package handler

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

	"github.com/gin-gonic/gin"
)

// ImageHandler 图片上传处理器
type ImageHandler struct {
	uploadDir string
}

// NewImageHandler 创建图片处理器
func NewImageHandler(uploadDir string) *ImageHandler {
	return &ImageHandler{uploadDir: uploadDir}
}

// Init 初始化上传目录
func (h *ImageHandler) Init() error {
	return os.MkdirAll(h.uploadDir, 0755)
}

// Upload 上传图片
func (h *ImageHandler) Upload(c *gin.Context) {
	file, err := c.FormFile("image")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "请选择图片文件"})
		return
	}

	// 验证文件类型
	ext := strings.ToLower(filepath.Ext(file.Filename))
	allowedExts := map[string]bool{
		".jpg":  true,
		".jpeg": true,
		".png":  true,
		".gif":  true,
		".webp": true,
		".bmp":  true,
	}

	if !allowedExts[ext] {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "不支持的图片格式，仅支持 jpg、png、gif、webp"})
		return
	}

	// 验证文件大小 (最大 5MB)
	if file.Size > 5*1024*1024 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "图片大小不能超过 5MB"})
		return
	}

	// 生成唯一文件名
	filename := fmt.Sprintf("%d_%s%s", time.Now().UnixNano(), randomString(8), ext)
	filepath := filepath.Join(h.uploadDir, filename)

	// 保存文件
	if err := c.SaveUploadedFile(file, filepath); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 500, "message": "保存图片失败"})
		return
	}

	// 返回访问 URL
	url := "/uploads/" + filename
	c.JSON(http.StatusOK, gin.H{
		"code":    0,
		"message": "上传成功",
		"data": gin.H{
			"url": url,
		},
	})
}

// randomString 生成随机字符串
func randomString(length int) string {
	const chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	result := make([]byte, length)
	for i := range result {
		result[i] = chars[time.Now().UnixNano()%int64(len(chars))]
		time.Sleep(time.Nanosecond)
	}
	return string(result)
}