import { Query } from 'mongoose';

class QueryBuilder<T> {
  public modelQuery: Query<T[], T>;
  private query: Record<string, unknown>;

  constructor(modelQuery: Query<T[], T>, query: Record<string, unknown>) {
    this.modelQuery = modelQuery;
    this.query = query;
  }

  search(searchFields: string[]) {
    const search = this.query.search as string;
    if (search) {
      this.modelQuery = this.modelQuery.find({
        $or: searchFields.map((f) => ({ [f]: { $regex: search, $options: 'i' } })),
      } as any);
    }
    return this;
  }

  filter() {
    const exclude = ['search', 'sort', 'page', 'limit', 'fields'];
    const filters = Object.fromEntries(
      Object.entries(this.query).filter(([k]) => !exclude.includes(k)),
    );
    this.modelQuery = this.modelQuery.find(filters as any);
    return this;
  }

  sort() {
    const sort = (this.query.sort as string)?.split(',').join(' ') || '-createdAt';
    this.modelQuery = this.modelQuery.sort(sort);
    return this;
  }

  paginate() {
    const page = Number(this.query.page) || 1;
    const limit = Number(this.query.limit) || 10;
    this.modelQuery = this.modelQuery.skip((page - 1) * limit).limit(limit);
    return this;
  }

  fields() {
    const fields = (this.query.fields as string)?.split(',').join(' ') || '-__v';
    this.modelQuery = this.modelQuery.select(fields);
    return this;
  }

  async countTotal() {
    const total = await this.modelQuery.model.countDocuments(this.modelQuery.getFilter());
    const page = Number(this.query.page) || 1;
    const limit = Number(this.query.limit) || 10;
    return { total, page, limit, totalPages: Math.ceil(total / limit) };
  }
}

export default QueryBuilder;