"""
Photos API router
"""
from typing import List, Optional, Dict, Any
from datetime import datetime
from pathlib import Path
from fastapi import APIRouter, Depends, HTTPException, Query, Response
from fastapi.responses import FileResponse
from sqlalchemy import select, and_, or_, func
from sqlalchemy.ext.asyncio import AsyncSession
import json
import os
import logging

logger = logging.getLogger(__name__)

from app.database import get_db
from app.models import Photo, Folder, Tag, PhotoTag
from app.models.heaps import heap_photos
from app.schemas.photos import PhotoResponse, PhotoUpdate, PhotoListResponse, BulkAction
from app.config import settings

router = APIRouter()

@router.get("", response_model=PhotoListResponse)
async def list_photos(
    q: Optional[str] = None,
    date_from: Optional[datetime] = None,
    date_to: Optional[datetime] = None,
    folder_id: Optional[str] = None,
    tag_ids: Optional[str] = None,
    media_type: Optional[str] = None,
    rating_min: Optional[int] = Query(None, ge=0, le=5),
    rating_max: Optional[int] = Query(None, ge=0, le=5),
    color_label: Optional[str] = None,
    is_picked: Optional[bool] = None,
    is_discarded: Optional[bool] = False,
    heap_id: Optional[str] = None,
    sort: str = "taken_at",
    order: str = "desc",
    page: int = Query(1, ge=1),
    per_page: int = Query(100, ge=1, le=500),
    db: AsyncSession = Depends(get_db)
):
    """List photos with filters and pagination"""
    
    # Build query
    query = select(Photo)
    
    # Apply filters
    filters = []
    
    # Text search (would use FTS5 in production)
    if q:
        search_pattern = f"%{q}%"
        filters.append(
            or_(
                Photo.filename.ilike(search_pattern),
                Photo.user_title.ilike(search_pattern),
                Photo.user_notes.ilike(search_pattern),
                Photo.exif_json.ilike(search_pattern)
            )
        )
    
    # Date range
    if date_from:
        filters.append(Photo.taken_at >= date_from)
    if date_to:
        filters.append(Photo.taken_at <= date_to)
    
    # Folder filter
    if folder_id:
        filters.append(Photo.folder_id == folder_id)
    
    # Media type filter
    if media_type:
        types = media_type.split(',')
        filters.append(Photo.media_type.in_(types))
    
    # Rating filter
    if rating_min is not None:
        filters.append(Photo.rating >= rating_min)
    if rating_max is not None:
        filters.append(Photo.rating <= rating_max)
    
    # Color label filter
    if color_label:
        if color_label == 'none':
            filters.append(Photo.color_label.is_(None))
        else:
            filters.append(Photo.color_label == color_label)
    
    # Flag filters
    if is_picked is not None:
        filters.append(Photo.is_picked == is_picked)

    # Discard filter — defaults to hiding discarded photos
    filters.append(Photo.is_discarded == is_discarded)

    # Heap membership filter — restrict to photos that belong to the heap.
    if heap_id:
        filters.append(
            Photo.id.in_(
                select(heap_photos.c.photo_id).where(heap_photos.c.heap_id == heap_id)
            )
        )

    # Apply all filters
    if filters:
        query = query.where(and_(*filters))
    
    # Apply sorting
    sort_column = getattr(Photo, sort, Photo.taken_at)
    if order == "desc":
        query = query.order_by(sort_column.desc())
    else:
        query = query.order_by(sort_column.asc())
    
    # Count total results
    count_query = select(func.count()).select_from(query.subquery())
    total_result = await db.execute(count_query)
    total = total_result.scalar()
    
    # Apply pagination
    offset = (page - 1) * per_page
    query = query.offset(offset).limit(per_page)
    
    # Execute query
    result = await db.execute(query)
    photos = result.scalars().all()
    
    # Convert to response
    return PhotoListResponse(
        photos=[PhotoResponse.from_orm(photo) for photo in photos],
        total=total,
        page=page,
        per_page=per_page,
        pages=(total + per_page - 1) // per_page
    )

@router.get("/{photo_id}", response_model=PhotoResponse)
async def get_photo(
    photo_id: str,
    db: AsyncSession = Depends(get_db)
):
    """Get single photo with full EXIF and tags"""
    result = await db.execute(
        select(Photo).where(Photo.id == photo_id)
    )
    photo = result.scalar_one_or_none()
    
    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")
    
    return PhotoResponse.from_orm(photo)

@router.get("/{photo_id}/thumb/{size}")
async def get_thumbnail(
    photo_id: str,
    size: str,
    response: Response,
    db: AsyncSession = Depends(get_db)
):
    """Serve thumbnail (with Nginx X-Accel-Redirect support)"""
    if size not in ['small', 'medium', 'large']:
        raise HTTPException(status_code=400, detail="Invalid thumbnail size")
    
    result = await db.execute(
        select(Photo).where(Photo.id == photo_id)
    )
    photo = result.scalar_one_or_none()
    
    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")
    
    # Check if thumbnail exists, generate if not
    thumb_dir = f"/data/thumbs/{photo_id}"
    thumb_path = f"{thumb_dir}/{size}.webp"
    
    if not os.path.exists(thumb_path):
        # Generate thumbnail on demand
        from app.tasks.thumbs import generate_thumbnails
        generate_thumbnails.delay(photo_id)
        
        # For now, return a placeholder or the original with reduced quality
        if os.path.exists(photo.filepath):
            from PIL import Image
            try:
                os.makedirs(thumb_dir, exist_ok=True)
                img = Image.open(photo.filepath)
                
                # Auto-rotate based on EXIF
                from PIL import ExifTags
                try:
                    for orientation in ExifTags.TAGS.keys():
                        if ExifTags.TAGS[orientation] == 'Orientation':
                            break
                    exif = img._getexif()
                    if exif is not None:
                        orient = exif.get(orientation)
                        if orient == 3:
                            img = img.rotate(180, expand=True)
                        elif orient == 6:
                            img = img.rotate(270, expand=True)
                        elif orient == 8:
                            img = img.rotate(90, expand=True)
                except:
                    pass
                
                # Generate thumbnail size
                sizes = {'small': 150, 'medium': 400, 'large': 800}
                target_size = sizes.get(size, 400)
                img.thumbnail((target_size, target_size), Image.Resampling.LANCZOS)
                
                # Save as WebP
                img.save(thumb_path, 'WEBP', quality=85, optimize=True)
                
            except Exception as e:
                logger.error(f"Error generating thumbnail: {e}")
                raise HTTPException(status_code=404, detail="Could not generate thumbnail")
    
    # Check if we're behind Nginx
    if os.environ.get('USE_X_ACCEL_REDIRECT'):
        # Use Nginx X-Accel-Redirect for better performance
        response.headers['X-Accel-Redirect'] = f'/internal_thumbs/{photo_id}/{size}.webp'
        response.headers['Content-Type'] = 'image/webp'
        return Response()
    else:
        # Direct file serving for development
        return FileResponse(thumb_path, media_type='image/webp')

@router.get("/{photo_id}/original")
async def get_original(
    photo_id: str,
    db: AsyncSession = Depends(get_db)
):
    """Serve original file (download for RAW, inline for web-safe formats)"""
    result = await db.execute(
        select(Photo).where(Photo.id == photo_id)
    )
    photo = result.scalar_one_or_none()

    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")

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

    # Pick a media type the browser can render inline for web-safe formats
    # so the loupe view and <video> tags work without forcing a download.
    ext = Path(photo.filepath).suffix.lower()
    inline_types = {
        '.jpg': 'image/jpeg', '.jpeg': 'image/jpeg',
        '.png': 'image/png', '.webp': 'image/webp', '.gif': 'image/gif',
        '.mp4': 'video/mp4', '.mov': 'video/quicktime',
        '.webm': 'video/webm', '.mkv': 'video/x-matroska',
    }
    media_type = inline_types.get(ext, 'application/octet-stream')

    return FileResponse(
        photo.filepath,
        filename=photo.filename if media_type == 'application/octet-stream' else None,
        media_type=media_type,
    )


# Extensions that the browser can decode natively. Anything else (RAW, HEIC,
# TIFF) needs the /proxy endpoint to convert to WebP for display.
_WEB_SAFE_DISPLAY_EXTS = {'.jpg', '.jpeg', '.png', '.webp', '.gif'}


def _generate_proxy_webp(src_path: str, dst_path: str) -> None:
    """Decode src_path with the appropriate backend and write a full-res WebP
    to dst_path. Used by GET /photos/{id}/proxy for RAW/HEIC/TIFF display.

    Conservative: catches per-format failures and falls back to extracting an
    embedded preview where possible (RAW), so a single broken file never
    crashes the request.
    """
    from PIL import Image
    ext = Path(src_path).suffix.lower()

    img = None

    # RAW formats — decode via rawpy at full size
    raw_exts = {'.cr2', '.cr3', '.nef', '.nrw', '.arw', '.srf',
                '.raf', '.rw2', '.orf', '.srw', '.pef', '.rwl', '.dng'}
    if ext in raw_exts:
        try:
            import rawpy
            with rawpy.imread(src_path) as raw:
                rgb = raw.postprocess(use_camera_wb=True, no_auto_bright=False)
            img = Image.fromarray(rgb, 'RGB')
        except Exception as e:
            logger.warning(f"rawpy decode failed for {src_path}: {e}; trying embedded preview")
            try:
                import rawpy
                with rawpy.imread(src_path) as raw:
                    thumb = raw.extract_thumb()
                    if thumb.format == rawpy.ThumbFormat.JPEG:
                        from io import BytesIO
                        img = Image.open(BytesIO(thumb.data))
            except Exception as e2:
                logger.error(f"RAW preview extraction also failed for {src_path}: {e2}")
                raise HTTPException(status_code=415, detail="Unable to decode RAW file")

    # HEIC/HEIF — pillow-heif registers a PIL plugin
    elif ext in {'.heic', '.heif'}:
        try:
            from pillow_heif import register_heif_opener
            register_heif_opener()
            img = Image.open(src_path)
        except Exception as e:
            logger.error(f"HEIC decode failed for {src_path}: {e}")
            raise HTTPException(status_code=415, detail="Unable to decode HEIC file")

    # TIFF and any other PIL-supported format
    else:
        try:
            img = Image.open(src_path)
        except Exception as e:
            logger.error(f"PIL open failed for {src_path}: {e}")
            raise HTTPException(status_code=415, detail="Unable to decode image")

    # Auto-rotate via EXIF
    try:
        from PIL import ImageOps
        img = ImageOps.exif_transpose(img)
    except Exception:
        pass

    if img.mode not in ('RGB', 'RGBA'):
        img = img.convert('RGB')

    os.makedirs(os.path.dirname(dst_path), exist_ok=True)
    img.save(dst_path, 'WEBP', quality=90, method=4)


@router.get("/{photo_id}/proxy")
async def get_proxy(
    photo_id: str,
    response: Response,
    db: AsyncSession = Depends(get_db),
):
    """Serve a full-resolution WebP proxy for non-web-safe formats (RAW, HEIC,
    TIFF) so the loupe view can display them inline. Web-safe formats are
    redirected to /original to avoid pointless transcoding.

    Cached at /data/proxies/{photo_id}.webp; subsequent requests serve the
    cached file (with optional X-Accel-Redirect for production).
    """
    result = await db.execute(select(Photo).where(Photo.id == photo_id))
    photo = result.scalar_one_or_none()

    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")

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

    ext = Path(photo.filepath).suffix.lower()

    # Web-safe formats don't need a proxy — serve the original directly so the
    # browser uses its native decoder. Saves disk and CPU.
    if ext in _WEB_SAFE_DISPLAY_EXTS:
        return FileResponse(
            photo.filepath,
            media_type={
                '.jpg': 'image/jpeg', '.jpeg': 'image/jpeg',
                '.png': 'image/png', '.webp': 'image/webp', '.gif': 'image/gif',
            }[ext],
        )

    proxy_dir = "/data/proxies"
    proxy_path = f"{proxy_dir}/{photo_id}.webp"

    if not os.path.exists(proxy_path):
        try:
            _generate_proxy_webp(photo.filepath, proxy_path)
        except HTTPException:
            raise
        except Exception as e:
            logger.error(f"Proxy generation failed for {photo_id}: {e}")
            raise HTTPException(status_code=500, detail="Proxy generation failed")

    if os.environ.get('USE_X_ACCEL_REDIRECT'):
        response.headers['X-Accel-Redirect'] = f'/internal_proxies/{photo_id}.webp'
        response.headers['Content-Type'] = 'image/webp'
        return Response()

    return FileResponse(proxy_path, media_type='image/webp')

@router.patch("/{photo_id}", response_model=PhotoResponse)
async def update_photo(
    photo_id: str,
    update: PhotoUpdate,
    db: AsyncSession = Depends(get_db)
):
    """Update photo metadata"""
    result = await db.execute(
        select(Photo).where(Photo.id == photo_id)
    )
    photo = result.scalar_one_or_none()
    
    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")
    
    # Apply updates
    update_data = update.dict(exclude_unset=True)
    for field, value in update_data.items():
        setattr(photo, field, value)
    
    await db.commit()
    await db.refresh(photo)
    
    return PhotoResponse.from_orm(photo)

@router.delete("/{photo_id}")
async def discard_photo(
    photo_id: str,
    db: AsyncSession = Depends(get_db)
):
    """Soft-discard a photo: sets is_discarded=true. The file stays on disk so
    restore is just a flag flip. Permanent deletion happens via DELETE
    /discard/{id} or DELETE /discard/empty.
    """
    result = await db.execute(
        select(Photo).where(Photo.id == photo_id)
    )
    photo = result.scalar_one_or_none()

    if not photo:
        raise HTTPException(status_code=404, detail="Photo not found")

    photo.is_discarded = True
    photo.discarded_at = datetime.utcnow()
    await db.commit()

    return {"status": "success", "message": "Photo discarded"}

@router.post("/bulk")
async def bulk_action(
    action: BulkAction,
    db: AsyncSession = Depends(get_db)
):
    """Perform bulk actions on multiple photos"""
    # Get photos
    result = await db.execute(
        select(Photo).where(Photo.id.in_(action.ids))
    )
    photos = result.scalars().all()
    
    if not photos:
        raise HTTPException(status_code=404, detail="No photos found")
    
    # Perform action based on type
    if action.action == 'discard':
        for photo in photos:
            photo.is_discarded = True
            photo.discarded_at = datetime.utcnow()
    elif action.action == 'restore':
        for photo in photos:
            photo.is_discarded = False
            photo.discarded_at = None
    elif action.action == 'set_rating':
        for photo in photos:
            photo.rating = action.value
    elif action.action == 'set_color':
        for photo in photos:
            photo.color_label = action.value
    elif action.action == 'pick':
        for photo in photos:
            photo.is_picked = True
            photo.is_discarded = False
    else:
        raise HTTPException(status_code=400, detail="Invalid action")
    
    await db.commit()
    
    return {
        "status": "success",
        "message": f"{action.action} applied to {len(photos)} photos"
    }