package util

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

// DetectFileType 根据返回的二进制内容推断 contentType + 扩展名
func DetectFileType(data []byte) (contentType string, ext string) {
	if len(data) == 0 {
		return "application/octet-stream", ".bin"
	}

	ct := http.DetectContentType(data)
	if idx := strings.Index(ct, ";"); idx > 0 {
		ct = strings.TrimSpace(ct[:idx])
	}

	switch ct {
	case "audio/mpeg":
		return ct, ".mp3"
	case "audio/wave", "audio/wav", "audio/x-wav":
		return ct, ".wav"
	case "audio/mp4", "audio/x-m4a":
		return ct, ".m4a"
	case "video/mp4":
		return ct, ".mp4"
	case "video/webm":
		return ct, ".webm"
	case "image/png":
		return ct, ".png"
	case "image/jpeg":
		return ct, ".jpg"
	case "image/gif":
		return ct, ".gif"
	case "image/webp":
		return ct, ".webp"
	case "application/pdf":
		return ct, ".pdf"
	case "text/plain":
		return ct, ".txt"
	case "application/json":
		return ct, ".json"
	case "application/zip":
		return ct, ".zip"
	case "application/octet-stream":
		return ct, ".bin"
	default:
		if parts := strings.Split(ct, "/"); len(parts) == 2 {
			sub := parts[1]
			if idx := strings.Index(sub, ";"); idx > 0 {
				sub = strings.TrimSpace(sub[:idx])
			}
			return ct, "." + sub
		}
		return ct, ".bin"
	}
}

// SaveTmpResult 将二进制数据写入临时文件
func SaveTmpResult(taskID string, data []byte, ext string) (string, error) {
	dir := filepath.Join(os.TempDir(), "model-asynch")
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return "", fmt.Errorf("创建临时目录失败: %w", err)
	}

	if ext == "" {
		ext = ".bin"
	}
	if ext[0] != '.' {
		ext = "." + ext
	}

	path := filepath.Join(dir, fmt.Sprintf("%s%s", taskID, ext))
	if err := os.WriteFile(path, data, 0o644); err != nil {
		return "", fmt.Errorf("写入临时文件失败: %w", err)
	}
	return path, nil
}