import { Sort } from 'app/common/SortSpec';

/**
 *
 * An interface for accessing the columns of a table by their
 * ID in _grist_Tables_column, which is the ID used in sort specifications.
 * Implementations of this interface can be supplied to SortFunc to
 * sort the rows of a table according to such a specification.
 *
 */
export interface ColumnGetters {
  /**
   *
   * Takes a _grist_Tables_column ID and returns a function that maps
   * rowIds to values for that column.  Those values should be display
   * values if available, drawn from a corresponding display column.
   *
   */
  getColGetter(spec: Sort.ColSpec): ColumnGetter | null;

  /**
   *
   * Returns a getter for the manual sort column if it is available.
   *
   */
  getManualSortGetter(): ColumnGetter | null;
}

/**
 * Like ColumnGetters, but takes the string `colId` rather than a `ColSpec`
 * or numeric row ID.
 */
export interface ColumnGettersByColId {
  getColGetterByColId(colId: string): ColumnGetter | null;
}

export type ColumnGetter = (rowId: number) => any;