package jef.operations;

import jef.Queryable;
import jef.expressions.Expression;
import jef.expressions.SelectExpression;
import jef.expressions.selectable.DatabaseFunctionExpression;

import java.io.Serializable;
import java.util.List;

public class CountOp<T extends Serializable> implements Operation<T> {
    private final Queryable<T> queryable;

    public CountOp(Queryable<T> queryable) {
        this.queryable = queryable;
    }

    @Override
    public String getTableAlias() {
        return String.valueOf((char) (queryable.getTableAlias().charAt(0) + (char) 1));
    }

    @Override
    public Expression getExpression() {
        return new SelectExpression(List.of(new DatabaseFunctionExpression("count(*)")), queryable.getExpression(), getTableAlias());
    }

//    @Override
//    public CountOp<T> clone() {
//        return new CountOp<>(queryable.clone());
//    }

    public long execute() {
        return 0;//TODO implement when sql execution part is ready
    }
}