/*
 * Copyright The WildFly Authors
 * SPDX-License-Identifier: Apache-2.0
 */
package org.jboss.as.test.module.util;

import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

import org.jboss.jandex.Index;
import org.jboss.jandex.IndexWriter;
import org.jboss.jandex.Indexer;
import org.jboss.logging.Logger;
import org.jboss.shrinkwrap.api.Node;
import org.jboss.shrinkwrap.api.ShrinkWrap;
import org.jboss.shrinkwrap.api.asset.ByteArrayAsset;
import org.jboss.shrinkwrap.api.exporter.ZipExporter;
import org.jboss.shrinkwrap.api.spec.JavaArchive;

/**
 * <p>Utility class with some convenience methods to create and remove modules.</p>
 *
 * @author Pedro Igor
 */
public class TestModule {

    private static final Logger log  = Logger.getLogger(TestModule.class);
    private static final String VALID_TARGET_DIR = File.separator + "target" + File.separator;
    private static final String ILLEGAL_BUILD_DIR = "build" + VALID_TARGET_DIR;
    private static final String ILLEGAL_DIST_DIR = "dist" + VALID_TARGET_DIR;

    private final String moduleName;
    private final File moduleXml;
    private final String[] dependencies;
    private final List<ClassCallback> classCallbacks = new ArrayList<TestModule.ClassCallback>();
    private final List<JavaArchive> resources = new ArrayList<JavaArchive>();


    /**
     * <p>Creates a new module with the given name and module definition.</p>
     *
     * @param moduleName The name of the module.
     * @param moduleXml The module definition file.
     */
    public TestModule(String moduleName, File moduleXml) {
        if (!moduleXml.exists()) {
            throw new IllegalArgumentException("The module definition must exists.");
        }

        this.moduleName = moduleName;
        this.moduleXml = moduleXml;
        this.dependencies = null;
    }

    /**
     * <p>Creates a new module with the given name and module dependencies. The module.xml will be generated</p>
     *
     * @param moduleName The name of the module.
     * @param dependencies Names of modules to add as dependencies of the module.
     */
    public TestModule(String moduleName, String...dependencies) {
        this.moduleName = moduleName;
        this.moduleXml = null;
        this.dependencies = dependencies;
    }

    /**
     * <p>Creates the module directory. If the module already exists, it will deleted first.</p>
     *
     * @throws java.io.IOException If any error occurs during the module creation.
     */
    public void create() throws IOException {
        create(true);
    }


    /**
     * Add a callback to handle classes being added
     *
     * @param callback the call back to add
     * @return this
     */
    public TestModule addClassCallback(ClassCallback callback) {
        classCallbacks.add(callback);
        return this;
    }

    /**
     * <p>Creates the module directory.</p>
     *
     * @param deleteFirst If the module already exists, this argument specifies if it should be deleted before continuing.
     *
     * @throws java.io.IOException
     */
    public void create(boolean deleteFirst) throws IOException {
        File moduleDirectory = getModuleDirectory(true);
        if (moduleDirectory.exists()) {
            if (!deleteFirst) {
                throw new IllegalArgumentException(moduleDirectory + " already exists.");
            }

            remove();
        }

        File mainDirectory = new File(moduleDirectory, "main");
        log.infof("creating module in: %s",mainDirectory);


        if (!mainDirectory.mkdirs()) {
            throw new IllegalArgumentException("Could not create " + mainDirectory);
        }

        try {
            if (moduleXml != null) {
                try (FileInputStream fis = new FileInputStream(this.moduleXml)) {
                    copyFile(new File(mainDirectory, "module.xml"), fis);
                }
            } else {
                generateModuleXml(mainDirectory);
            }
        } catch (IOException e) {
            throw new RuntimeException("Could not create module definition.", e);
        }

        for (JavaArchive resourceRoot : this.resources) {

            FileOutputStream jarFile = null;

            try {
                Indexer indexer = new Indexer();

                List<Class<?>> classes = new ArrayList<Class<?>>();
                for (Node content : resourceRoot.getContent().values()) {
                    final String path = content.getPath().get();
                    if (path.endsWith(".class")) {
                        indexer.index(content.getAsset().openStream());
                        if (classCallbacks.size() > 0) {
                            //TODO load class
                            String usePath = path.startsWith("/") ? path.substring(1, path.length() - 6) : path.substring(0, path.length() - 6);
                            usePath = usePath.replaceAll("/", ".");
                            Class<?> clazz = Class.forName(usePath);
                            classes.add(clazz);
                        }
                    }
                }
                for (ClassCallback callback : classCallbacks) {
                    callback.classesAdded(resourceRoot, classes);
                }
                Index index = indexer.complete();
                ByteArrayOutputStream data = new ByteArrayOutputStream();
                IndexWriter writer = new IndexWriter(data);

                writer.write(index);

                resourceRoot.addAsManifestResource(new ByteArrayAsset(data.toByteArray()), "jandex.idx");

                jarFile = new FileOutputStream(new File(mainDirectory, resourceRoot.getName()));
                resourceRoot.as(ZipExporter.class).exportTo(jarFile);
            } catch (Exception e) {
                throw new RuntimeException("Could not create module resource [" + resourceRoot.getName() + ".", e);
            } finally {
                if (jarFile != null) {
                    jarFile.flush();
                    jarFile.close();
                }
            }
        }
    }

    /**
     * <p>Removes the module from the modules directory. This operation can not be reverted.</p>
     */
    public void remove() {
        File moduleDir = getModuleDirectory(false);
        File dir = moduleDir.getParentFile();
        remove(moduleDir);

        // move up through the filesystem and prune anything empty directories up to modulesDirectory
        if (dir != null) {
            File modulesDirectory = getModulesDirectory(false);
            File parent;
            while ((parent = dir.getParentFile()) != null) {
                // check we haven't somehow wandered outside modulesDirectory, or reached the top level modulesDirectory.
                if (dir.equals(modulesDirectory) || !dir.getPath().contains(modulesDirectory.getPath())) {
                    break;
                }

                if (dir.isDirectory() && dir.listFiles() != null && dir.listFiles().length == 0) {
                    if (!dir.delete()) {
                        throw new RuntimeException("Could not delete directory [" + dir.getPath() + "].");
                    }
                }
                dir = parent;
            }
        }
    }

    /**
     * <p>Creates a {@link org.jboss.shrinkwrap.api.spec.JavaArchive} instance that will be used to create a jar file inside the
     * module's directory.</p>
     *
     * <p>The name of the archive must match one of the <code>resource-root</code> definitions defined in the module
     * definition.</p>
     *
     * @param fileName The name of the archive.
     *
     * @return
     */
    public JavaArchive addResource(String fileName) {
        JavaArchive resource = ShrinkWrap.create(JavaArchive.class, fileName);
        if (resources.isEmpty()) {
            //Add the test module to the first jar in the module to avoid having to do that from the tests
            resource.addClass(TestModule.class);
        }
        resources.add(resource);
        return resource;
    }

    public void addJavaArchive(File archive) {
        resources.add(ShrinkWrap.createFromZipFile(JavaArchive.class, archive));
    }

    private void remove(File file) {
        if (file.exists()) {
            if (file.isDirectory()) {
                for (String name : file.list()) {
                    remove(new File(file, name));
                }
            }

            if (!file.delete()) {
                //This will often not work on Windows
                log.error("Could not delete [" + file.getPath() + ".");
            }
        } else {
            throw new IllegalStateException("Module [" + this.moduleName + "] does not exists.");
        }
    }

    private File getModuleDirectory(boolean createParent) {
        return new File(getModulesDirectory(createParent), this.moduleName.replace('.', File.separatorChar));
    }

    public static File getModulesDirectory(boolean create) {
        String modulePath = System.getProperty("module.path", null);

        if (modulePath == null) {
            String jbossHome = System.getProperty("jboss.home", null);

            if (jbossHome == null) {
                throw new IllegalStateException("Neither -Dmodule.path nor -Djboss.home were set");
            }

            if (isImmutableModulePath(jbossHome)) {
                throw new IllegalStateException(String.format("Writing test modules in jboss.home directory %s is not allowed", jbossHome));
            }

            modulePath = jbossHome + File.separatorChar + "modules";
        } else {
            String pathElement = null;
            for (String candidate : modulePath.split(File.pathSeparator)) {
                if (!isImmutableModulePath(candidate)) {
                    pathElement = candidate;
                    break;
                }
            }
            if (pathElement == null) {
                throw new IllegalStateException(String.format("Writing test modules in module.path directories %s is not allowed", modulePath));
            }
            modulePath = pathElement;
        }

        File moduleDir = Path.of(modulePath).toFile();

        if (!moduleDir.exists()) {
            if (create && isUnderCurrentProjectBuildDir(moduleDir)) {
                // Test has configured a module path item under the current project build dir but it hasn't been created.
                // Try and create it.
                if (!moduleDir.mkdirs() && !moduleDir.exists()) {
                    throw new IllegalStateException("Cannot create module directory " + moduleDir.getAbsolutePath());
                }
            } else {
                throw new IllegalStateException("Determined module path does not exist");
            }
        }

        if (!moduleDir.isDirectory()) {
            throw new IllegalStateException("Determined module path is not a dir");
        }

        return moduleDir;
    }

    private static boolean isImmutableModulePath(String path) {
        String thePath = Path.of(path).toString();
        return thePath.contains(ILLEGAL_BUILD_DIR) || thePath.contains(ILLEGAL_DIST_DIR);
    }

    private static boolean isUnderCurrentProjectBuildDir(File moduleRoot) {
        String buildDir = System.getProperty("project.build.directory");
        if (buildDir == null && System.getProperty("basedir") != null) {
            buildDir = Paths.get(System.getProperty("basedir"), "target").toString();
        }
        if (buildDir != null) {
            File target = new File(buildDir);
            File parent = moduleRoot.getParentFile();
            while (parent != null) {
                if (target.equals(parent)) {
                    return true;
                }
                parent = parent.getParentFile();
            }
        }
        return false;
    }

    private static void copyFile(File target, InputStream src) throws IOException {
        final BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(target));
        try {
            int i = src.read();
            while (i != -1) {
                out.write(i);
                i = src.read();
            }
        } finally {
            out.close();
        }
    }

    public String getName() {
        return moduleName;
    }

    private void generateModuleXml(File mainDirectory) throws IOException {
        try (Writer writer = Files.newBufferedWriter(new File(mainDirectory, "module.xml").toPath(), StandardCharsets.UTF_8)){
            writer.write("<module xmlns=\"urn:jboss:module:1.5\" name=\"" + moduleName + "\">");
            writer.write("<resources>");
            for (JavaArchive jar : resources) {
                writer.write("<resource-root path=\"" + jar.getName() + "\"/>");
            }
            writer.write("</resources>");
            writer.write("<dependencies>");
            for (String dependency : dependencies) {
                writer.write("<module name=\"" + dependency + "\"/>");
            }
            writer.write("</dependencies>");
            writer.write("</module>");
        }
    }

    public interface ClassCallback {
        void classesAdded(JavaArchive jar, final List<Class<?>> classes);
    }
}
