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

namespace Application.Features.Api.Feed.DeleteComment;

public sealed class Handler(IAppDbContext db) : ICommandHandler<Command, Result>
{
    public async Task<Result> Handle(Command request, CancellationToken ct)
    {
        var comment = await db.FeedComment.FirstOrDefaultAsync(c => c.ID == request.CommentID && !c.IsDeleted, ct);
        if (comment is null)
        {
            return Result.Failure(Error.NotFound("Feed.CommentNotFound", "댓글을 찾을 수 없습니다."));
        }

        if (comment.MemberID != request.MemberID)
        {
            return Result.Failure(Error.Forbidden("Feed.NotOwner", "삭제 권한이 없습니다."));
        }

        comment.IsDeleted = true;
        comment.DeletedAt = DateTime.UtcNow;

        // 포스트 댓글 수 차감
        var post = await db.FeedPost.FirstOrDefaultAsync(p => p.ID == comment.FeedPostID, ct);
        if (post is not null)
        {
            post.Comments = post.Comments > 0 ? post.Comments - 1 : 0;
        }

        // 부모 댓글 Replies 차감
        if (comment.ParentID is int pid)
        {
            var parent = await db.FeedComment.FirstOrDefaultAsync(p => p.ID == pid, ct);
            if (parent is not null)
            {
                parent.Replies = parent.Replies > 0 ? parent.Replies - 1 : 0;
            }
        }

        await db.SaveChangesAsync(ct);

        return Result.Success();
    }
}