using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;

public partial class UniQuake: MonoBehaviour
{
    private const int DefaultMemSize = 0x8000000;  // 128 MB of heap space

    public int memorySize = DefaultMemSize;

    private QuakeParms quakeParms;
    private SystemModule systemModule;
    private RenderModule renderModule;
    private GameModule gameModule;

    private bool initialized = false;
    private double startTime;

    /// <summary>
    /// Camera and viewport that this instance of Quake will be rendering to
    /// </summary>
    public Camera Camera { get; set; }

    public MissionPack BaseGame { get; set; }
    public string ModDirectory { get; set; }
    public string[] AdditionalArguments { get; set; }
    
    /// <summary>
    /// Time since startup for this particular instance of Quake
    /// </summary>
    public double CurrentTime => Time.realtimeSinceStartupAsDouble - startTime;
    
    public GameAssets GameAssets { get; private set; }
    public GameState GameState { get; private set; }

    private Action<string> logHandler;
    private readonly StringBuilder logBuffer = new StringBuilder();

    void Start()
    {
        logHandler = PrintLog;  // Send each log statement to Unity immediately during startup
        
        systemModule = new SystemModule(this);
        renderModule = new RenderModule(this);
        gameModule = new GameModule(this);

        GameAssets = new GameAssets(this);
        GameState = new GameState(this);
        
        LoadLibrary();

        List<string> arguments = new List<string>
        {
            "",
            //"-fullscreen", "-width", "1920", "-height", "1080",
            "-window", "-width", "1440", "-height", "1080",
            //"-window", "-width", "2240", "-height", "1260",
        };

        switch (BaseGame)
        {
            case MissionPack.Hipnotic:
                arguments.Add("-hipnotic");
                break;
            case MissionPack.Rogue:
                arguments.Add("-rogue");
                break;
        }

        if (!string.IsNullOrEmpty(ModDirectory))
        {
            arguments.AddRange(new[] { "-game", ModDirectory });
        }

        if (Debug.isDebugBuild)
        {
            arguments.AddRange(new[] { "+developer", "1" });
        }
        
        if (AdditionalArguments != null)
            arguments.AddRange(AdditionalArguments);

        quakeParms = new QuakeParms
        {
            baseDir = Application.persistentDataPath,
            userDir = null, // TODO set this if user prefs need to be stored somewhere specific, otherwise this will be the same as baseDir
            numCpus = SystemInfo.processorCount,
            errState = 0,
        };
        quakeParms.SetArguments(arguments.ToArray());
        quakeParms.AllocateMemory(memorySize);

        startTime = Time.realtimeSinceStartupAsDouble;

        try
        {
            UniQuake_SetFmodSystem(AudioManager.Instance.FmodSystem.handle);
            UniQuake_Init(quakeParms.ToNativePtr(), systemModule.CallbacksPtr, renderModule.CallbacksPtr);
            initialized = true;
        }
        catch (QuakeException ex)
        {
            if (ex.ExitCode == 0)
                Debug.Log(ex.Message);
            else
                Debug.LogException(ex);

            Shutdown();
        }
        catch (Exception ex)
        {
            Debug.LogException(ex);
            Shutdown();
        }
    }

    void Update()
    {
        if (!initialized)
            return;

        logHandler = CollectLog;    // Collect and dump logs to Unity once per frame

        try
        {
            UniQuake_Update(Time.deltaTime);
        }
        catch (QuakeException ex)
        {
            if (ex.ExitCode == 0)
                Debug.Log(ex.Message);
            else
                Debug.LogException(ex);

            Shutdown();
        }
        catch (Exception ex)
        {
            Debug.LogException(ex);
            Shutdown();
        }
        
        FlushLog();
    }

    public void Shutdown()
    {
        initialized = false;
        UniQuake_Shutdown();
        Destroy(this);
    }

    private void OnApplicationQuit()
    {
        Shutdown();
    }

    private void OnDestroy()
    {
        GameState.Destroy();
        GameAssets.Destroy();
    
        gameModule.Destroy();
        renderModule.Destroy();
        systemModule.Destroy();

        if (quakeParms != null)
        {
            quakeParms.Destroy();
            quakeParms = null;
        }

        FreeLibrary();
    }

    public void AddLog(string log)
    {
        logHandler?.Invoke(log);
    }
    
    private void PrintLog(string log)
    {
        Debug.Log(log);
    }

    private void CollectLog(string log)
    {
        logBuffer.Append(log);
    }

    private void FlushLog()
    {
        if (logBuffer.Length > 0)
        {
            Debug.Log(logBuffer.ToString());
            logBuffer.Clear();
        }
    }
}

public enum MissionPack
{
    Quake,      // Vanilla Quake
    Hipnotic,   // Scourge of Armagon
    Rogue,      // Dissolution of Eternity 
}

public class QuakeException: Exception
{
    public int ExitCode { get; }

    public QuakeException(string message, int exitCode = 0)
        : base(message)
    {
        ExitCode = exitCode;
    }
}