feat(cli): add CLI entry point

src/Chip8.Cli/Program.cs

@@ -0,0 +1,133 @@
+using System;
+using System.IO;
+using Chip8.Core;
+using Chip8.Core.Audio;
+using Chip8.Core.Export;
+
+namespace Chip8.Cli;
+
+static class Program
+{
+    static int Main(string[] args)
+    {
+        if (args.Length == 0 || args[0] == "-h" || args[0] == "--help")
+        {
+            printUsage();
+            return args.Length == 0 ? 1 : 0;
+        }
+
+        switch (args[0])
+        {
+            case "asm":
+                return AsmCommand.run(args[1..]);
+            case "disasm":
+                return DisasmCommand.run(args[1..]);
+            case "debug":
+                return TuiDebugger.run(args[1..]);
+        }
+
+        Options options;
+        try
+        {
+            options = Options.parse(args);
+        }
+        catch (ArgumentException error)
+        {
+            Console.Error.WriteLine($"error: {error.Message}");
+            printUsage();
+            return 1;
+        }
+
+        if (!File.Exists(options.romPath))
+        {
+            Console.Error.WriteLine($"error: ROM not found: {options.romPath}");
+            return 1;
+        }
+
+        byte[] rom = File.ReadAllBytes(options.romPath);
+        var machine = new Machine(options.buildQuirks(), options.seed, options.buildPlatform());
+        machine.loadRom(rom);
+
+        if (options.headless || options.dumpPpmPath is not null || options.dumpWavPath is not null)
+        {
+            return runHeadless(machine, options);
+        }
+
+        RaylibFrontend.run(machine, options);
+        return 0;
+    }
+
+    static int runHeadless(Machine machine, Options options)
+    {
+        AudioTrack? track = null;
+        if (options.dumpWavPath is not null)
+        {
+            int frames = Math.Max(1, options.cycles / options.instructionsPerFrame);
+            track = new AudioRecorder().record(machine, frames, options.instructionsPerFrame);
+        }
+        else
+        {
+            for (int cycle = 0; cycle < options.cycles; cycle++)
+            {
+                machine.step();
+                if (cycle % options.instructionsPerFrame == options.instructionsPerFrame - 1)
+                {
+                    machine.tickTimers();
+                }
+            }
+        }
+
+        if (machine.platform == Platform.Chip8)
+        {
+            Console.Write(AsciiScreen.renderFramed(machine.display));
+        }
+        else
+        {
+            Console.Write(AsciiScreen.render(machine.video));
+        }
+
+        int litPixels = machine.platform == Platform.Chip8
+            ? AsciiScreen.litPixelCount(machine.display)
+            : AsciiScreen.litPixelCount(machine.video);
+        Console.WriteLine(
+            $"rom={Path.GetFileName(options.romPath)} cycles={options.cycles} " +
+            $"litPixels={litPixels} soundActive={machine.soundActive}");
+
+        if (options.dumpPpmPath is not null)
+        {
+            PpmImage.writeFile(options.dumpPpmPath, PpmImage.fromMachine(machine, options.buildPalette(), options.scale));
+            Console.WriteLine($"wrote frame to {options.dumpPpmPath}");
+        }
+
+        if (options.dumpWavPath is not null && track is not null)
+        {
+            WavFile.writeFile(options.dumpWavPath, track.toSamples(), AudioRecorder.defaultSampleRate);
+            Console.WriteLine($"wrote {track.durationSeconds:0.00}s of audio to {options.dumpWavPath}");
+        }
+
+        return 0;
+    }
+
+    static void printUsage()
+    {
+        Console.WriteLine("chip8-sharp - CHIP-8 / SUPER-CHIP / XO-CHIP emulator");
+        Console.WriteLine();
+        Console.WriteLine("usage: chip8 <rom> [options]");
+        Console.WriteLine("       chip8 asm <source.asm> [-o out.ch8] [--listing]");
+        Console.WriteLine("       chip8 disasm <rom.ch8> [--base 0x200]");
+        Console.WriteLine("       chip8 debug <rom.ch8> [--platform NAME]");
+        Console.WriteLine();
+        Console.WriteLine("  --headless        run without a window, dump the framebuffer as ASCII");
+        Console.WriteLine("  --cycles N        instructions to run in headless mode (default 2000)");
+        Console.WriteLine("  --ipf N           instructions per 60Hz frame (default 11)");
+        Console.WriteLine("  --scale N         window / PPM pixel scale (default 14)");
+        Console.WriteLine("  --seed N          deterministic RNG seed");
+        Console.WriteLine("  --platform NAME   chip8 (default), superchip, or xochip");
+        Console.WriteLine("  --quirks NAME     auto (default), modern, cosmac, superchip, xochip");
+        Console.WriteLine("  --palette NAME    octo (default), mono, grayscale, extended16");
+        Console.WriteLine("  --ppm PATH        export the final frame as a PPM image");
+        Console.WriteLine("  --wav PATH        export the buzzer audio as a WAV file");
+        Console.WriteLine();
+        Console.WriteLine("keys: 1234/QWER/ASDF/ZXCV map to the CHIP-8 hex pad");
+    }
+}