package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// 请求结构
type SaveImagesRequest struct {
	Title string            `json:"title"`
	Imgs  map[string]string `json:"imgs"`
}

// 下载详情
type DownloadDetail struct {
	Key     string `json:"key"`
	URL     string `json:"url"`
	Status  string `json:"status"` // success, skipped, failed
	Message string `json:"message"`
	SavedAs string `json:"saved_as,omitempty"`
}

// 响应结构
type SaveImagesResponse struct {
	Success  bool             `json:"success"`
	Message  string           `json:"message"`
	Title    string           `json:"title"`
	Folder   string           `json:"folder"`
	JsonPath string           `json:"json_path"`
	Total    int              `json:"total"`
	Saved    int              `json:"saved"`
	Skipped  int              `json:"skipped"`
	Failed   int              `json:"failed"`
	Details  []DownloadDetail `json:"details"`
}

func saveImagesHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "只支持POST请求", http.StatusMethodNotAllowed)
		return
	}

	// 解析请求
	var req SaveImagesRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "请求格式错误: "+err.Error(), http.StatusBadRequest)
		return
	}

	// 验证参数
	if req.Title == "" {
		http.Error(w, "标题不能为空", http.StatusBadRequest)
		return
	}
	if len(req.Imgs) == 0 {
		http.Error(w, "图片列表不能为空", http.StatusBadRequest)
		return
	}

	// 处理下载
	resp, err := processDownload(&req)
	if err != nil {
		http.Error(w, "处理失败: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// 返回响应
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(resp)
}

func processDownload(req *SaveImagesRequest) (*SaveImagesResponse, error) {
	// 清理标题（移除非法字符）
	cleanTitle := cleanFilename(req.Title)

	// 创建目录
	comicDir := filepath.Join(*downloadDir, cleanTitle)
	if err := os.MkdirAll(comicDir, 0755); err != nil {
		return nil, fmt.Errorf("创建目录失败: %v", err)
	}

	// JSON文件路径
	jsonFilename := cleanTitle + ".json"
	jsonPath := filepath.Join(comicDir, jsonFilename)

	// 检查现有文件
	existingFiles := make(map[string]bool)
	files, _ := os.ReadDir(comicDir)
	for _, file := range files {
		if !file.IsDir() {
			filename := file.Name()
			if strings.HasSuffix(filename, ".json") {
				continue
			}
			// 提取序号（去掉扩展名）
			ext := filepath.Ext(filename)
			key := strings.TrimSuffix(filename, ext)
			existingFiles[key] = true
		}
	}

	// 准备下载
	details := make([]DownloadDetail, 0, len(req.Imgs))
	needDownload := make(map[string]string)

	for key, url := range req.Imgs {
		// 获取文件扩展名
		ext := getFileExtension(url)
		filename := key + ext

		if existingFiles[key] {
			// 文件已存在，跳过
			details = append(details, DownloadDetail{
				Key:     key,
				URL:     url,
				Status:  "skipped",
				Message: "文件已存在",
				SavedAs: filename,
			})
			continue
		}

		// 需要下载
		needDownload[key] = url
		details = append(details, DownloadDetail{
			Key:     key,
			URL:     url,
			Status:  "pending",
			Message: "等待下载",
		})
	}

	// 下载图片
	var saved, failed int
	if len(needDownload) > 0 {
		successMap, errors := downloadImages(needDownload, comicDir)

		// 使用 successMap 来检查哪些下载成功
		// 虽然我们不直接使用 successMap，但它用于 downloadImages 函数的返回值
		_ = successMap // 明确标记为使用（避免未使用警告）

		// 更新下载详情
		for i, detail := range details {
			if detail.Status == "pending" {
				if err, ok := errors[detail.Key]; ok {
					details[i].Status = "failed"
					details[i].Message = err.Error()
					failed++
				} else {
					ext := getFileExtension(detail.URL)
					filename := detail.Key + ext
					details[i].Status = "success"
					details[i].Message = "下载成功"
					details[i].SavedAs = filename
					saved++
				}
			}
		}
	}

	// 保存JSON文件
	skipped := len(req.Imgs) - saved - failed
	finalImgs := make(map[string]string)
	for key, url := range req.Imgs {
		finalImgs[key] = url
	}

	saveJSON(comicDir, jsonFilename, req.Title, finalImgs)

	// 构建响应
	return &SaveImagesResponse{
		Success:  failed == 0,
		Message:  fmt.Sprintf("下载完成: 新增%d张, 跳过%d张, 失败%d张", saved, skipped, failed),
		Title:    req.Title,
		Folder:   comicDir,
		JsonPath: jsonPath,
		Total:    len(req.Imgs),
		Saved:    saved,
		Skipped:  skipped,
		Failed:   failed,
		Details:  details,
	}, nil
}

func saveJSON(dir, filename, title string, imgs map[string]string) error {
	data := map[string]interface{}{
		"title":      title,
		"imgs":       imgs,
		"created_at": time.Now().Format("2006-01-02 15:04:05"),
		"updated_at": time.Now().Format("2006-01-02 15:04:05"),
	}

	jsonData, err := json.MarshalIndent(data, "", "  ")
	if err != nil {
		return err
	}

	path := filepath.Join(dir, filename)
	return os.WriteFile(path, jsonData, 0644)
}

func cleanFilename(filename string) string {
	illegalChars := []string{"/", "\\", ":", "*", "?", "\"", "<", ">", "|", "\n", "\r", "\t"}
	result := filename
	for _, char := range illegalChars {
		result = strings.ReplaceAll(result, char, "_")
	}
	if len(result) > 200 {
		result = result[:200]
	}
	return strings.TrimSpace(result)
}

func getFileExtension(url string) string {
	// 默认扩展名
	ext := ".jpg"

	// 从URL提取扩展名
	if idx := strings.LastIndex(url, "."); idx != -1 {
		fileExt := strings.ToLower(url[idx:])
		// 检查是否为常见图片格式
		validExts := []string{".jpg", ".jpeg", ".png", ".webp", ".gif", ".bmp", ".tiff"}
		for _, validExt := range validExts {
			if strings.HasPrefix(fileExt, validExt) {
				ext = validExt
				break
			}
		}
	}

	return ext
}