Copyright (c) 2000, 2018 IBM Corporation and others.
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
/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * 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.text.templates;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;

import org.osgi.service.prefs.BackingStoreException;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;

import org.eclipse.text.templates.ContextTypeRegistry;
import org.eclipse.text.templates.TemplatePersistenceData;

import org.eclipse.jface.text.templates.Template;
import org.eclipse.jface.text.templates.TemplateException;

A collection of templates. Clients may instantiate this class. In order to
load templates contributed using the org.eclipse.ui.editors.templates
extension point, use a ContributionTemplateStore.
Since:
3.7/**
 * A collection of templates. Clients may instantiate this class. In order to
 * load templates contributed using the <code>org.eclipse.ui.editors.templates</code>
 * extension point, use a <code>ContributionTemplateStore</code>.
 *
 * @since 3.7
 */
public class TemplateStoreCore {

	
The stored templates. /** The stored templates. */
	private final List<TemplatePersistenceData> fTemplates= new ArrayList<>();
	
The preference store. /** The preference store. */
	private IEclipsePreferences fPreferenceStore;
	
The key into fPreferenceStore the value of which holds custom templates
encoded as XML.
/**
	 * The key into <code>fPreferenceStore</code> the value of which holds custom templates
	 * encoded as XML.
	 */
	private String fKey;
	
The context type registry, or null if all templates regardless
of context type should be loaded.
/**
	 * The context type registry, or <code>null</code> if all templates regardless
	 * of context type should be loaded.
	 */
	private ContextTypeRegistry fRegistry;
	
Set to true if property change events should be ignored (e.g. during writing
to the preference store).
Since:
3.2/**
	 * Set to <code>true</code> if property change events should be ignored (e.g. during writing
	 * to the preference store).
	 *
	 * @since 3.2
	 */
	private boolean fIgnorePreferenceStoreChanges= false;
	
The property listener, if any is registered, null otherwise.
Since:
3.2/**
	 * The property listener, if any is registered, <code>null</code> otherwise.
	 *
	 * @since 3.2
	 */
	private IPreferenceChangeListener fPropertyListener;


	
Creates a new template store.
Params:
store – the preference store in which to store custom templates
       under key
key – the key into store where to store custom
       templates/**
	 * Creates a new template store.
	 *
	 * @param store the preference store in which to store custom templates
	 *        under <code>key</code>
	 * @param key the key into <code>store</code> where to store custom
	 *        templates
	 */
	public TemplateStoreCore(IEclipsePreferences store, String key) {
		Assert.isNotNull(key);
		fPreferenceStore= store;
		fKey= key;
	}

	
Creates a new template store with a context type registry. Only templates
that specify a context type contained in the registry will be loaded by
this store if the registry is not null.
Params:
registry – a context type registry, or null if all
       templates should be loaded
store – the preference store in which to store custom templates
       under key
key – the key into store where to store custom
       templates/**
	 * Creates a new template store with a context type registry. Only templates
	 * that specify a context type contained in the registry will be loaded by
	 * this store if the registry is not <code>null</code>.
	 *
	 * @param registry a context type registry, or <code>null</code> if all
	 *        templates should be loaded
	 * @param store the preference store in which to store custom templates
	 *        under <code>key</code>
	 * @param key the key into <code>store</code> where to store custom
	 *        templates
	 */
	public TemplateStoreCore(ContextTypeRegistry registry, IEclipsePreferences store, String key) {
		this(store, key);
		fRegistry= registry;
	}

	
Loads the templates from contributions and preferences.
Throws:
IOException – if loading fails./**
	 * Loads the templates from contributions and preferences.
	 *
	 * @throws IOException if loading fails.
	 */
	public void load() throws IOException {
		fTemplates.clear();
		loadContributedTemplates();
		loadCustomTemplates();
	}

	
Starts listening for property changes on the preference store. If the configured preference key changes, the template store is reloaded. Call stopListeningForPreferenceChanges() to remove any listener and stop the auto-updating behavior. 
Since:
3.2/**
	 * Starts listening for property changes on the preference store. If the configured preference
	 * key changes, the template store is {@link #load() reloaded}. Call
	 * {@link #stopListeningForPreferenceChanges()} to remove any listener and stop the
	 * auto-updating behavior.
	 *
	 * @since 3.2
	 */
	public void startListeningForPreferenceChanges() {
		if (fPropertyListener == null) {
			fPropertyListener= new IPreferenceChangeListener() {
				@Override
				public void preferenceChange(PreferenceChangeEvent event) {
					/*
					 * Don't load if we are in the process of saving ourselves. We are in sync anyway after the
					 * save operation, and clients may trigger reloading by listening to preference store
					 * updates.
					 */
					if (!fIgnorePreferenceStoreChanges && fKey.equals(event.getKey()))
						try {
							load();
						} catch (IOException x) {
							handleException(x);
						}
				}
			};
			fPreferenceStore.addPreferenceChangeListener(fPropertyListener);
		}

	}

	
Stops the auto-updating behavior started by calling startListeningForPreferenceChanges(). 
Since:
3.2/**
	 * Stops the auto-updating behavior started by calling
	 * {@link #startListeningForPreferenceChanges()}.
	 *
	 * @since 3.2
	 */
	public void stopListeningForPreferenceChanges() {
		if (fPropertyListener != null) {
			fPreferenceStore.removePreferenceChangeListener(fPropertyListener);
			fPropertyListener= null;
		}
	}

	
Handles an IOException thrown during reloading the preferences due to a preference store update. The default is to write to stderr. 
Params:
x – the exception
Since:
3.2/**
	 * Handles an {@link IOException} thrown during reloading the preferences due to a preference
	 * store update. The default is to write to stderr.
	 *
	 * @param x the exception
	 * @since 3.2
	 */
	protected void handleException(IOException x) {
		x.printStackTrace();
	}

	
Hook method to load contributed templates. Contributed templates are superseded
by customized versions of user added templates stored in the preferences.

The default implementation does nothing.
Throws:
IOException – if loading fails/**
	 * Hook method to load contributed templates. Contributed templates are superseded
	 * by customized versions of user added templates stored in the preferences.
	 * <p>
	 * The default implementation does nothing.</p>
	 *
	 * @throws IOException if loading fails
	 */
	protected void loadContributedTemplates() throws IOException {
	}

	
Adds a template to the internal store. The added templates must have
a unique id.
Params:
data – the template data to add/**
	 * Adds a template to the internal store. The added templates must have
	 * a unique id.
	 *
	 * @param data the template data to add
	 */
	protected void internalAdd(TemplatePersistenceData data) {
		if (!data.isCustom()) {
			// check if the added template is not a duplicate id
			String id= data.getId();
			for (TemplatePersistenceData persistenceData : fTemplates) {
				if (persistenceData.getId() != null && persistenceData.getId().equals(id))
					return;
			}
			fTemplates.add(data);
		}
	}

	
Saves the templates to the preferences.
Throws:
IOException – if the templates cannot be written/**
	 * Saves the templates to the preferences.
	 *
	 * @throws IOException if the templates cannot be written
	 */
	public void save() throws IOException {
		ArrayList<TemplatePersistenceData> custom= new ArrayList<>();
		for (TemplatePersistenceData data : fTemplates) {
			if (data.isCustom() && !(data.isUserAdded() && data.isDeleted())) // don't save deleted user-added templates
				custom.add(data);
		}

		StringWriter output= new StringWriter();
		TemplateReaderWriter writer= new TemplateReaderWriter();
		writer.save(custom.toArray(new TemplatePersistenceData[custom.size()]), output);

		fIgnorePreferenceStoreChanges= true;
		try {
			fPreferenceStore.put(fKey, output.toString());
			fPreferenceStore.flush();
		} catch (BackingStoreException e) {
		} finally {
			fIgnorePreferenceStoreChanges= false;
		}
	}

	
Adds a template encapsulated in its persistent form.
Params:
data – the template to add/**
	 * Adds a template encapsulated in its persistent form.
	 *
	 * @param data the template to add
	 */
	public void add(TemplatePersistenceData data) {

		if (!validateTemplate(data.getTemplate()))
			return;

		if (data.isUserAdded()) {
			fTemplates.add(data);
		} else {
			for (TemplatePersistenceData persistenceData : fTemplates) {
				if (persistenceData.getId() != null && persistenceData.getId().equals(data.getId())) {
					persistenceData.setTemplate(data.getTemplate());
					persistenceData.setDeleted(data.isDeleted());
					persistenceData.setEnabled(data.isEnabled());
					return;
				}
			}

			// add an id which is not contributed as add-on
			if (data.getTemplate() != null) {
				TemplatePersistenceData newData= new TemplatePersistenceData(data.getTemplate(), data.isEnabled(), data.getId());
				fTemplates.add(newData);
			}
		}
	}

	
Removes a template from the store.
Params:
data – the template to remove/**
	 * Removes a template from the store.
	 *
	 * @param data the template to remove
	 */
	public void delete(TemplatePersistenceData data) {
		if (data.isUserAdded())
			fTemplates.remove(data);
		else
			data.setDeleted(true);
	}

	
Restores all contributed templates that have been deleted.
/**
	 * Restores all contributed templates that have been deleted.
	 */
	public void restoreDeleted() {
		for (TemplatePersistenceData data : fTemplates) {
			if (data.isDeleted())
				data.setDeleted(false);
		}
	}

	
Deletes all user-added templates and reverts all contributed templates.
Params:
doSave – true if the store should be saved after restoring
Since:
3.5/**
	 * Deletes all user-added templates and reverts all contributed templates.
	 *
	 * @param doSave <code>true</code> if the store should be saved after restoring
	 * @since 3.5
	 */
	public void restoreDefaults(boolean doSave) {
		String oldValue= null;
		if (!doSave)
			oldValue= fPreferenceStore.get(fKey, null);

		try {
			fIgnorePreferenceStoreChanges= true;
			// See IPreferenceStore for default String value
			fPreferenceStore.put(fKey, ""); //$NON-NLS-1$
		} finally {
			fIgnorePreferenceStoreChanges= false;
		}

		try {
			load();
		} catch (IOException x) {
			// can't log from jface-text
			handleException(x);
		}

		if (oldValue != null) {
			try {
				fIgnorePreferenceStoreChanges= true;
				fPreferenceStore.put(fKey, oldValue);
			} finally {
				fIgnorePreferenceStoreChanges= false;
			}
		}
	}

	
Deletes all user-added templates and reverts all contributed templates.

Note: the store will be saved after restoring.

/**
	 * Deletes all user-added templates and reverts all contributed templates.
	 * <p>
	 * <strong>Note:</strong> the store will be saved after restoring.
	 * </p>
	 */
	public void restoreDefaults() {
		restoreDefaults(true);
	}

	
Returns all enabled templates.
Returns:
all enabled templates/**
	 * Returns all enabled templates.
	 *
	 * @return all enabled templates
	 */
	public Template[] getTemplates() {
		return getTemplates(null);
	}

	
Returns all enabled templates for the given context type.
Params:
contextTypeId – the id of the context type of the requested templates, or null if all templates should be returned
Returns:
all enabled templates for the given context type/**
	 * Returns all enabled templates for the given context type.
	 *
	 * @param contextTypeId the id of the context type of the requested templates, or <code>null</code> if all templates should be returned
	 * @return all enabled templates for the given context type
	 */
	public Template[] getTemplates(String contextTypeId) {
		List<Template> templates= new ArrayList<>();
		for (TemplatePersistenceData data : fTemplates) {
			if (data.isEnabled() && !data.isDeleted() && (contextTypeId == null || contextTypeId.equals(data.getTemplate().getContextTypeId())))
				templates.add(data.getTemplate());
		}

		return templates.toArray(new Template[templates.size()]);
	}

	
Returns the first enabled template that matches the name.
Params:
name – the name of the template searched for
Returns:
the first enabled template that matches both name and context type id, or null if none is found/**
	 * Returns the first enabled template that matches the name.
	 *
	 * @param name the name of the template searched for
	 * @return the first enabled template that matches both name and context type id, or <code>null</code> if none is found
	 */
	public Template findTemplate(String name) {
		return findTemplate(name, null);
	}

	
Returns the first enabled template that matches both name and context type id.
Params:
name – the name of the template searched for
contextTypeId – the context type id to clip unwanted templates, or null if any context type is OK
Returns:
the first enabled template that matches both name and context type id, or null if none is found/**
	 * Returns the first enabled template that matches both name and context type id.
	 *
	 * @param name the name of the template searched for
	 * @param contextTypeId the context type id to clip unwanted templates, or <code>null</code> if any context type is OK
	 * @return the first enabled template that matches both name and context type id, or <code>null</code> if none is found
	 */
	public Template findTemplate(String name, String contextTypeId) {
		Assert.isNotNull(name);

		for (TemplatePersistenceData data : fTemplates) {
			Template template= data.getTemplate();
			if (data.isEnabled() && !data.isDeleted()
					&& (contextTypeId == null || contextTypeId.equals(template.getContextTypeId()))
					&& name.equals(template.getName()))
				return template;
		}

		return null;
	}

	
Returns the first enabled template that matches the given template id.
Params:
id – the id of the template searched for
Returns:
the first enabled template that matches id, or null if none is found
Since:
3.1/**
	 * Returns the first enabled template that matches the given template id.
	 *
	 * @param id the id of the template searched for
	 * @return the first enabled template that matches id, or <code>null</code> if none is found
	 * @since 3.1
	 */
	public Template findTemplateById(String id) {
		TemplatePersistenceData data= getTemplateData(id);
		if (data != null && !data.isDeleted())
			return data.getTemplate();

		return null;
	}

	
Returns all template data.
Params:
includeDeleted – whether to include deleted data
Returns:
all template data, whether enabled or not/**
	 * Returns all template data.
	 *
	 * @param includeDeleted whether to include deleted data
	 * @return all template data, whether enabled or not
	 */
	public TemplatePersistenceData[] getTemplateData(boolean includeDeleted) {
		List<TemplatePersistenceData> datas= new ArrayList<>();
		for (TemplatePersistenceData data : fTemplates) {
			if (includeDeleted || !data.isDeleted())
				datas.add(data);
		}

		return datas.toArray(new TemplatePersistenceData[datas.size()]);
	}

	
Returns the template data of the template with id id or
null if no such template can be found.
Params:
id – the id of the template data
Returns:
the template data of the template with id id or null
Since:
3.1/**
	 * Returns the template data of the template with id <code>id</code> or
	 * <code>null</code> if no such template can be found.
	 *
	 * @param id the id of the template data
	 * @return the template data of the template with id <code>id</code> or <code>null</code>
	 * @since 3.1
	 */
	public TemplatePersistenceData getTemplateData(String id) {
		Assert.isNotNull(id);
		for (TemplatePersistenceData data : fTemplates) {
			if (id.equals(data.getId()))
				return data;
		}

		return null;
	}

	private void loadCustomTemplates() throws IOException {
		String pref= fPreferenceStore.get(fKey, null);
		if (pref != null && !pref.trim().isEmpty()) {
			Reader input= new StringReader(pref);
			TemplateReaderWriter reader= new TemplateReaderWriter();
			TemplatePersistenceData[] datas= reader.read(input);
			for (TemplatePersistenceData data : datas) {
				add(data);
			}
		}
	}

	
Validates a template against the context type registered in the context
type registry. Returns always true if no registry is
present.
Params:
template – the template to validate
Returns:
true if validation is successful or no context
        type registry is specified, false if validation
        fails/**
	 * Validates a template against the context type registered in the context
	 * type registry. Returns always <code>true</code> if no registry is
	 * present.
	 *
	 * @param template the template to validate
	 * @return <code>true</code> if validation is successful or no context
	 *         type registry is specified, <code>false</code> if validation
	 *         fails
	 */
	private boolean validateTemplate(Template template) {
		String contextTypeId= template.getContextTypeId();
		if (contextExists(contextTypeId)) {
			if (fRegistry != null)
				try {
					fRegistry.getContextType(contextTypeId).validate(template.getPattern());
				} catch (TemplateException e) {
					return false;
				}
			return true;
		}

		return false;
	}

	
Returns true if a context type id specifies a valid context type
or if no context type registry is present.
Params:
contextTypeId – the context type id to look for
Returns:
true if the context type specified by the id
        is present in the context type registry, or if no registry is
        specified/**
	 * Returns <code>true</code> if a context type id specifies a valid context type
	 * or if no context type registry is present.
	 *
	 * @param contextTypeId the context type id to look for
	 * @return <code>true</code> if the context type specified by the id
	 *         is present in the context type registry, or if no registry is
	 *         specified
	 */
	private boolean contextExists(String contextTypeId) {
		return contextTypeId != null && (fRegistry == null || fRegistry.getContextType(contextTypeId) != null);
	}

	
Returns the registry.
Returns:
Returns the registry/**
	 * Returns the registry.
	 *
	 * @return Returns the registry
	 */
	protected ContextTypeRegistry getRegistry() {
		return fRegistry;
	}

	
Return the key into the Preference Store whose value contains
the custom templates encoded as XML.
Returns:
the key in the Preference Store/**
	 * Return the key into the Preference Store whose value contains
	 * the custom templates encoded as XML.
	 *
	 * @return the key in the Preference Store
	 */
	protected final String getKey () {
		return fKey;
	}

	
Return the stored templates
Returns:
the stored templates/**
	 * Return the stored templates
	 * @return the stored templates
	 */
	protected final List<TemplatePersistenceData> internalGetTemplates () {
		return fTemplates;
	}

}