/**

 * Copyright (c) 2010 Symbian Foundation and/or its subsidiary(-ies).

 * All rights reserved.

 * This component and the accompanying materials are made available

 * under the terms of the License "Eclipse Public License v1.0"

 * which accompanies this distribution, and is available

 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

 *

 * Initial Contributors:

 * Symbian Foundation - initial contribution.

 * Contributors:

 * Description:

 * Overview:

 * Details:

 * Platforms/Drives/Compatibility:

 * Assumptions/Requirement/Pre-requisites:

 * Failures and causes:

 */

package org.symbian.tools.tmw.previewer.internal;

import java.io.InputStream;

import java.util.HashMap;

import java.util.Map;

import org.eclipse.core.resources.IFile;

import org.eclipse.core.resources.IProject;

import org.eclipse.core.runtime.CoreException;

import org.eclipse.core.runtime.IConfigurationElement;

import org.eclipse.core.runtime.IPath;

import org.eclipse.core.runtime.Platform;

import org.symbian.tools.tmw.core.TMWCore;

import org.symbian.tools.tmw.core.projects.ITMWProject;

import org.symbian.tools.tmw.core.runtimes.IMobileWebRuntime;

import org.symbian.tools.tmw.previewer.core.IApplicationLayoutProvider;

import org.symbian.tools.tmw.previewer.core.IPreviewerExtensionsManager;

import org.symbian.tools.wrttools.previewer.PreviewerPlugin;

public class PreviewerExtensionsManagerImpl implements IPreviewerExtensionsManager {

    public static final class LazyProvider implements IApplicationLayoutProvider {

        private final IConfigurationElement element;

        private IApplicationLayoutProvider instance;

        public LazyProvider(IConfigurationElement element) {

            this.element = element;

        }

        public IPath getResourcePath(IFile file) {

            return getDelegate().getResourcePath(file);

        }

        private IApplicationLayoutProvider getDelegate() {

            if (instance == null) {

                try {

                    instance = (IApplicationLayoutProvider) element.createExecutableExtension("class");

                } catch (CoreException e) {

                    PreviewerPlugin.log(e);

                    instance = new IApplicationLayoutProvider() {

                        public IPath getResourcePath(IFile file) {

                            return null;

                        }

                        public InputStream getResourceFromPath(IProject project, IPath path) {

                            return null;

                        }

                        public IFile getWorkspaceFile(IProject project, IPath applicationPath) {

                            return null;

                        }

                    };

                }

            }

            return instance;

        }

        public InputStream getResourceFromPath(IProject project, IPath path) throws CoreException {

            return getDelegate().getResourceFromPath(project, path);

        }

        public IFile getWorkspaceFile(IProject project, IPath applicationPath) throws CoreException {

            return getDelegate().getWorkspaceFile(project, applicationPath);

        }

    }

    private Map<IMobileWebRuntime, IApplicationLayoutProvider> providers;

    public IApplicationLayoutProvider getLayoutProvider(IProject project) {

        final ITMWProject p = TMWCore.create(project);

        if (p != null && p.getTargetRuntime() != null) {

            checkRegistry();

            return providers.get(p.getTargetRuntime());

        }

        return null;

    }

    private synchronized void checkRegistry() {

        if (providers == null) {

            providers = new HashMap<IMobileWebRuntime, IApplicationLayoutProvider>();

            final IConfigurationElement[] configuration = Platform.getExtensionRegistry().getConfigurationElementsFor(

                    PreviewerPlugin.PLUGIN_ID, "layoutProviders");

            for (IConfigurationElement element : configuration) {

                final String runtimeId = element.getAttribute("runtime-id");

                final String version = element.getAttribute("runtime-version");

                final IMobileWebRuntime runtime = TMWCore.getRuntimesManager().getRuntime(runtimeId, version);

                if (runtime != null) {

                    providers.put(runtime, new LazyProvider(element));

                } else {

                    PreviewerPlugin.log(String.format("Runtime %s:$s referenced from %s was not found", runtimeId,

                            version, element.getContributor().getName()), null);

                }

            }

        }

    }

}