/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 by RapidMiner and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapidminer.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapid_i.deployment.update.client;

import java.net.URI;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.rapidminer.deployment.client.wsimport.PackageDescriptor;
import com.rapidminer.deployment.client.wsimport.UpdateService;
import com.rapidminer.gui.tools.SwingTools;
import com.rapidminer.tools.Tools;
import com.rapidminer.tools.plugin.Dependency;

/**
 * Cache for PackageDescriptor which is used by the Rapidminer Update Dialog.
 * If the needed information is not in the cache, it is fetched though the {@link UpdateService}.
 * @author Dominik Halfkann
 *
 */
public class PackageDescriptorCache {

	private final Map<String, PackageDescriptor> descriptors = new HashMap<String, PackageDescriptor>();
	private final Map<String, String> packageChanges = new HashMap<String, String>();

	private UpdateService updateService = null;

	public PackageDescriptor getPackageInfo(String packageId) {
		if (UpdateManager.PACKAGEID_RAPIDMINER.equals(packageId)) {
			packageId = UpdateManager.getRMPackageId();
		}
		if (descriptors.containsKey(packageId)) {
			//in Cache
			return descriptors.get(packageId);
		} else {
			//need to fetch Info
			fetchPackageInfo(packageId);
			if (descriptors.containsKey(packageId)) {
				return descriptors.get(packageId);
			} else {
				return null;
			}
		}
	}

	public String getPackageChanges(String packageId) {
		if (packageChanges.containsKey(packageId)) {
			//in Cache
			return packageChanges.get(packageId);
		} else {
			//need to fetch Info

			try {
				ManagedExtension ext = ManagedExtension.get(packageId);
				String installedVersion = ext != null ? ext.getLatestInstalledVersion() : null;
				URI changesURI;
				if (installedVersion != null) {
					changesURI = UpdateManager.getUpdateServerURI("/download/changes/"+packageId+"?baseVersion="+installedVersion);
				} else {
					changesURI = UpdateManager.getUpdateServerURI("/download/changes/"+packageId);
				}


				String changes = Tools.readTextFile(changesURI.toURL().openStream());
				packageChanges.put(packageId, changes);
				return changes;
			} catch (Exception e) {
				packageChanges.put(packageId, null);
				// no changes avaliable
				return null;
			}
		}
	}

	private void fetchPackageInfo(String packageId) {
		initUpdateService();
		if (updateService != null) {
			try {
				String targetPlatform = UpdateManager.TARGET_PLATFORM;
				if (!UpdateManager.PACKAGEID_RAPIDMINER.equals(packageId)) {
					targetPlatform = "ANY";
				}
				PackageDescriptor descriptor = updateService.getPackageInfo(packageId, updateService.getLatestVersion(packageId, targetPlatform), targetPlatform);
				// First add to cache, so we do never load it again
				descriptors.put(packageId, descriptor);
				if (descriptor != null) {
					// Now fetch all dependencies
					if (descriptor.getDependencies() != null) {
						List<Dependency> dependencies = Dependency.parse(descriptor.getDependencies());
						for (Dependency dependency : dependencies) {
							// Get the info, so load it and its dependencies as side effect
							getPackageInfo(dependency.getPluginExtensionId());
						}
					}
				}
			} catch (Exception e) {
				SwingTools.showSimpleErrorMessage("failed_update_server", e, UpdateManager.getBaseUrl());
			}
		}
	}

	private void initUpdateService() {
		if (updateService == null) {
			try {
				updateService = UpdateManager.getService();
			} catch (Exception e) {
				SwingTools.showSimpleErrorMessage("failed_update_server", e, UpdateManager.getBaseUrl());
			}
		}
	}

	public UpdateService getUpdateService() {
		initUpdateService();
		return updateService;
	}

}