fanqie-go/internal/fqapi/manga_proxy.go

package fqapi

import (
	"encoding/hex"
	"fmt"
	"time"
)

// HandleMangaImageProxy 处理漫画图片代理请求
func HandleMangaImageProxy(itemID string, index int) ([]byte, string, error) {
	// 从缓存获取图片信息
	cacheKey := fmt.Sprintf("%s_%d", itemID, index)

	mangaCacheMutex.RLock()
	imageInfo, exists := mangaImageCache[cacheKey]
	mangaCacheMutex.RUnlock()

	if !exists {
		return nil, "", fmt.Errorf("图片信息不存在，请先调用 /manga 接口")
	}

	// 检查缓存是否过期（5分钟）
	if time.Since(imageInfo.CachedAt) > 5*time.Minute {
		// 清理过期缓存
		mangaCacheMutex.Lock()
		delete(mangaImageCache, cacheKey)
		mangaCacheMutex.Unlock()
		return nil, "", fmt.Errorf("图片信息已过期，请重新调用 /manga 接口")
	}

	// 下载加密图片
	encryptedData, err := downloadImageWithRetry(imageInfo.PicURL, 2)
	if err != nil {
		return nil, "", fmt.Errorf("下载图片失败: %w", err)
	}

	// 解密图片
	keyBytes, err := hex.DecodeString(imageInfo.EncryptKey)
	if err != nil {
		return nil, "", fmt.Errorf("密钥解码失败: %w", err)
	}

	decryptedData, err := decryptImage(encryptedData, keyBytes)
	if err != nil {
		return nil, "", fmt.Errorf("解密失败: %w", err)
	}

	// 识别格式
	format := getImageFormat(decryptedData, imageInfo.PicURL)

	// 返回图片数据和MIME类型
	mimeType := fmt.Sprintf("image/%s", format)
	if format == "jpg" {
		mimeType = "image/jpeg"
	}

	return decryptedData, mimeType, nil
}

// CleanExpiredMangaCache 清理过期的漫画图片缓存
func CleanExpiredMangaCache() {
	mangaCacheMutex.Lock()
	defer mangaCacheMutex.Unlock()

	now := time.Now()
	for key, info := range mangaImageCache {
		if now.Sub(info.CachedAt) > 5*time.Minute {
			delete(mangaImageCache, key)
		}
	}
}