using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Text.Json;

namespace AssetExtractor;

/// <summary>
/// One-time migration tool: pulls sprites out of the Delphi DFM, converts .omap files
/// (TLZRW1 "LZH!" compressed text) to JSON, extracts tileset images from .oil files,
/// and copies the sound/music files into the MonoGame Content folder.
/// </summary>
public static class Program
{
    static string _srcDir = @"C:\Projects\Games\Delphi\Omega Games\Freedom Fighter";
    static string _outDir = @"C:\Projects\Games\Visual Studio\FreedomFighter\FreedomFighter\Content";

    static readonly string[] Maps = ["intro.omap", "test10.omap", "test7.omap", "test8.omap", "bonus.omap", "lvl5.omap"];

    public static void Main(string[] args)
    {
        if (args.Length > 0) _srcDir = args[0];
        if (args.Length > 1) _outDir = args[1];

        foreach (var sub in new[] { "gfx", "maps", "tilesets", "sfx", "music" })
            Directory.CreateDirectory(Path.Combine(_outDir, sub));

        var oilsNeeded = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

        ExtractDfmImages(Path.Combine(_srcDir, "GameU.dfm"));

        foreach (var map in Maps)
        {
            var oil = ConvertMap(Path.Combine(_srcDir, map));
            if (oil != null) oilsNeeded.Add(oil);
        }

        foreach (var oil in oilsNeeded)
            ExtractOilTileset(Path.Combine(_srcDir, oil));

        CopyAudio();

        Console.WriteLine("Done.");
    }

    // ---------------------------------------------------------------- DFM images

    record ImageItem(int Index, string Name, string File, int TileWidth, int TileHeight);

    static void ExtractDfmImages(string dfmPath)
    {
        var lines = File.ReadAllLines(dfmPath);
        var manifest = new Dictionary<string, List<ImageItem>>();

        string? currentList = null;
        string itemName = "";
        int tileW = 0, tileH = 0;
        StringBuilder? hex = null;
        byte[]? pictureData = null;
        int itemIndex = 0;

        void FlushItem()
        {
            if (currentList == null || pictureData == null) return;
            string safeName = itemName.Length > 0 ? itemName : "unnamed";
            string file = $"{currentList.ToLowerInvariant()}_{itemIndex:D2}_{safeName}.png";
            SaveGraphic(pictureData, Path.Combine(_outDir, "gfx", file));
            manifest.TryAdd(currentList, []);
            // TileWidth/TileHeight of 0 means "whole image is one frame"
            manifest[currentList].Add(new ImageItem(itemIndex, itemName, file, tileW, tileH));
            Console.WriteLine($"  {currentList}[{itemIndex}] '{itemName}' -> {file} ({tileW}x{tileH})");
            itemIndex++;
            pictureData = null;
            itemName = "";
            tileW = tileH = 0;
        }

        foreach (var raw in lines)
        {
            var line = raw.Trim();

            if (hex != null)
            {
                bool end = line.EndsWith('}');
                hex.Append(end ? line[..^1] : line);
                if (end)
                {
                    pictureData = Convert.FromHexString(hex.ToString());
                    hex = null;
                }
                continue;
            }

            if (line.StartsWith("object ") && line.Contains(": TOmegaImageList"))
            {
                FlushItem();
                currentList = line["object ".Length..line.IndexOf(':')].Trim();
                itemIndex = 0;
                continue;
            }

            if (currentList == null) continue;

            if (line.StartsWith("object "))  // next non-imagelist component
            {
                FlushItem();
                currentList = null;
                continue;
            }

            if (line == "item")
                FlushItem();
            else if (line.StartsWith("Name = '"))
                itemName = line["Name = '".Length..^1];
            else if (line.StartsWith("TileWidth = "))
                tileW = int.Parse(line["TileWidth = ".Length..]);
            else if (line.StartsWith("TileHeight = "))
                tileH = int.Parse(line["TileHeight = ".Length..]);
            else if (line.StartsWith("Picture.Data = {"))
                hex = new StringBuilder(line["Picture.Data = {".Length..]);
        }
        FlushItem();

        var json = JsonSerializer.Serialize(manifest, new JsonSerializerOptions { WriteIndented = true });
        File.WriteAllText(Path.Combine(_outDir, "gfx", "manifest.json"), json);
        Console.WriteLine("  wrote gfx/manifest.json");
    }

    /// <summary>Delphi TPicture blob: [1B class-name length][class name][payload].</summary>
    static void SaveGraphic(byte[] data, string outPath)
    {
        int nameLen = data[0];
        string cls = Encoding.ASCII.GetString(data, 1, nameLen);
        int payloadStart = 1 + nameLen;

        if (cls == "TPNGObject")
        {
            File.WriteAllBytes(outPath, data[payloadStart..]);
        }
        else if (cls == "TBitmap")
        {
            // payload: [4B length][BMP bytes]
            int len = BitConverter.ToInt32(data, payloadStart);
            var bmpBytes = new ReadOnlySpan<byte>(data, payloadStart + 4, len);
            SaveBmpAsKeyedPng(bmpBytes.ToArray(), outPath);
        }
        else
        {
            throw new InvalidDataException($"Unknown graphic class '{cls}'");
        }
    }

    /// <summary>Convert BMP to PNG, keying out the bottom-left pixel color (Delphi Transparent convention).</summary>
    static void SaveBmpAsKeyedPng(byte[] bmpBytes, string outPath)
    {
        using var ms = new MemoryStream(bmpBytes);
        using var src = new Bitmap(ms);
        using var dst = new Bitmap(src.Width, src.Height, PixelFormat.Format32bppArgb);
        var key = src.GetPixel(0, src.Height - 1);
        for (int y = 0; y < src.Height; y++)
            for (int x = 0; x < src.Width; x++)
            {
                var c = src.GetPixel(x, y);
                dst.SetPixel(x, y, c.R == key.R && c.G == key.G && c.B == key.B ? Color.Transparent : c);
            }
        dst.Save(outPath, ImageFormat.Png);
    }

    // ---------------------------------------------------------------- maps

    static string? ConvertMap(string mapPath)
    {
        if (!File.Exists(mapPath))
        {
            Console.WriteLine($"  MISSING map {mapPath}");
            return null;
        }

        var text = Encoding.Latin1.GetString(Lzh.Decompress(File.ReadAllBytes(mapPath)));
        var lines = text.Split("\r\n");
        int p = 0;
        string Next() => lines[p++];
        int NextInt() => int.Parse(Next());

        int w = NextInt();
        int h = NextInt();
        string oil = Next();
        int tileW = NextInt();
        int tileH = NextInt();

        // Layer1: 17 lines per tile; keep only the pattern index (game uses nothing else)
        var layer1 = new int[w][];
        for (int a = 0; a < w; a++)
        {
            layer1[a] = new int[h];
            for (int b = 0; b < h; b++)
            {
                p += 8;                       // x,y,r,g,b,alpha,rotation,image.index
                layer1[a][b] = NextInt();     // imageindex (pattern)
                p += 8;                       // animcount..animlooped
            }
        }

        p += w * h * 18;  // Layer2 (has extra DoCollision line)
        p += w * h * 17;  // Layer3

        var triggers = new List<object>();
        for (int a = 0; a < w; a++)
            for (int b = 0; b < h; b++)
            {
                string name = Next();
                string action = Next();
                string e1 = Next(), e2 = Next(), e3 = Next();
                if (action.Length > 0)
                    triggers.Add(new { x = a, y = b, name, action, extra1 = e1, extra2 = e2, extra3 = e3 });
            }

        var mapObj = new
        {
            widthCount = w,
            heightCount = h,
            oil = Path.GetFileName(oil),
            tileWidth = tileW,
            tileHeight = tileH,
            layer1,
            triggers
        };

        string outFile = Path.Combine(_outDir, "maps", Path.GetFileNameWithoutExtension(mapPath) + ".json");
        File.WriteAllText(outFile, JsonSerializer.Serialize(mapObj));
        Console.WriteLine($"  {Path.GetFileName(mapPath)}: {w}x{h}, oil='{oil}', {triggers.Count} triggers -> {Path.GetFileName(outFile)}");
        return oil;
    }

    // ---------------------------------------------------------------- OIL tilesets

    static readonly byte[] PngSig = [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];

    /// <summary>
    /// .oil = binary Delphi component stream. Rather than fully parsing TPF0 we scan for
    /// embedded graphics: "TPNGObject"+PNG or "TBitmap"+[len]+BMP. Item order is preserved;
    /// the game's maps only use item 0 (the tileset).
    /// </summary>
    static void ExtractOilTileset(string oilPath)
    {
        if (!File.Exists(oilPath))
        {
            Console.WriteLine($"  MISSING oil {oilPath}");
            return;
        }

        var data = File.ReadAllBytes(oilPath);
        string baseName = Path.GetFileNameWithoutExtension(oilPath).ToLowerInvariant();
        int found = 0;

        for (int i = 0; i < data.Length - 10; i++)
        {
            if (data[i] == 0x0A && Matches(data, i + 1, "TPNGObject"))
            {
                int start = i + 11;
                if (start + 8 < data.Length && data.AsSpan(start, 8).SequenceEqual(PngSig))
                {
                    int end = FindPngEnd(data, start);
                    if (end > 0)
                    {
                        Save(data[start..end], found);
                        found++;
                        i = end - 1;
                    }
                }
            }
            else if (data[i] == 0x07 && Matches(data, i + 1, "TBitmap"))
            {
                int lenPos = i + 8;
                if (lenPos + 4 >= data.Length) continue;
                int len = BitConverter.ToInt32(data, lenPos);
                int start = lenPos + 4;
                if (len > 14 && start + len <= data.Length && data[start] == 'B' && data[start + 1] == 'M')
                {
                    string file = Path.Combine(_outDir, "tilesets", $"{baseName}_{found:D2}.png");
                    SaveBmpAsKeyedPng(data[start..(start + len)], file);
                    Console.WriteLine($"  {Path.GetFileName(oilPath)}[{found}] (bmp) -> {Path.GetFileName(file)}");
                    found++;
                    i = start + len - 1;
                }
            }
        }

        Console.WriteLine($"  {Path.GetFileName(oilPath)}: {found} images extracted");

        void Save(byte[] png, int idx)
        {
            string file = Path.Combine(_outDir, "tilesets", $"{baseName}_{idx:D2}.png");
            File.WriteAllBytes(file, png);
            Console.WriteLine($"  {Path.GetFileName(oilPath)}[{idx}] (png) -> {Path.GetFileName(file)}");
        }
    }

    static bool Matches(byte[] data, int pos, string s)
    {
        if (pos + s.Length > data.Length) return false;
        for (int i = 0; i < s.Length; i++)
            if (data[pos + i] != (byte)s[i]) return false;
        return true;
    }

    static int FindPngEnd(byte[] data, int start)
    {
        // walk PNG chunks: [4B len BE][4B type][data][4B crc] until IEND
        int p = start + 8;
        while (p + 12 <= data.Length)
        {
            int len = (data[p] << 24) | (data[p + 1] << 16) | (data[p + 2] << 8) | data[p + 3];
            string type = Encoding.ASCII.GetString(data, p + 4, 4);
            p += 12 + len;
            if (type == "IEND") return p;
        }
        return -1;
    }

    // ---------------------------------------------------------------- audio

    static void CopyAudio()
    {
        // Files referenced by OmegaMusic1.Songs in GameU.dfm.
        // 'Level test.mp3' (index 1, level2 music) is missing from the source folder;
        // Track06.mp3 is copied as a substitute.
        (string src, string sub)[] files =
        [
            (@"Music\white light.mp3", "music"),
            (@"Music\G2 Final.mp3", "music"),
            (@"Music\Nazi_Rap.mid", "music"),
            (@"Music\Main Menu 2.mp3", "music"),
            (@"Music\G8 Final.mp3", "music"),
            (@"Music\Thunderization.mp3", "music"),
            (@"Music\Intro.mp3", "music"),
            (@"Music\Track06.mp3", "music"),
            (@"Sounds\fire1.wav", "sfx"),
            (@"Sounds\reload.wav", "sfx"),
            (@"Sounds\thump1.wav", "sfx"),
            (@"Sounds\beep.wav", "sfx"),
            (@"Sounds\hit4.wav", "sfx"),
            (@"Sounds\explode2.wav", "sfx"),
            (@"Sounds\missile.wav", "sfx"),
        ];

        foreach (var (src, sub) in files)
        {
            string from = Path.Combine(_srcDir, src);
            if (!File.Exists(from))
            {
                Console.WriteLine($"  MISSING audio {src}");
                continue;
            }
            string to = Path.Combine(_outDir, sub, Path.GetFileName(src));
            File.Copy(from, to, overwrite: true);
        }
        Console.WriteLine("  audio copied");
    }
}