using System;
using System.Runtime.InteropServices;
using System.Text;

namespace BSO
{
    /// <summary>Was der Loader (dinput8.dll) mitgibt - Gegenstueck zu HostApi in BSO.Loader\dinput8.cpp.</summary>
    [StructLayout(LayoutKind.Sequential)]
    public unsafe struct HostApi
    {
        public delegate* unmanaged<byte*, void> Log;
        public char* GameDir;
        public char* BsoDir;
    }

    /// <summary>
    /// Einstieg: der Loader startet .NET beim ersten DirectInput8Create und ruft Start auf, danach OnFrame einmal pro
    /// Bild im Hauptthread des Spiels. Protokoll: &lt;Spiel&gt;\BSO\BSO_Loader.txt.
    /// </summary>
    public static unsafe class Bootstrap
    {
        public const string ModVersion = "0.5.0";

        static HostApi* host;
        static int frameErrors;

        /// <summary>Ordner von BSO.dll (&lt;Spiel&gt;\BSO).</summary>
        public static string Folder { get; private set; }
        /// <summary>Ordner der Spiel-EXE (Bin_High_Win64).</summary>
        public static string GameFolder { get; private set; }

        [UnmanagedCallersOnly]
        public static void Start(HostApi* api)
        {
            try
            {
                host = api;
                Folder = new string(api->BsoDir);
                GameFolder = new string(api->GameDir);
                Log("BSO " + ModVersion + " gestartet (.NET " + Environment.Version + ")");
                Log("Kommandozeile: " + Environment.CommandLine);
                Config.Load();
            }
            catch (Exception e)
            {
                Log("Start fehlgeschlagen: " + e);
            }
        }

        [UnmanagedCallersOnly]
        public static void OnFrame()
        {
            try
            {
                Mem.NewFrame();
                if (!Vision.Init()) return;
                if (Vision.TimerAdvanced())
                {
                    Input.Update();
                    BorderlessWindow.Update();
                    LocalPlayer.Update();
                    Multiplayer.Update();
                    RemotePlayers.Update();
                    PositionHud.Update();
                }
                RemotePlayers.Draw();
                PositionHud.Draw();
            }
            catch (Exception e)
            {
                // Nicht jedes Bild ins Protokoll schreiben
                if (frameErrors++ < 5) Log("Fehler im Bild-Takt: " + e);
            }
        }

        public static void Log(string line)
        {
            if (host == null) return;
            byte[] bytes = Encoding.UTF8.GetBytes(line + "\0");
            fixed (byte* p = bytes) host->Log(p);
        }
    }
}