using System.Reactive.Linq;
using Microsoft.Extensions.Logging;
using TeamsISO.Engine.Controller;
using TeamsISO.Engine.Domain;
using TeamsISO.Engine.Interop;
using TeamsISO.Engine.Logging;
using TeamsISO.Engine.NdiInterop;
using TeamsISO.Engine.Persistence;
using TeamsISO.Engine.Pipeline;

namespace TeamsISO.Console;

using SysConsole = System.Console;

/// <summary>
/// Headless smoke runner. Wires up the engine end-to-end against the production NDI P/Invoke
/// interop and prints participant updates, alerts, and ISO state. Useful for first-validation
/// against a real Teams meeting before the WPF UI is alive.
///
/// Requires Windows + the NDI Runtime installed.
///
/// Usage:
///   teamsiso-console                   # discover only — print participants as they appear/leave
///   teamsiso-console --enable-all      # auto-enable an ISO for every discovered participant
/// </summary>
public static class Program
{
    public static async Task<int> Main(string[] args)
    {
        var enableAll = args.Contains("--enable-all", StringComparer.OrdinalIgnoreCase);
        using var loggerFactory = EngineLogging.CreateConsole(LogLevel.Information);
        var logger = loggerFactory.CreateLogger("TeamsISO.Console");

        if (!OperatingSystem.IsWindows())
        {
            logger.LogError("TeamsISO.Console requires Windows + the NDI Runtime. Current OS is not Windows.");
            return 1;
        }

        NdiInteropPInvoke interop;
        try
        {
            interop = new NdiInteropPInvoke(loggerFactory.CreateLogger<NdiInteropPInvoke>());
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Could not initialize NDI runtime. Install the NDI Runtime from https://ndi.video/tools/ and try again.");
            return 2;
        }

        var configPath = Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
            "TeamsISO", "config.json");
        var configStore = new ConfigStore(configPath, loggerFactory.CreateLogger<ConfigStore>());

        var probe = new NdiRuntimeProbe(interop, NdiVersion.ExpectedRuntimeVersionPrefix);
        var scaler = new ManagedNearestNeighborFrameScaler();

        // Pipeline factory: wires up real NDI receiver/processor/sender against the production interop.
        IsoPipeline PipelineFactory(IsoPipelineConfig config)
        {
            var clock = new PeriodicTimerFrameClock(config.Settings.FramerateHz);
            return new IsoPipeline(
                config, interop, scaler, clock,
                ExponentialBackoff.Default,
                (delay, ct) => Task.Delay(delay, ct),
                loggerFactory);
        }

        await using var controller = new IsoController(
            interop, PipelineFactory, configStore, probe, loggerFactory);

        // Wire up event printing
        var sub1 = controller.Participants
            .DistinctUntilChanged()
            .Subscribe(plist =>
            {
                logger.LogInformation("Participants ({Count}):", plist.Count);
                foreach (var p in plist)
                    logger.LogInformation("  - {Name}  source={Source}", p.DisplayName, p.CurrentSource?.FullName ?? "<none>");
            });
        var sub2 = controller.Alerts.Subscribe(a => logger.LogWarning("ALERT: {Message}", a.Message));

        using var cts = new CancellationTokenSource();
        SysConsole.CancelKeyPress += (_, e) => { e.Cancel = true; cts.Cancel(); };

        await controller.StartAsync(cts.Token);
        logger.LogInformation("Engine started. Default framerate: {Fps:F2} fps. Press Ctrl+C or 'q' Enter to quit.",
            controller.GlobalSettings.FramerateHz);

        if (enableAll)
        {
            // Auto-enable any participant we see, until cancellation.
            controller.Participants.Subscribe(async plist =>
            {
                foreach (var p in plist.Where(p => p.CurrentSource is not null))
                {
                    try { await controller.EnableIsoAsync(p.Id, customName: null, cts.Token); }
                    catch (Exception ex) { logger.LogWarning(ex, "Could not enable ISO for {Name}.", p.DisplayName); }
                }
            });
        }

        // Read until 'q' or cancellation.
        var input = Task.Run(() =>
        {
            while (!cts.IsCancellationRequested)
            {
                var line = SysConsole.ReadLine();
                if (line is null) return;
                if (line.Trim().Equals("q", StringComparison.OrdinalIgnoreCase))
                {
                    cts.Cancel();
                    return;
                }
            }
        });

        try { await Task.Delay(Timeout.Infinite, cts.Token); }
        catch (OperationCanceledException) { /* expected on quit */ }

        sub1.Dispose();
        sub2.Dispose();
        interop.Dispose();
        logger.LogInformation("Engine stopped.");
        return 0;
    }
}