/*******************************************************************************
 * Copyright (c) 2007, 2020 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jst.jsp.core.internal.util;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jst.jsp.core.internal.Logger;
import org.eclipse.wst.common.componentcore.ComponentCore;
import org.eclipse.wst.common.componentcore.ModuleCoreNature;
import org.eclipse.wst.common.componentcore.resources.IVirtualComponent;
import org.eclipse.wst.common.componentcore.resources.IVirtualFile;
import org.eclipse.wst.common.componentcore.resources.IVirtualFolder;
import org.eclipse.wst.common.componentcore.resources.IVirtualReference;
import org.eclipse.wst.common.componentcore.resources.IVirtualResource;
import org.eclipse.wst.common.project.facet.core.IFacetedProject;
import org.eclipse.wst.common.project.facet.core.IProjectFacet;
import org.eclipse.wst.common.project.facet.core.ProjectFacetsManager;

/**
 * Wrapper class for all Facet-related calls. If the Facet or ModuleCore
 * bundles are not available, this class will not load, or if it does, its
 * methods will cause NoClassDefFoundErrors. This allows us to
 * compartmentalize the dependencies.
 * 
 */
final class FacetModuleCoreSupportDelegate {
	private static final String SLASH = "/"; //$NON-NLS-1$

	/**
	 * Copied to avoid unneeded extra dependency (plus it's unclear why the
	 * valuse are in that plug-in).
	 * 
	 * @see org.eclipse.wst.common.componentcore.internal.util.IModuleConstants.JST_WEB_MODULE
	 */
	private final static String JST_WEB_MODULE = "jst.web"; //$NON-NLS-1$
	/**
	 * @see org.eclipse.wst.common.componentcore.internal.util.IModuleConstants.JST_WEBFRAGMENT_MODULE
	 */
	private final static String JST_WEBFRAGMENT_MODULE = "jst.webfragment"; //$NON-NLS-1$
	/**
	 * @param project
	 * @return the version of the JST Web facet, a default otherwise
	 * @throws CoreException
	 */
	static float getDynamicWebProjectVersion(IProject project) {
		if (project == null)
			return FacetModuleCoreSupport.DEFAULT_SERVLET_VERSION;

		// In the absence of any facet information, assume the highest level
		float version = FacetModuleCoreSupport.DEFAULT_SERVLET_VERSION;
		try {
			IFacetedProject faceted = ProjectFacetsManager.create(project);
			if (faceted != null && ProjectFacetsManager.isProjectFacetDefined(JST_WEB_MODULE)) {
				IProjectFacet webModuleFacet = ProjectFacetsManager.getProjectFacet(JST_WEB_MODULE);
				if (faceted.hasProjectFacet(webModuleFacet)) {
					version = Float.parseFloat(faceted.getInstalledVersion(webModuleFacet).getVersionString());
				}
			}
		}
		catch (NumberFormatException e) {
			Logger.logException(e);
		}
		catch (CoreException e) {
			Logger.logException(e);
		}
		return version;
	}

	/**
	 * @param path -
	 *            the full path to a resource within the workspace
	 * @return - the runtime path of the resource if one exists, null
	 *         otherwise
	 */
	static IPath getRuntimePath(IPath path) {
		if (path == null)
			return null;

		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(path.segment(0));

		if (!ModuleCoreNature.isFlexibleProject(project))
			return null;

		IVirtualResource[] virtualResources = ComponentCore.createResources(ResourcesPlugin.getWorkspace().getRoot().getFile(path));
		if (virtualResources != null && virtualResources.length > 0) {
			return virtualResources[0].getRuntimePath();
		}
		return null;
	}

	/**
	 * @param project
	 * @return the IPath to the "root" of the web contents
	 */
	static IPath getWebContentRootPath(IProject project) {
		if (project == null)
			return null;

		if (!ModuleCoreNature.isFlexibleProject(project))
			return null;

		IPath path = null;
		IVirtualComponent component = ComponentCore.createComponent(project);
		if (component != null && component.exists() && component.getRootFolder() != null) {
			path = component.getRootFolder().getWorkspaceRelativePath();
			if (component.getRootFolder().getFolder(FacetModuleCoreSupport.META_INF_RESOURCES_PATH).getUnderlyingFolder().isAccessible()) {
				path = path.append(FacetModuleCoreSupport.META_INF_RESOURCES_PATH);
			}
		}
		return path;
	}

	/**
	 * @param project
	 * @return
	 * @throws CoreException
	 */
	static boolean isDynamicWebProject(IProject project) {
		if (project == null)
			return false;
		
		try {
			if (ProjectFacetsManager.isProjectFacetDefined(JST_WEB_MODULE)) {
				IFacetedProject faceted = ProjectFacetsManager.create(project);
				IProjectFacet webModuleFacet = ProjectFacetsManager.getProjectFacet(JST_WEB_MODULE);
				if (faceted != null && faceted.hasProjectFacet(webModuleFacet)) {
					return true;
				}
			}
		}
		catch (CoreException e) {
			Logger.logException(e);
		}
		return false;
	}

	/**
	 * @param project
	 * @return
	 * @throws CoreException
	 */
	static boolean isWebFragmentProject(IProject project) {
		if (project == null)
			return false;
		
		try {
			if (ProjectFacetsManager.isProjectFacetDefined(JST_WEBFRAGMENT_MODULE)) {
				IFacetedProject faceted = ProjectFacetsManager.create(project);
				IProjectFacet webModuleFacet = ProjectFacetsManager.getProjectFacet(JST_WEBFRAGMENT_MODULE);
				if (faceted != null && faceted.hasProjectFacet(webModuleFacet)) {
					return true;
				}
			}
		}
		catch (CoreException e) {
			Logger.logException(e);
		}
		return false;
	}

	/*
	 * Handle resolution in a required web fragment
	 */
	private static IPath resolveInReferenced(IProject project, IPath runtimeReference) {
		IVirtualReference[] references = ComponentCore.createComponent(project).getReferences();
		if (references != null) {
			for (int i = 0; i < references.length; i++) {
				IVirtualComponent referencedComponent = references[i].getReferencedComponent();
				if (referencedComponent == null)
					continue;
				IVirtualComponent component = referencedComponent.getComponent();
				if (component == null)
					continue;
				IVirtualFolder rootFolder = component.getRootFolder();
				if (rootFolder == null)
					continue;
				IPath referencedPathRoot = rootFolder.getWorkspaceRelativePath();
				/* http://bugs.eclipse.org/410161 */
				if (referencedPathRoot != null) {
					/*
					 * See Servlet 3.0, section 4.6, web fragments as required
					 * projects
					 */
					/* https://bugs.eclipse.org/398698 */
					IPath resolved = referencedPathRoot.append(FacetModuleCoreSupport.META_INF_RESOURCES).append(runtimeReference);
					if (resolved != null && component.getProject().findMember(resolved.removeFirstSegments(1)) != null) {
						return resolved;
					}
					/*
					 * Handle multi-root fragments, and ones where the default root marked for deployment doesn't exist
					 */
					IVirtualFile virtualFile = ComponentCore.createFile(component.getProject(), FacetModuleCoreSupport.META_INF_RESOURCES_PATH.append(runtimeReference));
					if (virtualFile != null) {
						IFile[] underlyingFiles = virtualFile.getUnderlyingFiles();
						for (int j = 0; j < underlyingFiles.length; j++) {
							if (underlyingFiles[i].isAccessible()) {
								return underlyingFiles[i].getFullPath();
							}
						}
					}
					IVirtualFolder virtualFolder = ComponentCore.createFolder(component.getProject(), FacetModuleCoreSupport.META_INF_RESOURCES_PATH.append(runtimeReference));
					if (virtualFolder != null) {
						IContainer[] underlyingFolders = virtualFolder.getUnderlyingFolders();
						for (int j = 0; j < underlyingFolders.length; j++) {
							if (underlyingFolders[i].isAccessible()) {
								return underlyingFolders[i].getFullPath();
							}
						}
					}
				}
				// overlay?
				IVirtualResource member = rootFolder.findMember(runtimeReference);
				if (member != null) {
					return member.getWorkspaceRelativePath();
				}
			}
		}
		return null;
	}

	/**
	 * @param basePath -
	 *            the full path to a resource within the workspace
	 * @param reference -
	 *            the reference string to resolve
	 * @return - the full path within the workspace that corresponds to the
	 *         given reference according to the virtual pathing support
	 */
	static IPath resolve(IPath basePath, String reference) {
		if (reference == null || basePath == null || basePath.segmentCount() == 0)
			return null;

		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(basePath.segment(0));

		if (!ModuleCoreNature.isFlexibleProject(project))
			return null;

		if (basePath.segmentCount() > 1) {
			IResource baseResource = ResourcesPlugin.getWorkspace().getRoot().findMember(basePath);
			if (baseResource != null) {
				IVirtualResource[] virtualResources = ComponentCore.createResources(baseResource);
				for (int i = 0; i < virtualResources.length; i++) {
					IPath referenceRuntimePath = null;
					if (reference.startsWith(SLASH)) {
						referenceRuntimePath = new Path(reference);
					}
					else {
						IPath baseRuntimePath = virtualResources[i].getRuntimePath();
						referenceRuntimePath = baseRuntimePath.removeLastSegments(1).append(reference);
					}
					
					IVirtualFile virtualFile = ComponentCore.createFile(project, referenceRuntimePath);
					if (virtualFile != null && virtualFile.exists()) {
						IFile[] underlyingFiles = virtualFile.getUnderlyingFiles();
						for (int j = 0; j < underlyingFiles.length; j++) {
							if (underlyingFiles[j].isAccessible()) {
								return underlyingFiles[j].getFullPath();
							}
						}
						if (underlyingFiles.length > 0) {
							return underlyingFiles[0].getFullPath();
						}
					}
					else {
						// http://bugs.eclipse.org/338751 
						IVirtualFolder virtualFolder = ComponentCore.createFolder(project, referenceRuntimePath);
						if (virtualFolder != null && virtualFolder.exists()) {
							IContainer[] underlyingFolders = virtualFolder.getUnderlyingFolders();
							for (int j = 0; j < underlyingFolders.length; j++) {
								if (underlyingFolders[j].isAccessible()) {
									return underlyingFolders[j].getFullPath();
								}
							}
							if (underlyingFolders.length > 0) {
								return underlyingFolders[0].getFullPath();
							}
						}
						else {
							// check assembled projects
							return resolveInReferenced(project, referenceRuntimePath);
						}
					}
				}
			}
		}
		else {
			IVirtualFile virtualFile = ComponentCore.createFile(project, new Path(reference));
			if (virtualFile != null && virtualFile.exists()) {
				return virtualFile.getUnderlyingFile().getFullPath();
			}
		}
		return null;
	}

	static IPath[] getAcceptableRootPaths(IProject project) {
		if (!ModuleCoreNature.isFlexibleProject(project)) {
			return new IPath[]{project.getFullPath()};
		}

		List<IPath> paths = new ArrayList<>();
		IVirtualFolder componentFolder = ComponentCore.createFolder(project, Path.ROOT);
		if (componentFolder != null && componentFolder.exists()) {
			IContainer[] workspaceFolders = componentFolder.getUnderlyingFolders();
			for (int i = 0; i < workspaceFolders.length; i++) {
				if (workspaceFolders[i].getFolder(FacetModuleCoreSupport.META_INF_RESOURCES_PATH).isAccessible())
					paths.add(workspaceFolders[i].getFullPath().append(FacetModuleCoreSupport.META_INF_RESOURCES_PATH));
				else
					paths.add(workspaceFolders[i].getFullPath());
			}
			
			IVirtualReference[] references = ComponentCore.createComponent(project).getReferences();
			if (references != null) {
				for (int i = 0; i < references.length; i++) {
					IVirtualComponent referencedComponent = references[i].getReferencedComponent();
					if (referencedComponent == null)
						continue;
					IVirtualComponent component = referencedComponent.getComponent();
					if (component == null)
						continue;
					IVirtualFolder rootFolder = component.getRootFolder();
					if (rootFolder == null)
						continue;
					IPath referencedPathRoot = rootFolder.getWorkspaceRelativePath();
					/* http://bugs.eclipse.org/410161 */
					if (referencedPathRoot != null) {
						/*
						 * See Servlet 3.0, section 4.6 ; this is the only
						 * referenced module/component type we support
						 */
						IPath resourcesPath = referencedPathRoot.append(FacetModuleCoreSupport.META_INF_RESOURCES);
						if (resourcesPath != null && component.getProject().findMember(resourcesPath.removeFirstSegments(1)) != null) {
							paths.add(resourcesPath);
						}
					}
				}
			}

		}
		else {
			paths.add(project.getFullPath());
		}
		return paths.toArray(new IPath[paths.size()]);
	}

	static IPath getDefaultRoot(IProject project) {
		if (ModuleCoreNature.isFlexibleProject(project)) {
			IVirtualFolder componentFolder = ComponentCore.createFolder(project, Path.ROOT);
			if (componentFolder != null && componentFolder.exists()) {
				return componentFolder.getWorkspaceRelativePath();
			}
		}
		return null;
	}

	static IProject[] getReferenced(IProject current) {
		if (!ModuleCoreNature.isFlexibleProject(current))
			return new IProject[0];
		
		Set<IProject> projects = new HashSet<IProject>();
		IVirtualReference[] references = ComponentCore.createComponent(current).getReferences();
		if (references != null) {
			for (int i = 0; i < references.length; i++) {
				IVirtualComponent referencedComponent = references[i].getReferencedComponent();
				if (referencedComponent == null)
					continue;
				IProject project = referencedComponent.getProject();
				if (project == null || project.equals(current))
					continue;
				projects.add(project);
			}
		}
		return projects.toArray(new IProject[projects.size()]);
	}

	static IPath getRootContainerForPath(IProject project, IPath path) {
		if (ModuleCoreNature.isFlexibleProject(project)) {
			IVirtualFolder componentFolder = ComponentCore.createFolder(project, Path.ROOT);
			if (componentFolder != null && componentFolder.exists()) {
				IContainer[] workspaceFolders = componentFolder.getUnderlyingFolders();
				for (int i = 0; i < workspaceFolders.length; i++) {
					if (workspaceFolders[i].getFullPath().isPrefixOf(path)) {
						return workspaceFolders[i].getFullPath();
					}
				}
			}
		}
		return null;
	}
}