using Application.Abstractions.Data;
using Application.Abstractions.Hub;
using Application.Abstractions.Messaging;
using Application.Abstractions.Notification;
using SharedKernel;
using SharedKernel.Results;
using Domain.Entities.Donations;
using Domain.Entities.Donations.ValueObject;
using Domain.Entities.Notifications.ValueObject;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Api.Crew.AddMember;

internal sealed class Handler(
    IAppDbContext db,
    INotificationService notificationService,
    ICrewHubBroadcaster crewBroadcaster
) : ICommandHandler<Command, Result<Response>>
{
    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        var crew = await db.Crew.FirstOrDefaultAsync(c => c.ID == request.CrewID, ct);

        if (crew is null)
        {
            return Result.Failure<Response>(Error.NotFound("Crew.NotFound", "크루를 찾을 수 없습니다."));
        }

        // 자기 자신 초대 방지
        if (request.TargetMemberID == request.InvitedByMemberID)
        {
            return Result.Failure<Response>(Error.Problem("Crew.InviteSelfNotAllowed", "본인을 초대할 수 없습니다."));
        }

        // 이미 등록된 크루원 확인
        var alreadyMember = await db.CrewMember.AnyAsync(m => m.CrewID == request.CrewID && m.MemberID == request.TargetMemberID, ct);

        if (alreadyMember)
        {
            return Result.Failure<Response>(Error.Conflict("Crew.MemberAlreadyExists", "이미 등록된 크루원입니다."));
        }

        // 진행 중인 초대 확인 (만료된 건 새로 보내도 됨)
        var pendingInvite = await db.CrewInvitation
            .Where(i => i.CrewID == request.CrewID && i.TargetMemberID == request.TargetMemberID && i.Status == CrewInviteStatus.Pending)
            .FirstOrDefaultAsync(ct);

        if (pendingInvite is not null)
        {
            // 만료된 Pending 은 자동으로 Expired 처리하고 새 초대 발송
            if (pendingInvite.IsExpired())
            {
                pendingInvite.MarkExpired();
            }
            else
            {
                return Result.Failure<Response>(Error.Conflict("Crew.InviteAlreadyPending", "이미 진행 중인 초대가 있습니다."));
            }
        }

        // 초대 대상자 존재 확인
        var targetExists = await db.Member.AnyAsync(m => m.ID == request.TargetMemberID && !m.IsWithdraw && !m.IsDenied, ct);

        if (!targetExists)
        {
            return Result.Failure<Response>(Error.NotFound("Member.NotFound", "초대 대상 회원을 찾을 수 없습니다."));
        }

        // 초대 생성
        var invitation = CrewInvitation.Create(
            request.CrewID,
            request.TargetMemberID,
            request.InvitedByMemberID,
            request.Nickname,
            request.Role,
            request.SortOrder
        );

        db.CrewInvitation.Add(invitation);
        await db.SaveChangesAsync(ct);

        // 대상자에게 알림 발송 (SignalR push 포함) — invitation.ID 확정 후
        await notificationService.SendAsync(
            memberID: request.TargetMemberID,
            type: NotificationType.CrewInvitation,
            title: $"크루 초대: {crew.Name}",
            message: $"'{crew.Name}' 크루의 초대가 도착했습니다. 24시간 내 응답해 주세요.",
            actionUrl: $"/crew/invite/{invitation.ID}",
            relatedType: "CrewInvitation",
            relatedID: invitation.ID,
            imageUrl: null,
            ct: ct
        );

        // 운영자 그룹(crew:{crewID})에 멤버 리스트 변경 broadcast → 운영자 화면 자동 새로고침
        await crewBroadcaster.BroadcastMemberChangeAsync(
            crewID: request.CrewID,
            kind: "added",
            data: new
            {
                invitationID = invitation.ID,
                crewID = request.CrewID,
                targetMemberID = request.TargetMemberID,
                nickname = request.Nickname
            },
            ct: ct
        );

        return Result.Success(new Response(invitation.ID));
    }
}