"""
File serving and thumbnail generation API

Provides endpoints for:
- On-demand thumbnail generation for images and videos
- File serving with proper caching headers
"""

from typing import Dict

from fastapi import APIRouter, Depends, Query, Request
from fastapi.responses import Response
from PIL import Image
from pathlib import Path
import subprocess
import io

from slowapi import Limiter
from slowapi.util import get_remote_address

from ..core.dependencies import get_current_user
from ..core.exceptions import handle_exceptions, NotFoundError, ValidationError
from ..core.utils import validate_file_path
from modules.universal_logger import get_logger

router = APIRouter(prefix="/files", tags=["files"])
logger = get_logger('FilesRouter')
limiter = Limiter(key_func=get_remote_address)


@router.get("/thumbnail")
@limiter.limit("300/minute")
@handle_exceptions
async def get_thumbnail(
    request: Request,
    path: str = Query(..., description="File path"),
    current_user: Dict = Depends(get_current_user)
):
    """
    Generate and return thumbnail for image or video

    Args:
        path: Absolute path to file

    Returns:
        JPEG thumbnail (200x200px max, maintains aspect ratio)
    """
    # Validate file is within allowed directories (prevents path traversal)
    file_path = validate_file_path(path, require_exists=True)

    file_ext = file_path.suffix.lower()

    # Generate thumbnail based on type
    if file_ext in ['.jpg', '.jpeg', '.png', '.webp', '.gif', '.heic']:
        # Image thumbnail with PIL
        img = Image.open(file_path)

        # Convert HEIC if needed
        if file_ext == '.heic':
            img = img.convert('RGB')

        # Create thumbnail (maintains aspect ratio)
        img.thumbnail((200, 200), Image.Resampling.LANCZOS)

        # Convert to JPEG
        buffer = io.BytesIO()
        if img.mode in ('RGBA', 'LA', 'P'):
            # Convert transparency to white background
            background = Image.new('RGB', img.size, (255, 255, 255))
            if img.mode == 'P':
                img = img.convert('RGBA')
            background.paste(img, mask=img.split()[-1] if img.mode in ('RGBA', 'LA') else None)
            img = background

        img.convert('RGB').save(buffer, format='JPEG', quality=85, optimize=True)
        buffer.seek(0)

        return Response(
            content=buffer.read(),
            media_type="image/jpeg",
            headers={"Cache-Control": "public, max-age=3600"}
        )

    elif file_ext in ['.mp4', '.webm', '.mov', '.avi', '.mkv']:
        # Video thumbnail with ffmpeg
        result = subprocess.run(
            [
                'ffmpeg',
                '-ss', '00:00:01',  # Seek to 1 second
                '-i', str(file_path),
                '-vframes', '1',  # Extract 1 frame
                '-vf', 'scale=200:-1',  # Scale to 200px width, maintain aspect
                '-f', 'image2pipe',  # Output to pipe
                '-vcodec', 'mjpeg',  # JPEG codec
                'pipe:1'
            ],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            timeout=10,
            check=False
        )

        if result.returncode != 0:
            # Try without seeking (for very short videos)
            result = subprocess.run(
                [
                    'ffmpeg',
                    '-i', str(file_path),
                    '-vframes', '1',
                    '-vf', 'scale=200:-1',
                    '-f', 'image2pipe',
                    '-vcodec', 'mjpeg',
                    'pipe:1'
                ],
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                timeout=10,
                check=True
            )

        return Response(
            content=result.stdout,
            media_type="image/jpeg",
            headers={"Cache-Control": "public, max-age=3600"}
        )

    else:
        raise ValidationError("Unsupported file type")