
        )

    # Build fallback chain based on preference
    if prefer == "whisperx":
        chain = [
            ("WhisperX", try_whisperx_simple),
            ("Whisper", lambda: transcribe_whisper(response, file, language, None, auth)),
            ("Voxtral", lambda: transcribe_voxtral(response, file, language or "de", False, auth)),
            ("Mistral API", lambda: transcribe_voxtral_api(response, file, language, False, auth)),
        ]
    elif prefer == "voxtral":
        chain = [
            ("Voxtral", lambda: transcribe_voxtral(response, file, language or "de", False, auth)),
            ("WhisperX", try_whisperx_simple),
            ("Whisper", lambda: transcribe_whisper(response, file, language, None, auth)),
            ("Mistral API", lambda: transcribe_voxtral_api(response, file, language, False, auth)),
        ]
    else:
        chain = [
            ("Whisper", lambda: transcribe_whisper(response, file, language, None, auth)),
            ("WhisperX", try_whisperx_simple),
            ("Voxtral", lambda: transcribe_voxtral(response, file, language or "de", False, auth)),
            ("Mistral API", lambda: transcribe_voxtral_api(response, file, language, False, auth)),
        ]

    last_error = None
    for name, fn in chain:
        try:
            result = await fn()
            return result
        except Exception as e:
            last_error = e
            logger.warning(f"{name} failed: {e}")
            await file.seek(0)

    raise HTTPException(
        status_code=503,
        detail=f"All transcription backends failed. Last error: {last_error}"
    )


@app.exception_handler(Exception)
async def global_exception_handler(request, exc):
    logger.error(f"Unhandled error: {exc}")
    return JSONResponse(
        status_code=500,
        content={"detail": "Internal server error", "error": str(exc)},
    )


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