/**
 *    Copyright 2009-2016 the original author or authors.
 *
 *    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.
 */
package com.googlecode.htmlcompressor.velocity;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;

import org.apache.velocity.context.InternalContextAdapter;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.TemplateInitException;
import org.apache.velocity.runtime.RuntimeServices;
import org.apache.velocity.runtime.directive.Directive;
import org.apache.velocity.runtime.parser.node.Node;
import org.apache.velocity.runtime.log.Log;

import com.google.javascript.jscomp.CompilationLevel;
import com.googlecode.htmlcompressor.compressor.ClosureJavaScriptCompressor;
import com.googlecode.htmlcompressor.compressor.HtmlCompressor;

/**
 * Velocity directive that compresses an HTML content within #compressHtml ... #end block. Compression parameters are
 * set by default (no JavaScript and CSS compression).
 *
 * @author <a href="mailto:serg472@gmail.com">Sergiy Kovalchuk</a>
 * @see HtmlCompressor
 */
public class HtmlCompressorDirective extends Directive {

    /** The Constant htmlCompressor. */
    private static final HtmlCompressor htmlCompressor = new HtmlCompressor();

    /** The log. */
    private Log                         log;

    @Override
    public String getName() {
        return "compressHtml";
    }

    @Override
    public int getType() {
        return BLOCK;
    }

    @Override
    public void init(RuntimeServices rs, InternalContextAdapter context, Node node) throws TemplateInitException {
        super.init(rs, context, node);
        log = rs.getLog();

        boolean compressJavaScript = rs.getBoolean("userdirective.compressHtml.compressJavaScript", false);

        // set compressor properties
        htmlCompressor.setEnabled(rs.getBoolean("userdirective.compressHtml.enabled", true));
        htmlCompressor.setRemoveComments(rs.getBoolean("userdirective.compressHtml.removeComments", true));
        htmlCompressor.setRemoveMultiSpaces(rs.getBoolean("userdirective.compressHtml.removeMultiSpaces", true));
        htmlCompressor.setRemoveIntertagSpaces(rs.getBoolean("userdirective.compressHtml.removeIntertagSpaces", false));
        htmlCompressor.setRemoveQuotes(rs.getBoolean("userdirective.compressHtml.removeQuotes", false));
        htmlCompressor.setPreserveLineBreaks(rs.getBoolean("userdirective.compressHtml.preserveLineBreaks", false));
        htmlCompressor.setCompressJavaScript(compressJavaScript);
        htmlCompressor.setCompressCss(rs.getBoolean("userdirective.compressHtml.compressCss", false));
        htmlCompressor.setYuiJsNoMunge(rs.getBoolean("userdirective.compressHtml.yuiJsNoMunge", false));
        htmlCompressor.setYuiJsPreserveAllSemiColons(rs.getBoolean(
                "userdirective.compressHtml.yuiJsPreserveAllSemiColons", false));
        htmlCompressor.setYuiJsLineBreak(rs.getInt("userdirective.compressHtml.yuiJsLineBreak", -1));
        htmlCompressor.setYuiCssLineBreak(rs.getInt("userdirective.compressHtml.yuiCssLineBreak", -1));
        htmlCompressor.setSimpleDoctype(rs.getBoolean("userdirective.compressHtml.simpleDoctype", false));
        htmlCompressor.setRemoveScriptAttributes(rs.getBoolean("userdirective.compressHtml.removeScriptAttributes",
                false));
        htmlCompressor.setRemoveStyleAttributes(rs
                .getBoolean("userdirective.compressHtml.removeStyleAttributes", false));
        htmlCompressor.setRemoveLinkAttributes(rs.getBoolean("userdirective.compressHtml.removeLinkAttributes", false));
        htmlCompressor.setRemoveFormAttributes(rs.getBoolean("userdirective.compressHtml.removeFormAttributes", false));
        htmlCompressor.setRemoveInputAttributes(rs
                .getBoolean("userdirective.compressHtml.removeInputAttributes", false));
        htmlCompressor.setSimpleBooleanAttributes(rs.getBoolean("userdirective.compressHtml.simpleBooleanAttributes",
                false));
        htmlCompressor.setRemoveJavaScriptProtocol(rs.getBoolean("userdirective.compressHtml.removeJavaScriptProtocol",
                false));
        htmlCompressor.setRemoveHttpProtocol(rs.getBoolean("userdirective.compressHtml.removeHttpProtocol", false));
        htmlCompressor.setRemoveHttpsProtocol(rs.getBoolean("userdirective.compressHtml.removeHttpsProtocol", false));

        if (compressJavaScript
                && rs.getString("userdirective.compressHtml.jsCompressor", HtmlCompressor.JS_COMPRESSOR_YUI)
                        .equalsIgnoreCase(HtmlCompressor.JS_COMPRESSOR_CLOSURE)) {
            String closureOptLevel = rs.getString("userdirective.compressHtml.closureOptLevel",
                    ClosureJavaScriptCompressor.COMPILATION_LEVEL_SIMPLE);

            ClosureJavaScriptCompressor closureCompressor = new ClosureJavaScriptCompressor();
            if (closureOptLevel.equalsIgnoreCase(ClosureJavaScriptCompressor.COMPILATION_LEVEL_ADVANCED)) {
                closureCompressor.setCompilationLevel(CompilationLevel.ADVANCED_OPTIMIZATIONS);
            } else if (closureOptLevel.equalsIgnoreCase(ClosureJavaScriptCompressor.COMPILATION_LEVEL_WHITESPACE)) {
                closureCompressor.setCompilationLevel(CompilationLevel.WHITESPACE_ONLY);
            } else {
                closureCompressor.setCompilationLevel(CompilationLevel.SIMPLE_OPTIMIZATIONS);
            }

            htmlCompressor.setJavaScriptCompressor(closureCompressor);
        }
    }

    @Override
    public boolean render(InternalContextAdapter context, Writer writer, Node node) throws IOException,
            MethodInvocationException {

        // render content
        StringWriter content = new StringWriter();
        node.jjtGetChild(0).render(context, content);

        // compress
        try {
            writer.write(htmlCompressor.compress(content.toString()));
        } catch (Exception e) {
            writer.write(content.toString());
            String msg = "Failed to compress content: " + content.toString();
            log.error(msg, e);
            throw new RuntimeException(msg, e);

        }
        return true;

    }

}
