/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

*/

package com.nokia.carbide.cpp.internal.api.sdk;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.ObjectStreamClass;

import java.io.ObjectStreamException;

import java.util.*;

import org.eclipse.core.runtime.IPath;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Path;

import org.eclipse.core.runtime.Platform;

import com.nokia.carbide.cpp.epoc.engine.EpocEnginePlugin;

import com.nokia.carbide.cpp.epoc.engine.model.sbv.ISBVView;

import com.nokia.carbide.cpp.epoc.engine.preprocessor.*;

import com.nokia.carbide.cpp.internal.sdk.core.model.SymbianSDK;

import com.nokia.carbide.cpp.sdk.core.*;

import com.nokia.carbide.internal.api.cpp.epoc.engine.preprocessor.BasicIncludeFileLocator;

import com.nokia.carbide.internal.api.cpp.epoc.engine.preprocessor.MacroScanner;

import com.nokia.cpp.internal.api.utils.core.ExternalFileInfoCollection;

import com.nokia.cpp.internal.api.utils.core.FileUtils;

import com.nokia.cpp.internal.api.utils.core.Logging;

import com.nokia.cpp.internal.api.utils.core.ObjectUtils;

/**

 * This class holds the externally gathered data for a build context,

 * such as the #include paths and macros defined in the SDK.

 * <p> 

 * Unlike CarbideBuildConfiguration (which, unfortunately extends 

 * SymbianBuildContext), this will not be created multiple times for

 * multiple projects, but only once for a different build context

 * in an SDK or devkit.

 */

public class SymbianBuildContextDataCache {

	public static boolean DEBUG = false;

	// by default, only check HRH-included files if changed in last second (for ordinary operations)

	// or the last minute (when doing a long project operation).  see #startThrottle() and #stopThrottle()

	private static final long DEFAULT_HRH_INFO_CHECK_QUANTUM = 1000; // 1 sec

	private static final long THROTTLED_HRH_INFO_CHECK_QUANTUM = 60000; // 60 sec

	// compiler prefixes are very unlikely to change, but we need to check

	// occasionally in case a user installs a new one...

	private static final long DEFAULT_COMPILER_PREFIX_INFO_CHECK_QUANTUM = 15 * 60 * 1000;	// 15 minutes

	// This is a count of times #startProjectOperation() was called without

	// balancing #endProjectOperation().  

	private static int inProjectOperationCount;

	private static Map<String, SymbianBuildContextDataCache> cacheMap = new HashMap<String, SymbianBuildContextDataCache>();

	public static synchronized SymbianBuildContextDataCache getCache(ISymbianBuildContext context) {

		// don't hash on ISymbianBuildContext itself since it is sometimes a ICarbideBuildConfiguration

		String key = getBuildContextKey(context);

		SymbianBuildContextDataCache cache = cacheMap.get(key);

		if (cache == null) {

			cache = new SymbianBuildContextDataCache(context);

			cache.loadCacheFile();

			cacheMap.put(key, cache);

		}

		return cache;

	}

	/**

	 * @param context

	 * @return

	 */

	private static String getBuildContextKey(ISymbianBuildContext context) {

		String key = context.getPlatformString() + "/" + context.getTargetString() + "/";

		ISymbianSDK sdk = context.getSDK();

		if (sdk != null)

			key += sdk.getEPOCROOT();

		return key;

	}

	//private File prefixFileParsed;

	private List<File> hrhFilesParsed = new ArrayList<File>();

	private ExternalFileInfoCollection hrhFileInfo = null; 

	private List<IDefine> variantHRHMacros = new ArrayList<IDefine>();

	private List<IDefine> compilerPrefixMacros = new ArrayList<IDefine>();

	private ExternalFileInfoCollection compilerPrefixFileInfo = null; 

	private List<File> systemIncludes;

	private ISymbianSDK sdk;

	private IPath compilerPrefixFile;

	private String platformString;

	private String displayString;

	private String contextKey;

	private boolean changed;

	private File cacheFile;

	private SymbianBuildContextDataCache(ISymbianBuildContext context) {

		if (DEBUG) System.out.println("Creating cache for " + context.getDisplayString());

		this.platformString = context.getPlatformString();

		this.displayString = context.getDisplayString();

		this.sdk = context.getSDK();

		this.contextKey = getBuildContextKey(context);

	}

	/* (non-Javadoc)

	 * @see java.lang.Object#toString()

	 */

	@Override

	public String toString() {

		return "Cache for " + displayString;

	}

	public List<IDefine> getVariantHRHDefines() {

		// we parse the variant hrh file to gather macros.  this can be time consuming so do it

		// once and cache the values.  only reset the cache when the hrh or any of its includes

		// has changed.

		boolean buildCache = false;

		if (hrhFileInfo == null) {

			// hasn't been built yet, or was flushed

			buildCache = true;

		} else {

			// Cache exists.  See if any of the files have changed

			if (sdk != null && hrhFileInfo.anyChanged()) {

				buildCache = true;

			}

		}

		if (buildCache) {

			gatherVariantHRHDefines();

		}

		return variantHRHMacros;

	}

	/**

	 * Re-gather the #defines from the variant HRH file 

	 */

	private void gatherVariantHRHDefines() {

		changed = true;

		variantHRHMacros.clear();

		synchronized (this) {

			List<IDefine> macros = new ArrayList<IDefine>();

			Map<String, IDefine> namedMacros = new HashMap<String, IDefine>();

			File prefixFile = sdk.getPrefixFile();

			if (prefixFile == null){

				// Check that the prefix file may have become available since the SDK was scanned last.

				// This can happen, for e.g., if the user opens the IDE _then_ does a subst on a drive that already has an SDK entry.

				IPath prefixCheck = ((SymbianSDK)sdk).getPrefixFromVariantCfg();

				if (prefixCheck != null){

					prefixFile = prefixCheck.toFile();

					sdk.setPrefixFile(prefixCheck);

				}

			}

			File[] includedFiles = null;

			if (prefixFile != null) {

				// add any BSF/SBV includes so the headers are picked up from the correct location

				IBSFPlatform bsfPlat = sdk.getBSFCatalog().findPlatform(platformString);

				ISBVPlatform sbvPlat = sdk.getSBVCatalog().findPlatform(platformString);

				if (bsfPlat != null) {

					for (IPath path : bsfPlat.getSystemIncludePaths()) {

						systemPaths.add(path.toFile());

					}

				} else if (sbvPlat != null) {

					LinkedHashMap<IPath, String> platPaths = sbvPlat.getBuildIncludePaths();

					Set<IPath> set = platPaths.keySet();

					for (IPath path : set) {

						String pathType = platPaths.get(path);

						if (pathType.equalsIgnoreCase(ISBVView.INCLUDE_FLAG_PREPEND) || pathType.equalsIgnoreCase(ISBVView.INCLUDE_FLAG_SET)){

							systemPaths.add(path.toFile());

						}

					}

				}

				MacroScanner scanner = new MacroScanner(

						new BasicIncludeFileLocator(null, systemPaths.toArray(new File[systemPaths.size()])),

						DefaultModelDocumentProvider.getInstance(),

						DefaultTranslationUnitProvider.getInstance());

				scanner.scanFile(prefixFile);

				List<IDefine> scannedMacros = (List<IDefine>)scanner.getMacroDefinitions();

				for (IDefine scannedMacro : scannedMacros){

					// we don't want duplicate macros, so check to see if it's already there.

					// if it is, remove it and then add the newer one.  this is consistent with

					// how it would be from a compiler standpoint.

					IDefine macro = namedMacros.get(scannedMacro.getName());

					if (macro != null) {

						macros.remove(macro);

					}

					macros.add(scannedMacro);

					namedMacros.put(scannedMacro.getName(), scannedMacro);

				}

				hrhFilesParsed.clear();

				includedFiles = scanner.getIncludedFiles();

				for (File inc : includedFiles) {

					hrhFilesParsed.add(inc);

				}

				List<String> variantCFGMacros = new ArrayList<String>();

				variantCFGMacros = sdk.getVariantCFGMacros();

				for (String cfgMacros : variantCFGMacros){

					// we don't want duplicate macros, so check to see if it's already there.

					IDefine existingMacro = namedMacros.get(cfgMacros);

					if (existingMacro != null) {

						macros.remove(existingMacro);

					}

					IDefine macro = DefineFactory.createSimpleFreeformDefine(cfgMacros);

					macros.add(macro);

					namedMacros.put(macro.getName(), macro);

				}

			} 

			// cache the info about when we created the cache

			if (hrhFileInfo == null) {

				hrhFileInfo = new ExternalFileInfoCollection(

						EpocEnginePlugin.getExternalFileInfoCache(),

						includedFiles,

						DEFAULT_HRH_INFO_CHECK_QUANTUM);

			} else {

				hrhFileInfo.setFiles(includedFiles);

			}

			variantHRHMacros = macros;

			saveCacheFile();

		}

	}

	public List<File> getPrefixFileIncludes() {

		return hrhFilesParsed;

	}

	public synchronized List<IDefine> getCompilerMacros(IPath prefixFile) {

		// we assume that the prefix file will not change often,

		// (if at all) for a build context, so dump the cache if the prefix file changes.

		if (compilerPrefixFile != null && !compilerPrefixFile.equals(prefixFile)) {

			compilerPrefixFileInfo = null;

		}

		compilerPrefixFile = prefixFile;

		if (compilerPrefixFileInfo == null ||

				compilerPrefixFileInfo.anyChanged()) {

			changed = true;

			compilerPrefixMacros.clear();

			synchronized (this) {

				List<IDefine> macros = new ArrayList<IDefine>();

				if (prefixFile != null) {

					List<File> userPaths = new ArrayList<File>();

					List<File> systemPaths = new ArrayList<File>();

					userPaths.add(prefixFile.removeLastSegments(1).toFile());

					systemPaths.add(prefixFile.removeLastSegments(1).toFile());

					IPath includePath = sdk.getIncludePath();

					if (includePath != null) {

						File includeDir = includePath.toFile().getAbsoluteFile();

						userPaths.add(includeDir);

						systemPaths.add(includeDir);

					}

					// get macros from the compiler prefix file: note, this is a stupid

					// scan that will get the last version #defined, even if inside an #if.

					MacroScanner scanner = new MacroScanner(

							new BasicIncludeFileLocator(userPaths.toArray(new File[userPaths.size()]), systemPaths.toArray(new File[systemPaths.size()])),

							DefaultModelDocumentProvider.getInstance(), 

							DefaultTranslationUnitProvider.getInstance());

					scanner.scanFile(prefixFile.toFile());

					for (IDefine define : scanner.getMacroDefinitions()) {

						macros.add(define);

					}

					// store off the info about what we read for this cache

					File[] files = scanner.getIncludedFiles();

					if (compilerPrefixFileInfo == null)

						compilerPrefixFileInfo = new ExternalFileInfoCollection(

								EpocEnginePlugin.getExternalFileInfoCache(),

								files,

								DEFAULT_COMPILER_PREFIX_INFO_CHECK_QUANTUM);

					else

						compilerPrefixFileInfo.setFiles(files);

				}

				compilerPrefixMacros = macros;

				saveCacheFile();

			}

		}

		return compilerPrefixMacros;

	}

	/**

	 * Get the list of #include paths detected for this context.

	 * @return List or <code>null</code>

	 */

	public synchronized List<File> getSystemIncludePaths() {

		if (systemIncludes == null) {

			gatherBuildContextSystemIncludePaths();

		}

		return systemIncludes;

	}

	/**

	 * Fetch the list of include paths for the build context

	 */

	private void gatherBuildContextSystemIncludePaths() {

		changed = true;

		systemIncludes = new ArrayList<File>();

		if (DEBUG) System.out.println("Scanning include paths for " + displayString);

		IBSFPlatform bsfplatform = sdk.getBSFCatalog().findPlatform(platformString);

		ISBVPlatform sbvPlatform = sdk.getSBVCatalog().findPlatform(platformString);

		// look in the epoc32 directory of the SDK

		IPath includePath = sdk.getIncludePath();

		if (includePath != null) {

			File includeDir = includePath.toFile().getAbsoluteFile();

			File dir;

			// get additional include directories from BSF platform, if defined

			if (bsfplatform != null) {

				IPath[] systemIncludePaths = bsfplatform.getSystemIncludePaths();

				for (IPath path : systemIncludePaths) {

					dir = path.toFile();

					if (dir.exists() && dir.isDirectory()) {

						systemIncludes.add(dir);

					}

				}

			} else if (sbvPlatform != null){

				LinkedHashMap<IPath, String> platPaths = sbvPlatform.getBuildIncludePaths();

				Set<IPath> set = platPaths.keySet();

				for (IPath path : set) {

					String pathType = platPaths.get(path);

					if (pathType.equalsIgnoreCase(ISBVView.INCLUDE_FLAG_PREPEND) || pathType.equalsIgnoreCase(ISBVView.INCLUDE_FLAG_SET)){

						dir = path.toFile();

						systemIncludes.add(dir);

					}

				}

			}

			else {

				// legacy behavior 

				if (platformString.equals(ISymbianBuildContext.EMULATOR_PLATFORM)) {

					dir = new File(includeDir, "wins"); //$NON-NLS-1$

					if (dir.exists() && dir.isDirectory()) {

						systemIncludes.add(dir);

					}

				}

			}

			// add OEM dir

			dir = new File(includeDir, "oem"); //$NON-NLS-1$

			if (dir.exists() && dir.isDirectory()) {

				systemIncludes.add(dir);

			}

			// and finally the normal include dir

			systemIncludes.add(includeDir);

			// and finally, finally, if this is an SBV add any paths with the append flag

			if (sbvPlatform != null){

				Map<IPath, String> platPaths = sbvPlatform.getBuildIncludePaths();

				Set<IPath> set = platPaths.keySet();

				for (IPath path : set) {

					String pathType = platPaths.get(path);

					if (pathType.equalsIgnoreCase(ISBVView.INCLUDE_FLAG_APPEND)){

						dir = path.toFile();

						systemIncludes.add(dir);

					}

				}	

			}

		}

		// also search files in same folder as variant.hrh

		File prefix = sdk.getPrefixFile();

		if (sbvPlatform != null){

			// might be an alternate HRH file to use

			IPath varVarHRH = sbvPlatform.getBuildVariantHRHFile();

			if (!varVarHRH.toFile().equals(prefix) && varVarHRH.toFile().exists()){

				prefix = varVarHRH.toFile();

			} 

		}

		if (prefix != null) {

			systemIncludes.add(prefix.getParentFile());

		}

		saveCacheFile();

	}

	/**

	 * Let cache know that the client is beginning an operation that

	 * will iterate all the build contexts.  We use this information

	 * to optimize file info checks.

	 * <p>

	 * Each call must be balanced by an {@link #endProjectOperation()} call.

	 * Use a try ... finally block to make sure.

	 */

	public static synchronized void startProjectOperation() {

		inProjectOperationCount++;

		if (inProjectOperationCount == 1) {

			for (SymbianBuildContextDataCache cache : cacheMap.values()) {

				cache.startThrottle();

			}

		}

	}

	/**

	 * Let cache know that a project-wide operation is done, so

	 * we can resume normal info checking behavior.

	 */

	public static synchronized void endProjectOperation() {

		inProjectOperationCount--;

		if (inProjectOperationCount < 0) {

			Logging.log(SDKCorePlugin.getDefault(), 

					Logging.newStatus(SDKCorePlugin.getDefault(), 

							new IllegalStateException("project operation count not balanced")));

			inProjectOperationCount = 0;

		}

		if (inProjectOperationCount == 0) {

			for (SymbianBuildContextDataCache cache : cacheMap.values()) {

				cache.stopThrottle();

				cache.saveCacheFile();

			}

		}

	}

	/**

	 * Throttle file info checks on this cache if we suspect the same

	 * files will be checked over and over again in a short time (e.g. through

	 * multiple contexts on the same SDK).

	 */

	private void startThrottle() {

		if (hrhFileInfo != null) {

			hrhFileInfo.setRecheckQuantum(THROTTLED_HRH_INFO_CHECK_QUANTUM);

		}

		// note: compiler prefix infos already have a long delay, but

		// this is a good place to refresh

		if (compilerPrefixFileInfo != null) {

			compilerPrefixFileInfo.refresh();

		}

	}

	/**

	 * End file info throttling.

	 */

	private void stopThrottle() {

		if (hrhFileInfo != null)

			hrhFileInfo.setRecheckQuantum(DEFAULT_HRH_INFO_CHECK_QUANTUM);

		// note: compiler prefix infos already have a long delay

	}

	/**

	 * Refresh the cached data when there are substantial changes in the given SDKs.

	 * 

	 * @param sdks SDKs for whose contexts the caches should be removed, or <code>null</code> for all of them

	 */

	public static synchronized void refreshForSDKs(ISymbianSDK[] sdks) {

		// refresh each context cache, meaning, delete its memory and disk values

		Collection<String> values = cacheMap.keySet();

		String[] keyArray = (String[]) values.toArray(new String[values.size()]);

		for (String key : keyArray) {

			SymbianBuildContextDataCache cache = cacheMap.get(key);

			boolean forSDK = sdkInArray(sdks, cache.sdk);

			if (forSDK) {

				cache.reset();

				cacheMap.remove(key);

			}

		}

	}

	private static boolean sdkInArray(ISymbianSDK[] sdks, ISymbianSDK anSDK) {

		if (sdks == null)

			return true;

		if (anSDK == null)

			return false;

		// object identity is not appropriate; user may have renamed or moved an SDK

		for (ISymbianSDK sdk : sdks) {

			if (ObjectUtils.equals(sdk.getEPOCROOT(), anSDK.getEPOCROOT())

					|| ObjectUtils.equals(sdk.getUniqueId(), anSDK.getUniqueId()))

				return true;