using FluidExplorer.Services;
using Microsoft.UI.Dispatching;
using Microsoft.UI.Xaml;

namespace FluidExplorer;

public partial class App : Application
{
    /// <summary>启动阶段日志：WinUI 启动期的异常在窗口出现前就终止进程，必须落盘才能定位。</summary>
    private static readonly string LogPath = Path.Combine(AppContext.BaseDirectory, "startup.log");

    public App()
    {
        Log("App ctor: begin");
        InitializeComponent();
        Log("App ctor: InitializeComponent done");
        UnhandledException += OnUnhandledException;
        AppDomain.CurrentDomain.UnhandledException += (_, e) => Log($"AppDomain unhandled: {e.ExceptionObject}");
        TaskScheduler.UnobservedTaskException += (_, e) =>
        {
            Log($"Unobserved task exception: {e.Exception}");
            e.SetObserved();
        };

        // 诊断开关：宿主/非托管路径上的异常不会走 UnhandledException，需要首次异常钩子才能看到来源
        if (Environment.GetEnvironmentVariable("FLUID_DEBUG_EXPLOG") == "1")
        {
            AppDomain.CurrentDomain.FirstChanceException += (_, e) =>
            {
                var ex = e.Exception;
                var stack = ex.StackTrace ?? string.Empty;
                if (stack.Contains("FluidExplorer", StringComparison.Ordinal) || ex.Source?.Contains("FluidExplorer", StringComparison.Ordinal) == true)
                    Log($"first-chance {ex.GetType().FullName}: {ex.Message}{Environment.NewLine}{stack}");
            };
        }
    }

    public static AppServices Services { get; private set; } = null!;

    /// <summary>当前主窗口（原版右键菜单、窗口图标、对话框都需要它的 HWND / XamlRoot）。</summary>
    public static MainWindow MainWindowInstance { get; private set; } = null!;

    protected override void OnLaunched(LaunchActivatedEventArgs args)
    {
        try
        {
            Log("OnLaunched: begin");
            Services = new AppServices(DispatcherQueue.GetForCurrentThread());
            Log("OnLaunched: services ready");
            Services.WireSearchIndex();
            Log("OnLaunched: search index wired");

            MainWindowInstance = new MainWindow(Services);
            Log("OnLaunched: window constructed");
            MainWindowInstance.Activate();
            Log("OnLaunched: window activated");
        }
        catch (Exception ex)
        {
            Log($"OnLaunched FAILED: {ex}");
            throw;
        }
    }

    internal static void Log(string message)
    {
        try
        {
            File.AppendAllText(LogPath, $"[{DateTime.Now:HH:mm:ss.fff}] {message}{Environment.NewLine}");
        }
        catch
        {
            // 日志失败绝不能影响主流程
        }
    }

    private static void OnUnhandledException(object sender, Microsoft.UI.Xaml.UnhandledExceptionEventArgs e)
    {
        Log($"XAML unhandled: {e.Message}{Environment.NewLine}{e.Exception}");
        try
        {
            var log = Path.Combine(
                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
                "FluidExplorer", "crash.log");
            Directory.CreateDirectory(Path.GetDirectoryName(log)!);
            File.AppendAllText(log, $"[{DateTime.Now:O}] {e.Message}\n{e.Exception}\n\n");
        }
        catch
        {
            // 忽略
        }
        e.Handled = true;
    }
}