"""Asset API Routes"""
from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Form, Query
from fastapi.responses import FileResponse
from sqlalchemy.orm import Session
from sqlalchemy import desc
from typing import List, Optional
from uuid import UUID, uuid4
import os
import shutil
from PIL import Image
import io

from app.database import get_db
from app.models.asset import Asset
from app.models.user import User
from app.schemas.asset import AssetCreate, AssetResponse, AssetUpdate
from app.config import settings

router = APIRouter()

THUMBNAIL_SIZE = (256, 256)
THUMBNAIL_QUALITY = 85


def get_file_type(mime_type: str) -> str:
    """Determine file type from mime type"""
    if mime_type.startswith("image/"):
        return "image"
    elif mime_type.startswith("video/"):
        return "video"
    elif mime_type.startswith("audio/"):
        return "audio"
    else:
        return "document"


def generate_thumbnail(file_path: str, file_type: str, asset_id: str) -> Optional[str]:
    """Generate a thumbnail for an asset"""
    try:
        thumbnail_dir = os.path.join(settings.storage_path, "thumbnails")
        os.makedirs(thumbnail_dir, exist_ok=True)
        thumbnail_path = os.path.join(thumbnail_dir, f"{asset_id}.jpg")

        if file_type == "image":
            with Image.open(file_path) as img:
                img.thumbnail(THUMBNAIL_SIZE, Image.Resampling.LANCZOS)
                # Convert to RGB if necessary (for PNG with alpha)
                if img.mode in ('RGBA', 'LA', 'P'):
                    img = img.convert('RGB')
                img.save(thumbnail_path, 'JPEG', quality=THUMBNAIL_QUALITY)
            return thumbnail_path
        elif file_type == "video":
            try:
                import ffmpeg
                # Try creating thumbnail at 1s mark
                (
                    ffmpeg
                    .input(file_path, ss=1)
                    .output(thumbnail_path, vframes=1, vf=f'scale={THUMBNAIL_SIZE[0]}:-1')
                    .overwrite_output()
                    .run(capture_stdout=True, capture_stderr=True)
                )
                return thumbnail_path
            except Exception as e:
                print(f"Failed to generate video thumbnail: {e}")
                return None
    except Exception as e:
        print(f"Failed to generate thumbnail: {e}")
        return None


@router.get("/", response_model=List[AssetResponse])
def get_assets(
    skip: int = 0,
    limit: int = 50,
    file_type: Optional[str] = None,
    module: Optional[str] = None,
    db: Session = Depends(get_db)
):
    """Get all assets with optional filtering"""
    query = db.query(Asset)

    if file_type:
        query = query.filter(Asset.file_type == file_type)
    if module:
        query = query.filter(Asset.source_module == module)

    assets = query.order_by(Asset.created_at.desc()).offset(skip).limit(limit).all()
    return assets


@router.get("/library")
def get_asset_library(
    file_types: Optional[str] = Query(None, description="Comma-separated file types: image,video,audio"),
    search: Optional[str] = None,
    page: int = Query(1, ge=1),
    limit: int = Query(20, le=100),
    db: Session = Depends(get_db)
):
    """Get user's asset library with thumbnails for selection in tools"""
    # Get test user for now
    user = db.query(User).filter(User.email == "test@forge.ai").first()

    query = db.query(Asset).filter(Asset.is_temporary == False)

    if user:
        query = query.filter(Asset.user_id == user.id)

    if file_types:
        types = [t.strip() for t in file_types.split(",")]
        query = query.filter(Asset.file_type.in_(types))

    if search:
        query = query.filter(Asset.original_filename.ilike(f"%{search}%"))

    total = query.count()
    assets = query.order_by(desc(Asset.created_at)).offset((page - 1) * limit).limit(limit).all()

    return {
        "items": [
            {
                "id": str(a.id),
                "filename": a.original_filename or a.stored_filename,
                "file_type": a.file_type,
                "mime_type": a.mime_type,
                "width": a.width,
                "height": a.height,
                "thumbnail_url": f"/api/v1/assets/{a.id}/thumbnail" if a.thumbnail_path else None,
                "file_url": f"/api/v1/assets/{a.id}/download",
                "created_at": a.created_at.isoformat(),
                "source_module": a.source_module
            }
            for a in assets
        ],
        "total": total,
        "page": page,
        "limit": limit,
        "pages": (total + limit - 1) // limit
    }


@router.get("/{asset_id}/thumbnail")
def get_asset_thumbnail(asset_id: UUID, db: Session = Depends(get_db)):
    """Get asset thumbnail for fast preview"""
    asset = db.query(Asset).filter(Asset.id == asset_id).first()
    if not asset:
        raise HTTPException(status_code=404, detail="Asset not found")

    # If thumbnail exists, serve it
    if asset.thumbnail_path and os.path.exists(asset.thumbnail_path):
        return FileResponse(asset.thumbnail_path, media_type="image/jpeg")

    # Generate thumbnail on-demand if it doesn't exist
    if asset.file_type in ["image", "video"] and os.path.exists(asset.file_path):
        thumbnail_path = generate_thumbnail(asset.file_path, asset.file_type, str(asset.id))
        if thumbnail_path:
            asset.thumbnail_path = thumbnail_path
            db.commit()
            return FileResponse(thumbnail_path, media_type="image/jpeg")

    # Fallback: serve original (not ideal but works)
    if os.path.exists(asset.file_path):
        return FileResponse(asset.file_path, media_type=asset.mime_type)

    raise HTTPException(status_code=404, detail="Thumbnail not available")


@router.get("/{asset_id}", response_model=AssetResponse)
def get_asset(asset_id: UUID, db: Session = Depends(get_db)):
    """Get asset by ID"""
    asset = db.query(Asset).filter(Asset.id == asset_id).first()
    if not asset:
        raise HTTPException(status_code=404, detail="Asset not found")
    return asset


@router.get("/{asset_id}/download")
def download_asset(asset_id: UUID, db: Session = Depends(get_db)):
    """Download an asset file"""
    asset = db.query(Asset).filter(Asset.id == asset_id).first()
    if not asset:
        raise HTTPException(status_code=404, detail="Asset not found")

    file_path = asset.file_path
    if not os.path.exists(file_path):
        raise HTTPException(status_code=404, detail="File not found on disk")

    return FileResponse(
        file_path,
        filename=asset.original_filename or asset.stored_filename,
        media_type=asset.mime_type
    )


async def process_upload(
    file: UploadFile,
    db: Session,
    user: Optional[User] = None,
    project_id: Optional[str] = None,
    source_module: Optional[str] = None,
    is_temporary: bool = False,
    overwrite: bool = False
) -> Asset:
    """Core logic for uploading/saving an asset"""
    
    # Check for duplicates if not temporary
    existing_asset = None
    if not is_temporary and user:
        existing_asset = db.query(Asset).filter(
            Asset.user_id == user.id,
            Asset.original_filename == file.filename,
            Asset.is_temporary == False
        ).first()

        if existing_asset:
            if not overwrite:
                # Return conflict with existing ID
                # We interpret 409 specially in frontend
                raise HTTPException(
                    status_code=409, 
                    detail={"message": "File exists", "asset_id": str(existing_asset.id)}
                )
            else:
                # Overwrite: Delete existing file on disk but KEEP the record
                if os.path.exists(existing_asset.file_path):
                    try:
                        os.remove(existing_asset.file_path)
                    except OSError:
                        pass
                if existing_asset.thumbnail_path and os.path.exists(existing_asset.thumbnail_path):
                    try:
                        os.remove(existing_asset.thumbnail_path)
                    except OSError:
                        pass
                
                # Reuse the existing ID
                asset_id = existing_asset.id

    # Determine file type
    file_type = get_file_type(file.content_type)

    # Generate unique ID if new, otherwise reuse
    if not 'asset_id' in locals():
        asset_id = uuid4()
        
    ext = os.path.splitext(file.filename)[1] if file.filename else ""
    stored_filename = f"{asset_id}{ext}"

    # Determine storage path
    storage_dir = os.path.join(settings.storage_path, f"{file_type}s")
    os.makedirs(storage_dir, exist_ok=True)
    file_path = os.path.join(storage_dir, stored_filename)

    # Save file
    try:
        with open(file_path, "wb") as buffer:
            # Read in chunks to handle large files
            while content := await file.read(1024 * 1024):
                buffer.write(content)
        await file.seek(0) # Reset cursor
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to save file: {str(e)}")

    # Extract metadata
    width, height, duration_seconds = None, None, None
    
    try:
        if file_type == "image":
            with Image.open(file_path) as img:
                width, height = img.size
        elif file_type == "video":
            # Placeholder for video metadata
            # In production, use ffmpeg probe
            from app.utils.video import extract_video_metadata
            metadata = extract_video_metadata(file_path)
            width = metadata.get('width')
            height = metadata.get('height')
            duration_seconds = metadata.get('duration_seconds')
    except Exception:
        pass # Ignore metadata extraction errors

    # Generate thumbnail
    thumbnail_path = generate_thumbnail(file_path, file_type, str(asset_id))

    # Create or Update Asset record
    file_size = os.path.getsize(file_path)
    
    if existing_asset:
        # Update existing record
        existing_asset.stored_filename = stored_filename
        existing_asset.file_path = file_path
        existing_asset.thumbnail_path = thumbnail_path
        existing_asset.file_type = file_type
        existing_asset.mime_type = file.content_type
        existing_asset.file_size_bytes = file_size
        existing_asset.width = width
        existing_asset.height = height
        existing_asset.duration_seconds = duration_seconds
        existing_asset.source_module = source_module
        # Don't update project_id unless specified? For now keep it simple.
        if project_id:
             existing_asset.project_id = UUID(project_id)
        
        db.commit()
        db.refresh(existing_asset)
        return existing_asset
    else:
        # Create new record
        asset = Asset(
            id=asset_id,
            user_id=user.id if user else None,
            project_id=UUID(project_id) if project_id else None,
            original_filename=file.filename,
            stored_filename=stored_filename,
            file_path=file_path,
            thumbnail_path=thumbnail_path,
            file_type=file_type,
            mime_type=file.content_type,
            file_size_bytes=file_size,
            width=width,
            height=height,
            duration_seconds=duration_seconds,
    
            source_module=source_module,
            is_temporary=is_temporary
        )
    
        db.add(asset)
        db.commit()
        db.refresh(asset)
    
        return asset


@router.post("/upload", response_model=AssetResponse)
async def upload_asset(
    file: UploadFile = File(...),
    project_id: Optional[str] = Form(None),
    source_module: Optional[str] = Form(None),
    is_temporary: bool = Form(False),
    overwrite: bool = Form(False),
    db: Session = Depends(get_db)
):
    """Upload a new asset"""
    # Get test user
    user = db.query(User).filter(User.email == "test@forge.ai").first()
    
    return await process_upload(
        file=file,
        db=db,
        user=user,
        project_id=project_id,
        source_module=source_module,
        is_temporary=is_temporary,
        overwrite=overwrite
    )


@router.patch("/{asset_id}", response_model=AssetResponse)
def update_asset(asset_id: UUID, asset_update: AssetUpdate, db: Session = Depends(get_db)):
    """Update asset details (e.g. rename)"""
    asset = db.query(Asset).filter(Asset.id == asset_id).first()
    if not asset:
        raise HTTPException(status_code=404, detail="Asset not found")
    
    if asset_update.original_filename:
        asset.original_filename = asset_update.original_filename
    
    db.commit()
    db.refresh(asset)
    return asset


@router.delete("/{asset_id}")
def delete_asset(asset_id: UUID, db: Session = Depends(get_db)):
    """Delete an asset"""
    asset = db.query(Asset).filter(Asset.id == asset_id).first()
    if not asset:
        raise HTTPException(status_code=404, detail="Asset not found")

    # Delete file from disk
    if os.path.exists(asset.file_path):
        os.remove(asset.file_path)

    # Delete from database
    db.delete(asset)
    db.commit()

    return {"message": "Asset deleted"}