using Nonemm.Digital;

namespace Nonemm.EngineProbe;

/// Starts MMTTY through the bridge, asks it the questions in `EngineProbe`, and
/// writes what it answered to a file. It has to run where MMTTY runs: a sound
/// card and a Wine prefix with XMMT.ocx registered.
public static class Program
{
    private const string Usage = """
        usage: engine probe --engine <path to MMTTY.EXE> [options]

          --engine <path>   the engine to start, as a Linux path
          --bridge <path>   the bridge program (default bridge/nonemm-mmtty-bridge.exe)
          --prefix <path>   WINEPREFIX to run in (default: Wine's own)
          --ptt <port>      serial port to key (default: none, so no radio is keyed)
          --out <file>      where to write the report (default engine-probe.log)
          --log <folder>    where to write the protocol log, if it is wanted

        The probe transmits: MMTTY makes tones on the sound card for about half a
        minute. It keys no serial port unless --ptt says so, but a rig listening to
        that sound card through VOX will still go on the air.
        """;

    public static async Task<int> Main(string[] arguments)
    {
        Dictionary<string, string> options;
        try
        {
            options = Read(arguments);
        }
        catch (ArgumentException problem)
        {
            Console.Error.WriteLine(problem.Message);
            Console.Error.WriteLine();
            Console.Error.WriteLine(Usage);
            return 1;
        }

        using CancellationTokenSource stopping = new();
        Console.CancelKeyPress += (_, e) =>
        {
            e.Cancel = true;
            stopping.Cancel();
        };

        using ProbeLog log = new(Option(options, "out", "engine-probe.log"));
        MmttyEngine engine = new(
            new WineBridgeChannel(
                Option(options, "bridge", Path.Combine("bridge", "nonemm-mmtty-bridge.exe")),
                options.GetValueOrDefault("prefix"),
                logFolder: options.GetValueOrDefault("log")),
            new MmttyOptions
            {
                EnginePath = options["engine"],
                PttPort = Option(options, "ptt", ""),
            });
        try
        {
            log.Write($"starting {options["engine"]}");
            await engine.StartAsync(stopping.Token).ConfigureAwait(false);
            log.Write($"MMTTY {engine.Version} is up");
            await new EngineProbe(engine, log).RunAsync(stopping.Token).ConfigureAwait(false);
        }
        catch (OperationCanceledException)
        {
            log.Write("stopped");
        }
        catch (Exception problem)
        {
            log.Write($"failed: {problem.Message}");
            Console.Error.WriteLine(problem);
            return 1;
        }
        finally
        {
            await Shutdown(engine, log).ConfigureAwait(false);
            Console.WriteLine();
            Console.WriteLine($"the report is in {log.Path}");
        }
        return 0;
    }

    /// The engine is left keyed if the probe stopped partway through, so the
    /// transmission is aborted before the engine is shut down, whatever
    /// happened.
    private static async Task Shutdown(MmttyEngine engine, ProbeLog log)
    {
        try
        {
            await engine.AbortAsync().ConfigureAwait(false);
            await engine.StopAsync().ConfigureAwait(false);
        }
        catch (Exception problem)
        {
            log.Write($"the engine did not shut down cleanly: {problem.Message}");
        }
        engine.Dispose();
    }

    private static Dictionary<string, string> Read(string[] arguments)
    {
        Dictionary<string, string> options = [];
        for (int i = 0; i < arguments.Length; i += 2)
        {
            if (!arguments[i].StartsWith("--", StringComparison.Ordinal))
            {
                throw new ArgumentException($"expected an option, found {arguments[i]}");
            }
            if (i + 1 >= arguments.Length)
            {
                throw new ArgumentException($"{arguments[i]} needs a value");
            }
            options[arguments[i][2..]] = arguments[i + 1];
        }
        if (!options.ContainsKey("engine"))
        {
            throw new ArgumentException("--engine is required");
        }
        return options;
    }

    private static string Option(Dictionary<string, string> options, string name, string fallback) =>
        options.TryGetValue(name, out string? given) ? given : fallback;
}