"""
API routes for the transcription service.
"""

import logging
import time
from pathlib import Path
import csv

from fastapi import APIRouter, UploadFile, File, HTTPException, BackgroundTasks, Form
from fastapi.responses import FileResponse

from app.core.config import get_settings
from app.schemas.models import TranscriptionResponse, HealthResponse
from app.services.audio_processor import AudioProcessor, AudioProcessingError
from app.services.transcription import TranscriptionService, AVAILABLE_MODELS
from app.services.diarization import DiarizationService
from app.services.processor import Processor
from app.services.emo import EmotionService

logger = logging.getLogger(__name__)
settings = get_settings()

router = APIRouter()


@router.get("/api/health", response_model=HealthResponse)
async def health_check():
    """Health check endpoint."""
    return HealthResponse(
        status="healthy",
        models_loaded=TranscriptionService.is_loaded()
        and DiarizationService.is_loaded(),
        device=settings.resolved_device,
    )


@router.get("/api/models")
async def get_models():
    """Get available Whisper models."""
    return {"models": list(AVAILABLE_MODELS.keys()), "default": settings.default_whisper_model}


@router.post("/api/transcribe", response_model=TranscriptionResponse)
async def transcribe_audio(
    background_tasks: BackgroundTasks,
    file: UploadFile = File(..., description="Audio file to transcribe"),
    model: str = Form(default="PhoWhisper Lora Finetuned", description="Whisper model to use"),
    language: str = Form(default="vi", description="Language code")
):
    """
    Upload and transcribe an audio file.

    Uses diarize-first workflow:
    1. Diarization to identify speakers
    2. Transcribe each speaker segment
    3. Return combined result
    4. Predict emotion segments
    """
    upload_path = None

    try:
        # Read file content
        file_content = await file.read()

        # Validate
        try:
            AudioProcessor.validate_file(
                file.filename or "audio.wav", len(file_content)
            )
        except AudioProcessingError as e:
            raise HTTPException(status_code=400, detail=str(e))

        # Save upload
        upload_path = await AudioProcessor.save_upload(
            file_content, file.filename or "audio.wav"
        )

        # Process with new workflow
        logger.info(f"Processing audio with model={model}, language={language}")
        result = await Processor.process_audio(
            audio_path=upload_path, language=language
        )

        # Name output files
        base_name = Path(file.filename or "audio").stem

        txt_filename = f"{base_name}_output.txt"
        csv_filename = f"{base_name}_output.csv"

        txt_path = settings.processed_dir / txt_filename
        csv_path = settings.processed_dir / csv_filename

        # Write TXT
        txt_path.write_text(result.txt_content, encoding="utf-8")

        # Write CSV (UTF-8)
        roles = result.roles or {}
        with csv_path.open("w", newline="", encoding="utf-8-sig") as f:
            writer = csv.DictWriter(
                f,
                fieldnames=["start", "end", "speaker", "text", "emotion", "icon"],
            )
            writer.writeheader()
            for seg in result.segments:
                emotion = seg.emotion or ""
                icon = (
                    EmotionService.meta.get(emotion, {}).get("emoji", "")
                    if emotion
                    else ""
                )

                writer.writerow(
                    {
                        "start": round(seg.start, 2),
                        "end": round(seg.end, 2),
                        "speaker": roles.get(seg.speaker, seg.speaker),
                        "text": seg.text,
                        "emotion": emotion,
                        "icon": icon,
                    }
                )

        # Schedule cleanup
        background_tasks.add_task(cleanup_files, upload_path)

        # Build response
        segments = []

        for seg in result.segments:
            if seg.role == "KH":
                emotion = seg.emotion
                icon = seg.icon
            else:
                emotion = None
                icon = None

            segments.append(
                {
                    "start": seg.start,
                    "end": seg.end,
                    "speaker": seg.speaker,
                    "role": seg.role,
                    "text": seg.text,
                    "emotion": emotion,
                    "icon": icon,
                }
            )

        return TranscriptionResponse(
            success=True,
            segments=segments,
            speaker_count=result.speaker_count,
            speakers=result.speakers,
            duration=result.duration,
            processing_time=result.processing_time,
            roles=result.roles,
            emotion_timeline=[
                {"time": p.time, "emotion": p.emotion, "icon": p.icon}
                for p in (result.emotion_timeline or [])
            ],
            emotion_changes=[
                {
                    "time": c.time,
                    "emotion_from": c.emotion_from,
                    "emotion_to": c.emotion_to,
                    "icon_from": c.icon_from,
                    "icon_to": c.icon_to,
                }
                for c in (result.emotion_changes or [])
            ],
            download_txt=f"/api/download/{txt_filename}",
            download_csv=f"/api/download/{csv_filename}",
        )

    except HTTPException:
        raise
    except Exception as e:
        logger.exception("Processing failed")
        if upload_path and upload_path.exists():
            background_tasks.add_task(cleanup_files, upload_path)
        raise HTTPException(status_code=500, detail=f"Processing failed: {str(e)}")


@router.get("/api/download/{filename}")
async def download_file(filename: str):
    """
    Download a generated transcript file.
    Supports: .txt, .srt files
    """
    # Security: only allow specific extensions and no path traversal
    if not filename.endswith((".txt", ".csv")) or "/" in filename or ".." in filename:
        raise HTTPException(status_code=400, detail="Invalid filename")

    filepath = settings.processed_dir / filename

    if not filepath.exists():
        raise HTTPException(status_code=404, detail="File not found")

    # Determine media type
    if filename.endswith(".txt"):
        media_type = "text/plain; charset=utf-8"
    elif filename.endswith(".csv"):
        media_type = "text/csv; charset=utf-8"
    elif filename.endswith(".srt"):
        media_type = "application/x-subrip"
    else:
        media_type = "application/octet-stream"

    return FileResponse(
        path=filepath,
        filename=filename,
        media_type=media_type,
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )


async def cleanup_files(*paths: Path):
    """Background task to cleanup temporary files."""
    import asyncio

    # Wait a bit before cleanup
    await asyncio.sleep(5)

    await AudioProcessor.cleanup_files(*paths)