package handler

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

	"soul-api/internal/config"
	"soul-api/internal/oss"

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

const (
	maxImageUploadBytes      = 5 * 1024 * 1024   // 5MB
	maxVideoUploadBytes      = 100 * 1024 * 1024 // 100MB（章节富文本视频）
	maxAttachmentUploadBytes = 30 * 1024 * 1024  // 30MB（章节附件）
)

var allowedImageCT = map[string]bool{"image/jpeg": true, "image/png": true, "image/gif": true, "image/webp": true}
var allowedVideoCT = map[string]bool{
	"video/mp4": true, "video/quicktime": true, "video/webm": true, "video/x-msvideo": true,
}
var allowedAttachmentCT = map[string]bool{
	"application/pdf":                          true,
	"application/zip":                          true,
	"application/x-zip-compressed":             true,
	"application/msword":                       true,
	"application/vnd.openxmlformats-officedocument.wordprocessingml.document":   true,
	"application/vnd.ms-excel":                 true,
	"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet":         true,
	"application/vnd.ms-powerpoint":            true,
	"application/vnd.openxmlformats-officedocument.presentationml.presentation":   true,
	"text/plain": true, "application/json": true,
}

var allowedAttachmentExt = map[string]bool{
	".pdf": true, ".zip": true, ".doc": true, ".docx": true, ".xls": true, ".xlsx": true,
	".ppt": true, ".pptx": true, ".txt": true, ".json": true, ".csv": true, ".md": true,
}

func uploadBookFolderCategory(folder string) string {
	switch folder {
	case "book-videos":
		return "video"
	case "book-attachments":
		return "attachment"
	default:
		return "image"
	}
}

func isAllowedVideo(ct string) bool {
	if strings.HasPrefix(ct, "video/") {
		return true
	}
	return allowedVideoCT[ct]
}

func isAllowedAttachment(file *multipart.FileHeader, ct string) bool {
	if allowedAttachmentCT[ct] {
		return true
	}
	ext := strings.ToLower(filepath.Ext(file.Filename))
	return allowedAttachmentExt[ext]
}

// UploadPost POST /api/upload 通用上传（multipart：file + folder）
// - 默认 folder（如 avatars、book-images）：图片，≤5MB
// - folder=book-videos：视频，≤100MB
// - folder=book-attachments：常见文档/压缩包，≤30MB
// 若管理端已配置 OSS，优先上传到 OSS；OSS 失败或未配置时回退本地磁盘（容灾）
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
	}
	folder := c.PostForm("folder")
	if folder == "" {
		folder = "avatars"
	}
	ct := file.Header.Get("Content-Type")
	cat := uploadBookFolderCategory(folder)

	switch cat {
	case "video":
		if file.Size > maxVideoUploadBytes {
			c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "视频大小不能超过100MB"})
			return
		}
		if !isAllowedVideo(ct) {
			c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "仅支持常见视频格式（如 mp4、mov、webm）"})
			return
		}
	case "attachment":
		if file.Size > maxAttachmentUploadBytes {
			c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "附件大小不能超过30MB"})
			return
		}
		if !isAllowedAttachment(file, ct) {
			c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "不支持的附件类型（可用 pdf、zip、Office 文档、txt 等）"})
			return
		}
	default:
		if file.Size > maxImageUploadBytes {
			c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "图片大小不能超过5MB"})
			return
		}
		if !allowedImageCT[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 == "" {
		switch cat {
		case "video":
			ext = ".mp4"
		case "attachment":
			ext = ".bin"
		default:
			ext = ".jpg"
		}
	}
	name := fmt.Sprintf("%d_%s%s", time.Now().UnixNano(), randomStrUpload(6), ext)
	objectKey := filepath.ToSlash(filepath.Join("uploads", folder, name))

	// 优先尝试 OSS（已配置时）
	if oss.IsEnabled() {
		f, err := file.Open()
		if err == nil {
			url, uploadErr := oss.Upload(objectKey, f)
			_ = f.Close()
			if uploadErr == nil && url != "" {
				c.JSON(http.StatusOK, gin.H{"success": true, "url": url, "data": gin.H{"url": url, "fileName": name, "size": file.Size, "type": ct}})
				return
			}
			// OSS 失败，回退本地（容灾）
		}
	}

	// 本地磁盘存储（OSS 未配置或失败时）
	uploadDir := config.Get().UploadDir
	if uploadDir == "" {
		uploadDir = "uploads"
	}
	dir := filepath.Join(uploadDir, folder)
	_ = os.MkdirAll(dir, 0755)
	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
	}
	relPath := "/uploads/" + filepath.ToSlash(filepath.Join(folder, name))
	fullURL := relPath
	if cfg := config.Get(); cfg != nil && cfg.BaseURL != "" {
		fullURL = cfg.BaseURLJoin(relPath)
	}
	c.JSON(http.StatusOK, gin.H{"success": true, "url": fullURL, "data": gin.H{"url": fullURL, "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
// path 支持：/uploads/xxx（本地）或 https://bucket.oss-xxx.aliyuncs.com/uploads/xxx（OSS）
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
	}
	// OSS 公网 URL：从 OSS 删除
	if oss.IsOSSURL(path) {
		objectKey := oss.ParseObjectKeyFromURL(path)
		if objectKey != "" {
			if err := oss.Delete(objectKey); err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "OSS 删除失败"})
				return
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "message": "删除成功"})
			return
		}
	}
	// 本地路径：支持 /uploads/xxx、uploads/xxx 或含 /uploads/ 的完整 URL
	if idx := strings.Index(path, "/uploads/"); idx >= 0 {
		path = path[idx+1:] // 从 uploads/ 开始
	}
	rel := strings.TrimPrefix(path, "/uploads/")
	rel = strings.TrimPrefix(rel, "uploads/")
	if rel == "" || strings.Contains(rel, "..") {
		c.JSON(http.StatusForbidden, gin.H{"success": false, "error": "无权限删除此文件"})
		return
	}
	uploadDir := config.Get().UploadDir
	if uploadDir == "" {
		uploadDir = "uploads"
	}
	fullPath := filepath.Join(uploadDir, filepath.FromSlash(rel))
	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"})
}