/**
 * Copyright (C) 2009-2013 FoundationDB, LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.foundationdb.sql.optimizer.plan;

import java.util.Deque;
import java.util.ArrayDeque;

public class PlanToString implements PlanVisitor, ExpressionVisitor
{
    public PlanToString(PlanNode.SummaryConfiguration configuration) {
        this.summaryConfiguration = configuration;
    }

    public static String of(PlanNode plan, PlanNode.SummaryConfiguration configuration) {
        PlanToString str = new PlanToString(configuration);
        str.add(plan);
        return str.toString();
    }
    
    private StringBuilder string = new StringBuilder();
    private Deque<PlanNode> pending = new ArrayDeque<>();
    private int planDepth = 0, expressionDepth = 0;
    private final PlanNode.SummaryConfiguration summaryConfiguration;


    protected void add(PlanNode n) {
        pending.addLast(n);
    }

    @Override
    public String toString() {
        while (!pending.isEmpty()) {
            PlanNode p = pending.removeFirst();
            if (string.length() > 0)
                string.append("\n");
            p.accept(this);
        }
        return string.toString();
    }

    @Override
    public boolean visitEnter(PlanNode n) {
        boolean result = visit(n);
        planDepth++;
        return result;
    }

    @Override
    public boolean visitLeave(PlanNode n) {
        planDepth--;
        return true;
    }

    @Override
    public boolean visit(PlanNode n) {
        if (expressionDepth > 0) {
            // Don't print subquery in expression until get back out to top-level.
            add(n);
            return false;
        }
        if (string.length() > 0) string.append("\n");
        for (int i = 0; i < planDepth; i++)
            string.append("  ");
        string.append(n.summaryString(summaryConfiguration));
        return true;
    }
    
    @Override
    public boolean visitEnter(ExpressionNode n) {
        boolean result = visit(n);
        expressionDepth++;
        return result;
    }

    @Override
    public boolean visitLeave(ExpressionNode n) {
        expressionDepth--;
        return true;
    }

    @Override
    public boolean visit(ExpressionNode n) {
        return true;
    }

}