import {
  Dictionary,
  Filter,
  QueryPagination,
  QueryTable,
  Sort,
} from '../types';
import {
  countQuery,
  deleteQuery,
  insertQuery,
  selectQuery,
  updateQuery,
} from './Query.utils';

export interface IQueryModifier {
  range: (from: number, to: number) => QueryModifier;
  toSql: () => string;
}

export class QueryModifier implements IQueryModifier {
  protected pagination?: QueryPagination;

  constructor(
    protected table: QueryTable,
    protected action: 'count' | 'delete' | 'insert' | 'select' | 'update',
    protected options?: {
      actionValue?: string[] | Dictionary<any> | Dictionary<any>[];
      actionOptions?: { returning: boolean };
      filters?: Filter[];
      sorts?: Sort[];
    }
  ) {}

  /**
   * Limits the result to rows within the specified range, inclusive.
   *
   * @param from  The starting index from which to limit the result, inclusive.
   * @param to  The last index to which to limit the result, inclusive.
   */
  range(from: number, to: number) {
    this.pagination = { offset: from, limit: to - from + 1 };
    return this;
  }

  /**
   * Return SQL string for query chains
   */
  toSql() {
    try {
      const { actionValue, actionOptions, filters, sorts } = this.options ?? {};
      switch (this.action) {
        case 'count': {
          return countQuery(this.table, { filters });
        }
        case 'delete': {
          return deleteQuery(this.table, filters, {
            returning: actionOptions?.returning,
          });
        }
        case 'insert': {
          return insertQuery(this.table, actionValue as Dictionary<any>[], {
            returning: actionOptions?.returning,
          });
        }
        case 'select': {
          return selectQuery(this.table, actionValue as string[] | undefined, {
            filters,
            pagination: this.pagination,
            sorts,
          });
        }
        case 'update': {
          return updateQuery(this.table, actionValue as Dictionary<any>, {
            filters,
            returning: actionOptions?.returning,
          });
        }
        default: {
          return '';
        }
      }
    } catch (error) {
      throw error;
    }
  }
}