using System.Collections.Concurrent;
using Yuanshen.Gameserver.Network.Session;
using Yuanshen.Gameserver.Database;
using Yuanshen.Gameserver.Game;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace Yuanshen.Gameserver.Network;
internal class NetSessionManager
{
    private static readonly TimeSpan AutoSaveInterval = TimeSpan.FromSeconds(10);

    private readonly ConcurrentDictionary<long, NetSession> _sessions;
    private readonly ILogger _logger;
    private readonly IServiceScopeFactory _serviceScopeFactory;
    private readonly Yuanshen.Gameserver.Game.ConsoleBridge _consoleBridge;

    public NetSessionManager(ILogger<NetSessionManager> logger, IServiceScopeFactory serviceScopeFactory, Yuanshen.Gameserver.Game.ConsoleBridge consoleBridge)
    {
        _sessions = new();

        _logger = logger;
        _serviceScopeFactory = serviceScopeFactory;
        _consoleBridge = consoleBridge;
    }

    public async Task RunSessionAsync(long sessionId, INetworkUnit networkUnit)
    {
        try
        {
            await using AsyncServiceScope serviceScope = _serviceScopeFactory.CreateAsyncScope();
            NetSession session = serviceScope.ServiceProvider.GetRequiredService<NetSession>();
            _consoleBridge.Attach(serviceScope.ServiceProvider);
            PlayerPersistence persistence = serviceScope.ServiceProvider.GetRequiredService<PlayerPersistence>();
            persistence.Bind(sessionId);

            using CancellationTokenSource sessionEnded = new();
            Task autoSave = RunAutoSaveAsync(persistence, sessionEnded.Token);

            try
            {
                session.Establish(sessionId, networkUnit);
                await session.RunAsync();
            }
            catch (OperationCanceledException)
            {
            }
            catch (Exception exception)
            {
                _logger.LogError("Exception occurred during handling a session, trace: {exception}", exception);
            }
            finally
            {
                await sessionEnded.CancelAsync();
                await autoSave;

                if (await persistence.SaveAsync())
                    _logger.LogInformation("Player {uid} state persisted on disconnect", persistence.PlayerUid);

                persistence.Release();
                _consoleBridge.Detach(serviceScope.ServiceProvider);
            }
        }
        catch (Exception exception)
        {
            _logger.LogError("Failed to start session {sessionId}: {exception}", sessionId, exception);
        }
    }

    private static async Task RunAutoSaveAsync(PlayerPersistence persistence, CancellationToken cancellationToken)
    {
        using PeriodicTimer timer = new(AutoSaveInterval);

        try
        {
            while (await timer.WaitForNextTickAsync(cancellationToken))
                await persistence.SaveAsync();
        }
        catch (OperationCanceledException)
        {
        }
    }

    public void Add(NetSession session)
    {
        _sessions[session.SessionId] = session;
        _logger.LogInformation("New connection from {endPoint}", session.EndPoint);
    }

    public bool TryRemove(NetSession session)
    {
        bool removed = _sessions.TryRemove(session.SessionId, out _);
        if (removed)
        {
            _logger.LogInformation("Client from {endPoint} disconnected", session.EndPoint);
        }

        return removed;
    }
}