/**
 ********************************************************************************
 * Copyright (c) 2015-2021 Robert Bosch GmbH and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Robert Bosch GmbH - initial API and implementation
 ********************************************************************************
 */

package org.eclipse.app4mc.amalthea.model.emf;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.zip.ZipFile;

import org.eclipse.app4mc.amalthea.model.AmaltheaIndex;
import org.eclipse.emf.common.CommonPlugin;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.xmi.XMLHelper;
import org.eclipse.emf.ecore.xmi.XMLResource;
import org.eclipse.emf.ecore.xmi.impl.XMIHelperImpl;
import org.eclipse.emf.ecore.xmi.impl.XMIResourceImpl;

public class AmaltheaResource extends XMIResourceImpl {

	public AmaltheaResource() {
		super();
		addDefaults();
	}

	public AmaltheaResource(final URI uri) {
		super(uri);
		addDefaults();
	}

	private void addDefaults() {
		getDefaultSaveOptions().put(XMLResource.OPTION_ENCODING, "UTF-8");
		// Add some performance tweaks to improve loading of big models
		// http://sdqweb.ipd.kit.edu/wiki/EMF_Model_Loading_Performance_Tweaks
		getDefaultLoadOptions().put(XMLResource.OPTION_DEFER_ATTACHMENT, Boolean.TRUE);
		getDefaultLoadOptions().put(XMLResource.OPTION_DEFER_IDREF_RESOLUTION, Boolean.TRUE);
		getDefaultLoadOptions().put(XMLResource.OPTION_USE_XML_NAME_TO_FEATURE_MAP, new HashMap<>());

		// Also store defaults (this option has no effect on enums)
		getDefaultLoadOptions().put(XMLResource.OPTION_KEEP_DEFAULT_CONTENT, Boolean.TRUE);
		getDefaultSaveOptions().put(XMLResource.OPTION_KEEP_DEFAULT_CONTENT, Boolean.TRUE);

		// Use AmaltheaResourceHandler
		getDefaultLoadOptions().put(XMLResource.OPTION_RESOURCE_HANDLER, new AmaltheaResourceHandler());
		getDefaultSaveOptions().put(XMLResource.OPTION_RESOURCE_HANDLER, new AmaltheaResourceHandler());
	}

	// Zip option
	//  - can be set explicitly to avoid computation (with problematic URI to file conversion)
	//  - will be computed otherwise

	private boolean computeZipOption = true;

	@Override
	public boolean useZip() {
		// if not already set then compute and cache value
		if (computeZipOption) {
			setUseZip(isZipFile(getURI()));
		}

		return super.useZip();
	}

	@Override
	public void setUseZip(boolean useZip) {
		super.setUseZip(useZip);

		// if explicitly set then do not compute value
		computeZipOption = false;
	}

	private boolean isZipFile(final URI uri) {
		boolean result = false;

		URI fileURI = convertToAbsoluteFileURI(uri);
		if (fileURI != null) {
			String fileString = fileURI.toFileString();
			if (fileString != null) {
				try (ZipFile f = new ZipFile(fileString)) {
					// zipped file detected
					result = true;
				} catch (IOException e) {
					// IOException includes ZipException -> not a zip file
				}
			}
		}

		return result;
	}

	private URI convertToAbsoluteFileURI(final URI uri) {
		URI result;

		// Try to convert to absolute file URI
		result = CommonPlugin.asLocalURI(uri);

		// Resulting URI still relative?
		if (result.isRelative()) {
			// Try with normalize URI
			result = getURIConverter().normalize(uri);
			result = CommonPlugin.asLocalURI(result);
		}

		return result;
	}

	/**
	 * @see org.eclipse.emf.ecore.xmi.impl.XMLResourceImpl#useUUIDs()
	 */
	@Override
	protected boolean useUUIDs() {
		return false;
	}

	@Override
	protected boolean useIDs() {
		return true;
	}

	protected void resetIDMaps() {
		synchronized(this) {
			idToEObjectMap = null;
			eObjectToIDMap = null;
		}
	}

	@Override
	protected EObject getEObjectByID(String id) {
		if (id == null)
			return null;

		// first: check extrinsic IDs map (only available while saving model)

		if (idToEObjectMap != null) {
			EObject eObject = idToEObjectMap.get(id);
			if (eObject != null) {
				return eObject;
			}
		}

		// second: check intrinsic IDs map (only available while loading model)

		Map<String, EObject> map = getIntrinsicIDToEObjectMap();
		if (map != null) {
			EObject eObject = map.get(id);
			if (eObject != null) {
				return eObject;
			}
		}

		// third: check Amalthea index

		return AmaltheaIndex.getEObjectByID(this, id);

		// -----------------------------------------------------------------------------------
		// Load option is OPTION_DEFER_IDREF_RESOLUTION = true
		//
		// -> no fallback solution if ID is not stored in cache(s)
		//
		// This prevents time consuming iterations (especially in case of very large models)
		// -----------------------------------------------------------------------------------

	}

	/*
	 * @see org.eclipse.emf.ecore.xmi.impl.XMIResourceImpl#createXMLHelper()
	 */
	@Override
	protected XMLHelper createXMLHelper() {

		// Overwrite creation of HREFs (required for serialized references)
		//  - internal reference -> prefix #
		//  - cross-document reference -> prefix amlt:/#

		return new XMIHelperImpl(this) {
			@Override
			protected URI getHREF(Resource otherResource, EObject obj) {
				String prefix = (resource == otherResource) ? "#" : "amlt:/#";
				return URI.createURI(prefix + getIDREF(obj), true);
			}
		};
	}

}