/*******************************************************************************
 * Copyright (c) 2007, 2014 Wind River Systems, Inc. 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:
 *     Markus Schorn - initial API and implementation
 *     Sergey Prigogin (Google)
 *******************************************************************************/
package org.eclipse.cdt.internal.core.pdom.indexer;

import java.io.File;
import java.util.HashMap;

import org.eclipse.cdt.core.CCorePlugin;
import org.eclipse.cdt.core.index.IIndexFileLocation;
import org.eclipse.cdt.core.index.IndexLocationFactory;
import org.eclipse.cdt.core.model.AbstractLanguage;
import org.eclipse.cdt.core.model.CModelException;
import org.eclipse.cdt.core.model.CoreModel;
import org.eclipse.cdt.core.model.CoreModelUtil;
import org.eclipse.cdt.core.model.ICProject;
import org.eclipse.cdt.core.model.ILanguage;
import org.eclipse.cdt.core.model.ITranslationUnit;
import org.eclipse.cdt.core.model.LanguageManager;
import org.eclipse.cdt.core.parser.ExtendedScannerInfo;
import org.eclipse.cdt.core.parser.FileContent;
import org.eclipse.cdt.core.parser.IScannerInfo;
import org.eclipse.cdt.internal.core.CCoreInternals;
import org.eclipse.cdt.internal.core.parser.InternalParserUtil;
import org.eclipse.cdt.internal.core.pdom.AbstractIndexerTask.UnusedHeaderStrategy;
import org.eclipse.cdt.internal.core.pdom.IndexerInputAdapter;
import org.eclipse.cdt.internal.core.resources.PathCanonicalizationStrategy;
import org.eclipse.cdt.utils.UNCPathConverter;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.content.IContentType;

/**
 * Provides information about translation-units.
 * @since 5.0
 */
public class ProjectIndexerInputAdapter extends IndexerInputAdapter {
	private static final boolean CASE_INSENSITIVE_FILE_SYSTEM = new File("a").equals(new File("A")); //$NON-NLS-1$//$NON-NLS-2$
	private static final AbstractLanguage[] NO_LANGUAGE = new AbstractLanguage[0];

	private final ICProject fCProject;
	private final HashMap<String, IIndexFileLocation> fIflCache;
	private final FileExistsCache fExistsCache;
	private AbstractLanguage fLangC;
	private AbstractLanguage fLangCpp;
	private String fProjectPrefix;

	public ProjectIndexerInputAdapter(ICProject cproject) {
		this(cproject, true);
	}

	public ProjectIndexerInputAdapter(ICProject cproject, boolean useCache) {
		fCProject = cproject;
		fProjectPrefix = cproject.getProject().getFullPath().toString() + IPath.SEPARATOR;
		if (useCache) {
			fIflCache = new HashMap<>();
			fExistsCache = new FileExistsCache(isCaseInsensitiveFileSystem());
		} else {
			fIflCache = null;
			fExistsCache = null;
		}
		ILanguage l = LanguageManager.getInstance().getLanguageForContentTypeID(CCorePlugin.CONTENT_TYPE_CHEADER);
		if (l instanceof AbstractLanguage) {
			fLangC = (AbstractLanguage) l;
		}
		l = LanguageManager.getInstance().getLanguageForContentTypeID(CCorePlugin.CONTENT_TYPE_CXXHEADER);
		if (l instanceof AbstractLanguage) {
			fLangCpp = (AbstractLanguage) l;
		}
	}

	@Override
	public boolean isCaseInsensitiveFileSystem() {
		if (Platform.OS_MACOSX.equals(Platform.getOS()))
			return true;
		return CASE_INSENSITIVE_FILE_SYSTEM;
	}

	@Override
	public IIndexFileLocation resolveASTPath(String astPath) {
		if (fIflCache == null) {
			return doResolveASTPath(astPath);
		}
		IIndexFileLocation result = fIflCache.get(astPath);
		if (result == null) {
			result = doResolveASTPath(astPath);
			fIflCache.put(astPath, result);
		}
		return result;
	}

	private IIndexFileLocation doResolveASTPath(String astPath) {
		return IndexLocationFactory.getIFLExpensive(fCProject, astPath);
	}

	@Override
	public IIndexFileLocation resolveIncludeFile(String includePath) {
		if (fIflCache == null) {
			return doResolveASTPath(includePath);
		}
		if (!fExistsCache.isFile(includePath)) {
			return null;
		}
		IIndexFileLocation result = fIflCache.get(includePath);
		if (result == null) {
			result = doResolveASTPath(includePath);
			if (result.getFullPath() == null && !UNCPathConverter.isUNC(includePath)) {
				File location = new File(includePath);
				String canonicalPath = PathCanonicalizationStrategy.getCanonicalPath(location);
				if (!includePath.equals(canonicalPath)) {
					result = IndexLocationFactory.getExternalIFL(canonicalPath);
					fIflCache.put(canonicalPath, result);
				}
			}
			fIflCache.put(includePath, result);
		}
		return result;
	}

	@Override
	public boolean doesIncludeFileExist(String includePath) {
		if (fExistsCache != null) {
			return fExistsCache.isFile(includePath);
		}
		return new File(includePath).isFile();
	}

	@Override
	public long getFileSize(String astFilePath) {
		return new File(astFilePath).length();
	}

	@Override
	public String getASTPath(IIndexFileLocation ifl) {
		IPath path = IndexLocationFactory.getAbsolutePath(ifl);
		if (path != null) {
			return path.toOSString();
		}
		return ifl.getURI().getPath();
	}

	@Override
	public IScannerInfo getBuildConfiguration(int linkageID, Object tu) {
		IScannerInfo info = ((ITranslationUnit) tu).getScannerInfo(true);
		if (info == null) {
			info = new ExtendedScannerInfo();
		}
		return info;
	}

	@Override
	public long getLastModified(IIndexFileLocation ifl) {
		String fullPath = ifl.getFullPath();
		if (fullPath != null) {
			IResource res = ResourcesPlugin.getWorkspace().getRoot().findMember(new Path(fullPath));
			if (res != null) {
				return res.getLocalTimeStamp();
			}
			return 0;
		}
		IPath location = IndexLocationFactory.getAbsolutePath(ifl);
		if (location != null) {
			return location.toFile().lastModified();
		}
		return 0;
	}

	@Override
	public long getFileSize(IIndexFileLocation ifl) {
		String fullPath = ifl.getFullPath();
		IPath location = null;
		if (fullPath != null) {
			IResource res = ResourcesPlugin.getWorkspace().getRoot().findMember(new Path(fullPath));
			if (res != null) {
				location = res.getLocation();
			}
		} else {
			location = IndexLocationFactory.getAbsolutePath(ifl);
		}
		if (location != null) {
			return location.toFile().length();
		}
		return 0;
	}

	@Override
	public String getEncoding(IIndexFileLocation ifl) {
		String fullPath = ifl.getFullPath();
		if (fullPath != null) {
			IResource res = ResourcesPlugin.getWorkspace().getRoot().findMember(new Path(fullPath));
			if (res instanceof IFile) {
				try {
					return ((IFile) res).getCharset();
				} catch (CoreException e) {
				}
			}
		}
		return InternalParserUtil.SYSTEM_DEFAULT_ENCODING;
	}

	@Override
	public AbstractLanguage[] getLanguages(Object tuo, UnusedHeaderStrategy strategy) {
		if (tuo instanceof PotentialTranslationUnit) {
			if (fLangC != null) {
				if (fLangCpp != null) {
					return new AbstractLanguage[] { fLangC, fLangCpp };
				}
				return new AbstractLanguage[] { fLangC };
			}
			if (fLangCpp != null) {
				return new AbstractLanguage[] { fLangCpp };
			}
			return NO_LANGUAGE;
		}

		ITranslationUnit tu = (ITranslationUnit) tuo;
		try {
			ILanguage lang = tu.getLanguage();
			if (lang instanceof AbstractLanguage) {
				final boolean both = strategy == UnusedHeaderStrategy.useBoth;
				final boolean useC = strategy == UnusedHeaderStrategy.useC;
				final boolean useCpp = strategy == UnusedHeaderStrategy.useCPP;
				if ((both || useC || useCpp) && tu.isHeaderUnit()) {
					String filename = tu.getElementName();
					if (filename.indexOf('.') >= 0) {
						final String contentTypeId = tu.getContentTypeId();
						if (contentTypeId.equals(CCorePlugin.CONTENT_TYPE_CXXHEADER) && fLangC != null) {
							if (both)
								return new AbstractLanguage[] { (AbstractLanguage) lang, fLangC };
							if (useC)
								return new AbstractLanguage[] { fLangC };
						} else if (contentTypeId.equals(CCorePlugin.CONTENT_TYPE_CHEADER) && fLangCpp != null) {
							if (both)
								return new AbstractLanguage[] { (AbstractLanguage) lang, fLangCpp };
							if (useCpp)
								return new AbstractLanguage[] { fLangCpp };
						}
					}
				}
				return new AbstractLanguage[] { (AbstractLanguage) lang };
			}
		} catch (CoreException e) {
			CCorePlugin.log(e);
		}
		return NO_LANGUAGE;
	}

	@Override
	public boolean isFileBuildConfigured(Object tuo) {
		ITranslationUnit tu = (ITranslationUnit) tuo;
		return !CoreModel.isScannerInformationEmpty(tu.getResource());
	}

	@Override
	public boolean isIndexedOnlyIfIncluded(Object tu) {
		return tu instanceof PotentialTranslationUnit;
	}

	@Override
	public boolean isIndexedUnconditionally(IIndexFileLocation ifl) {
		return CCoreInternals.getPDOMManager().isFileIndexedUnconditionally(ifl);
	}

	@Override
	public int getIndexingPriority(IIndexFileLocation ifl) {
		return CCoreInternals.getPDOMManager().getIndexingPriority(ifl);
	}

	@Override
	public boolean isSourceUnit(Object tuo) {
		ITranslationUnit tu = (ITranslationUnit) tuo;
		return tu.isSourceUnit();
	}

	@Override
	public boolean isSource(String filename) {
		IContentType ct = CCorePlugin.getContentType(fCProject.getProject(), filename);
		if (ct != null) {
			String id = ct.getId();
			if (CCorePlugin.CONTENT_TYPE_CSOURCE.equals(id) || CCorePlugin.CONTENT_TYPE_CXXSOURCE.equals(id)) {
				return true;
			}
		}
		return false;
	}

	@Override
	public IIndexFileLocation resolveFile(Object tuo) {
		ITranslationUnit tu = (ITranslationUnit) tuo;
		return IndexLocationFactory.getIFL(tu);
	}

	@Override
	public boolean canBePartOfSDK(IIndexFileLocation ifl) {
		final String fullPath = ifl.getFullPath();
		return fullPath == null || !fullPath.startsWith(fProjectPrefix);
	}

	@Override
	public Object getInputFile(IIndexFileLocation location) {
		try {
			return CoreModelUtil.findTranslationUnitForLocation(location, fCProject);
		} catch (CModelException e) {
			CCorePlugin.log(e);
		}
		return null;
	}

	@Override
	public FileContent getCodeReader(Object tuo) {
		ITranslationUnit tu = (ITranslationUnit) tuo;
		if (tu.getLocation() == null)
			return null;

		final FileContent reader = FileContent.create(tu);
		if (reader != null) {
			IIndexFileLocation ifl = IndexLocationFactory.getIFL(tu);
			fIflCache.put(reader.getFileLocation(), ifl);
		}
		return reader;
	}
}
