using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO.Ports;
using VPlasma.Core.Device;
using VPlasma.Core.Protocol;

namespace VPlasma.Wire;

/// <summary>
/// Differential-test helper for the plasma display work. Generates repeatable
/// command streams, replays them to any target (the real panel, the Matrix
/// Portal replica, or a virtual port), captures live traffic, and renders the
/// vPLASMA "golden image" for comparison. Feed the same stream to all three
/// and the glass should match.
///
/// <para>Commands:</para>
/// <code>
/// synth   --kind selftest|demo|charset|banner  --out stream.bin
/// render  --in stream.bin  --out frame.png  [--scale 8] [--orient h|v]
/// replay  --in stream.bin  --port COM3  [--baud 9600] [--paced]
/// capture --port COM12 --out stream.bin  [--tee COM3] [--seconds N]
/// </code>
/// </summary>
internal static class Program
{
    private static int Main(string[] args)
    {
        if (args.Length == 0)
            return Usage();

        var a = new Args(args);
        try
        {
            switch (args[0].ToLowerInvariant())
            {
                case "synth": return Synth(a);
                case "render": return Render(a);
                case "replay": return Replay(a);
                case "capture": return Capture(a);
                case "-h" or "--help" or "help": return Usage();
                default:
                    Console.Error.WriteLine($"Unknown command '{args[0]}'.");
                    return Usage();
            }
        }
        catch (Exception ex)
        {
            Console.Error.WriteLine($"Error: {ex.Message}");
            return 1;
        }
    }

    // ---- synth: build a repeatable command stream --------------------------

    private static int Synth(Args a)
    {
        string kind = a.Get("kind", "selftest").ToLowerInvariant();
        string outPath = a.Require("out");

        var b = new List<byte>();
        switch (kind)
        {
            case "selftest":
                for (int p = 0; p < PlasmaSelfTest.PageCount; p++)
                    b.AddRange(PlasmaSelfTest.BuildPage(p));
                break;
            case "demo":
                foreach (byte[] screen in PlasmaFirmwareDemo.Screens)
                    b.AddRange(screen);
                break;
            case "banner":
                b.AddRange(PlasmaSelfTest.BuildPage(0));
                break;
            case "charset":
                b.Add(PlasmaProtocol.Esc); b.Add(PlasmaProtocol.CmdClearScreen);
                b.Add(PlasmaProtocol.Esc); b.Add(PlasmaProtocol.CmdCursorMode); b.Add(0x00);
                for (int c = 0x20; c <= 0x7E; c++) b.Add((byte)c);
                break;
            default:
                Console.Error.WriteLine("--kind must be selftest | demo | banner | charset");
                return 1;
        }

        File.WriteAllBytes(outPath, b.ToArray());
        Console.WriteLine($"Wrote {b.Count} bytes to {outPath}  (kind={kind})");
        return 0;
    }

    // ---- render: the vPLASMA golden image ----------------------------------

    private static int Render(Args a)
    {
        string inPath = a.Require("in");
        string outPath = a.Require("out");
        int scale = a.GetInt("scale", 8);
        bool vertical = a.Get("orient", "h").StartsWith("v", StringComparison.OrdinalIgnoreCase);

        var device = new VPlasmaDevice();
        if (vertical)
            device.Orientation = PlasmaOrientation.Vertical;
        byte[] data = File.ReadAllBytes(inPath);
        device.OnReceived(data, data.Length);

        var frame = new byte[VPlasmaDevice.Width * VPlasmaDevice.Height];
        device.CopyFrame(frame);
        RenderPng(frame, outPath, scale);

        Console.WriteLine($"Fed {data.Length} bytes; rendered {VPlasmaDevice.Width}×{VPlasmaDevice.Height} " +
                          $"({device.TextCharsDrawn} chars, {device.GraphicsRows} graphics rows) → {outPath}");
        return 0;
    }

    private static void RenderPng(byte[] frame, string outPath, int scale)
    {
        int pitch = scale;
        int dot = Math.Max(1, scale - 2);
        int W = VPlasmaDevice.Width, H = VPlasmaDevice.Height;

        using var bmp = new Bitmap(W * pitch, H * pitch, PixelFormat.Format24bppRgb);
        using var g = Graphics.FromImage(bmp);
        g.Clear(Color.FromArgb(20, 18, 16));
        using var glass = new SolidBrush(Color.FromArgb(26, 14, 6));
        g.FillRectangle(glass, 0, 0, bmp.Width, bmp.Height);

        using var unlit = new SolidBrush(Color.FromArgb(46, 24, 10));
        using var lit = new SolidBrush(Color.FromArgb(255, 106, 26));
        using var half = new SolidBrush(Color.FromArgb(150, 62, 15));

        for (int y = 0; y < H; y++)
        {
            for (int x = 0; x < W; x++)
            {
                byte px = frame[y * W + x];
                // Static image: render a flashing dot in its "on" phase.
                Brush brush = (px & VPlasmaDevice.PixelLit) != 0
                    ? ((px & VPlasmaDevice.PixelHalf) != 0 ? half : lit)
                    : unlit;
                g.FillRectangle(brush, x * pitch, y * pitch, dot, dot);
            }
        }
        bmp.Save(outPath, ImageFormat.Png);
    }

    // ---- replay: send a stream to a target port ----------------------------

    private static int Replay(Args a)
    {
        string inPath = a.Require("in");
        string portName = a.Require("port");
        int baud = a.GetInt("baud", PlasmaProtocol.BaudRate);
        bool paced = a.Has("paced");

        byte[] data = File.ReadAllBytes(inPath);
        using var port = new SerialPort(portName, baud, Parity.None, 8, StopBits.One)
        {
            Handshake = Handshake.None,
            WriteTimeout = 5000,
            DtrEnable = true,
            RtsEnable = true,
        };
        port.Open();

        if (paced)
        {
            // One byte per 10-bit frame time — for virtual ports with no UART.
            long period = Stopwatch.Frequency * 10 / baud;
            long slot = Stopwatch.GetTimestamp();
            var one = new byte[1];
            foreach (byte t in data)
            {
                slot = Math.Max(slot + period, Stopwatch.GetTimestamp());
                while (Stopwatch.GetTimestamp() < slot) { /* spin */ }
                one[0] = t;
                port.Write(one, 0, 1);
            }
        }
        else
        {
            // A real UART at `baud` paces itself; a USB-CDC target takes it fast.
            port.Write(data, 0, data.Length);
        }

        Console.WriteLine($"Replayed {data.Length} bytes to {portName} @ {baud} 8N1{(paced ? " (paced)" : "")}.");
        Thread.Sleep(200); // let the last bytes drain before closing
        return 0;
    }

    // ---- capture: log live traffic (optionally teeing to the display) ------

    private static int Capture(Args a)
    {
        string portName = a.Require("port");
        string outPath = a.Require("out");
        string? teeName = a.Get("tee", "");
        int seconds = a.GetInt("seconds", 0);

        using var port = new SerialPort(portName, a.GetInt("baud", PlasmaProtocol.BaudRate),
            Parity.None, 8, StopBits.One) { Handshake = Handshake.None, ReadTimeout = 200 };
        port.Open();

        SerialPort? tee = null;
        if (!string.IsNullOrWhiteSpace(teeName))
        {
            tee = new SerialPort(teeName, a.GetInt("baud", PlasmaProtocol.BaudRate), Parity.None, 8, StopBits.One)
            { Handshake = Handshake.None, DtrEnable = true, RtsEnable = true };
            tee.Open();
        }

        using var outFile = File.Create(outPath);
        var stop = new ManualResetEventSlim(false);
        Console.CancelKeyPress += (_, e) => { e.Cancel = true; stop.Set(); };
        var deadline = seconds > 0 ? Stopwatch.StartNew() : null;

        Console.WriteLine($"Capturing {portName} → {outPath}" +
                          (tee != null ? $" (tee → {teeName})" : "") +
                          $". {(seconds > 0 ? $"{seconds}s or " : "")}Ctrl+C to stop.");
        long total = 0;
        var buf = new byte[512];
        while (!stop.IsSet && (deadline is null || deadline.Elapsed.TotalSeconds < seconds))
        {
            int n;
            try { n = port.Read(buf, 0, buf.Length); }
            catch (TimeoutException) { continue; }
            if (n <= 0) continue;
            outFile.Write(buf, 0, n);
            tee?.Write(buf, 0, n);
            total += n;
            Console.Write($"\r{total} bytes captured");
        }
        Console.WriteLine($"\nDone. {total} bytes → {outPath}");
        tee?.Dispose();
        return 0;
    }

    // ---- tiny arg parser ---------------------------------------------------

    private sealed class Args
    {
        private readonly Dictionary<string, string> _kv = new(StringComparer.OrdinalIgnoreCase);
        private readonly HashSet<string> _flags = new(StringComparer.OrdinalIgnoreCase);

        public Args(string[] args)
        {
            for (int i = 1; i < args.Length; i++)
            {
                if (!args[i].StartsWith("--")) continue;
                string key = args[i].Substring(2);
                if (i + 1 < args.Length && !args[i + 1].StartsWith("--"))
                    _kv[key] = args[++i];
                else
                    _flags.Add(key);
            }
        }

        public bool Has(string k) => _flags.Contains(k) || _kv.ContainsKey(k);
        public string Get(string k, string dflt) => _kv.TryGetValue(k, out var v) ? v : dflt;
        public int GetInt(string k, int dflt) => _kv.TryGetValue(k, out var v) && int.TryParse(v, out var n) ? n : dflt;
        public string Require(string k) => _kv.TryGetValue(k, out var v)
            ? v : throw new ArgumentException($"--{k} is required");
    }

    private static int Usage()
    {
        Console.WriteLine("""
            vPLASMA wire tool — differential-test helper.

              synth   --kind selftest|demo|banner|charset  --out stream.bin
                      Build a repeatable command stream.

              render  --in stream.bin  --out frame.png  [--scale 8] [--orient h|v]
                      Feed the stream through the vPLASMA engine and save the
                      resulting 128×32 frame as a PNG (the golden image).

              replay  --in stream.bin  --port COM3  [--baud 9600] [--paced]
                      Send the stream to a target: the real panel, the Matrix
                      Portal replica (USB-CDC), or a virtual port (--paced).

              capture --port COM12 --out stream.bin  [--tee COM3] [--seconds N]
                      Log live traffic to a file; --tee forwards it on to the
                      real display so capture is non-intrusive. Ctrl+C to stop.

            Differential test: `synth` a stream once, `render` the golden PNG,
            `replay` the same stream to the replica and to the real panel, and
            compare the three.
            """);
        return 0;
    }
}