/*
 * 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 org.apache.maven.tools.plugin.extractor;

import java.io.File;
import java.io.IOException;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

import org.apache.maven.plugin.descriptor.InvalidPluginDescriptorException;
import org.apache.maven.plugin.descriptor.MojoDescriptor;
import org.apache.maven.project.MavenProject;
import org.apache.maven.tools.plugin.PluginToolsRequest;
import org.codehaus.plexus.util.DirectoryScanner;
import org.codehaus.plexus.util.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @deprecated Scripting support for Mojos is deprecated and is planned to be removed in Maven 4.0
 * @author jdcasey
 */
@Deprecated
public abstract class AbstractScriptedMojoDescriptorExtractor implements MojoDescriptorExtractor {
    private static final Logger LOGGER = LoggerFactory.getLogger(AbstractScriptedMojoDescriptorExtractor.class);

    @Override
    public boolean isDeprecated() {
        return true;
    }

    /** {@inheritDoc} */
    @Override
    public List<MojoDescriptor> execute(PluginToolsRequest request)
            throws ExtractionException, InvalidPluginDescriptorException {
        LOGGER.debug("Running: " + getClass().getName());
        String metadataExtension = getMetadataFileExtension(request);
        String scriptExtension = getScriptFileExtension(request);

        MavenProject project = request.getProject();

        @SuppressWarnings("unchecked")
        Map<String, Set<File>> scriptFilesKeyedByBasedir =
                gatherFilesByBasedir(project.getBasedir(), project.getScriptSourceRoots(), scriptExtension, request);

        List<MojoDescriptor> mojoDescriptors;
        if (!(metadataExtension == null || metadataExtension.isEmpty())) {
            @SuppressWarnings("unchecked")
            Map<String, Set<File>> metadataFilesKeyedByBasedir = gatherFilesByBasedir(
                    project.getBasedir(), project.getScriptSourceRoots(), metadataExtension, request);

            mojoDescriptors = extractMojoDescriptorsFromMetadata(metadataFilesKeyedByBasedir, request);
        } else {
            mojoDescriptors = extractMojoDescriptors(scriptFilesKeyedByBasedir, request);
        }

        copyScriptsToOutputDirectory(
                scriptFilesKeyedByBasedir, project.getBuild().getOutputDirectory(), request);

        if (!mojoDescriptors.isEmpty()) {
            LOGGER.warn("Scripting support for mojos is deprecated and is planned to be removed in Maven 4.");
            LOGGER.warn("Found " + mojoDescriptors.size() + " scripted mojos.");
        }

        return mojoDescriptors;
    }

    /**
     * @param scriptFilesKeyedByBasedir not null
     * @param outputDirectory not null
     * @param request the request
     * @throws ExtractionException if any
     */
    protected void copyScriptsToOutputDirectory(
            Map<String, Set<File>> scriptFilesKeyedByBasedir, String outputDirectory, PluginToolsRequest request)
            throws ExtractionException {
        File outputDir = new File(outputDirectory);

        if (!outputDir.exists()) {
            outputDir.mkdirs();
        }

        for (Map.Entry<String, Set<File>> entry : scriptFilesKeyedByBasedir.entrySet()) {
            File sourceDir = new File(entry.getKey());

            Set<File> scripts = entry.getValue();

            for (File scriptFile : scripts) {
                String relativePath =
                        scriptFile.getPath().substring(sourceDir.getPath().length());

                if (relativePath.charAt(0) == File.separatorChar) {
                    relativePath = relativePath.substring(1);
                }

                File outputFile = new File(outputDir, relativePath).getAbsoluteFile();

                if (!outputFile.getParentFile().exists()) {
                    outputFile.getParentFile().mkdirs();
                }

                try {
                    FileUtils.copyFile(scriptFile, outputFile);
                } catch (IOException e) {
                    throw new ExtractionException(
                            "Cannot copy script file: " + scriptFile + " to output: " + outputFile, e);
                }
            }
        }
    }

    /**
     * @param basedir not null
     * @param directories not null
     * @param scriptFileExtension not null
     * @param request the request
     * @return map with subdirs paths as key
     */
    protected Map<String, Set<File>> gatherFilesByBasedir(
            File basedir, List<String> directories, String scriptFileExtension, PluginToolsRequest request) {
        Map<String, Set<File>> sourcesByBasedir = new TreeMap<>();

        for (String resourceDir : directories) {
            Set<File> sources = new HashSet<>();

            LOGGER.debug("Scanning script dir: " + resourceDir + " with extractor: "
                    + getClass().getName());
            File dir = new File(resourceDir);
            if (!dir.isAbsolute()) {
                dir = new File(basedir, resourceDir).getAbsoluteFile();
            }

            resourceDir = dir.getPath();

            if (dir.exists()) {
                DirectoryScanner scanner = new DirectoryScanner();

                scanner.setBasedir(dir);
                scanner.addDefaultExcludes();
                scanner.setIncludes(new String[] {"**/*" + scriptFileExtension});
                scanner.scan();

                String[] relativePaths = scanner.getIncludedFiles();

                for (String relativePath : relativePaths) {
                    File scriptFile = new File(dir, relativePath).getAbsoluteFile();

                    if (scriptFile.isFile() && relativePath.endsWith(scriptFileExtension)) {
                        sources.add(scriptFile);
                    }
                }

                sourcesByBasedir.put(resourceDir, sources);
            }
        }

        return sourcesByBasedir;
    }

    /**
     * Should be implemented in the sub classes.
     *
     * @param metadataFilesByBasedir could be null
     * @param request The plugin request, never <code>null</code>.
     * @return always null
     * @throws ExtractionException if any
     * @throws InvalidPluginDescriptorException if any
     */
    protected List<MojoDescriptor> extractMojoDescriptorsFromMetadata(
            Map<String, Set<File>> metadataFilesByBasedir, PluginToolsRequest request)
            throws ExtractionException, InvalidPluginDescriptorException {
        return null;
    }

    /**
     * Should be implemented in the sub classes.
     * @param request the request
     * @return always null
     */
    protected String getMetadataFileExtension(PluginToolsRequest request) {
        return null;
    }

    /**
     * Should be implemented in the sub classes.
     *
     * @param scriptFilesKeyedByBasedir could be null
     * @param request The plugin request, never <code>null</code>.
     * @return always null
     * @throws ExtractionException if any
     * @throws InvalidPluginDescriptorException if any
     */
    protected List<MojoDescriptor> extractMojoDescriptors(
            Map<String, Set<File>> scriptFilesKeyedByBasedir, PluginToolsRequest request)
            throws ExtractionException, InvalidPluginDescriptorException {
        return null;
    }

    /**
     * @param request the request
     * @return the file extension like <code>.bsh</code> for BeanShell.
     */
    protected abstract String getScriptFileExtension(PluginToolsRequest request);
}