using Ryujinx.Common.Logging;
using Ryujinx.HLE.Debugger.Gdb;
using Ryujinx.HLE.HOS.Kernel.Process;
using Ryujinx.HLE.HOS.Kernel.Threading;
using System;
using System.Collections.Concurrent;
using System.Linq;
using System.Net.Sockets;
using System.Threading;
using IExecutionContext = Ryujinx.Cpu.IExecutionContext;


namespace Ryujinx.HLE.Debugger
{
    public partial class Debugger : IDisposable
    {
        internal Switch Device { get; private set; }

        public ushort GdbStubPort { get; private set; }

        private readonly BlockingCollection<Message.IMarker> _messages = new(1);
        private readonly Thread _debuggerThread;
        private readonly Thread _messageHandlerThread;

        private TcpListener _listenerSocket;
        private Socket _clientSocket;
        private NetworkStream _readStream;
        private NetworkStream _writeStream;

        private GdbCommandProcessor _commandProcessor;
        private GdbCommands _commands;

        private bool _shuttingDown;
        private readonly ManualResetEventSlim _breakHandlerEvent = new(false);

        internal ulong? CThread;
        internal ulong? GThread;

        public readonly BreakpointManager BreakpointManager;

        public Debugger(Switch device, ushort port)
        {
            Device = device;
            GdbStubPort = port;

            ARMeilleure.Optimizations.EnableDebugging = true;

            _debuggerThread = new Thread(DebuggerThreadMain);
            _debuggerThread.Start();
            _messageHandlerThread = new Thread(MessageHandlerMain);
            _messageHandlerThread.Start();
            BreakpointManager = new BreakpointManager(this);
        }

        internal KProcess Process => Device.System?.DebugGetApplicationProcess();
        internal IDebuggableProcess DebugProcess => Device.System?.DebugGetApplicationProcessDebugInterface();

        internal KThread[] GetThreads() => DebugProcess.ThreadUids.Select(DebugProcess.GetThread).ToArray();

        internal bool IsProcess32Bit => DebugProcess.GetThread(GThread ?? DebugProcess.ThreadUids.First()).Context.IsAarch32;

        internal bool WriteRegister(IExecutionContext ctx, int registerId, StringStream ss) =>
            IsProcess32Bit
                ? ctx.WriteRegister32(registerId, ss)
                : ctx.WriteRegister64(registerId, ss);

        internal string ReadRegister(IExecutionContext ctx, int registerId) =>
            IsProcess32Bit
                ? ctx.ReadRegister32(registerId)
                : ctx.ReadRegister64(registerId);

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                _shuttingDown = true;

                _listenerSocket.Stop();
                _clientSocket?.Shutdown(SocketShutdown.Both);
                _clientSocket?.Close();
                _readStream?.Close();
                _writeStream?.Close();
                _debuggerThread.Join();
                _messages.Add(Message.Kill);
                _messageHandlerThread.Join();
                _messages.Dispose();
                _breakHandlerEvent.Dispose();
            }
        }

        public void BreakHandler(IExecutionContext ctx, ulong address, int imm)
        {
            DebugProcess.DebugInterruptHandler(ctx);

            _breakHandlerEvent.Reset();
            _messages.Add(new ThreadBreakMessage(ctx, address, imm));
            // Messages.Add can block, so we log it after adding the message to make sure user can see the log at the same time GDB receives the break message
            Logger.Notice.Print(LogClass.GdbStub, $"Break hit on thread {ctx.ThreadUid} at pc {address:x016}");
            // Wait for the process to stop before returning to avoid BreakHandler being called multiple times from the same breakpoint
            _breakHandlerEvent.Wait(5000);
        }

        public void StepHandler(IExecutionContext ctx)
        {
            DebugProcess.DebugInterruptHandler(ctx);
        }
    }
}