using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.Member.Follow.GetFollowing;

public sealed class Handler(IAppDbContext db) : IQueryHandler<Query, Result<Response>>
{
    public async Task<Result<Response>> Handle(Query request, CancellationToken ct)
    {
        var target = await db.Member.AsNoTracking().Where(x => x.SID == request.MemberSID && !x.IsWithdraw).Select(x => new { x.ID }).FirstOrDefaultAsync(ct);

        if (target is null)
        {
            return Result.Failure<Response>(Error.NotFound("Follow.MemberNotFound", "회원을 찾을 수 없습니다."));
        }

        var query = db.MemberFollow.AsNoTracking().Where(x => x.FollowerMemberID == target.ID);

        var total = await query.LongCountAsync(ct);
        var skip = (request.Page - 1) * request.PerPage;

        var list = await query
            .OrderByDescending(x => x.CreatedAt)
            .Skip(skip)
            .Take(request.PerPage)
            .Select(x => new Response.Row
            {
                SID = x.Followee.SID,
                Name = x.Followee.Name,
                Thumb = x.Followee.Thumb,
                Summary = x.Followee.Summary,
                IsCreator = x.Followee.IsCreator,
                FollowedAt = x.CreatedAt
            })
            .ToListAsync(ct);

        return new Response
        {
            Total = total,
            List = list
        };
    }
}