from __future__ import annotations

import time

from fastapi import HTTPException, status
from PIL import Image, ImageFilter

from ..config import Settings
from ..image_io import DownloadedImage, load_normalized_image
from .base import EngineHealth, UpscaleEngine, UpscaleResult


MODE_PROFILES = {
    "standard": {"profile": "general", "sharpen_percent": 120, "radius": 1.0, "threshold": 3},
    "artwork": {"profile": "artwork", "sharpen_percent": 150, "radius": 1.2, "threshold": 2},
    "photo": {"profile": "photo", "sharpen_percent": 95, "radius": 0.8, "threshold": 4},
    "illustration": {"profile": "illustration", "sharpen_percent": 135, "radius": 1.0, "threshold": 2},
}


class PillowUpscaleEngine(UpscaleEngine):
    def __init__(self, settings: Settings) -> None:
        self.settings = settings

    def health(self) -> EngineHealth:
        return EngineHealth(
            status="ok",
            engine="pillow",
            device=self.settings.device,
            models_loaded=True,
        )

    def upscale(self, downloaded: DownloadedImage, scale: int, mode: str, output_format: str) -> UpscaleResult:
        started_at = time.perf_counter()
        profile = MODE_PROFILES[mode]
        image = load_normalized_image(downloaded.path)
        width, height = image.size
        target_width = width * scale
        target_height = height * scale

        if target_width > self.settings.max_output_width or target_height > self.settings.max_output_height:
            raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Worker rejected the image.")

        result = image.resize((target_width, target_height), Image.Resampling.LANCZOS)
        result = result.filter(
            ImageFilter.UnsharpMask(
                radius=profile["radius"],
                percent=profile["sharpen_percent"],
                threshold=profile["threshold"],
            )
        )

        return UpscaleResult(
            image=result,
            metadata={
                "engine": "pillow",
                "model": "pillow-lanczos",
                "requested_scale": scale,
                "native_model_scale": scale,
                "mode": mode,
                "device": self.settings.device,
                "profile": profile["profile"],
                "real_ai_upscale": False,
                "processing_seconds": round(time.perf_counter() - started_at, 3),
                "input_width": width,
                "input_height": height,
                "output_width": target_width,
                "output_height": target_height,
                "output_format": output_format,
            },
        )