import { Injectable } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';
import { FilterQuery, Model, Types } from 'mongoose';
import { Follow, FollowDocument } from '../follows/schemas/follow.schema';
import { Post, PostDocument } from '../posts/schemas/post.schema';

@Injectable()
export class FeedRepository {
  constructor(
    @InjectModel(Post.name) private readonly postModel: Model<PostDocument>,
    @InjectModel(Follow.name) private readonly followModel: Model<FollowDocument>,
  ) {}

  async findFollowingIds(userId: string): Promise<string[]> {
    const rows = await this.followModel
      .find({ followerId: new Types.ObjectId(userId) })
      .select({ followingId: 1 })
      .lean()
      .exec();

    return rows.map((row) => row.followingId.toString());
  }

  async findCandidatePosts(
    filter: FilterQuery<PostDocument>,
    limit: number,
  ): Promise<PostDocument[]> {
    const activeFilter: FilterQuery<PostDocument> = {
      ...filter,
      isDeleted: { $ne: true },
    };

    return this.postModel
      .find(activeFilter)
      .populate({
        path: 'authorId',
        select:
          'name username stageName avatar isVerified isDisabled location latitude longitude musicGenres musicRoles favoriteInstruments favoriteMaqamat',
      })
      .sort({ createdAt: -1 })
      .limit(limit)
      .exec();
  }

  async findTrendingPublicPosts(skip: number, limit: number): Promise<PostDocument[]> {
    return this.postModel
      .find({ visibility: 'public', isDeleted: { $ne: true } })
      .populate({ path: 'authorId', select: 'name username stageName avatar isVerified isDisabled' })
      .sort({ likesCount: -1, commentsCount: -1, savesCount: -1, createdAt: -1 })
      .skip(skip)
      .limit(limit)
      .exec();
  }

  async count(filter: FilterQuery<PostDocument>): Promise<number> {
    return this.postModel.countDocuments({ ...filter, isDeleted: { $ne: true } }).exec();
  }
}