using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace HXX.Scanner.Copier
{
    enum OverwriteStrategy
    {
        Skip,       // 跳过已存在的文件
        Overwrite,  // 强制覆盖
        Prompt      // 询问用户
    }

    class DirCopy2
    {
        public static void CopyDirectory(string sourceDir, string targetDir, OverwriteStrategy strategy)
        {
            Directory.CreateDirectory(targetDir);

            foreach (string file in Directory.GetFiles(sourceDir))
            {
                string targetFile = Path.Combine(targetDir, Path.GetFileName(file));

                if (File.Exists(targetFile))
                {
                    bool shouldOverwrite = false;
                    switch (strategy)
                    {
                        case OverwriteStrategy.Skip:
                            continue;
                        case OverwriteStrategy.Overwrite:
                            shouldOverwrite = true;
                            break;
                        case OverwriteStrategy.Prompt:
                            Console.Write($"文件 {targetFile} 已存在，是否覆盖？(Y/N): ");
                            shouldOverwrite = Console.ReadKey().Key == ConsoleKey.Y;
                            Console.WriteLine();
                            break;
                    }

                    if (shouldOverwrite)
                    {
                        // 处理文件锁定：尝试多次复制
                        RetryCopy(file, targetFile, 3);
                    }
                }
                else
                {
                    File.Copy(file, targetFile);
                    Console.WriteLine($"已拷贝文件: {targetFile}");
                }
            }

            foreach (string subDir in Directory.GetDirectories(sourceDir))
            {
                string targetSubDir = Path.Combine(targetDir, Path.GetFileName(subDir));
                CopyDirectory(subDir, targetSubDir, strategy);
            }
        }

        /// <summary>
        /// 带重试机制的文件复制（处理文件锁定）
        /// </summary>
        static void RetryCopy(string source, string target, int retryCount)
        {
            for (int i = 0; i < retryCount; i++)
            {
                try
                {
                    File.Copy(source, target, true);
                    Console.WriteLine($"已覆盖文件: {target}");
                    return;
                }
                catch (IOException) when (i < retryCount - 1)
                {
                    System.Threading.Thread.Sleep(1000); // 等待1秒后重试
                }
            }

            throw new IOException($"无法复制文件 {source}：目标文件被锁定");
        }
    }
}