package middleware

import (
	"bytes"
	"fmt"
	"net/http"
	"path/filepath"
	"strings"

	"tss-rocks-be/internal/config"

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

// ValidateUpload 验证上传的文件
func ValidateUpload(cfg *config.UploadConfig) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get file from form
		file, err := c.FormFile("file")
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "No file uploaded"})
			c.Abort()
			return
		}

		// 获取文件类型和扩展名
		contentType := file.Header.Get("Content-Type")
		ext := strings.ToLower(filepath.Ext(file.Filename))

		// 如果 Content-Type 为空，尝试从文件扩展名判断
		if contentType == "" {
			switch ext {
			case ".jpg", ".jpeg":
				contentType = "image/jpeg"
			case ".png":
				contentType = "image/png"
			case ".gif":
				contentType = "image/gif"
			case ".webp":
				contentType = "image/webp"
			case ".mp4":
				contentType = "video/mp4"
			case ".webm":
				contentType = "video/webm"
			case ".mp3":
				contentType = "audio/mpeg"
			case ".ogg":
				contentType = "audio/ogg"
			case ".wav":
				contentType = "audio/wav"
			case ".pdf":
				contentType = "application/pdf"
			case ".doc":
				contentType = "application/msword"
			case ".docx":
				contentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
			}
		}

		// 根据 Content-Type 确定文件类型和限制
		var maxSize int64
		var allowedTypes []string
		var fileType string

		limits := cfg.Limits
		switch {
		case strings.HasPrefix(contentType, "image/"):
			maxSize = int64(limits.Image.MaxSize) * 1024 * 1024
			allowedTypes = limits.Image.AllowedTypes
			fileType = "image"
		case strings.HasPrefix(contentType, "video/"):
			maxSize = int64(limits.Video.MaxSize) * 1024 * 1024
			allowedTypes = limits.Video.AllowedTypes
			fileType = "video"
		case strings.HasPrefix(contentType, "audio/"):
			maxSize = int64(limits.Audio.MaxSize) * 1024 * 1024
			allowedTypes = limits.Audio.AllowedTypes
			fileType = "audio"
		case strings.HasPrefix(contentType, "application/"):
			maxSize = int64(limits.Document.MaxSize) * 1024 * 1024
			allowedTypes = limits.Document.AllowedTypes
			fileType = "document"
		default:
			c.JSON(http.StatusBadRequest, gin.H{
				"error": fmt.Sprintf("Unsupported file type: %s", contentType),
			})
			c.Abort()
			return
		}

		// 检查文件类型是否允许
		typeAllowed := false
		for _, allowed := range allowedTypes {
			if contentType == allowed {
				typeAllowed = true
				break
			}
		}
		if !typeAllowed {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": fmt.Sprintf("Unsupported %s type: %s", fileType, contentType),
			})
			c.Abort()
			return
		}

		// 检查文件大小
		if file.Size > maxSize {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": fmt.Sprintf("File size exceeds the limit (%d MB) for %s files", limits.Image.MaxSize, fileType),
			})
			c.Abort()
			return
		}

		c.Next()
	}
}

// GetValidatedFile 从上下文中获取验证过的文件内容
func GetValidatedFile(c *gin.Context, filename string) (*bytes.Buffer, string, bool) {
	file, exists := c.Get("validated_file_" + filename)
	if !exists {
		return nil, "", false
	}

	contentType, exists := c.Get("validated_content_type_" + filename)
	if !exists {
		return nil, "", false
	}

	return file.(*bytes.Buffer), contentType.(string), true
}