from PIL import Image
import os
from config import Config
from logger import logger

class ImageProcessor:
    @staticmethod
    def resize_by_ratio(img, ratio_width, ratio_height):
        """等比例缩放至目标比例（最长边适配）"""
        w, h = img.size
        target_ratio = ratio_width / ratio_height
        current_ratio = w / h
        if current_ratio > target_ratio:
            new_w = int(h * target_ratio)
            new_h = h
        else:
            new_w = w
            new_h = int(w / target_ratio)
        return img.resize((new_w, new_h), Image.Resampling.LANCZOS)

    @staticmethod
    def resize_by_pixel(img, target_width, target_height):
        """等比例缩放至不超过目标像素（保持比例，以较长边为准）"""
        w, h = img.size
        ratio_w = target_width / w
        ratio_h = target_height / h
        ratio = min(ratio_w, ratio_h)
        new_w = int(w * ratio)
        new_h = int(h * ratio)
        return img.resize((new_w, new_h), Image.Resampling.LANCZOS)

    @staticmethod
    def convert_image(input_path, output_path, target_format, quality=None):
        """转换图片格式，可选缩放（尺寸解析在外部处理）"""
        try:
            with Image.open(input_path) as img:
                # 转换模式（RGBA转RGB对于JPEG）
                if target_format.lower() in ['jpg', 'jpeg'] and img.mode in ('RGBA', 'P'):
                    rgb_img = Image.new('RGB', img.size, (255, 255, 255))
                    rgb_img.paste(img, mask=img.split()[-1] if img.mode == 'RGBA' else None)
                    img = rgb_img
                save_kwargs = {}
                if target_format.lower() in ['jpg', 'jpeg', 'webp']:
                    save_kwargs['quality'] = quality if quality is not None else Config.DEFAULT_QUALITY
                img.save(output_path, format=target_format.upper(), **save_kwargs)
                logger.info(f"转换成功: {input_path} -> {output_path}")
                return True
        except Exception as e:
            logger.error(f"转换失败 {input_path}: {e}")
            return False