/*
 * Copyright 2016-2018 shardingsphere.io.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * </p>
 */

package io.shardingsphere.core.parsing.antlr.extractor.statement.handler;

import java.util.Collection;

import org.antlr.v4.runtime.ParserRuleContext;
import org.antlr.v4.runtime.tree.ParseTree;

import com.google.common.base.Optional;

import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.result.ColumnDefinitionExtractResult;
import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.result.ExtractResult;
import io.shardingsphere.core.parsing.antlr.extractor.statement.phrase.ColumnDefinitionPhraseExtractor;
import io.shardingsphere.core.parsing.antlr.extractor.statement.util.ASTUtils;
import io.shardingsphere.core.parsing.antlr.sql.ddl.AlterTableStatement;
import io.shardingsphere.core.parsing.antlr.sql.ddl.ColumnDefinition;
import io.shardingsphere.core.parsing.parser.sql.SQLStatement;

/**
 * Add column extract handler.
 * 
 * @author duhongjun
 */
public class AddColumnExtractHandler implements ASTExtractHandler,ASTExtractHandler1 {
    
    private final ColumnDefinitionPhraseExtractor columnDefinitionPhraseExtractor = new ColumnDefinitionPhraseExtractor();
    
    @Override
    public final void extract(final ParserRuleContext ancestorNode, final SQLStatement statement) {
        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(ancestorNode, RuleName.ADD_COLUMN)) {
            extractAddColumn(each, (AlterTableStatement) statement);
        }
    }
    
    private void extractAddColumn(final ParserRuleContext addColumnNode, final AlterTableStatement alterTableStatement) {
        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(addColumnNode, RuleName.COLUMN_DEFINITION)) {
            Optional<ColumnDefinition> columnDefinition = columnDefinitionPhraseExtractor.extract(each);
            if (columnDefinition.isPresent()) {
                setColumnDefinition(addColumnNode, alterTableStatement, columnDefinition.get());
            }
        }
    }
    
    private void setColumnDefinition(final ParserRuleContext addColumnNode, final AlterTableStatement alterTableStatement, final ColumnDefinition columnDefinition) {
        if (!alterTableStatement.findColumnDefinition(columnDefinition.getName()).isPresent()) {
            alterTableStatement.getAddColumns().add(columnDefinition);
            postVisitColumnDefinition(addColumnNode, alterTableStatement, columnDefinition.getName());
        }
    }
    
    protected void postVisitColumnDefinition(final ParseTree ancestorNode, final SQLStatement statement, final String columnName) {
    }

    @Override
    public ExtractResult extract(ParserRuleContext ancestorNode) {
        Collection<ParserRuleContext> result = ASTUtils.getAllDescendantNodes(ancestorNode, RuleName.ADD_COLUMN);
        if(result.isEmpty()) {
            return null;
        }
        ColumnDefinitionExtractResult extractResult = new ColumnDefinitionExtractResult();
        for (ParserRuleContext each : result) {
            extractAddColumn(each, extractResult);
        }
        return extractResult;
    }
    
    
    private void extractAddColumn(final ParserRuleContext addColumnNode, final ColumnDefinitionExtractResult result) {
        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(addColumnNode, RuleName.COLUMN_DEFINITION)) {
            Optional<ColumnDefinition> columnDefinition = columnDefinitionPhraseExtractor.extract(each);
            if (columnDefinition.isPresent()) {
                columnDefinition.get().setAdd(true);
                postExtractColumnDefinition(addColumnNode, columnDefinition.get());
                result.getColumnDefintions().add(columnDefinition.get());
            }
        }
    }
    
    protected void postExtractColumnDefinition(final ParseTree ancestorNode, final ColumnDefinition columnDefinition) {
        
    }
}

@@ -1294,160 +1294,24 @@
 ddl.
-AlterTableStatement;%0Aimport io.shardingsphere.core.parsing.antlr.sql.ddl.ColumnDefinition;%0Aimport io.shardingsphere.core.parsing.parser.sql.SQLStatement
+ColumnDefinition
 ;%0A%0A/
@@ -1442,27 +1442,8 @@
 dler
-,ASTExtractHandler1
  %7B%0A 
@@ -1572,1442 +1572,8 @@
 r();
-%0A    %0A    @Override%0A    public final void extract(final ParserRuleContext ancestorNode, final SQLStatement statement) %7B%0A        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(ancestorNode, RuleName.ADD_COLUMN)) %7B%0A            extractAddColumn(each, (AlterTableStatement) statement);%0A        %7D%0A    %7D%0A    %0A    private void extractAddColumn(final ParserRuleContext addColumnNode, final AlterTableStatement alterTableStatement) %7B%0A        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(addColumnNode, RuleName.COLUMN_DEFINITION)) %7B%0A            Optional%3CColumnDefinition%3E columnDefinition = columnDefinitionPhraseExtractor.extract(each);%0A            if (columnDefinition.isPresent()) %7B%0A                setColumnDefinition(addColumnNode, alterTableStatement, columnDefinition.get());%0A            %7D%0A        %7D%0A    %7D%0A    %0A    private void setColumnDefinition(final ParserRuleContext addColumnNode, final AlterTableStatement alterTableStatement, final ColumnDefinition columnDefinition) %7B%0A        if (!alterTableStatement.findColumnDefinition(columnDefinition.getName()).isPresent()) %7B%0A            alterTableStatement.getAddColumns().add(columnDefinition);%0A            postVisitColumnDefinition(addColumnNode, alterTableStatement, columnDefinition.getName());%0A        %7D%0A    %7D%0A    %0A    protected void postVisitColumnDefinition(final ParseTree ancestorNode, final SQLStatement statement, final String columnName) %7B%0A    %7D
 %0A%0A  

remove unused code