/*******************************************************************************
 * Copyright (c) 2016 xored software, Inc. and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     xored software, Inc. - initial API and implementation
 *******************************************************************************/
package org.eclipse.dltk.core;

import org.eclipse.dltk.ast.declarations.ModuleDeclaration;
import org.eclipse.dltk.ast.declarations.ModuleDeclarationWrapper;
import org.eclipse.dltk.ast.parser.ASTCacheManager;
import org.eclipse.dltk.ast.parser.IASTCache;
import org.eclipse.dltk.ast.parser.IASTCache.ASTCacheEntry;
import org.eclipse.dltk.ast.parser.IModuleDeclaration;
import org.eclipse.dltk.ast.parser.ISourceParser;
import org.eclipse.dltk.compiler.CharOperation;
import org.eclipse.dltk.compiler.env.IModuleSource;
import org.eclipse.dltk.compiler.problem.IProblemReporter;
import org.eclipse.dltk.compiler.problem.ProblemCollector;
import org.eclipse.dltk.compiler.util.Util;
import org.eclipse.dltk.core.ISourceModuleInfoCache.ISourceModuleInfo;
import org.eclipse.dltk.core.RuntimePerformanceMonitor.PerformanceNode;
import org.eclipse.dltk.internal.core.ModelManager;

public class SourceParserUtil {
	private static final String AST = "ast"; //$NON-NLS-1$
	private static final String ERRORS = "errors"; //$NON-NLS-1$

	private static boolean useASTCaching = true;
	private static boolean useASTPersistenceCaching = true;

	public static IModuleDeclaration parse(IModuleSource module,
			String natureId, IProblemReporter reporter) {
		final IModelElement element = module.getModelElement();
		final ISourceParser parser = DLTKLanguageManager.getSourceParser(
				element != null ? element.getScriptProject().getProject()
						: null, natureId);
		return parser.parse(module, reporter);
	}

	public static IModuleDeclaration parse(final ISourceModule module,
			IProblemReporter reporter) {
		final IDLTKLanguageToolkit toolkit = DLTKLanguageManager
				.getLanguageToolkit(module);
		if (toolkit == null) {
			return null;
		}
		IModuleDeclaration moduleDeclaration = null;
		PerformanceNode p1 = RuntimePerformanceMonitor.begin();

		final String errorKey;
		final String astKey;
		final ISourceModuleInfo mifo = getCache().get(module);
		if (mifo != null && useASTCaching) {
			errorKey = getKey(ERRORS, 0);
			astKey = getKey(AST, 0);
			moduleDeclaration = (IModuleDeclaration) mifo.get(astKey);
			if (moduleDeclaration != null) {
				if (reporter != null) {
					final ProblemCollector collector = (ProblemCollector) mifo
							.get(errorKey);
					if (collector != null) {
						collector.copyTo(reporter);
					}
				}
			}
			if (moduleDeclaration == null && useASTPersistenceCaching) {
				// Try to retrieve information from persistence cache.
				IASTCache[] providers = ASTCacheManager.getProviders(toolkit
						.getNatureId());
				if (providers != null) {
					for (IASTCache provider : providers) {
						ASTCacheEntry restored = provider.restoreModule(module);
						if (restored != null) {
							if (reporter != null) {
								if (restored.problems != null) {
									restored.problems.copyTo(reporter);
								}
							}
							// Store to local cache.
							mifo.put(astKey, restored.module);
							if (restored.problems != null
									&& !restored.problems.isEmpty()) {
								mifo.put(errorKey, restored.problems);
							} else {
								mifo.remove(errorKey);
							}
							moduleDeclaration = restored.module;
							break;
						}
					}
				}
			}
		} else {
			errorKey = null;
			astKey = null;
		}
		p1.done(toolkit.getNatureId(), "Retrive AST from cache", 0);
		if (moduleDeclaration == null) {
			p1.renew();
			ISourceParser sourceParser = DLTKLanguageManager.getSourceParser(
					module.getScriptProject().getProject(),
					toolkit.getNatureId());
			if (sourceParser != null) {
				// if (sourceParser instanceof ISourceParserExtension) {
				// ((ISourceParserExtension) sourceParser).setFlags(flags);
				// }
				final ProblemCollector collector = mifo != null ? new ProblemCollector()
						: null;
				final IModuleSource source;
				if (module instanceof IModuleSource) {
					source = (IModuleSource) module;
				} else {
					source = new IModuleSource() {

						@Override
						public String getFileName() {
							return module.getPath().toString();
						}

						@Override
						public String getSourceContents() {
							try {
								return module.getSource();
							} catch (ModelException e) {
								return Util.EMPTY_STRING;
							}
						}

						@Override
						public IModelElement getModelElement() {
							return module;
						}

						@Override
						public char[] getContentsAsCharArray() {
							try {
								return module.getSourceAsCharArray();
							} catch (ModelException e) {
								return CharOperation.NO_CHAR;
							}
						}
					};
				}
				moduleDeclaration = sourceParser.parse(source,
						collector != null ? collector : reporter);
				if (collector != null && reporter != null) {
					collector.copyTo(reporter);
				}
				p1.done(toolkit.getNatureId(), "AST parse time", 0);
				if (moduleDeclaration != null && mifo != null && useASTCaching) {
					mifo.put(astKey, moduleDeclaration);
					if (useASTPersistenceCaching) {
						// Store to persistence cache
						IASTCache[] providers = ASTCacheManager
								.getProviders(toolkit.getNatureId());
						if (providers != null) {
							for (IASTCache provider : providers) {
								provider.storeModule(module, moduleDeclaration,
										collector);
							}
						}
					}
					if (collector != null && !collector.isEmpty()) {
						mifo.put(errorKey, collector);
					} else {
						mifo.remove(errorKey);
					}
				}
			}
		}
		return moduleDeclaration;
	}

	public static ModuleDeclaration getModuleDeclaration(ISourceModule module) {
		return getModuleDeclaration(module, null);
	}

	public static ModuleDeclaration getModuleDeclaration(ISourceModule module,
			IProblemReporter reporter) {
		return wrap(parse(module, reporter));
	}

	@Deprecated
	public static ModuleDeclaration getModuleDeclaration(ISourceModule module,
			IProblemReporter reporter, int flags) {
		return getModuleDeclaration(module, reporter);
	}

	@Deprecated
	public static ModuleDeclaration getModuleDeclaration(ISourceModule module,
			IProblemReporter reporter, ISourceModuleInfo mifo) {
		return getModuleDeclaration(module, reporter);
	}

	@Deprecated
	public static ModuleDeclaration getModuleDeclaration(ISourceModule module,
			IProblemReporter reporter, ISourceModuleInfo mifo, int flags) {
		return getModuleDeclaration(module, reporter);
	}

	/**
	 * @param baseKey
	 * @param flags
	 * @return
	 */
	private static String getKey(String baseKey, int flags) {
		return flags == 0 ? baseKey : baseKey + flags;
	}

	/**
	 * Parse the specified source
	 * 
	 * @param module
	 * @param nature
	 * @param reporter
	 * @return
	 */
	public static ModuleDeclaration getModuleDeclaration(IModuleSource module,
			String natureId, IProblemReporter reporter) {
		final IModuleDeclaration result = parse(module, natureId, reporter);
		return wrap(result);
	}

	private static ModuleDeclaration wrap(final IModuleDeclaration result) {
		if (result != null) {
			if (result instanceof ModuleDeclaration) {
				return (ModuleDeclaration) result;
			}
			return new ModuleDeclarationWrapper(result);
		} else {
			return null;
		}
	}

	/**
	 * This is for use in parsers.
	 */
	public static IModuleDeclaration getModuleFromCache(ISourceModuleInfo mifo,
			IProblemReporter reporter) {
		final int flags = 0;// FIXME remove later
		if (mifo != null && useASTCaching) {
			final IModuleDeclaration moduleDeclaration = (IModuleDeclaration) mifo
					.get(getKey(AST, flags));
			if (moduleDeclaration != null && reporter != null) {
				final ProblemCollector collector = (ProblemCollector) mifo
						.get(getKey(ERRORS, flags));
				if (collector != null) {
					collector.copyTo(reporter);
				}
			}
			return moduleDeclaration;
		}
		return null;
	}

	public static void putModuleToCache(ISourceModuleInfo info,
			IModuleDeclaration module, ProblemCollector collector) {
		final int flags = 0; // TODO remove later
		if (info != null && useASTCaching) {
			info.put(getKey(AST, flags), module);
			final String errorKey = getKey(ERRORS, flags);
			if (collector != null && !collector.isEmpty()) {
				info.put(errorKey, collector);
			} else {
				info.remove(errorKey);
			}
		}
	}

	/**
	 * Performance testing only
	 */
	public static void disableCache() {
		useASTCaching = false;
	}

	public static void enableCache() {
		useASTCaching = true;
	}

	public static void clearCache() {
		getCache().clear();
	}

	public static ISourceModuleInfoCache getCache() {
		return ModelManager.getModelManager().getSourceModuleInfoCache();
	}
}