/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

package freemarker.core;

/**
 * An instruction that indicates that that opening
 * and trailing whitespace on this line should be trimmed.
 */
final class TrimInstruction extends TemplateElement {
    
    private final int TYPE_T = 0;  
    private final int TYPE_LT = 1;  
    private final int TYPE_RT = 2;  
    private final int TYPE_NT = 3;  

    final boolean left, right;

    TrimInstruction(boolean left, boolean right) {
        this.left = left;
        this.right = right;
    }

    @Override
    TemplateElement[] accept(Environment env) {
        // This instruction does nothing at render-time, only parse-time.
        return null;
    }

    @Override
    protected String dump(boolean canonical) {
        StringBuilder sb = new StringBuilder();
        if (canonical) sb.append('<');
        sb.append(getNodeTypeSymbol());
        if (canonical) sb.append("/>");
        return sb.toString();
    }
    
    @Override
    String getNodeTypeSymbol() {
        if (left && right) {
            return "#t";
        } else if (left) {
            return "#lt";
        } else if (right) {
            return "#rt";
        } else {
            return "#nt";
        }
    }
    
    @Override
    boolean isIgnorable(boolean stripWhitespace) {
        return true;
    }

    @Override
    int getParameterCount() {
        return 1;
    }

    @Override
    Object getParameterValue(int idx) {
        if (idx != 0) throw new IndexOutOfBoundsException();
        int type;
        if (left && right) {
            type = TYPE_T;
        } else if (left) {
            type = TYPE_LT;
        } else if (right) {
            type = TYPE_RT;
        } else {
            type = TYPE_NT;
        }
        return Integer.valueOf(type);
    }

    @Override
    ParameterRole getParameterRole(int idx) {
        if (idx != 0) throw new IndexOutOfBoundsException();
        return ParameterRole.AST_NODE_SUBTYPE;
    }

    @Override
    boolean isOutputCacheable() {
        return true;
    }

    @Override
    boolean isNestedBlockRepeater() {
        return false;
    }
    
}