using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using Windows.Win32;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace AMNet.Server;

public static class DllMain
{
    private const string WebAddress = "http://card.ppc.moe";

    // instance metrics
    internal static long LastPollTime = -1;
    internal static long ServerStartedAt;

    static DllMain()
    {
        PInvoke.AllocConsole();

        App = WebServer.BuildServer(Config.ReadKey(Config.IOSection, "serverAddress", 1024, "http://+:6070").Split(';'));
    }

    private static WebApplication App { get; }

    [UnmanagedCallersOnly(EntryPoint = "aime_io_get_api_version")]
    public static ushort GetApiVersion() => 0x0100;

    [UnmanagedCallersOnly(EntryPoint = "aime_io_init")]
    public static int Init()
    {
        CancellationTokenRegistration? cancellationRegistration = null;
        cancellationRegistration = App.Lifetime.ApplicationStarted.Register(() =>
        {
            App.Logger.LogInformation("AMNet Server ({gameId}) started successfully.", Config.GameId);
            App.Logger.LogInformation("Visit {addr} from a mobile device on the same network to get started.", WebAddress);

            // ReSharper disable once AccessToModifiedClosure
            cancellationRegistration?.Dispose();
        });

        Volatile.Write(ref ServerStartedAt, Environment.TickCount64);
        App.RunAsync();
        return 0;
    }

    [UnmanagedCallersOnly(EntryPoint = "aime_io_nfc_poll")]
    public static int NfcPoll(byte unitNo)
    {
        Volatile.Write(ref LastPollTime, Environment.TickCount64);

        if (!Config.EnableAimeTxt)
        {
            return 1;
        }

        // check keyboard input for the enter key being held down (0x0D)
        var enterPressed = (PInvoke.GetAsyncKeyState(0x0D) & 0x8000) != 0;

        if (!enterPressed)
        {
            return 0;
        }

        try
        {
            using var aimeTxtReader = new StreamReader(File.OpenRead(Config.AimeTxtPath), Encoding.UTF8);

            var fileName = Path.GetFileName(Config.AimeTxtPath);
            var cardResult = App.Services.GetRequiredService<CardPresenter>().SetCard(aimeTxtReader.ReadLine());

            if (cardResult == null)
            {
                App.Logger.LogWarning("Failed to read card from {file}: invalid format", fileName);
            }
            else
            {
                App.Logger.LogInformation("Card loaded from {fileName}", fileName);
            }
        }
        catch (IOException e)
        {
            App.Logger.LogWarning("Failed to read '{path}': {message}", Path.GetFullPath(Config.AimeTxtPath), e.Message);
        }

        return 0;
    }

    [UnmanagedCallersOnly(EntryPoint = "aime_io_nfc_get_aime_id")]
    public static int GetAimeId(byte unitNo, IntPtr luid, nint luidSize)
    {
        if (unitNo != 0)
        {
            return 1;
        }

        var card = App.Services.GetRequiredService<CardPresenter>().TakeActiveCard();
        if (card?.Expired != false)
        {
            return 1;
        }

        try
        {
            Marshal.Copy(card.Value, 0, luid, (int)luidSize);
            return 0;
        }
        finally
        {
            App.Logger.LogInformation("Card read in: {cardId}", card);
        }
    }

    [UnmanagedCallersOnly(EntryPoint = "aime_io_nfc_get_felica_id")]
    public static unsafe int GetFelicaId(byte unitNo, ulong* idm) => 1; // felica not supported

    [UnmanagedCallersOnly(EntryPoint = "aime_io_led_set_color")]
    public static void SetLedColour(byte unitNo, byte r, byte g, byte b)
    {
        // do nothing
    }
}