/*
 * Copyright (c) 2013, OpenCloudDB/MyCAT and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software;Designed and Developed mainly by many Chinese 
 * opensource volunteers. you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License version 2 only, as published by the
 * Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Any questions about this component can be directed to it's project Web address 
 * https://code.google.com/p/opencloudb/.
 *
 */
package com.akiban.sql.parser;

import com.akiban.sql.StandardException;

/**
 * A TableElementNode is an item in a TableElementList, and represents
 * a single table element such as a column or constraint in a CREATE TABLE
 * or ALTER TABLE statement.
 *
 */

public class TableElementNode extends QueryTreeNode
{
    public static enum ElementType {
        AT_UNKNOWN, AT_ADD_FOREIGN_KEY_CONSTRAINT, AT_ADD_PRIMARY_KEY_CONSTRAINT,
        AT_ADD_UNIQUE_CONSTRAINT, AT_ADD_CHECK_CONSTRAINT, AT_DROP_CONSTRAINT,
        AT_MODIFY_COLUMN, AT_DROP_COLUMN, AT_DROP_INDEX, AT_ADD_INDEX,
        AT_RENAME, AT_RENAME_COLUMN
    }

    String name;
    // TODO: I don't think the following comment was actually realized;
    // there are still subclasses and this one isn't made directly that
    // I can see.
    ElementType elementType;            // simple element nodes can share this class,
    // eg., drop column and rename table/column/index
    // etc., no need for more classes, an effort to
    // minimize footprint

    /**
     * Initializer for a TableElementNode
     *
     * @param name The name of the table element, if any
     */

    public void init(Object name) {
        this.name = (String)name;
    }

    /**
     * Initializer for a TableElementNode
     *
     * @param name The name of the table element, if any
     */

    public void init(Object name, Object elementType) {
        this.name = (String)name;
        this.elementType = (ElementType)elementType;
    }

    /**
     * Fill this node with a deep copy of the given node.
     */
    public void copyFrom(QueryTreeNode node) throws StandardException {
        super.copyFrom(node);

        TableElementNode other = (TableElementNode)node;
        this.name = other.name;
        this.elementType = other.elementType;
    }

    /**
     * Convert this object to a String.  See comments in QueryTreeNode.java
     * for how this should be done for tree printing.
     *
     * @return This object as a String
     */

    public String toString() {
        return "name: " + name + "\n" +
            "elementType: " + getElementType() + "\n" +
            super.toString();
    }

    /**
     * Does this element have a primary key constraint.
     *
     * @return boolean Whether or not this element has a primary key constraint
     */
    boolean hasPrimaryKeyConstraint() {
        return false;
    }

    /**
     * Does this element have a unique key constraint.
     *
     * @return boolean Whether or not this element has a unique key constraint
     */
    boolean hasUniqueKeyConstraint() {
        return false;
    }

    /**
     * Does this element have a foreign key constraint.
     *
     * @return boolean Whether or not this element has a foreign key constraint
     */
    boolean hasForeignKeyConstraint() {
        return false;
    }

    /**
     * Does this element have a check constraint.
     *
     * @return boolean Whether or not this element has a check constraint
     */
    boolean hasCheckConstraint() {
        return false;
    }

    /**
     * Does this element have a constraint on it.
     *
     * @return boolean Whether or not this element has a constraint on it
     */
    boolean hasConstraint() {
        return false;
    }

    /**
     * Get the name from this node.
     *
     * @return String The name.
     */
    public String getName() {
        return name;
    }

    /**
     * Get the type of this table element.
     *
     * @return one of the constants at the front of this file
     */
    ElementType getElementType() {
        if (hasForeignKeyConstraint()) {
            return ElementType.AT_ADD_FOREIGN_KEY_CONSTRAINT; 
        }
        else if (hasPrimaryKeyConstraint()) {
            return ElementType.AT_ADD_PRIMARY_KEY_CONSTRAINT; 
        }
        else if (hasUniqueKeyConstraint()) { 
            return ElementType.AT_ADD_UNIQUE_CONSTRAINT; 
        }
        else if (hasCheckConstraint()) { 
            return ElementType.AT_ADD_CHECK_CONSTRAINT; 
        }
        else if (this instanceof ConstraintDefinitionNode) { 
            return ElementType.AT_DROP_CONSTRAINT; 
        }
        else if (this instanceof ModifyColumnNode) {
            if (getNodeType() == NodeTypes.DROP_COLUMN_NODE) { 
                return ElementType.AT_DROP_COLUMN; 
            }
            else { 
                return ElementType.AT_MODIFY_COLUMN; 
            }
        }
        else { 
            return elementType; 
        }
    }

}