using System.Diagnostics;
using System.Text.Json;
using MeetingAssistant.LaunchProfiles;
using Microsoft.Extensions.Options;

namespace MeetingAssistant.MacOs;

public sealed class MacOsDesktopControlService : IHostedService, IDisposable
{
    private readonly ILaunchProfileOptionsProvider launchProfiles;
    private readonly IOptions<MeetingAssistantOptions> options;
    private readonly IHostApplicationLifetime applicationLifetime;
    private readonly ILogger<MacOsDesktopControlService> logger;
    private Process? helper;
    private string? manifestPath;

    public MacOsDesktopControlService(
        ILaunchProfileOptionsProvider launchProfiles,
        IOptions<MeetingAssistantOptions> options,
        IHostApplicationLifetime applicationLifetime,
        ILogger<MacOsDesktopControlService> logger)
    {
        this.launchProfiles = launchProfiles;
        this.options = options;
        this.applicationLifetime = applicationLifetime;
        this.logger = logger;
    }

    public Task StartAsync(CancellationToken cancellationToken)
    {
        if (!OperatingSystem.IsMacOS())
        {
            return Task.CompletedTask;
        }

        var helperPath = Path.Combine(AppContext.BaseDirectory, "Native", "macos-desktop-controls");
        if (!File.Exists(helperPath))
        {
            logger.LogWarning("macOS desktop controls helper was not found at {HelperPath}", helperPath);
            return Task.CompletedTask;
        }

        var manifest = MacOsDesktopControlManifest.Create(
            options.Value.Api.PublicBaseUrl,
            launchProfiles.GetProfiles(),
            launchProfiles.GetHotkeys());
        manifestPath = Path.Combine(
            Path.GetTempPath(),
            $"meeting-assistant-desktop-{Environment.ProcessId}.json");
        File.WriteAllText(
            manifestPath,
            JsonSerializer.Serialize(
                manifest,
                new JsonSerializerOptions(JsonSerializerDefaults.Web)));

        helper = Process.Start(new ProcessStartInfo
        {
            FileName = helperPath,
            ArgumentList = { manifestPath },
            UseShellExecute = false,
            CreateNoWindow = true
        });

        if (helper is null)
        {
            throw new InvalidOperationException("Could not start the macOS desktop controls helper.");
        }

        helper.EnableRaisingEvents = true;
        helper.Exited += (_, _) =>
        {
            if (!applicationLifetime.ApplicationStopping.IsCancellationRequested)
            {
                logger.LogWarning("macOS desktop controls helper exited unexpectedly");
            }
        };
        logger.LogInformation("Started macOS menu-bar controls with {HotkeyCount} global hotkeys", manifest.Hotkeys.Count);
        return Task.CompletedTask;
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        if (helper is { HasExited: false })
        {
            helper.Kill();
            helper.WaitForExit(TimeSpan.FromSeconds(2));
        }

        DeleteManifest();
        return Task.CompletedTask;
    }

    public void Dispose()
    {
        helper?.Dispose();
        DeleteManifest();
    }

    private void DeleteManifest()
    {
        if (manifestPath is not null && File.Exists(manifestPath))
        {
            File.Delete(manifestPath);
            manifestPath = null;
        }
    }
}