using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using Console = Game.Console;

namespace Game;

#if false
public class PlayerInputDemo : PlayerInput
{
    protected List<PlayerInputState> buffer = new List<PlayerInputState>();
    protected IEnumerator<PlayerInputState> bufferEnumerable;

    public bool IsPlaying
    {
        get
        {
            return bufferEnumerable != null;
        }
    }

    public PlayerInputDemo(string demoPath)
    {
        if (!File.Exists(demoPath))
            return;

        int expectedPlayerInputStateSize = Unsafe.SizeOf<PlayerInputState>();

        Stopwatch sw = Stopwatch.StartNew();

        using FileStream fileStream = File.OpenRead(demoPath);
        using GZipStream stream = new GZipStream(fileStream, CompressionMode.Decompress);

        int ver = stream.ReadByte();
        int inputStateSize = stream.ReadByte();
        if (ver != DemoVer || inputStateSize != expectedPlayerInputStateSize)
        {
            Console.Print("demover mismatch: version " + ver + " != " + DemoVer + ", inputStateSize " +
                          inputStateSize + " != " + Unsafe.SizeOf<PlayerInputState>());
            stream.Close();
            return;
        }

        Span<byte> b = stackalloc byte[expectedPlayerInputStateSize];
        while (true)
        {
            int bytesLeftInBuffer = expectedPlayerInputStateSize;
            do
            {
                int readBytes = stream.Read(b.Slice(expectedPlayerInputStateSize - bytesLeftInBuffer, bytesLeftInBuffer));
                if (readBytes == 0)
                    break;
                bytesLeftInBuffer -= readBytes;
            } while (bytesLeftInBuffer > 0);

            if (bytesLeftInBuffer > 0)
                break; // EOF;

            buffer.Add(MemoryMarshal.Read<PlayerInputState>(b));
        }

        sw.Stop();

        bufferEnumerable = buffer.GetEnumerator();

        Console.Print($"Demo parse time {sw.Elapsed.TotalMilliseconds}ms, frames: {buffer.Count} ");

        OnEndFrame(); // advances to first frame
    }

    public override void OnEndFrame()
    {
        // TODO: check if the current state frame matches the current frame number before advancing

        /*asdf++;
        if (asdf < 8)
            return;*/

        if (bufferEnumerable == null || !bufferEnumerable.MoveNext())
        {
            if (buffer.Any())
            {
                bufferEnumerable.Dispose();
                bufferEnumerable = null;
                buffer.Clear();
                Console.Print("Demo ended");
            }

            return;
        }

        //var actorState = currentState.actor;
        currentState.input = bufferEnumerable.Current;
        //frame++;
        //currentState.actor = actorState;
    }
}
#endif