from __future__ import annotations

import io
from dataclasses import dataclass

from PIL import Image, ImageOps

from app.config import get_settings


@dataclass
class PreparedImage:
    jpeg_bytes: bytes
    width: int
    height: int
    original_bytes: int
    compressed_bytes: int
    mime: str = "image/jpeg"

    def to_meta(self) -> dict[str, int | str]:
        return {
            "mime": self.mime,
            "width": self.width,
            "height": self.height,
            "original_bytes": self.original_bytes,
            "compressed_bytes": self.compressed_bytes,
        }


def prepare_image(raw_bytes: bytes) -> PreparedImage:
    settings = get_settings()
    max_edge = max(256, int(settings.vision_max_edge_px))
    quality = max(40, min(95, int(settings.vision_jpeg_quality)))

    with Image.open(io.BytesIO(raw_bytes)) as img:
        img = ImageOps.exif_transpose(img)
        img = img.convert("RGB")
        width, height = img.size
        if max(width, height) > max_edge:
            img.thumbnail((max_edge, max_edge), Image.Resampling.LANCZOS)
            width, height = img.size

        buffer = io.BytesIO()
        img.save(buffer, format="JPEG", quality=quality, optimize=True)
        jpeg_bytes = buffer.getvalue()

    return PreparedImage(
        jpeg_bytes=jpeg_bytes,
        width=width,
        height=height,
        original_bytes=len(raw_bytes),
        compressed_bytes=len(jpeg_bytes),
    )