import QueryTable from "../query-table";
import NumberColumn from "./number-column";
import GenericsHelper from "../helpers/generics-helper";
import QueryColumnCondition from "../condition/query-column-condition";
import {ColumnModifier, ColumnName} from "../helpers/internal-types";


abstract class QueryColumn<Table extends QueryTable<any, any>, T> {

    protected _$type: GenericsHelper<T>;
    protected _type: string;

    constructor(
        protected _table: Table,
        protected _name: ColumnName,
        protected _modifiers: ColumnModifier[] = []
    ) {}

    abstract count(): NumberColumn<Table>; // TODO I had to copy-paste the implementation to every child class to avoid a circular dependency

    as(alias: string): this {
        return new (<any>this.constructor)(this._table, this._name, this._modifiers.concat({ name: 'as', params: alias }));
    }

    isNull() {
        return new QueryColumnCondition<Table, T>(this, 'is-null');
    }

    isNotNull() {
        return new QueryColumnCondition<Table, T>(this, 'is-not-null');
    }
}

export default QueryColumn;