using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Domain.Entities.Members.Logs;
using Domain.Entities.Members.ValueObject;
using Domain.Entities.Store.ValueObject;
using Microsoft.EntityFrameworkCore;
using SharedKernel.Results;

namespace Application.Features.Api.Member.Items.Use;

internal sealed class Handler(IAppDbContext db) : ICommandHandler<Command, Result<Response>>
{
    public async Task<Result<Response>> Handle(Command request, CancellationToken ct)
    {
        var now = DateTime.UtcNow;

        var item = await db.MemberItem.FirstOrDefaultAsync(i => i.ID == request.MemberItemID, ct);

        if (item is null || item.MemberID != request.MemberID)
        {
            return Result.Failure<Response>(Error.NotFound("MemberItem.NotFound", "보유 아이템을 찾을 수 없습니다."));
        }

        if (!item.IsAvailable)
        {
            return Result.Failure<Response>(Error.Conflict("MemberItem.Unavailable", "이미 사용했거나 회수된 아이템입니다."));
        }

        string detail;

        switch (item.Kind)
        {
            case ItemKind.ChatBanLift:
            {
                var bans = await db.ChatBan
                    .Where(b => b.MemberID == request.MemberID && (b.ExpiresAt == null || b.ExpiresAt > now))
                    .ToListAsync(ct);

                if (bans.Count == 0)
                {
                    return Result.Failure<Response>(Error.Problem("MemberItem.NoActiveBan", "해제할 채팅 제재가 없습니다."));
                }

                foreach (var ban in bans)
                {
                    ban.Lift(now);
                }

                detail = $"채팅 제재 {bans.Count}건 해제";
                break;
            }

            case ItemKind.PostReset:
            {
                var affected = await db.Post
                    .Where(p => p.MemberID == request.MemberID && !p.IsDeleted && p.Reports == 0 && p.Comments == 0)
                    .ExecuteUpdateAsync(s => s
                        .SetProperty(p => p.IsDeleted, true)
                        .SetProperty(p => p.DeletedAt, now), ct);

                if (affected == 0)
                {
                    return Result.Failure<Response>(Error.Problem("MemberItem.NoResettablePost", "초기화할 글이 없습니다. (신고·댓글 없는 본인 글만 대상)"));
                }

                detail = $"예전 글 {affected}건 초기화";
                break;
            }

            case ItemKind.ExpBooster:
            {
                detail = $"경험치 부스터 {item.DurationDays}일 활성화";
                break;
            }

            default:
                return Result.Failure<Response>(Error.Problem("MemberItem.NotDirectlyUsable",
                    "이 아이템은 해당 기능(쪽지 보내기·프로필 변경) 이용 시 자동으로 사용됩니다."));
        }

        item.MarkUsed(now);
        db.MemberItemUsageLog.Add(MemberItemUsageLog.Create(item.MemberID, item.ID, item.ProductID, item.Kind, MemberItemUsageAction.Used, detail));

        await db.SaveChangesAsync(ct);

        return Result.Success(new Response(item.Kind, detail));
    }
}