using Microsoft.Extensions.DependencyInjection;
using Microsoft.Iris.Debug;
using Microsoft.Iris.Debug.Data;
using Microsoft.Iris.DebugAdapter.Server.Handlers;
using Newtonsoft.Json.Linq;
using OmniSharp.Extensions.DebugAdapter.Protocol.Events;
using OmniSharp.Extensions.DebugAdapter.Server;
using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.Iris.DebugAdapter.Server;

public class IrisDebugAdapterServer : IDebuggerServer, IRemoteDebuggerState, IDisposable
{
    private readonly TaskCompletionSource<bool> _serverStopped;
    private Stream _inputStream, _outputStream;
    private InterpreterCommand _debuggerCommand;

    public IrisDebugAdapterServer(IrisDebugServerOptions options)
    {
        _serverStopped = new();

        Options = options;
        ConnectionString = options.ConnectionString;
    }

    internal IrisDebugServerOptions Options { get; }

    internal DebugAdapterServer? Server { get; private set; }

    public InterpreterCommand DebuggerCommand
    {
        get => _debuggerCommand;
        set
        {
            _debuggerCommand = value;

            if (Server is null)
                return;
        }
    }

    public string ConnectionString { get; }

    /// <summary>
    /// Start the debug server listening.
    /// </summary>
    /// <returns>A task that completes when the server is ready.</returns>
    public async Task StartAsync()
    {
        Server = DebugAdapterServer.Create(options =>
        {
            // We need to let the PowerShell Context Service know that we are in a debug session
            // so that it doesn't send the powerShell/startDebugger message.
            //_psesHost = ServiceProvider.GetService<PsesInternalHost>();
            //_psesHost.DebugContext.IsDebugServerActive = true;

            options
                .WithInput(_inputStream)
                .WithOutput(_outputStream)
                .WithServices(serviceCollection =>
                    serviceCollection
                        .AddOptions()
                        .AddIrisDebugServices(this, Options.SymbolDir, Options.SourceDir)
                )
                // TODO: Consider replacing all WithHandler with AddSingleton
                .WithHandler<AttachHandler>()
                //.WithHandler<DisconnectHandler>()
                .WithHandler<BreakpointHandler>()
                //.WithHandler<ConfigurationDoneHandler>()
                .WithHandler<ThreadsHandler>()
                .WithHandler<StackTraceHandler>()
                //.WithHandler<ScopesHandler>()
                //.WithHandler<VariablesHandler>()
                .WithHandler<ContinueHandler>()
                .WithHandler<NextHandler>()
                .WithHandler<PauseHandler>()
                .WithHandler<StepInHandler>()
                //.WithHandler<StepOutHandler>()
                .WithHandler<SourceHandler>()
                //.WithHandler<SetVariableHandler>()
                //.WithHandler<DebugEvaluateHandler>()
                // The OnInitialize delegate gets run when we first receive the _Initialize_ request:
                // https://microsoft.github.io/debug-adapter-protocol/specification#Requests_Initialize
                .OnInitialize(async (server, _, cancellationToken) =>
                {
                    System.Diagnostics.Debug.WriteLine("SERVER: OnInitialize called");
                    Console.WriteLine("SERVER: OnInitialize called");
                })
                .OnInitialized((_, _, response, _) =>
                {
                    System.Diagnostics.Debug.WriteLine("SERVER: OnInitialized called");
                    Console.WriteLine("SERVER: OnInitialized called");
                    return Task.CompletedTask;
                })
            ;
        });
        
        await Server.Initialize(default).ConfigureAwait(false);

        Connected?.Invoke(this, EventArgs.Empty);

        await WaitForShutdownAsync().ConfigureAwait(false);
    }

    public void Dispose()
    {
        // Note that the lifetime of the DebugContext is longer than the debug server;
        // It represents the debugger on the PowerShell process we're in,
        // while a new debug server is spun up for every debugging session
        //_psesHost.DebugContext.IsDebugServerActive = false;
        Server?.Dispose();
        _inputStream.Dispose();
        _outputStream.Dispose();
        _serverStopped.SetResult(true);
    }

    public async Task WaitForShutdownAsync() => await _serverStopped.Task.ConfigureAwait(false);

    public event EventHandler? SessionEnded;
    public event Action<IDebuggerState, object> Connected;

    internal void OnSessionEnded() => SessionEnded?.Invoke(this, EventArgs.Empty);

    public MarkupLineNumberEntry[] OnLineNumberTableRequested(string uri)
    {
        return [];
    }

    public void LogInterpreterDecode(object context, InterpreterInstruction instruction)
    {
    }

    public void LogInterpreterExecute(object context, InterpreterEntry entry)
    {
    }

    public void LogDispatcher(string message)
    {
    }

    public void WaitForContinue()
    {
        System.Diagnostics.Debugger.Launch();
        if (DebuggerCommand is InterpreterCommand.Break)
        {
            Server?.SendStopped(new()
            {
                Reason = new("unknown"),
                ThreadId = 0,
            });
        }

        while (DebuggerCommand is InterpreterCommand.Break) ;

        Server?.SendContinued(new()
        {
            ThreadId = 0,
        });
    }

    public void Start()
    {
        ConnectionStringHelper.CreateFromString(ConnectionString, out _inputStream, out _outputStream);

        Thread serverThread = new(() =>
        {
            _ = StartAsync();
            //.ContinueWith(t =>
            //{
            //    if (t.Exception is not null)
            //        System.Diagnostics.Debug.WriteLine(t.Exception);
            //});
        });
        serverThread.IsBackground = true;
        serverThread.Start();
    }
}