using Infrastructure.Attribute;
using Infrastructure.Extensions;
using ZR.LiveForum.Model.Liveforum.Dto;
using ZR.LiveForum.Model.Liveforum;
using ZR.Repository;
using ZR.Service.Liveforum.ILiveforumService;

namespace ZR.Service.Liveforum
{
    /// <summary>
    /// 点赞表，存储用户对帖子和评论的点赞记录Service业务层处理
    /// </summary>
    [AppService(ServiceType = typeof(IT_LikesService), ServiceLifetime = LifeTime.Transient)]
    public class T_LikesService : BaseService<T_Likes>, IT_LikesService
    {
        /// <summary>
        /// 查询点赞表，存储用户对帖子和评论的点赞记录列表
        /// </summary>
        /// <param name="parm"></param>
        /// <returns></returns>
        public PagedInfo<T_LikesDto> GetList(T_LikesQueryDto parm)
        {
            var predicate = QueryExp(parm);

            var query = Queryable()
                .Where(predicate.ToExpression())
                .LeftJoin<T_Users>((l, u) => l.UserId == u.Id)
                .LeftJoin<T_Posts>((l, u, p) => l.TargetType == 1 && l.TargetId == p.Id)
                .LeftJoin<T_Comments>((l, u, p, c) => l.TargetType == 2 && l.TargetId == c.Id);

            // 默认按创建时间倒序
            query = query.OrderBy((l, u, p, c) => l.CreatedAt, OrderByType.Desc);

            var response = query.Select((l, u, p, c) => new T_LikesDto()
            {
                Id = l.Id,
                UserId = l.UserId,
                TargetType = l.TargetType,
                TargetId = l.TargetId,
                CreatedAt = l.CreatedAt,
                UserName = u.NickName,
                // 根据TargetType选择对应的信息：1-帖子标题，2-评论内容
                TargetInfo = l.TargetType == 1 ? p.Title : (l.TargetType == 2 ? c.Content : null),
            }, true);

            var resp = ToPage(response, parm);
            return resp;
        }

        /// <summary>
        /// 分页查询（排序已在Select之前完成）
        /// </summary>
        private PagedInfo<T> ToPage<T>(ISugarQueryable<T> source, PagerInfo parm)
        {
            var page = new PagedInfo<T>();
            var total = 0;
            page.PageSize = parm.PageSize;
            page.PageIndex = parm.PageNum;
            // 注意：排序已经在 Select 之前完成了，这里不再需要排序
            page.Result = source
                .ToPageList(parm.PageNum, parm.PageSize, ref total);
            page.TotalNum = total;
            return page;
        }


        /// <summary>
        /// 获取详情
        /// </summary>
        /// <param name="Id"></param>
        /// <returns></returns>
        public T_Likes GetInfo(long Id)
        {
            var response = Queryable()
                .Where(x => x.Id == Id)
                .First();

            return response;
        }

        /// <summary>
        /// 添加点赞表，存储用户对帖子和评论的点赞记录
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public T_Likes AddT_Likes(T_Likes model)
        {
            return Insertable(model).ExecuteReturnEntity();
        }

        /// <summary>
        /// 修改点赞表，存储用户对帖子和评论的点赞记录
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public int UpdateT_Likes(T_Likes model)
        {
            return Update(model, true);
        }

        /// <summary>
        /// 根据帖子ID查询该帖子的所有点赞记录
        /// </summary>
        /// <param name="postId">帖子ID</param>
        /// <param name="parm">分页参数</param>
        /// <returns></returns>
        public PagedInfo<T_LikesDto> GetLikesByPostId(long postId, PagerInfo parm)
        {
            var query = Queryable()
                .Where(l => l.TargetType == 1 && l.TargetId == postId)
                .LeftJoin<T_Users>((l, u) => l.UserId == u.Id);

            // 默认按创建时间倒序
            query = query.OrderBy((l, u) => l.CreatedAt, OrderByType.Desc);

            var response = query.Select((l, u) => new T_LikesDto()
            {
                Id = l.Id,
                UserId = l.UserId,
                TargetType = l.TargetType,
                TargetId = l.TargetId,
                CreatedAt = l.CreatedAt,
                UserName = u.NickName,
                TargetInfo = null, // 帖子点赞时不需要显示目标信息
            }, true);

            var resp = ToPage(response, parm);
            return resp;
        }

        /// <summary>
        /// 查询导出表达式
        /// </summary>
        /// <param name="parm"></param>
        /// <returns></returns>
        private static Expressionable<T_Likes> QueryExp(T_LikesQueryDto parm)
        {
            var predicate = Expressionable.Create<T_Likes>();

            predicate = predicate.AndIF(parm.UserId != null, it => it.UserId == parm.UserId);
            return predicate;
        }
    }
}