package handler

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

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

const uploadDir = "uploads"
const maxUploadBytes = 5 * 1024 * 1024 // 5MB
var allowedTypes = map[string]bool{"image/jpeg": true, "image/png": true, "image/gif": true, "image/webp": true}

// UploadPost POST /api/upload 上传图片（表单 file）
func UploadPost(c *gin.Context) {
	file, err := c.FormFile("file")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "请选择要上传的文件"})
		return
	}
	if file.Size > maxUploadBytes {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "文件大小不能超过5MB"})
		return
	}
	ct := file.Header.Get("Content-Type")
	if !allowedTypes[ct] && !strings.HasPrefix(ct, "image/") {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "仅支持图片格式"})
		return
	}
	ext := filepath.Ext(file.Filename)
	if ext == "" {
		ext = ".jpg"
	}
	folder := c.PostForm("folder")
	if folder == "" {
		folder = "avatars"
	}
	dir := filepath.Join(uploadDir, folder)
	_ = os.MkdirAll(dir, 0755)
	name := fmt.Sprintf("%d_%s%s", time.Now().UnixNano(), randomStrUpload(6), ext)
	dst := filepath.Join(dir, name)
	if err := c.SaveUploadedFile(file, dst); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"success": false, "error": "保存失败"})
		return
	}
	url := "/" + filepath.ToSlash(filepath.Join(uploadDir, folder, name))
	c.JSON(http.StatusOK, gin.H{"success": true, "url": url, "data": gin.H{"url": url, "fileName": name, "size": file.Size, "type": ct}})
}

func randomStrUpload(n int) string {
	const letters = "abcdefghijklmnopqrstuvwxyz0123456789"
	b := make([]byte, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}

// UploadDelete DELETE /api/upload
func UploadDelete(c *gin.Context) {
	path := c.Query("path")
	if path == "" {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "请指定 path"})
		return
	}
	if !strings.HasPrefix(path, "/uploads/") && !strings.HasPrefix(path, "uploads/") {
		c.JSON(http.StatusForbidden, gin.H{"success": false, "error": "无权限删除此文件"})
		return
	}
	fullPath := strings.TrimPrefix(path, "/")
	if err := os.Remove(fullPath); err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "文件不存在或删除失败"})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "message": "删除成功"})
}