using ChessCubing.Server.Users;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.SignalR;

namespace ChessCubing.Server.Social;

[Authorize]
public sealed class SocialHub(
    ConnectedUserTracker tracker,
    MySqlSocialStore socialStore,
    MySqlUserProfileStore profileStore,
    PlayInviteCoordinator playInviteCoordinator) : Hub
{
    private readonly ConnectedUserTracker _tracker = tracker;
    private readonly MySqlSocialStore _socialStore = socialStore;
    private readonly MySqlUserProfileStore _profileStore = profileStore;
    private readonly PlayInviteCoordinator _playInviteCoordinator = playInviteCoordinator;

    public override async Task OnConnectedAsync()
    {
        var siteUser = RequireCurrentUser();
        var becameOnline = _tracker.TrackConnection(Context.ConnectionId, siteUser.Subject);

        await SendPresenceSnapshotAsync(siteUser.Subject, Context.ConnectionAborted);

        if (becameOnline)
        {
            var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(siteUser.Subject, Context.ConnectionAborted);
            await NotifyPresenceChangedAsync(relevantSubjects, siteUser.Subject, isOnline: true);
        }

        await base.OnConnectedAsync();
    }

    public override async Task OnDisconnectedAsync(Exception? exception)
    {
        var (subject, becameOffline) = _tracker.RemoveConnection(Context.ConnectionId);
        if (becameOffline && !string.IsNullOrWhiteSpace(subject))
        {
            var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(subject, CancellationToken.None);
            await NotifyPresenceChangedAsync(relevantSubjects, subject, isOnline: false);
        }

        await base.OnDisconnectedAsync(exception);
    }

    public async Task RequestPresenceSnapshot()
    {
        var siteUser = RequireCurrentUser();
        await SendPresenceSnapshotAsync(siteUser.Subject, Context.ConnectionAborted);
    }

    public async Task<PlayInviteMessage> SendPlayInvite(string recipientSubject, string recipientColor)
    {
        var sender = RequireCurrentUser();
        var normalizedRecipientSubject = recipientSubject.Trim();

        if (!await _socialStore.AreFriendsAsync(sender.Subject, normalizedRecipientSubject, Context.ConnectionAborted))
        {
            throw new HubException("Seuls tes amis peuvent recevoir une invitation de partie.");
        }

        if (!_tracker.IsOnline(normalizedRecipientSubject))
        {
            throw new HubException("Cet ami n'est plus connecte pour le moment.");
        }

        var senderProfile = await _profileStore.GetOrCreateAsync(sender, Context.ConnectionAborted);
        var recipientProfile = await _profileStore.FindBySubjectAsync(normalizedRecipientSubject, Context.ConnectionAborted);
        if (recipientProfile is null)
        {
            throw new HubException("Le profil de cet ami est introuvable.");
        }

        try
        {
            var message = _playInviteCoordinator.CreateInvite(
                new PlayInviteParticipant(sender.Subject, sender.Username, senderProfile.DisplayName),
                new PlayInviteParticipant(recipientProfile.Subject, recipientProfile.Username, recipientProfile.DisplayName),
                recipientColor);

            await Clients.Users([sender.Subject, recipientProfile.Subject])
                .SendAsync("PlayInviteUpdated", message, Context.ConnectionAborted);

            return message;
        }
        catch (SocialValidationException exception)
        {
            throw new HubException(exception.Message);
        }
    }

    public async Task RespondToPlayInvite(string inviteId, bool accept)
    {
        var recipient = RequireCurrentUser();

        try
        {
            if (accept)
            {
                var accepted = _playInviteCoordinator.AcceptInvite(inviteId, recipient.Subject);
                await Clients.Users([accepted.SenderSubject, accepted.RecipientSubject])
                    .SendAsync("PlayInviteAccepted", accepted.Session, Context.ConnectionAborted);
                return;
            }

            var declined = _playInviteCoordinator.DeclineInvite(inviteId, recipient.Subject);
            await Clients.Users([declined.SenderSubject, declined.RecipientSubject])
                .SendAsync("PlayInviteClosed", declined.ClosedMessage, Context.ConnectionAborted);
        }
        catch (SocialValidationException exception)
        {
            throw new HubException(exception.Message);
        }
    }

    public async Task CancelPlayInvite(string inviteId)
    {
        var sender = RequireCurrentUser();

        try
        {
            var cancelled = _playInviteCoordinator.CancelInvite(inviteId, sender.Subject);
            await Clients.Users([cancelled.SenderSubject, cancelled.RecipientSubject])
                .SendAsync("PlayInviteClosed", cancelled.ClosedMessage, Context.ConnectionAborted);
        }
        catch (SocialValidationException exception)
        {
            throw new HubException(exception.Message);
        }
    }

    private AuthenticatedSiteUser RequireCurrentUser()
        => AuthenticatedSiteUserFactory.FromClaimsPrincipal(Context.User ?? new System.Security.Claims.ClaimsPrincipal())
           ?? throw new HubException("La session utilisateur est incomplete.");

    private async Task SendPresenceSnapshotAsync(string subject, CancellationToken cancellationToken)
    {
        var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(subject, cancellationToken);
        var onlineSubjects = relevantSubjects
            .Where(_tracker.IsOnline)
            .Distinct(StringComparer.Ordinal)
            .ToArray();

        await Clients.Caller.SendAsync(
            "PresenceSnapshot",
            new PresenceSnapshotMessage { OnlineSubjects = onlineSubjects },
            cancellationToken);
    }

    private Task NotifyPresenceChangedAsync(IReadOnlyList<string> subjects, string changedSubject, bool isOnline)
    {
        var distinctSubjects = subjects
            .Where(subject => !string.IsNullOrWhiteSpace(subject))
            .Distinct(StringComparer.Ordinal)
            .ToArray();

        return distinctSubjects.Length == 0
            ? Task.CompletedTask
            : Clients.Users(distinctSubjects).SendAsync(
                "PresenceChanged",
                new PresenceChangedMessage
                {
                    Subject = changedSubject,
                    IsOnline = isOnline,
                });
    }
}