/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.cauldron.bld.ivy;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URL;
import java.text.ParseException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;

import org.apache.ivy.Ivy;
import org.apache.ivy.core.IvyContext;
import org.apache.ivy.core.module.descriptor.Artifact;
import org.apache.ivy.core.module.descriptor.Configuration;
import org.apache.ivy.core.module.descriptor.DefaultDependencyArtifactDescriptor;
import org.apache.ivy.core.module.descriptor.DefaultDependencyDescriptor;
import org.apache.ivy.core.module.descriptor.DefaultModuleDescriptor;
import org.apache.ivy.core.module.descriptor.DependencyDescriptor;
import org.apache.ivy.core.module.descriptor.ModuleDescriptor;
import org.apache.ivy.core.module.id.ModuleRevisionId;
import org.apache.ivy.core.settings.IvySettings;
import org.apache.ivy.plugins.parser.ModuleDescriptorParser;
import org.apache.ivy.plugins.parser.ModuleDescriptorParserRegistry;
import org.apache.ivy.plugins.parser.ParserSettings;
import org.apache.ivy.plugins.parser.xml.XmlModuleDescriptorParser;
import org.apache.ivy.plugins.parser.xml.XmlModuleDescriptorWriter;
import org.apache.ivy.plugins.repository.Resource;
import org.apache.ivy.plugins.repository.file.FileResource;
import org.apache.ivy.plugins.repository.url.URLResource;
import org.apache.ivy.plugins.resolver.DependencyResolver;
import org.cauldron.bld.config.BldFactory;
import org.cauldron.bld.config.IBldProject;
import org.cauldron.sigil.model.IModelElement;
import org.cauldron.sigil.model.common.VersionRange;
import org.cauldron.sigil.model.eclipse.ISigilBundle;
import org.cauldron.sigil.model.osgi.IBundleModelElement;
import org.cauldron.sigil.model.osgi.IPackageImport;
import org.cauldron.sigil.model.osgi.IRequiredBundle;
import org.cauldron.sigil.repository.IResolution;

public class SigilParser implements ModuleDescriptorParser {

	private static DelegateParser instance;

	// used by ProjectRepository
    static DelegateParser instance() {
		if (instance == null)
			throw new IllegalStateException("SigilParser is not instantiated.");
		return instance;
	}

	public SigilParser() {
		if (instance == null) {
			instance = new DelegateParser();
		}
	}
	
	/**
	 * In IvyDE, IvyContext is not available, so we can't find the SigilResolver.
	 * This allows us to construct one.
	 * @deprecated temporary to support IvyDE
	 */
	public void setConfig(String config) {
		instance.config = config;
	}

	/**
	 * sets delegate parser.
	 * If not set, we delegate to the default Ivy parser.
	 * @param type name returned by desired parser's getType() method.
	 */
	public void setDelegateType(String type) {
		for (ModuleDescriptorParser parser : ModuleDescriptorParserRegistry.getInstance().getParsers()) {
			if (parser.getType().equals(type)) {
				instance.delegate = parser;
				break;
			}
		}

		if (instance.delegate == null) {
			throw new IllegalArgumentException("Can't find parser delegateType=" + type);
		}
	}

	/**
	 * sets default file name the delegate parser accepts.
	 * If not set, defaults to "ivy.xml".
	 * @param name
	 */
	public void setDelegateFile(String name) {
		instance.ivyFile = name;
	}

	/**
	 * sets the dependencies to keep from the delegate parser.
	 * If not set, all existing dependencies are dropped.
	 * @param regex pattern matching dependency names to keep.
	 */
	public void setKeepDependencies(String regex) {
		instance.keepDependencyPattern = Pattern.compile(regex);
	}
	
	/**
	 * reduce level of info logging.
	 * @param quiet
	 */
	public void setQuiet(String quiet) {
		instance.quiet = Boolean.parseBoolean(quiet);
	}

	/**
	 * sets the SigilResolver we use.
	 * If not set, we use the first SigilResolver we find.
	 * @param name
	 */
	public void setResolver(String name) {
		instance.resolverName = name;
	}

	/**
	 * adds override element: <override name="X" pattern="Y" replace="Z"/>. Overrides
	 * Ivy variables using a pattern substitution on the resource directory path.
	 * 
	 * @deprecated
	 * This is only needed when a delegate parser expects Ant variables to be set
	 * during the ivy:buildlist task (or the ProjectRepository initialisation),
	 * which they are not. The delegate parser should really be fixed, as otherwise
	 * the ivy:buildlist task won't work without this workaround.
	 */
	// e.g. <override name="ant.project.name" pattern=".*/([^/]+)/([^/]+)$" replace="$1-$2"/>
	public void addConfiguredOverride(Map<String, String> var) {
		final String name = var.get("name");
		final String regex = var.get("pattern");
		final String replace = var.get("replace");

		if (name == null || regex == null || replace == null)
			throw new IllegalArgumentException("override must contain name, pattern and replace attributes.");

		instance.varRegex.put(name, Pattern.compile(regex));
		instance.varReplace.put(name, replace);
	}

	// implement ModuleDescriptorParser interface by delegation to singleton instance.

	public boolean accept(Resource res) {
		return instance.accept(res);
	}

	public Artifact getMetadataArtifact(ModuleRevisionId mrid, Resource res) {
		return instance.getMetadataArtifact(mrid, res);
	}

	public String getType() {
		return instance.getType();
	}

	public ModuleDescriptor parseDescriptor(ParserSettings settings, URL xmlURL, boolean validate)
			throws ParseException, IOException {
		return instance.parseDescriptor(settings, xmlURL, validate);
	}

	public ModuleDescriptor parseDescriptor(ParserSettings settings, URL xmlURL, Resource res, boolean validate)
			throws ParseException, IOException {
		return instance.parseDescriptor(settings, xmlURL, res, validate);
	}

	public void toIvyFile(InputStream source, Resource res, File destFile, ModuleDescriptor md) throws ParseException,
			IOException {
		instance.toIvyFile(source, res, destFile, md);
	}

	/**
	 * delegating parser.
	 * (optionally) removes original dependencies and augments with sigil-determined dependencies.
	 */
	static class DelegateParser extends XmlModuleDescriptorParser {

		private static final String SIGIL_BUILDLIST = IBldProject.PROJECT_FILE;
		private static final String KEEP_ALL = ".*";
		
		private IBldResolver resolver;
		private ParserSettings defaultSettings;
		private Map<String, DefaultModuleDescriptor> rawCache = new HashMap<String, DefaultModuleDescriptor>();
		private Map<String, DefaultModuleDescriptor> augmentedCache = new HashMap<String, DefaultModuleDescriptor>();

		private HashMap<String, String> varReplace = new HashMap<String, String>();
		private HashMap<String, Pattern> varRegex = new HashMap<String, Pattern>();

		private ModuleDescriptorParser delegate;
		private String ivyFile = "ivy.xml";
		private String resolverName;
		private Pattern keepDependencyPattern;
    	private boolean quiet;
    	private String config;

		@Override
		public boolean accept(Resource res) {
			boolean accept = (res instanceof SigilResolver.SigilIvy)
					|| res.getName().endsWith("/" + SIGIL_BUILDLIST)
					|| ((instance.getSigilURI(res) != null) &&
						((instance.delegate != null ? instance.delegate.accept(res) : false) || super.accept(res)));
			if (accept)
    			Log.verbose("accepted: " + res);
			return accept;
		}

		@Override
		public void toIvyFile(InputStream source, Resource res, File destFile, ModuleDescriptor md)
				throws ParseException, IOException {
			Log.verbose("writing resource: " + res + " toIvyFile: " + destFile);
			// source allows us to keep layout and comments,
			// but this doesn't work if source is not ivy.xml.
			// So just write file directly from descriptor.
			try {
				XmlModuleDescriptorWriter.write(md, destFile);
			} finally {
				if (source != null)
					source.close();
			}
		}
		
		@Override
		public ModuleDescriptor parseDescriptor(ParserSettings settings, URL xmlURL, boolean validate)
				throws ParseException, IOException {
			return parseDescriptor(settings, xmlURL, new URLResource(xmlURL), validate);
		}

		@Override
		public ModuleDescriptor parseDescriptor(ParserSettings settings, URL xmlURL, Resource res, boolean validate)
				throws ParseException, IOException {
			String cacheKey = xmlURL.toString() + settings.hashCode();
			DefaultModuleDescriptor dmd = augmentedCache.get(cacheKey);

			if (dmd == null) {
				dmd = rawCache.get(cacheKey);
				if (dmd == null) {
					dmd = delegateParse(settings, xmlURL, res, validate);
    			}

				if (!quiet)
    				Log.info("augmenting module=" + dmd.getModuleRevisionId().getName() +
						" ant.project.name=" + settings.substitute("${ant.project.name}"));
				
				addDependenciesToDescriptor(res, dmd);
				augmentedCache.put(cacheKey, dmd);
				
				Log.verbose("augmented dependencies: " + Arrays.asList(dmd.getDependencies()));
			}

			return dmd;
		}
		
		// used by ProjectRepository
		ModuleDescriptor parseDescriptor(URL projectURL) throws ParseException, IOException {
			if (defaultSettings == null) {
				Ivy ivy = IvyContext.getContext().peekIvy();
				if (ivy == null)
					throw new IllegalStateException("can't get default settings - no ivy context.");
				defaultSettings = ivy.getSettings();
			}
			
			URL ivyURL = new URL(projectURL, ivyFile);
			String cacheKey = ivyURL.toString() + defaultSettings.hashCode();
			DefaultModuleDescriptor dmd = rawCache.get(cacheKey);
			
			if (dmd == null) {
				URLResource res = new URLResource(ivyURL);
				// Note: this doesn't contain the augmented dependencies, which is OK,
				// since the ProjectRepository only needs the id and status.
				dmd = delegateParse(defaultSettings, ivyURL, res, false);
				rawCache.put(cacheKey, dmd);
			}

			return dmd;
		}

		private DefaultModuleDescriptor delegateParse(ParserSettings settings, URL xmlURL, Resource res,
				boolean validate) throws ParseException, IOException {
			String resName = res.getName();

			if (resName.endsWith("/" + SIGIL_BUILDLIST)) {
				String name = resName.substring(0, resName.length() - SIGIL_BUILDLIST.length());
				res = res.clone(name + ivyFile);
				xmlURL = new URL(xmlURL, ivyFile);
			}

			if (settings instanceof IvySettings) {
				IvySettings ivySettings = (IvySettings) settings;
				String dir = new File(res.getName()).getParent();

				for (String name : varRegex.keySet()) {
					Pattern regex = varRegex.get(name);
					String replace = varReplace.get(name);

					String value = regex.matcher(dir).replaceAll(replace);

					Log.debug("overriding variable " + name + "=" + value);
					ivySettings.setVariable(name, value);
				}
			}

			ModuleDescriptor md = null;
			if (delegate == null || !delegate.accept(res)) {
				md = super.parseDescriptor(settings, xmlURL, res, validate);
			} else {
				md = delegate.parseDescriptor(settings, xmlURL, res, validate);
			}

			return mungeDescriptor(md, res);
		}

		/**
		 * clones descriptor and removes dependencies, as descriptor MUST have
		 * 'this' as the parser given to its constructor.
		 * Only dependency names matched by keepDependencyPattern are kept,
		 * as we're going to add our own dependencies later.
		 */
		private DefaultModuleDescriptor mungeDescriptor(ModuleDescriptor md, Resource res) {

			if ((md instanceof DefaultModuleDescriptor) &&
					(md.getParser() == this) &&
					(KEEP_ALL.equals(keepDependencyPattern))) {
				return (DefaultModuleDescriptor) md;
			}
				
			DefaultModuleDescriptor dmd = new DefaultModuleDescriptor(this, res);

			dmd.setModuleRevisionId(md.getModuleRevisionId());
			dmd.setPublicationDate(md.getPublicationDate());

			for (Configuration c : md.getConfigurations()) {
				String conf = c.getName();

				dmd.addConfiguration(c);

				for (Artifact a : md.getArtifacts(conf)) {
					dmd.addArtifact(conf, a);
				}
			}

			if (keepDependencyPattern != null) {
    			for (DependencyDescriptor dependency : md.getDependencies()) {
    				String name = dependency.getDependencyId().getName();
    				if (keepDependencyPattern.matcher(name).matches()) {
    					dmd.addDependency(dependency);
    				}
    			}
			}

			return dmd;
		}

		/*
		 * find URI to Sigil project file. This assumes that it is in the same
		 * directory as the ivy file.
		 */
		private URI getSigilURI(Resource res) {
			URI uri = null;

			if (res instanceof URLResource) {
				URL url = ((URLResource) res).getURL();
				uri = URI.create(url.toString()).resolve(IBldProject.PROJECT_FILE);
				try {
					InputStream stream = uri.toURL().openStream(); // check file
																	// exists
					stream.close();
				} catch (IOException e) {
					uri = null;
				}
			} else if (res instanceof FileResource) {
				uri = ((FileResource) res).getFile().toURI().resolve(IBldProject.PROJECT_FILE);
				if (!(new File(uri).exists()))
					uri = null;
			}

			return uri;
		}

		/*
		 * add sigil dependencies to ModuleDescriptor.
		 */
		private void addDependenciesToDescriptor(Resource res, DefaultModuleDescriptor md) throws IOException {
			// FIXME: transitive should be configurable
			final boolean transitive = true; // ivy default is true
			final boolean changing = false;
			final boolean force = false;

			URI uri = getSigilURI(res);
			if (uri == null)
				return;

			IBldProject project;

			project = BldFactory.getProject(uri);

			IBundleModelElement requirements = project.getDependencies();
			Log.verbose("requirements: " + Arrays.asList(requirements.children()));

			// preserve version range for Require-Bundle
			// XXX: synthesise bundle version range corresponding to package version ranges?
			HashMap<String, VersionRange> versions = new HashMap<String, VersionRange>();
			for (IModelElement child : requirements.children()) {
				if (child instanceof IRequiredBundle) {
					IRequiredBundle bundle = (IRequiredBundle) child;
					versions.put(bundle.getSymbolicName(), bundle.getVersions());
				}
			}

			IBldResolver resolver = findResolver();
			if (resolver == null) {
				// this can happen in IvyDE, but it retries and is OK next time.
				Log.warn("failed to find resolver - IvyContext not yet available.");
				return;
			}
			
			IResolution resolution = resolver.resolve(requirements, false);
			Log.verbose("resolution: " + resolution.getBundles());

			ModuleRevisionId masterMrid = md.getModuleRevisionId();
			DefaultDependencyDescriptor dd;
			ModuleRevisionId mrid;

			for (ISigilBundle bundle : resolution.getBundles()) {
				IBundleModelElement info = bundle.getBundleInfo();
				String name = info.getSymbolicName();

				if (name == null) {
					// e.g. SystemProvider with framework=null
					continue;
				}

				if (bundle instanceof ProjectRepository.ProjectBundle) {
					ProjectRepository.ProjectBundle pb = (ProjectRepository.ProjectBundle) bundle;
					String org = pb.getOrg();
					if (org == null)
						org = masterMrid.getOrganisation();
					String id = pb.getId();
					String module = pb.getModule();
					String rev = pb.getRevision();

					mrid = ModuleRevisionId.newInstance(org, module, rev);
					dd = new SigilDependencyDescriptor(md, mrid, force, changing, transitive);

					if (!id.equals(module)) { // non-default artifact
						dd.addDependencyArtifact(module,
								new DefaultDependencyArtifactDescriptor(dd, id, "jar", "jar", null, null));
					}
				} else {
					VersionRange version = versions.get(name);
					String rev = version != null ? version.toString() : info.getVersion().toString();
					mrid = ModuleRevisionId.newInstance(SigilResolver.ORG_SIGIL, name, rev);
					dd = new SigilDependencyDescriptor(md, mrid, force, changing, transitive);
				}

				int nDeps = 0;
				boolean foundDefault = false;

				// TODO: make dependency configurations configurable SIGIL-176
				for (String conf : md.getConfigurationsNames()) {
					if (conf.equals("default")) {
						foundDefault = true;
					} else if (md.getArtifacts(conf).length == 0) {
						dd.addDependencyConfiguration(conf, conf + "(default)");
						nDeps++;
					}
				}

				if (nDeps > 0) {
					if (foundDefault)
						dd.addDependencyConfiguration("default", "default");
				} else {
					dd.addDependencyConfiguration("*", "*");    // all configurations
				}

				md.addDependency(dd);
			}

			boolean resolved = true;
			for (IModelElement child : requirements.children()) {
				ISigilBundle provider = resolution.getProvider(child);
				if (provider == null) {
					resolved = false;
					// this is parse phase, so only log verbose message.
					// error is produced during resolution phase.
					Log.verbose("WARN: can't resolve: " + child);

					String name;
					String version;
					if (child instanceof IRequiredBundle) {
						IRequiredBundle rb = (IRequiredBundle) child;
						name = rb.getSymbolicName();
						version = rb.getVersions().toString();
					} else {
						IPackageImport pi = (IPackageImport) child;
						name = "import!" + pi.getPackageName();
						version = pi.getVersions().toString();
					}

					mrid = ModuleRevisionId.newInstance("!" + SigilResolver.ORG_SIGIL, name, version);
					dd = new SigilDependencyDescriptor(md, mrid, force, changing, transitive);
					dd.addDependencyConfiguration("*", "*"); // all
					// configurations
					md.addDependency(dd);
				}
			}

			if (!resolved) {
				// Ivy does not show warnings or errors logged from parse phase, until after resolution.
				// but <buildlist> ant task doesn't do resolution, so errors would be silently ignored.
				// Hence, we must use Message.info to ensure this failure is seen.
				if (!quiet)
    				Log.info("WARN: resolution failed in: " + masterMrid.getName() + ". Use -v for details.");
			}
		}

		/*
		 * find named resolver, or first resolver that implements IBldResolver.
		 */
		private IBldResolver findResolver() {
			if (resolver == null) {
				Ivy ivy = IvyContext.getContext().peekIvy();
				if (ivy != null) {
    				if (resolverName != null) {
    					DependencyResolver r = ivy.getSettings().getResolver(resolverName);
    					if (r == null) {
    						throw new Error("SigilParser: resolver \"" + resolverName + "\" not defined.");
    					} else if (r instanceof IBldResolver) {
    						resolver = (IBldResolver) r;
    					} else {
    						throw new Error("SigilParser: resolver \"" + resolverName + "\" is not a SigilResolver.");
    					}
    				} else {
    					for (Object r : ivy.getSettings().getResolvers()) {
    						if (r instanceof IBldResolver) {
    							resolver = (IBldResolver) r;
    							break;
    						}
    					}
    				}
    
    				if (resolver == null) {
    					throw new Error("SigilParser: can't find SigilResolver. Check ivysettings.xml.");
    				}
				} else if (config != null) {
					Log.warn("creating duplicate resolver to support IvyDE.");
					resolver = new SigilResolver();
					((SigilResolver)resolver).setConfig(config);
				}
			}
			return resolver;
		}
	}

}

/*
 * this is only needed so that we can distinguish sigil-added dependencies from
 * existing ones.
 */
class SigilDependencyDescriptor extends DefaultDependencyDescriptor {
	public SigilDependencyDescriptor(DefaultModuleDescriptor md, ModuleRevisionId mrid, boolean force,
			boolean changing, boolean transitive) {
		super(md, mrid, force, changing, transitive);
	}
}