import Context from '../Context.js';
import WhereExprBuilder from '../model/WhereExprBuilder.js';
import * as model from '../model/index.js';
import * as types from '../model/types.js';
import DBSet from './DBSet.js';
import QuerySet from './QuerySet.js';

class LinkSet<T extends Object, U extends Object> extends QuerySet<T> {
  private foreignFunc: types.IJoinFunc<WhereExprBuilder<T>, U>;

  constructor(context: Context, entityType: types.IEntityType<T>, dbSet: DBSet, foreignFunc: types.IJoinFunc<WhereExprBuilder<T>, U>) {
    super(context, entityType, dbSet);
    this.foreignFunc = foreignFunc;
  }

  apply(parentObj: U) {
    let eb = new model.WhereExprBuilder<T>(this.dbSet.fieldMap);
    let expr = this.foreignFunc(eb, parentObj);

    if (expr && expr.exps.length > 0) {
      this.stat.where = this.stat.where.add(expr);
    }
  }
}

export default LinkSet;