package com.redhat.thermostat.tools.eclipse.plugin.wizards;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;

import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.NotEnabledException;
import org.eclipse.core.commands.NotHandledException;
import org.eclipse.core.commands.common.NotDefinedException;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IProjectDescription;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.handlers.IHandlerService;

import com.redhat.thermostat.tools.eclipse.plugin.Activator;
import com.redhat.thermostat.tools.eclipse.plugin.wizards.PluginXmlCreator.Decisions;

/** Creates a Thermostat project using the preferred thermostat defaults, settings, and style */
public class ProjectCreator {

    private static final String POM_FILE_NAME = "pom.xml";
    private static final String POM_HEADER = ""
            + "<?xml version='1.0' encoding='UTF-8'?>\n"
            + "<project xsi:schemaLocation='http://maven.apache.org/POM/4.0.0\n"
            + "                             http://maven.apache.org/xsd/maven-4.0.0.xsd'\n"
            + "         xmlns='http://maven.apache.org/POM/4.0.0'\n"
            + "         xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'>\n"
            + "\n"
            + "  <modelVersion>4.0.0</modelVersion>\n"
            + "\n";
    private static final String POM_FOOTER = ""
            + "</project>\n";

    private static final String OSGI_DEPENDENCIES_WITH_VERSION = ""
            + "      <dependency>\n"
            + "        <groupId>org.osgi</groupId>\n"
            + "        <artifactId>org.osgi.core</artifactId>\n"
            + "        <version>4.3.1</version>\n"
            + "      </dependency>\n"
            + "      <dependency>\n"
            + "        <groupId>org.osgi</groupId>\n"
            + "        <artifactId>org.osgi.compendium</artifactId>\n"
            + "        <version>4.3.1</version>\n"
            + "      </dependency>\n";

    private static final String OSGI_DEPENDENCIES = ""
            + "    <dependency>\n"
            + "      <groupId>org.osgi</groupId>\n"
            + "      <artifactId>org.osgi.core</artifactId>\n"
            + "    </dependency>\n"
            + "    <dependency>\n"
            + "      <groupId>org.osgi</groupId>\n"
            + "      <artifactId>org.osgi.compendium</artifactId>\n"
            + "    </dependency>\n";

    private static final String BUNDLE_PLUGIN_WITH_VERSION = ""
            + "        <plugin>\n"
            + "          <groupId>org.apache.felix</groupId>\n"
            + "          <artifactId>maven-bundle-plugin</artifactId>\n"
            + "          <version>2.3.7</version>\n"
            + "        </plugin>\n";

    private static final String BUNDLE_PLUGIN = ""
            + "      <plugin>\n"
            + "        <groupId>org.apache.felix</groupId>\n"
            + "        <artifactId>maven-bundle-plugin</artifactId>\n"
            + "        <extensions>true</extensions>\n"
            + "      </plugin>\n";

    private static final String BUNDLE_ACTIVATOR_NAME = "Activator";
    private static final String BUNDLE_ACTIVATOR = ""
            + "package ${package.name};\n" // ${package.name} is replaced with actual package name
            + "\n"
            + "import org.osgi.framework.BundleActivator;\n"
            + "import org.osgi.framework.BundleContext;\n"
            + "\n"
            + "public class " + BUNDLE_ACTIVATOR_NAME + " implements BundleActivator {\n"
            + "\n"
            + "    public void start(BundleContext context) throws Exception {\n"
            + "        // TODO Auto-generated method stub\n"
            + "    }\n"
            + "\n"
            + "    public void stop(BundleContext context) throws Exception {\n"
            + "        // TODO Auto-generated method stub\n"
            + "    }\n"
            + "\n"
            + "}\n";

    private IHandlerService serviceHandler;

    private String packagePrefix;
    private String groupId;
    private String artifactId;
    private String version;
    private String thermostatVersion;

    private String parentId;

    public ProjectCreator(String groupId, String artifactId, String version, String packagePrefix, String thermostatVersion) {
        this((IHandlerService) PlatformUI.getWorkbench().getService(IHandlerService.class), groupId, artifactId, version, packagePrefix, thermostatVersion);
    }

    public ProjectCreator(IHandlerService handler, String groupId, String artifactId, String version, String packagePrefix, String thermostatVersion) {
        this.serviceHandler = handler;
        this.groupId = groupId;
        this.artifactId = artifactId;
        this.version = version;
        this.packagePrefix = packagePrefix;

        this.thermostatVersion = thermostatVersion;

        this.parentId = artifactId + "-parent";

    }

    public void create() throws CoreException, IOException {
        List<Project> projects = new ArrayList<>();
        Project project;

        Project parent;
        project = parent = createParentModuleProject();
        projects.add(project);

        project = createCommonSubproject(parent);
        projects.add(project);

        project = createJavaSubproject(parent, "agent");
        projects.add(project);

        project = createJavaSubproject(parent, "client");
        projects.add(project);

        project = createJavaSubproject(parent, "cli");
        projects.add(project);

        project = createDistributionProject(parent);
        projects.add(project);

        refreshProjects(projects);
    }

    private Project createParentModuleProject() throws CoreException, IOException {
        String projectName = artifactId;
        Project project = createMavenProject(null, projectName);

        String pomContents = ""
                + POM_HEADER
                + "  <groupId>" + groupId + "</groupId>\n"
                + "  <artifactId>" + parentId + "</artifactId>\n"
                + "  <version>" + version + "</version>\n"
                + "  <packaging>pom</packaging>\n"
                + "\n"
                + "  <modules>\n"
                + "    <module>" + this.artifactId + "-agent</module>\n"
                + "    <module>" + this.artifactId + "-common</module>\n"
                + "    <module>" + this.artifactId + "-client</module>\n"
                + "    <module>" + this.artifactId + "-cli</module>\n"
                + "    <module>" + this.artifactId + "-distribution</module>\n"
                + "  </modules>\n"
                + "\n"
                + "  <build>\n"
                + "    <pluginManagement>\n"
                + "      <plugins>\n"
                + BUNDLE_PLUGIN_WITH_VERSION
                + "      </plugins>\n"
                + "    </pluginManagement>\n"
                + "  </build>\n"
                + "\n"
                + "  <dependencyManagement>\n"
                + "    <dependencies>\n"
                + OSGI_DEPENDENCIES_WITH_VERSION
                + "    </dependencies>\n"
                + "  </dependencyManagement>\n"
                + POM_FOOTER;

        createPomFile(project, pomContents);

        return project;
    }

    private Project createCommonSubproject(Project parent) throws IOException, CoreException {
        String suffix = "common";
        String artifactId = this.artifactId + "-" + suffix;
        String packageName = packagePrefix + "." + suffix;
        Project project = createJavaCodeProject(parent, artifactId, packageName);

        String pomContents = ""
                + POM_HEADER
                + "\n"
                + createParentSection(groupId, parentId, version)
                + "\n"
                + "  <artifactId>" + artifactId + "</artifactId>\n"
                + "  <packaging>bundle</packaging>\n"
                + "\n"
                + "  <build>\n"
                + "    <plugins>\n"
                + BUNDLE_PLUGIN
                + "    </plugins>\n"
                + "  </build>\n"
                + "\n"
                + "  <dependencies>\n"
                + OSGI_DEPENDENCIES
                + "  </dependencies>\n"
                + POM_FOOTER;

        createPomFile(project, pomContents);

        return project;
    }

    private Project createJavaSubproject(Project parent, String subproject) throws CoreException, IOException {
        String artifactId = this.artifactId + "-" + subproject;
        String subpackage = this.packagePrefix + "." + subproject;

        Project project = createJavaCodeProject(parent, artifactId, subpackage);

        String pomContents = ""
                + POM_HEADER
                + createParentSection(groupId, parentId, version)
                + "\n"
                + "  <artifactId>" + artifactId + "</artifactId>\n"
                + "  <packaging>bundle</packaging>\n"
                + "\n"
                + "  <build>\n"
                + "    <plugins>\n"
                + BUNDLE_PLUGIN
                + "    </plugins>\n"
                + "  </build>\n"
                + "\n"
                + "  <dependencies>\n"
                + "    <dependency>\n"
                + "      <groupId>" + groupId + "</groupId>\n"
                + "      <artifactId>" + this.artifactId + "-common</artifactId>\n"
                + "      <version>" + version + "</version>\n"
                + "    </dependency>\n"
                + OSGI_DEPENDENCIES
                + "  </dependencies>\n"
                + POM_FOOTER;

        createPomFile(project, pomContents);

        return project;
    }

    private Project createJavaCodeProject(Project parent, String projectName, String packageName) throws CoreException {
        Project projects = createJavaAndMavenProject(parent, projectName);

        IProject project = projects.project;

        IFolder srcFolder = project.getFolder("src");
        srcFolder.create(false, true, null);

        IFolder srcMainFolder = srcFolder.getFolder("main");
        srcMainFolder.create(true, true, null);

        IFolder srcMainJavaFolder = srcMainFolder.getFolder("java");
        srcMainJavaFolder.create(true, true, null);

        IFolder srcTestFolder = srcFolder.getFolder("test");
        srcTestFolder.create(true, true, null);

        IFolder srcTestJavaFolder = srcTestFolder.getFolder("java");
        srcTestJavaFolder.create(true, true, null);

        createBundleActivator(projects, srcMainJavaFolder, packageName);

        return projects;
    }

    private void createBundleActivator(Project projects, IFolder root, String packageName) throws CoreException {
        IJavaProject javaProject = projects.javaProject;

        IPackageFragment pack = javaProject.getPackageFragmentRoot(root)
                                    .createPackageFragment(packageName, false, null);

        String bundleActivatorContents = BUNDLE_ACTIVATOR.replace("${package.name}", pack.getElementName());
        pack.createCompilationUnit(BUNDLE_ACTIVATOR_NAME + ".java", bundleActivatorContents, false, null);
    }

    private Project createDistributionProject(Project parent) throws CoreException, IOException {
        String artifactId = this.artifactId + "-distribution";

        Project projects = createJavaAndMavenProject(parent, artifactId);

        String pomContents = ""
                + POM_HEADER
                + createParentSection(groupId, parentId, version)
                + "\n"
                + "  <artifactId>" + artifactId + "</artifactId>\n"
                + "  <packaging>jar</packaging>\n"
                + "\n"
                + "  <properties>\n"
                + "    <thermostat.plugin>" + this.artifactId + "</thermostat.plugin>\n"
                + "  </properties>\n"
                + "\n"
                + "  <build>\n"
                + "    <plugins>\n"
                + "      <plugin>\n"
                + "        <artifactId>maven-assembly-plugin</artifactId>\n"
                + "        <dependencies>\n"
                + "          <dependency>\n"
                + "            <groupId>com.redhat.thermostat</groupId>\n"
                + "            <artifactId>thermostat-assembly</artifactId>\n"
                + "            <version>" + thermostatVersion + "</version>\n"
                + "          </dependency>\n"
                + "        </dependencies>\n"
                + "        <configuration>\n"
                + "          <descriptorRefs>\n"
                + "            <descriptorRef>plugin-assembly</descriptorRef>\n"
                + "          </descriptorRefs>\n"
                + "          <appendAssemblyId>false</appendAssemblyId>\n"
                + "        </configuration>\n"
                + "        <executions>\n"
                + "          <execution>\n"
                + "            <id>assemble-plugin</id>\n"
                + "            <phase>package</phase>\n"
                + "            <goals>\n"
                + "              <goal>single</goal>\n"
                + "            </goals>\n"
                + "          </execution>\n"
                + "        </executions>\n"
                + "      </plugin>\n"
                + "    </plugins>\n"
                + "  </build>\n"
                + "\n"
                + "  <!-- Explicitly list all plug-in artifacts, transitive dependencies\n"
                + "       are not included in assembly. -->\n"
                + "  <dependencies>\n"
                + "    <dependency>\n"
                + "      <groupId>" + groupId + "</groupId>\n"
                + "      <artifactId>" + this.artifactId + "-agent</artifactId>\n"
                + "      <version>${project.version}</version>\n"
                + "    </dependency>\n"
                + "    <dependency>\n"
                + "      <groupId>" + groupId + "</groupId>\n"
                + "      <artifactId>" + this.artifactId + "-common</artifactId>\n"
                + "      <version>${project.version}</version>\n"
                + "    </dependency>\n"
                + "    <dependency>\n"
                + "      <groupId>" + groupId + "</groupId>\n"
                + "      <artifactId>" + this.artifactId + "-client</artifactId>\n"
                + "      <version>${project.version}</version>\n"
                + "    </dependency>\n"
                + "    <dependency>\n"
                + "      <groupId>" + groupId + "</groupId>\n"
                + "      <artifactId>" + this.artifactId + "-cli</artifactId>\n"
                + "      <version>${project.version}</version>\n"
                + "    </dependency>\n"
                + "  </dependencies>\n"
                + POM_FOOTER;

        createPomFile(projects, pomContents);

        IProject project = projects.project;

        IFolder srcFolder = project.getFolder("src");
        srcFolder.create(false, true, null);

        IFolder srcMainFolder = srcFolder.getFolder("main");
        srcMainFolder.create(true, true, null);

        IFolder srcMainResourcesFolder = srcMainFolder.getFolder("resources");
        srcMainResourcesFolder.create(true, true, null);

        createThermostatPluginXml(project.getName());

        return projects;
    }

    private void createThermostatPluginXml(String projectName) throws CoreException, IOException {
        PluginXmlCreator creator = new PluginXmlCreator(ResourcesPlugin.getWorkspace().getRoot());
        creator.create(projectName, new NullProgressMonitor(), new Decisions() {
            @Override
            public boolean overwriteExistingFile() {
                return true;
            }
        });
    }

    private Project createJavaAndMavenProject(Project parent, String projectName) throws CoreException {
        Project project = createMavenProject(parent, projectName);

        addJavaNature(project.project);

        IJavaProject javaProject = JavaCore.create(project.project);

        return new Project(project.project, javaProject);
    }

    private Project createMavenProject(Project parent, String projectName) throws CoreException {
        IWorkspace workspace = ResourcesPlugin.getWorkspace();
        IWorkspaceRoot root = workspace.getRoot();

        IProject project = root.getProject(projectName);

        if (project.exists()) {
            project.delete(true, null);
        }
        try {
            if (parent == null) {
                project.create(null);
            } else {
                IProjectDescription description = workspace.newProjectDescription(projectName);
                description.setLocation(parent.project.getLocation().append(projectName));
                project.create(description, null);
            }
            project.open(null);
        } catch (CoreException e) {
            e.printStackTrace();
        }

        addMavenNature(project);

        return new Project(project, null);
    }

    private void addJavaNature(IProject project) throws CoreException {
        IProjectDescription description = project.getDescription();
        addJavaNature(description);
        project.setDescription(description, null);
    }

    private void addJavaNature(IProjectDescription description) {
        addNature(description, JavaCore.NATURE_ID);
    }

    private void addMavenNature(IProject project) throws CoreException {
        IProjectDescription description = project.getDescription();
        addMavenNature(description);
        project.setDescription(description, null);
    }

    private void addMavenNature(IProjectDescription description) {
        // provided by m2e
        // TODO what's the symbolic constant for this? IMavenConstants.NATURE_ID?
        addNature(description, "org.eclipse.m2e.core.maven2Nature");
    }

    private void addNature(IProjectDescription description, String nature) {
        String[] existingNatureIds = description.getNatureIds();
        Set<String> natures = new TreeSet<>(Arrays.asList(existingNatureIds));
        natures.add(nature);
        String[] newNatureIds = natures.toArray(new String[natures.size()]);
        description.setNatureIds(newNatureIds);
    }

    private void createPomFile(Project projects, String contents) throws IOException, CoreException {
        IProject project = projects.project;
        IFile pomFile = project.getFile(POM_FILE_NAME);
        try (InputStream contentStream = new ByteArrayInputStream(contents.getBytes(StandardCharsets.UTF_8))) {
            if (pomFile.exists()) {
                pomFile.setContents(contentStream, true, true, null);
            } else {
                pomFile.create(contentStream, true, null);
            }
        }
    }

    private String createParentSection(String groupId, String parentId, String version) {
        return ""
            + "  <parent>\n"
            + "    <groupId>" + groupId + "</groupId>\n"
            + "    <artifactId>" + parentId + "</artifactId>\n"
            + "    <version>" + version + "</version>\n"
            + "  </parent>\n";
    }

    private void refreshProjects(List<Project> projects) throws CoreException {
        // Refresh projects
        ResourcesPlugin.getWorkspace().getRoot().refreshLocal(IWorkspaceRoot.DEPTH_INFINITE, new NullProgressMonitor());

        // Refresh again, just to make sure changes are sane by the time maven sees them
        ResourcesPlugin.getWorkspace().getRoot().refreshLocal(IWorkspaceRoot.DEPTH_INFINITE, new NullProgressMonitor());

        // TODO wait for refresh to complete

        tellM2eAboutNewProjects(projects);
    }

    private void tellM2eAboutNewProjects(List<Project> projects) throws CoreException {
        try {
            refreshMavenProjectUsingInternalApi(projects);
        } catch (UnsupportedOperationException e) {
            try {
                refreshMavenProjectUsingUglyButPublicCommandFallback();
            } catch (UnsupportedOperationException e2) {
                Status s = new Status(IStatus.ERROR, Activator.PLUGIN_ID, "Error refreshing maven configuration", e2);
                throw new CoreException(s);
            }
        }
    }

    private void refreshMavenProjectUsingInternalApi(List<Project> projects) throws UnsupportedOperationException {
        List<IProject> actualProjects = new ArrayList<>();
        for (Project project : projects) {
            actualProjects.add(project.project);
        }
        IProject[] projectsToUpdate = actualProjects.toArray(new IProject[0]);

        try {
            // UpdateMavenProjectJob updateProjectsJob = new UpdateMavenProjectJob(projectsToUpdate);
            Class<?> klass = Class.forName("org.eclipse.m2e.core.ui.internal.UpdateMavenProjectJob");
            Constructor<?> constructor = klass.getConstructor(IProject[].class);
            Object updateProjectsJob = constructor.newInstance((Object)projectsToUpdate);

            // updateProjectsJob.schedule();
            Method schedule = klass.getMethod("schedule");
            schedule.invoke(updateProjectsJob);
        } catch (ReflectiveOperationException | SecurityException | IllegalArgumentException e) {
            throw new UnsupportedOperationException("Incompatible m2e version", e);
        }
    }

    /** This interrupts the UI by showing a completely un-needed prompt */
    private void refreshMavenProjectUsingUglyButPublicCommandFallback() throws UnsupportedOperationException {
        final String UPADATE_MAVEN_PROJECT_COMMAND = "org.eclipse.m2e.core.ui.command.updateProject";
        try {
            serviceHandler.executeCommand(UPADATE_MAVEN_PROJECT_COMMAND, null);
        } catch (ExecutionException | NotDefinedException | NotEnabledException | NotHandledException e) {
            throw new UnsupportedOperationException("Unable to refresh m2e using " + UPADATE_MAVEN_PROJECT_COMMAND);
        }
    }

    private static class Project {
        private final IProject project;
        private final IJavaProject javaProject;

        public Project(IProject project, IJavaProject javaProject) {
            this.project = project;
            this.javaProject = javaProject;
        }
    }
}