using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using UnityEngine;

public class TimFile {

    public enum Format : byte {
        Bpp4Bit = 0,
        Bpp8Bit = 1,
        Bpp16Bit = 2,
        Bpp24Bit = 3
    }
    [Serializable]
    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct Header {
        public uint h1;
        public uint h2;

        public byte Tag {
            get { return (byte)(h1 & 0xff); }
        }
        public byte Version {
            get { return (byte)((h1 >> 8) & 0xff); }
        }

        public Format Format {
            get { return (Format)(h2 & 0x3); }
        }

        public bool ColorLutPresent {
            get { return (h2 & 0x08) != 0; }
        }

    }

    [Serializable]
    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct ImageBlockHeader {
        public uint length;
        public ushort x;
        public ushort y;
        public ushort width;
        public ushort height;
    }

    public class ImageBlock {
        public ImageBlockHeader header;
        public ushort[] data;
    }

    public Header header;
    public ImageBlock lut;
    public ImageBlock image;


    public int ImageWidth {
        get {
            switch (header.Format) {
                case Format.Bpp4Bit:
                    return image.header.width * 4;
                case Format.Bpp8Bit:
                    return image.header.width * 2;
                case Format.Bpp16Bit:
                    return image.header.width * 1;
                case Format.Bpp24Bit:
                    return (int)(image.header.width / 1.5f);
                default:
                    return image.header.width;
            }
        }
    }

    public int ImageHeight {
        get {
            return image.header.height;
        }
    }

    private static ImageBlock ReadImageBlock(BinaryReader reader) {
        ImageBlock result = new ImageBlock();

        result.header.length = reader.ReadUInt32();
        result.header.x = reader.ReadUInt16();
        result.header.y = reader.ReadUInt16();
        result.header.width = reader.ReadUInt16();
        result.header.height = reader.ReadUInt16();


        var dataSize = result.header.length - 12;

        result.data = new ushort[dataSize / 2];

        for (int i = 0; i < result.data.Length; ++i) {
            result.data[i] = reader.ReadUInt16();
        }

        return result;
    }

    public static TimFile Parse(byte[] data) {

        TimFile result = new TimFile();

        MemoryStream src = new MemoryStream(data);
        BinaryReader r = new BinaryReader(src);

        result.header.h1 = r.ReadUInt32();
        result.header.h2 = r.ReadUInt32();

        if (result.header.ColorLutPresent) {
            result.lut = ReadImageBlock(r);
        }

        result.image = ReadImageBlock(r);
        return result;
    }
}