/*
 * Copyright 2000-2012 JetBrains s.r.o.
 *
 * Licensed 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.jetbrains.jps.incremental;

import com.intellij.openapi.util.io.FileSystemUtil;
import com.intellij.openapi.util.io.FileUtil;
import gnu.trove.THashSet;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.jetbrains.jps.ModuleChunk;
import org.jetbrains.jps.builders.BuildRootDescriptor;
import org.jetbrains.jps.builders.BuildRootIndex;
import org.jetbrains.jps.builders.BuildTarget;
import org.jetbrains.jps.builders.FileProcessor;
import org.jetbrains.jps.builders.impl.BuildTargetChunk;
import org.jetbrains.jps.builders.java.JavaBuilderUtil;
import org.jetbrains.jps.builders.java.JavaSourceRootDescriptor;
import org.jetbrains.jps.cmdline.ProjectDescriptor;
import org.jetbrains.jps.incremental.storage.Timestamps;
import org.jetbrains.jps.model.java.JpsJavaClasspathKind;
import org.jetbrains.jps.model.java.JpsJavaExtensionService;
import org.jetbrains.jps.model.module.JpsModule;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

/**
 * @author Eugene Zhuravlev
 *         Date: 7/8/12
 */
public class FSOperations {
  public static final GlobalContextKey<Set<File>> ALL_OUTPUTS_KEY = GlobalContextKey.create("_all_project_output_dirs_");

  /**
   * @param context
   * @param file
   * @return true if file is marked as "dirty" in the <b>current</b> compilation round 
   * @throws IOException
   */
  public static boolean isMarkedDirty(CompileContext context, final File file) throws IOException {
    final JavaSourceRootDescriptor rd = context.getProjectDescriptor().getBuildRootIndex().findJavaRootDescriptor(context, file);
    if (rd != null) {
      final ProjectDescriptor pd = context.getProjectDescriptor();
      return pd.fsState.isMarkedForRecompilation(context, rd, file);
    }
    return false;
  }
  
  /**
   * Note: marked file will well be visible as "dirty" only on the <b>next</b> compilation round!
   * @throws IOException
   */
  public static void markDirty(CompileContext context, final File file) throws IOException {
    final JavaSourceRootDescriptor rd = context.getProjectDescriptor().getBuildRootIndex().findJavaRootDescriptor(context, file);
    if (rd != null) {
      final ProjectDescriptor pd = context.getProjectDescriptor();
      pd.fsState.markDirty(context, file, rd, pd.timestamps.getStorage(), false);
    }
  }

  public static void markDirtyIfNotDeleted(CompileContext context, final File file) throws IOException {
    final JavaSourceRootDescriptor rd = context.getProjectDescriptor().getBuildRootIndex().findJavaRootDescriptor(context, file);
    if (rd != null) {
      final ProjectDescriptor pd = context.getProjectDescriptor();
      pd.fsState.markDirtyIfNotDeleted(context, file, rd, pd.timestamps.getStorage());
    }
  }

  public static void markDeleted(CompileContext context, File file) throws IOException {
    final JavaSourceRootDescriptor rd = context.getProjectDescriptor().getBuildRootIndex().findJavaRootDescriptor(context, file);
    if (rd != null) {
      final ProjectDescriptor pd = context.getProjectDescriptor();
      pd.fsState.registerDeleted(rd.target, file, pd.timestamps.getStorage());
    }
  }

  public static void markDirty(CompileContext context, final ModuleChunk chunk, @Nullable FileFilter filter) throws IOException {
    final ProjectDescriptor pd = context.getProjectDescriptor();
    for (ModuleBuildTarget target : chunk.getTargets()) {
      markDirtyFiles(context, target, pd.timestamps.getStorage(), true, null, filter);
    }
  }

  public static void markDirtyRecursively(CompileContext context, ModuleChunk chunk) throws IOException {
    Set<JpsModule> modules = chunk.getModules();
    Set<ModuleBuildTarget> targets = chunk.getTargets();
    final Set<ModuleBuildTarget> dirtyTargets = new HashSet<ModuleBuildTarget>(targets);

    // now mark all modules that depend on dirty modules
    final JpsJavaClasspathKind classpathKind = JpsJavaClasspathKind.compile(chunk.containsTests());
    boolean found = false;
    for (BuildTargetChunk targetChunk : context.getProjectDescriptor().getBuildTargetIndex().getSortedTargetChunks(context)) {
      if (!found) {
        if (targetChunk.getTargets().equals(chunk.getTargets())) {
          found = true;
        }
      }
      else {
        for (final BuildTarget<?> target : targetChunk.getTargets()) {
          if (target instanceof ModuleBuildTarget) {
            final Set<JpsModule> deps = getDependentModulesRecursively(((ModuleBuildTarget)target).getModule(), classpathKind);
            if (Utils.intersects(deps, modules)) {
              for (BuildTarget<?> buildTarget : targetChunk.getTargets()) {
                if (buildTarget instanceof ModuleBuildTarget) {
                  dirtyTargets.add((ModuleBuildTarget)buildTarget);
                }
              }
              break;
            }
          }
        }
      }
    }

    final Timestamps timestamps = context.getProjectDescriptor().timestamps.getStorage();
    for (ModuleBuildTarget target : dirtyTargets) {
      markDirtyFiles(context, target, timestamps, true, null, null);
    }

    if (JavaBuilderUtil.isCompileJavaIncrementally(context)) {
      // mark as non-incremental only the module that triggered non-incremental change
      for (ModuleBuildTarget target : targets) {
        context.markNonIncremental(target);
      }
    }
  }

  private static Set<JpsModule> getDependentModulesRecursively(final JpsModule module, final JpsJavaClasspathKind kind) {
    return JpsJavaExtensionService.dependencies(module).includedIn(kind).recursivelyExportedOnly().getModules();
  }

  public static void processFilesToRecompile(CompileContext context, ModuleChunk chunk, FileProcessor<JavaSourceRootDescriptor, ModuleBuildTarget> processor) throws IOException {
    for (ModuleBuildTarget target : chunk.getTargets()) {
      processFilesToRecompile(context, target, processor);
    }
  }

  public static void processFilesToRecompile(CompileContext context, @NotNull ModuleBuildTarget target, FileProcessor<JavaSourceRootDescriptor, ModuleBuildTarget> processor) throws IOException {
    context.getProjectDescriptor().fsState.processFilesToRecompile(context, target, processor);
  }

  static void markDirtyFiles(CompileContext context,
                             BuildTarget<?> target,
                             Timestamps timestamps,
                             boolean forceMarkDirty,
                             @Nullable THashSet<File> currentFiles,
                             @Nullable FileFilter filter) throws IOException {
    for (BuildRootDescriptor rd : context.getProjectDescriptor().getBuildRootIndex().getTargetRoots(target, context)) {
      if (!rd.getRootFile().exists() ||
          //temp roots are managed by compilers themselves
          (rd instanceof JavaSourceRootDescriptor && ((JavaSourceRootDescriptor)rd).isTemp)) {
        continue;
      }
      if (filter == null) {
        context.getProjectDescriptor().fsState.clearRecompile(rd);
      }
      final FSCache fsCache = rd.canUseFileCache() ? context.getProjectDescriptor().getFSCache() : FSCache.NO_CACHE;
      traverseRecursively(context, rd, rd.getRootFile(), timestamps, forceMarkDirty, currentFiles, filter, fsCache);
    }
  }

  private static void traverseRecursively(CompileContext context,
                                          final BuildRootDescriptor rd,
                                          final File file,
                                          @NotNull final Timestamps tsStorage,
                                          final boolean forceDirty,
                                          @Nullable Set<File> currentFiles, @Nullable FileFilter filter, @NotNull FSCache fsCache) throws IOException {
    BuildRootIndex rootIndex = context.getProjectDescriptor().getBuildRootIndex();
    final File[] children = fsCache.getChildren(file);
    if (children != null) { // is directory
      if (children.length > 0 && rootIndex.isDirectoryAccepted(file, rd)) {
        for (File child : children) {
          traverseRecursively(context, rd, child, tsStorage, forceDirty, currentFiles, filter, fsCache);
        }
      }
    }
    else { // is file
      if (rootIndex.isFileAccepted(file, rd) && (filter == null || filter.accept(file))) {
        boolean markDirty = forceDirty;
        if (!markDirty) {
          markDirty = tsStorage.getStamp(file, rd.getTarget()) != FileSystemUtil.lastModified(file);
        }
        if (markDirty) {
          // if it is full project rebuild, all storages are already completely cleared;
          // so passing null because there is no need to access the storage to clear non-existing data
          final Timestamps marker = context.isProjectRebuild() ? null : tsStorage;
          context.getProjectDescriptor().fsState.markDirty(context, file, rd, marker, false);
        }
        if (currentFiles != null) {
          currentFiles.add(file);
        }
      }
    }
  }

  public static void pruneEmptyDirs(CompileContext context, @Nullable final Set<File> dirsToDelete) {
    if (dirsToDelete == null || dirsToDelete.isEmpty()) return;

    Set<File> doNotDelete = ALL_OUTPUTS_KEY.get(context);
    if (doNotDelete == null) {
      doNotDelete = new THashSet<File>(FileUtil.FILE_HASHING_STRATEGY);
      for (BuildTarget<?> target : context.getProjectDescriptor().getBuildTargetIndex().getAllTargets()) {
        doNotDelete.addAll(target.getOutputRoots(context));
      }
      ALL_OUTPUTS_KEY.set(context, doNotDelete);
    }

    Set<File> additionalDirs = null;
    Set<File> toDelete = dirsToDelete;
    while (toDelete != null) {
      for (File file : toDelete) {
        // important: do not force deletion if the directory is not empty!
        final boolean deleted = !doNotDelete.contains(file) && file.delete();
        if (deleted) {
          final File parentFile = file.getParentFile();
          if (parentFile != null) {
            if (additionalDirs == null) {
              additionalDirs = new THashSet<File>(FileUtil.FILE_HASHING_STRATEGY);
            }
            additionalDirs.add(parentFile);
          }
        }
      }
      toDelete = additionalDirs;
      additionalDirs = null;
    }
  }
}