using System.Diagnostics;
using Dpz.Core.Service.Mediator.Features.Code.Commands;
using Hangfire;
using JetBrains.Annotations;
using LibGit2Sharp;
using Mediator;

namespace Dpz.Core.Web.Jobs.Hangfire;

/// <summary>
/// 同步代码任务执行器
/// </summary>
[UsedImplicitly]
public class SyncCodeActivator(
    IMediator mediator,
    IConfiguration configuration,
    ILogger<SyncCodeActivator> logger
) : JobActivator
{
    private static readonly SemaphoreSlim SyncLock = new(1, 1);

    [ProlongExpirationTime]
    public async Task SyncAsync()
    {
        // 检查是否有实例正在运行
        if (!await SyncLock.WaitAsync(0))
        {
            logger.LogWarning("同步代码任务已有实例正在执行，跳过本次执行");
            return;
        }

        try
        {
            var sourceCodePath = configuration["CodeView:SourceCodeRoot"];
            if (string.IsNullOrWhiteSpace(sourceCodePath) || !Directory.Exists(sourceCodePath))
            {
                logger.LogError("源码目录：{Path}，未配置或不存在", sourceCodePath);
                return;
            }

            // Git 拉取
            try
            {
                logger.LogInformation("正在拉取源代码");
                var cancelTokenSource = new CancellationTokenSource(TimeSpan.FromMinutes(30));
                var st = new Stopwatch();
                st.Start();

                // 尝试清理可能存在的锁文件
                CleanupGitLockFiles(sourceCodePath);

                using (var repo = new Repository(sourceCodePath))
                {
                    try
                    {
                        Commands.Checkout(repo, "master");
                        cancelTokenSource.Token.ThrowIfCancellationRequested();
                    }
                    catch (LockedFileException)
                    {
                        logger.LogWarning("检测到 Git 索引锁定，尝试清理锁文件后重试");
                        CleanupGitLockFiles(sourceCodePath);
                        cancelTokenSource.Token.ThrowIfCancellationRequested();
                        Commands.Checkout(repo, "master");
                        cancelTokenSource.Token.ThrowIfCancellationRequested();
                    }

                    var options = new PullOptions { FetchOptions = new FetchOptions() };
                    var signature = new Signature(
                        new Identity("dpz.core", "service@dpangzi.com"),
                        DateTimeOffset.Now
                    );

                    cancelTokenSource.Token.ThrowIfCancellationRequested();
                    var result = Commands.Pull(repo, signature, options);

                    if (result?.Status == MergeStatus.UpToDate)
                    {
                        logger.LogInformation("源代码已经是最新的");
                    }
                }

                st.Stop();
                logger.LogInformation(
                    "源代码拉取完毕，耗时：{ElapsedMilliseconds}ms",
                    st.ElapsedMilliseconds
                );
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "拉取源代码失败");
                return;
            }

            // 代码同步
            try
            {
                logger.LogInformation("正在同步代码到数据库");
                await mediator.Send(new SyncCodeFileSystemEntriesRequest());
            }
            catch (Exception ex)
            {
                logger.LogError(ex, "同步代码到数据库失败");
            }
        }
        finally
        {
            SyncLock.Release();
        }
    }

    /// <summary>
    /// 清理 Git 锁文件
    /// </summary>
    /// <param name="repositoryPath">仓库路径</param>
    private void CleanupGitLockFiles(string repositoryPath)
    {
        try
        {
            var gitDir = Path.Combine(repositoryPath, ".git");
            var indexLockPath = Path.Combine(gitDir, "index.lock");

            if (File.Exists(indexLockPath))
            {
                logger.LogWarning("发现残留的 index.lock 文件，正在删除：{Path}", indexLockPath);
                File.Delete(indexLockPath);
                logger.LogInformation("index.lock 文件已删除");
            }

            // 也检查 HEAD.lock
            var headLockPath = Path.Combine(gitDir, "HEAD.lock");
            if (File.Exists(headLockPath))
            {
                logger.LogWarning("发现残留的 HEAD.lock 文件，正在删除：{Path}", headLockPath);
                File.Delete(headLockPath);
                logger.LogInformation("HEAD.lock 文件已删除");
            }
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "清理 Git 锁文件时发生异常");
        }
    }
}