using Application.Abstractions.Cache;
using Application.Abstractions.Chat;
using Application.Abstractions.Data;
using Application.Abstractions.Hub;
using Microsoft.AspNetCore.SignalR;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.IdentityModel.JsonWebTokens;
using SharedKernel.Extensions;
using StackExchange.Redis;

namespace Infrastructure.Hubs;

/// <summary>
/// 공통 Hub — 모든 페이지에서 사용
/// 접속자 추적 + 채팅 + 알림 + 쪽지 + 크루 초대/동의/toast + YouTube 채팅 통합
/// </summary>
public sealed class AppHub(
    IConnectionMultiplexer redis,
    IPresenceTracker presence,
    IVisitorTracker visitors,
    IServiceScopeFactory scopeFactory
) : Hub<IAppHubClient>
{
    // ── 연결 관리 ────────────────────────────────────────────────

    public override async Task OnConnectedAsync()
    {
        var memberID = GetMemberID();
        var httpContext = Context.GetHttpContext();
        var ip = httpContext?.GetClientIP() ?? "Unknown";
        var ua = httpContext?.GetUserAgent() ?? "Unknown";

        if (memberID > 0)
        {
            var db = redis.GetDatabase();
            await db.HashSetAsync(CacheKeys.ChatConnections, Context.ConnectionId, memberID);

            // Online presence (refcount). 0→1 전환이면 구독자에게 broadcast.
            var wasFirst = await presence.AddConnectionAsync(memberID, Context.ConnectionId);

            // 개인 그룹 (알림/쪽지용)
            await Groups.AddToGroupAsync(Context.ConnectionId, $"member:{memberID}");

            if (wasFirst)
            {
                await Clients.Group(PresenceGroup(memberID)).ReceivePresenceChange(memberID, true);
            }

            // 전역 접속자 기록 (Admin 현재 접속자 페이지용)
            var memberName = Context.User?.FindFirst(JwtRegisteredClaimNames.Name)?.Value;

            string? email = null;
            using (var scope = scopeFactory.CreateScope())
            {
                var appDb = scope.ServiceProvider.GetRequiredService<IAppDbContext>();
                email = await appDb.Member.AsNoTracking().Where(x => x.ID == memberID).Select(x => x.Email).FirstOrDefaultAsync();
            }

            await visitors.AddAsync(new ConnectedUser(Context.ConnectionId, memberID, email, memberName, ip, ua, false, DateTime.UtcNow));
        }
        else
        {
            // 비로그인 게스트도 전역 접속자에 기록
            await visitors.AddAsync(new ConnectedUser(Context.ConnectionId, null, null, null, ip, ua, true, DateTime.UtcNow));
        }

        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        // 전역 접속자 제거 (Admin 현재 접속자 페이지용)
        await visitors.RemoveAsync(Context.ConnectionId);

        var db = redis.GetDatabase();
        var memberIDValue = await db.HashGetAsync(CacheKeys.ChatConnections, Context.ConnectionId);
        await db.HashDeleteAsync(CacheKeys.ChatConnections, Context.ConnectionId);

        if (memberIDValue.HasValue && int.TryParse(memberIDValue.ToString(), out var memberID) && memberID > 0)
        {
            var wasLast = await presence.RemoveConnectionAsync(memberID, Context.ConnectionId);

            if (wasLast)
            {
                await Clients.Group(PresenceGroup(memberID)).ReceivePresenceChange(memberID, false);
            }
        }

        await base.OnDisconnectedAsync(exception);
    }

    // ── 채팅 그룹 참가/퇴장 ──────────────────────────────────────

    public async Task JoinChat(string room)
    {
        await Groups.AddToGroupAsync(Context.ConnectionId, $"chat:{room}");
    }

    public async Task LeaveChat(string room)
    {
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, $"chat:{room}");
    }

    // ── 채팅 메시지 전송 ─────────────────────────────────────────

    public async Task SendMessage(string room, ChatMessage message)
    {
        await Clients.Group($"chat:{room}").ReceiveMessage(message);
    }

    // ── 채널 그룹 (크루 초대/동의 실시간 등) ─────────────────────

    public async Task JoinChannel(string channelSID)
    {
        await Groups.AddToGroupAsync(Context.ConnectionId, $"channel:{channelSID}");
    }

    public async Task LeaveChannel(string channelSID)
    {
        await Groups.RemoveFromGroupAsync(Context.ConnectionId, $"channel:{channelSID}");
    }

    // ── Presence 구독 (특정 멤버들의 online 변화 수신) ───────────

    /// <summary>여러 멤버의 presence 변화 수신을 구독.</summary>
    public async Task SubscribePresence(int[] memberIDs)
    {
        if (memberIDs is null || memberIDs.Length == 0)
        {
            return;
        }

        foreach (var id in memberIDs.Distinct())
        {
            if (id > 0)
            {
                await Groups.AddToGroupAsync(Context.ConnectionId, PresenceGroup(id));
            }
        }
    }

    /// <summary>구독 해제.</summary>
    public async Task UnsubscribePresence(int[] memberIDs)
    {
        if (memberIDs is null || memberIDs.Length == 0)
        {
            return;
        }

        foreach (var id in memberIDs.Distinct())
        {
            if (id > 0)
            {
                await Groups.RemoveFromGroupAsync(Context.ConnectionId, PresenceGroup(id));
            }
        }
    }

    // ── Private ──────────────────────────────────────────────────

    private int GetMemberID()
    {
        // JWT sub 클레임 (Infrastructure/DependencyInjection.cs 에서 MapInboundClaims=false 이므로 그대로 "sub" 이름).
        var claim = Context.User?.FindFirst(JwtRegisteredClaimNames.Sub)?.Value;
        return int.TryParse(claim, out var id) ? id : 0;
    }

    private static string PresenceGroup(int memberID) => $"presence:{memberID}";
}