using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.ServiceProcess;
using System.Threading;
using System.Threading.Tasks;

namespace HikvisionAttendanceService;

internal static class Program
{
    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool AllocConsole();

    private static bool ArgsContainFlag(string[] args, string flag) =>
        args.Any(a => string.Equals(a, flag, StringComparison.OrdinalIgnoreCase));

    private static bool ArgsContainTestFlag(string[] args) =>
        ArgsContainFlag(args, "--test");

    private static bool ShouldRunAsConsole(string[] args)
    {
        if (ArgsContainFlag(args, "--console") || ArgsContainFlag(args, "--debug"))
            return true;

        // F5 / Debug from Visual Studio / Cursor: run interactively instead of ServiceBase.
        if (Debugger.IsAttached)
            return true;

        // Double-click / direct run of exe outside SCM.
        if (Environment.UserInteractive)
            return true;

        return false;
    }

    private static async Task Main(string[] args)
    {
        if (ArgsContainTestFlag(args))
        {
            Console.WriteLine("Program entry (test): rawArgCount=" + args.Length + " rawArgs=" + string.Join(" ", args));
            await AttendanceTestMode.RunAsync(args).ConfigureAwait(false);
            return;
        }

        if (ShouldRunAsConsole(args))
        {
            await RunConsoleHostAsync(args).ConfigureAwait(false);
            return;
        }

        ServiceBase.Run(new ServiceBase[]
        {
            new HikvisionAttendanceWindowsService()
        });
    }

    /// <summary>
    /// Same runtime path as the Windows Service OnStart/OnStop, but runnable under debugger (F5).
    /// Press Ctrl+C (or Stop Debugging) to shut down cleanly.
    /// </summary>
    private static async Task RunConsoleHostAsync(string[] args)
    {
        try
        {
            // Make console output visible when debugging a WinExe project.
            if (Environment.UserInteractive)
                AllocConsole();
        }
        catch
        {
            // ignore: console may already exist
        }

        Environment.CurrentDirectory = AppContext.BaseDirectory;
        var baseDir = AppContext.BaseDirectory;
        var configPath = Path.Combine(baseDir, "serviceconfig.json");
        if (!File.Exists(configPath))
            configPath = Path.Combine(baseDir, "appsettings.json");

        var config = HikvisionAttendanceWindowsService.HikvisionServiceConfig.Load(configPath);
        var logger = new HikvisionAttendanceWindowsService.FileLogger(config.LogDirectory);

        Console.WriteLine("HikvisionAttendanceService console/debug host starting...");
        Console.WriteLine("Config: " + configPath);
        Console.WriteLine("LogDirectory: " + config.LogDirectory);
        Console.WriteLine("Press Ctrl+C to stop.");
        logger.Ops(OpsMarkers.Service, "CONSOLE HOST START time=" + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") +
            " config=\"" + configPath + "\" debuggerAttached=" + Debugger.IsAttached);

        using var cts = new CancellationTokenSource();
        Console.CancelKeyPress += (_, e) =>
        {
            e.Cancel = true;
            Console.WriteLine("Shutdown requested...");
            logger.Ops(OpsMarkers.Service, "STOP REQUESTED reason=\"Ctrl+C\"");
            cts.Cancel();
        };

        using var manager = new HikvisionAttendanceManager(config, logger);
        try
        {
            await manager.RunAsync(cts.Token).ConfigureAwait(false);
        }
        catch (OperationCanceledException)
        {
            // expected on stop
        }
        catch (Exception ex)
        {
            logger.Error("Console/debug host failed", ex);
            logger.OpsError(OpsMarkers.Service, "CONSOLE HOST FAILED reason=\"" + ex.Message + "\"");
            Console.WriteLine("FATAL: " + ex.Message);
            throw;
        }

        logger.Ops(OpsMarkers.Service, "CONSOLE HOST END");
        Console.WriteLine("HikvisionAttendanceService stopped.");
    }
}