import asyncio
from pathlib import Path
from PIL import Image
import subprocess
from typing import Optional
from .settings import settings

THUMBNAIL_SIZE = (300, 300)
THUMBNAIL_DIR = "thumbnails"


async def generate_thumbnail(
    file_path: str, mime_type: str, user_id: int
) -> Optional[str]:
    try:
        if mime_type.startswith("image/"):
            return await generate_image_thumbnail(file_path, user_id)
        elif mime_type.startswith("video/"):
            return await generate_video_thumbnail(file_path, user_id)
        return None
    except Exception as e:
        print(f"Error generating thumbnail for {file_path}: {e}")
        return None


async def generate_image_thumbnail(file_path: str, user_id: int) -> Optional[str]:
    loop = asyncio.get_event_loop()

    def _generate():
        base_path = Path(settings.STORAGE_PATH)
        thumbnail_dir = base_path / str(user_id) / THUMBNAIL_DIR
        thumbnail_dir.mkdir(parents=True, exist_ok=True)

        file_name = Path(file_path).name
        thumbnail_name = f"thumb_{file_name}"
        if not thumbnail_name.lower().endswith((".jpg", ".jpeg", ".png")):
            thumbnail_name += ".jpg"

        thumbnail_path = thumbnail_dir / thumbnail_name

        actual_file_path = (
            base_path / str(user_id) / file_path
            if not Path(file_path).is_absolute()
            else Path(file_path)
        )

        with Image.open(actual_file_path) as img:
            img.thumbnail(THUMBNAIL_SIZE, Image.Resampling.LANCZOS)

            if img.mode in ("RGBA", "LA", "P"):
                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.save(str(thumbnail_path), "JPEG", quality=85, optimize=True)

        return str(thumbnail_path.relative_to(base_path / str(user_id)))

    return await loop.run_in_executor(None, _generate)


async def generate_video_thumbnail(file_path: str, user_id: int) -> Optional[str]:
    loop = asyncio.get_event_loop()

    def _generate():
        base_path = Path(settings.STORAGE_PATH)
        thumbnail_dir = base_path / str(user_id) / THUMBNAIL_DIR
        thumbnail_dir.mkdir(parents=True, exist_ok=True)

        file_name = Path(file_path).stem
        thumbnail_name = f"thumb_{file_name}.jpg"
        thumbnail_path = thumbnail_dir / thumbnail_name

        actual_file_path = (
            base_path / str(user_id) / file_path
            if not Path(file_path).is_absolute()
            else Path(file_path)
        )

        subprocess.run(
            [
                "ffmpeg",
                "-i",
                str(actual_file_path),
                "-ss",
                "00:00:01",
                "-vframes",
                "1",
                "-vf",
                f"scale={THUMBNAIL_SIZE[0]}:{THUMBNAIL_SIZE[1]}:force_original_aspect_ratio=decrease",
                "-y",
                str(thumbnail_path),
            ],
            check=True,
            capture_output=True,
        )

        return str(thumbnail_path.relative_to(base_path / str(user_id)))

    try:
        return await loop.run_in_executor(None, _generate)
    except subprocess.CalledProcessError:
        return None


async def delete_thumbnail(thumbnail_path: str, user_id: int):
    try:
        base_path = Path(settings.STORAGE_PATH)
        full_path = base_path / str(user_id) / thumbnail_path
        if full_path.exists():
            full_path.unlink()
    except Exception as e:
        print(f"Error deleting thumbnail {thumbnail_path}: {e}")