/*
 * Copyright 2000-2010 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 jetbrains.buildServer.buildTriggers.vcs.mercurial;

import jetbrains.buildServer.BuildAgent;
import jetbrains.buildServer.Used;
import jetbrains.buildServer.buildTriggers.vcs.AbstractVcsPropertiesProcessor;
import jetbrains.buildServer.buildTriggers.vcs.mercurial.command.*;
import jetbrains.buildServer.log.Loggers;
import jetbrains.buildServer.serverSide.*;
import jetbrains.buildServer.util.EventDispatcher;
import jetbrains.buildServer.util.FileUtil;
import jetbrains.buildServer.util.StringUtil;
import jetbrains.buildServer.util.filters.Filter;
import jetbrains.buildServer.util.filters.FilterUtil;
import jetbrains.buildServer.vcs.*;
import jetbrains.buildServer.vcs.patches.PatchBuilder;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Mercurial VCS plugin for TeamCity works as follows:
 * <ul>
 * <li>clones repository to internal storage
 * <li>before any operation with working copy of repository pulls changes from the original repository
 * <li>executes corresponding hg command
 * </ul>
 *
 * <p>Working copy of repository is created in the $TEAMCITY_DATA_PATH/system/caches/hg_&lt;hash code> folder.
 * <p>Personal builds (remote runs) are not yet supported, they require corresponding functionality from the IDE.
 */
public class MercurialVcsSupport extends ServerVcsSupport implements LabelingSupport, VcsFileContentProvider, BranchSupport {
  private ConcurrentMap<String, Lock> myWorkDirLocks= new ConcurrentHashMap<String, Lock>();
  private VcsManager myVcsManager;
  private File myDefaultWorkFolderParent;

  public MercurialVcsSupport(@NotNull final VcsManager vcsManager,
                             @NotNull ServerPaths paths,
                             @NotNull final SBuildServer server,
                             @NotNull EventDispatcher<BuildServerListener> dispatcher) {
    myVcsManager = vcsManager;
    myDefaultWorkFolderParent = new File(paths.getCachesDir(), "mercurial");
    dispatcher.addListener(new BuildServerAdapter() {
      @Override
      public void cleanupFinished() {
        super.cleanupFinished();
        server.getExecutor().submit(new Runnable() {
          public void run() {
            removeOldWorkFolders();
          }
        });
      }

      @Override
      public void sourcesVersionReleased(@NotNull final BuildAgent agent) {
        super.sourcesVersionReleased(agent);
        server.getExecutor().submit(new Runnable() {
          public void run() {
            Set<File> clonedRepos = getAllClonedRepos();
            if (clonedRepos == null) return;
            for (File f: clonedRepos) {
              lockWorkDir(f);
              try {
                FileUtil.delete(f);
              } finally {
                unlockWorkDir(f);
              }
            }
          }
        });
      }
    });
  }

  private Collection<ModifiedFile> computeModifiedFilesForMergeCommit(final Settings settings, final ChangeSet cur) throws VcsException {
    ChangedFilesCommand cfc = new ChangedFilesCommand(settings);
    cfc.setRevId(cur.getId());
    return cfc.execute();
  }

  private List<VcsChange> toVcsChanges(final List<ModifiedFile> modifiedFiles, String prevVer, String curVer) {
    List<VcsChange> files = new ArrayList<VcsChange>();
    for (ModifiedFile mf: modifiedFiles) {
      VcsChangeInfo.Type changeType = getChangeType(mf.getStatus());
      if (changeType == null) {
        Loggers.VCS.warn("Unable to convert status: " + mf.getStatus() + " to VCS change type");
        changeType = VcsChangeInfo.Type.NOT_CHANGED;
      }
      files.add(new VcsChange(changeType, mf.getStatus().getName(), mf.getPath(), mf.getPath(), prevVer, curVer));
    }
    return files;
  }

  private VcsChangeInfo.Type getChangeType(final ModifiedFile.Status status) {
    switch (status) {
      case ADDED:return VcsChangeInfo.Type.ADDED;
      case MODIFIED:return VcsChangeInfo.Type.CHANGED;
      case REMOVED:return VcsChangeInfo.Type.REMOVED;
    }
    return null;
  }

  @NotNull
  public byte[] getContent(@NotNull final VcsModification vcsModification,
                           @NotNull final VcsChangeInfo change,
                           @NotNull final VcsChangeInfo.ContentType contentType,
                           @NotNull final VcsRoot vcsRoot) throws VcsException {
    syncClonedRepository(vcsRoot);
    String version = contentType == VcsChangeInfo.ContentType.AFTER_CHANGE ? change.getAfterChangeRevisionNumber() : change.getBeforeChangeRevisionNumber();
    return getContent(change.getRelativeFileName(), vcsRoot, version);
  }

  @NotNull
  public byte[] getContent(@NotNull final String filePath, @NotNull final VcsRoot vcsRoot, @NotNull final String version) throws VcsException {
    syncClonedRepository(vcsRoot);
    Settings settings = createSettings(vcsRoot);
    CatCommand cc = new CatCommand(settings);
    cc.setRevId(new ChangeSet(version).getId());
    File parentDir = cc.execute(Collections.singletonList(filePath));
    try {
      File file = new File(parentDir, filePath);
      if (file.isFile()) {
        try {
          return FileUtil.loadFileBytes(file);
        } catch (IOException e) {
          throw new VcsException("Failed to load content of file: " + file.getAbsolutePath(), e);
        }
      } else {
        Loggers.VCS.warn("Unable to obtain content of the file: " + filePath);
      }
    } finally {
      deleteTmpDir(parentDir);
    }
    return new byte[0];
  }

  @NotNull
  public String getName() {
    return Constants.VCS_NAME;
  }

  @NotNull
  @Used("jsp")
  public String getDisplayName() {
    return "Mercurial";
  }

  @Nullable
  public PropertiesProcessor getVcsPropertiesProcessor() {
    return new AbstractVcsPropertiesProcessor() {
      public Collection<InvalidProperty> process(final Map<String, String> properties) {
        List<InvalidProperty> result = new ArrayList<InvalidProperty>();
        if (isEmpty(properties.get(Constants.HG_COMMAND_PATH_PROP))) {
          result.add(new InvalidProperty(Constants.HG_COMMAND_PATH_PROP, "Path to 'hg' command must be specified"));
        } 
        if (isEmpty(properties.get(Constants.REPOSITORY_PROP))) {
          result.add(new InvalidProperty(Constants.REPOSITORY_PROP, "Repository must be specified"));
        }
        if (isEmpty(properties.get(Constants.SERVER_CLONE_PATH_PROP))) {
          properties.put(Constants.SERVER_CLONE_PATH_PROP, myDefaultWorkFolderParent.getAbsolutePath());
        }
        return result;
      }
    };
  }

  @NotNull
  public String getVcsSettingsJspFilePath() {
    return "mercurialSettings.jsp";
  }

  @NotNull
  public String getCurrentVersion(@NotNull final VcsRoot root) throws VcsException {
    // we will return full version of the most recent change as current version
    syncClonedRepository(root);
    Settings settings = createSettings(root);
    BranchesCommand branches = new BranchesCommand(settings);
    Map<String, ChangeSet> result = branches.execute();
    if (!result.containsKey(settings.getBranchName())) {
      throw new VcsException("Unable to find current version for the branch: " + settings.getBranchName());
    }

    return result.get(settings.getBranchName()).getFullVersion();
  }

  public boolean sourcesUpdatePossibleIfChangesNotFound(@NotNull final VcsRoot root) {
    return false;
  }

  @NotNull
  public String describeVcsRoot(final VcsRoot vcsRoot) {
    return "mercurial: " + vcsRoot.getProperty(Constants.REPOSITORY_PROP);
  }

  @Override
  public TestConnectionSupport getTestConnectionSupport() {
    return new TestConnectionSupport() {
      public String testConnection(@NotNull final VcsRoot vcsRoot) throws VcsException {
        Settings settings = createSettings(vcsRoot);
        IdentifyCommand id = new IdentifyCommand(settings);
        StringBuilder res = new StringBuilder();
        res.append(quoteIfNeeded(settings.getHgCommandPath()));
        res.append(" identify ");
        final String obfuscatedUrl = CommandUtil.removePrivateData(settings.getRepositoryUrl(), Collections.singleton(settings.getPassword()));
        res.append(quoteIfNeeded(obfuscatedUrl));
        res.append('\n').append(id.execute());
        return res.toString();
      }
    };
  }

  private String quoteIfNeeded(@NotNull String str) {
    if (str.indexOf(' ') != -1) {
      return "\"" + str + "\"";
    }

    return str;
  }

  @Nullable
  public Map<String, String> getDefaultVcsProperties() {
    Map<String, String> defaults = new HashMap<String, String>();
    defaults.put(Constants.HG_COMMAND_PATH_PROP, "hg");
    defaults.put(Constants.SERVER_CLONE_PATH_PROP, myDefaultWorkFolderParent.getAbsolutePath());
    return defaults;
  }

  public String getVersionDisplayName(@NotNull final String version, @NotNull final VcsRoot root) throws VcsException {
    return new ChangeSet(version).getId();
  }

  @NotNull
  public Comparator<String> getVersionComparator() {
    // comparator is called when TeamCity needs to sort modifications in the order of their appearance,
    // currently we sort changes by revision number, not sure however that this is a good idea,
    // probably it would be better to sort them by timestamp (and to add timestamp into the version).
    return new Comparator<String>() {
      public int compare(final String o1, final String o2) {
        try {
          return new ChangeSet(o1).getRevNumber() - new ChangeSet(o2).getRevNumber();
        } catch (Exception e) {
          return 1;
        }
      }
    };
  }

  // builds patch from version to version
  private void buildIncrementalPatch(final Settings settings, @NotNull final ChangeSet fromVer, @NotNull final ChangeSet toVer, final PatchBuilder builder, final CheckoutRules checkoutRules)
    throws VcsException, IOException {
    StatusCommand st = new StatusCommand(settings);
    st.setFromRevId(fromVer.getId());
    st.setToRevId(toVer.getId());
    List<ModifiedFile> modifiedFiles = st.execute();
    List<String> notDeletedFiles = new ArrayList<String>();
    for (ModifiedFile f: modifiedFiles) {
      if (f.getStatus() != ModifiedFile.Status.REMOVED) {
        notDeletedFiles.add(f.getPath());
      }
    }

    if (notDeletedFiles.isEmpty()) return;

    CatCommand cc = new CatCommand(settings);
    cc.setRevId(toVer.getId());
    File parentDir = cc.execute(notDeletedFiles);

    try {
      for (ModifiedFile f: modifiedFiles) {
        String mappedPath = checkoutRules.map(f.getPath());
        if (mappedPath == null) continue; // skip
        final File virtualFile = new File(mappedPath);
        if (f.getStatus() == ModifiedFile.Status.REMOVED) {
          builder.deleteFile(virtualFile, true);
        } else {
          File realFile = new File(parentDir, f.getPath());
          FileInputStream is = new FileInputStream(realFile);
          try {
            builder.changeOrCreateBinaryFile(virtualFile, null, is, realFile.length());
          } finally {
            is.close();
          }
        }
      }
    } finally {
      deleteTmpDir(parentDir);
    }
  }

  private void deleteTmpDir(File parentDir) {
    boolean dirDeleted = FileUtil.delete(parentDir);
    if (!dirDeleted) {
      Loggers.VCS.warn("Can not delete directory \"" + parentDir.getAbsolutePath() + "\"");
    }
  }

  // builds patch by exporting files using specified version
  private void buildFullPatch(final Settings settings, @NotNull final ChangeSet toVer, final PatchBuilder builder, final CheckoutRules checkoutRules)
    throws IOException, VcsException {
    CloneCommand cl = new CloneCommand(settings);
    // clone from the local repository
    cl.setRepository(settings.getLocalRepositoryDir().getAbsolutePath());
    cl.setToId(toVer.getId());
    cl.setUpdateWorkingDir(false);
    File tempDir = FileUtil.createTempDirectory("mercurial", toVer.getId());
    try {
      final File repRoot = new File(tempDir, "rep");
      cl.setDestDir(repRoot.getAbsolutePath());
      cl.execute();

      UpdateCommand up = new UpdateCommand(settings);
      up.setWorkDirectory(repRoot.getAbsolutePath());
      up.setToId(toVer.getId());
      up.execute();

      buildPatchFromDirectory(builder, repRoot, new FileFilter() {
        public boolean accept(final File file) {
          return !(file.isDirectory() && ".hg".equals(file.getName()));
        }
      }, checkoutRules);
    } finally {
      FileUtil.delete(tempDir);
    }
  }

  private void buildPatchFromDirectory(final PatchBuilder builder, final File repRoot, final FileFilter filter, final CheckoutRules checkoutRules) throws IOException {
    buildPatchFromDirectory(repRoot, builder, repRoot, filter, checkoutRules);
  }

  private void buildPatchFromDirectory(File curDir, final PatchBuilder builder, final File repRoot, final FileFilter filter, final CheckoutRules checkoutRules) throws IOException {
    File[] files = curDir.listFiles(filter);
    if (files != null) {
      for (File realFile: files) {
        String relPath = realFile.getAbsolutePath().substring(repRoot.getAbsolutePath().length());
        String mappedPath = checkoutRules.map(relPath);
        if (mappedPath != null && mappedPath.length() > 0) {
          final File virtualFile = new File(mappedPath);
          if (realFile.isDirectory()) {
            builder.createDirectory(virtualFile);
            buildPatchFromDirectory(realFile, builder, repRoot, filter, checkoutRules);
          } else {
            final FileInputStream is = new FileInputStream(realFile);
            try {
              builder.createBinaryFile(virtualFile, null, is, realFile.length());
            } finally {
              is.close();
            }
          }
        } else {
          if (realFile.isDirectory()) {
            buildPatchFromDirectory(realFile, builder, repRoot, filter, checkoutRules);
          }
        }
      }
    }
  }

  // updates current working copy of repository by pulling changes from the repository specified in VCS root
  private void syncClonedRepository(final VcsRoot root) throws VcsException {
    Settings settings = createSettings(root);
    File workDir = settings.getLocalRepositoryDir();
    lockWorkDir(workDir);
    try {
      if (settings.hasCopyOfRepository()) {
        // update
        PullCommand pull = new PullCommand(settings);
        pull.execute();
      } else {
        // clone
        CloneCommand cl = new CloneCommand(settings);
        cl.setDestDir(workDir.getAbsolutePath());
        cl.setUpdateWorkingDir(false);
        cl.execute();
      }
    } finally {
      unlockWorkDir(workDir);
    }
  }

  @Override
  public LabelingSupport getLabelingSupport() {
    return this;
  }

  @NotNull
  public VcsFileContentProvider getContentProvider() {
    return this;
  }

  public List<ModificationData> collectChanges(@NotNull VcsRoot fromRoot, @NotNull String fromRootRevision,
                                               @NotNull VcsRoot toRoot, @Nullable String toRootRevision,
                                               @NotNull CheckoutRules checkoutRules) throws VcsException {
    //we get all branches while clone, if vcs roots are related it is doesn't matter in which one search for branch point
    syncClonedRepository(fromRoot);
    String branchPoint = getBranchPoint(fromRoot, fromRootRevision, toRootRevision);
    return ((CollectChangesByCheckoutRules) getCollectChangesPolicy()).collectChanges(fromRoot, branchPoint, toRootRevision, checkoutRules);
  }

  private String getBranchPoint(@NotNull VcsRoot root, String branchOneRev, String branchTwoRev) throws VcsException {
    Settings settings = createSettings(root);
    LogCommand lc = new LogCommand(settings);
    lc.setFromRevId(new ChangeSetRevision(branchOneRev).getId());
    lc.setToRevId(new ChangeSetRevision(branchTwoRev).getId());
    lc.setLimit(1);
    List<ChangeSet> changeSets = lc.execute();
    ChangeSet cs = changeSets.get(0);
    if (cs.isInitial()) {
      return cs.getId();
    } else {
      return cs.getParents().get(0).getId();
    }
  }

  @NotNull
  public CollectChangesPolicy getCollectChangesPolicy() {
    return new CollectChangesByCheckoutRules() {
      public List<ModificationData> collectChanges(@NotNull VcsRoot root, @NotNull String fromVersion, @Nullable String currentVersion, @NotNull CheckoutRules checkoutRules) throws VcsException {
        syncClonedRepository(root);

        // first obtain changes between specified versions
        List<ModificationData> result = new ArrayList<ModificationData>();
        if (currentVersion == null) return result;

        Settings settings = createSettings(root);
        LogCommand lc = new LogCommand(settings);
        String fromId = new ChangeSetRevision(fromVersion).getId();
        lc.setFromRevId(fromId);
        lc.setToRevId(new ChangeSetRevision(currentVersion).getId());
        List<ChangeSet> changeSets = lc.execute();
        if (changeSets.isEmpty()) {
          return result;
        }

        // invoke status command for each changeset and determine what files were modified in these changesets
        StatusCommand st = new StatusCommand(settings);
        ChangeSet prev = new ChangeSet(fromVersion);
        for (ChangeSet cur : changeSets) {
          if (cur.getId().equals(fromId)) continue; // skip already reported changeset

          String prevId = prev.getId();
          List<ChangeSetRevision> curParents = cur.getParents();
          boolean merge = curParents != null && curParents.size() > 1;
          if (curParents != null && !merge) {
            prevId = curParents.get(0).getId();
          }

          List<ModifiedFile> modifiedFiles = new ArrayList<ModifiedFile>();
          if (merge) {
            modifiedFiles.addAll(computeModifiedFilesForMergeCommit(settings, cur));
          } else {
            st.setFromRevId(prevId);
            st.setToRevId(cur.getId());
            modifiedFiles = st.execute();
          }

          // changeset full version will be set into VcsChange structure and
          // stored in database (note that getContent method will be invoked with this version)
          List<VcsChange> files = toVcsChanges(modifiedFiles, prev.getFullVersion(), cur.getFullVersion());
          if (files.isEmpty() && !merge) continue;
          ModificationData md = new ModificationData(cur.getTimestamp(), files, cur.getDescription(), cur.getUser(), root, cur.getFullVersion(), cur.getId());
          if (merge) {
            md.setCanBeIgnored(false);
          }
          result.add(md);
          prev = cur;
        }

        return result;
      }
    };
  }

  @NotNull
  public BuildPatchPolicy getBuildPatchPolicy() {
    return new BuildPatchByCheckoutRules() {
      public void buildPatch(@NotNull final VcsRoot root,
                             @Nullable final String fromVersion,
                             @NotNull final String toVersion,
                             @NotNull final PatchBuilder builder,
                             @NotNull final CheckoutRules checkoutRules) throws IOException, VcsException {
        syncClonedRepository(root);
        Settings settings = createSettings(root);
        if (fromVersion == null) {
          buildFullPatch(settings, new ChangeSet(toVersion), builder, checkoutRules);
        } else {
          buildIncrementalPatch(settings, new ChangeSet(fromVersion), new ChangeSet(toVersion), builder, checkoutRules);
        }
      }
    };
  }

  private void lockWorkDir(@NotNull File workDir) {
    getWorkDirLock(workDir).lock();
  }

  private void unlockWorkDir(@NotNull File workDir) {
    getWorkDirLock(workDir).unlock();
  }

  @Override
  public boolean allowSourceCaching() {
    // since a copy of repository for each VCS root is already stored on disk
    // we do not need separate cache for our patches
    return false;
  }

  private Lock getWorkDirLock(final File workDir) {
    String path = workDir.getAbsolutePath();
    Lock lock = myWorkDirLocks.get(path);
    if (lock == null) {
      lock = new ReentrantLock();
      Lock curLock = myWorkDirLocks.putIfAbsent(path, lock);
      if (curLock != null) {
        lock = curLock;
      }
    }
    return lock;
  }

  private void removeOldWorkFolders() {
    Set<File> workDirs = getAllClonedRepos();
    if (workDirs == null) return;

    for (VcsRoot vcsRoot: getMercurialVcsRoots()) {
      try {
        Settings s = createSettings(vcsRoot);
        workDirs.remove(PathUtil.getCanonicalFile(s.getLocalRepositoryDir()));
      } catch (VcsException e) {
        Loggers.VCS.error(e);
      }
    }

    for (File f: workDirs) {
      lockWorkDir(f);
      try {
        FileUtil.delete(f);
      } finally {
        unlockWorkDir(f);
      }
    }
  }

  private Collection<VcsRoot> getMercurialVcsRoots() {
    List<VcsRoot> res = new ArrayList<VcsRoot>(myVcsManager.getAllRegisteredVcsRoots());
    FilterUtil.filterCollection(res, new Filter<VcsRoot>() {
      public boolean accept(@NotNull final VcsRoot data) {
        return getName().equals(data.getVcsName());
      }
    });
    return res;
  }

  @Nullable
  private Set<File> getAllClonedRepos() {
    File workFoldersParent = myDefaultWorkFolderParent;
    if (!workFoldersParent.isDirectory()) return null;

    Set<File> workDirs = new HashSet<File>();
    File[] files = workFoldersParent.listFiles(new FileFilter() {
      public boolean accept(final File file) {
        return file.isDirectory() && file.getName().startsWith(Settings.DEFAULT_WORK_DIR_PREFIX);
      }
    });
    if (files != null) {
      for (File f: files) {
        workDirs.add(PathUtil.getCanonicalFile(f));
      }
    }
    return workDirs;
  }

  public String label(@NotNull String label, @NotNull String version, @NotNull VcsRoot root, @NotNull CheckoutRules checkoutRules) throws VcsException {
    syncClonedRepository(root);

    Settings settings = createSettings(root);

    // I do not know why but hg tag does not work correctly if
    // update command was not invoked for the current repo
    // in such case if there were no tags before Mercurial attempts to
    // create new head when tag is pushed to the parent repository
    UpdateCommand uc = new UpdateCommand(settings);
    uc.execute();

    String fixedTagname = fixTagName(label);
    TagCommand tc = new TagCommand(settings);
    tc.setRevId(new ChangeSet(version).getId());
    tc.setTag(fixedTagname);
    tc.execute();

    PushCommand pc = new PushCommand(settings);
//    pc.setForce(true);
    pc.execute();
    return fixedTagname;
  }

  private String fixTagName(final String label) {
    // according to Mercurial documentation http://hgbook.red-bean.com/hgbookch8.html#x12-1570008
    // tag name must not contain:
    // Colon (ASCII 58, �:�)
    // Carriage return (ASCII 13, �\r�)
    // Newline (ASCII 10, �\n�)
    // all these characters will be replaced with _ (underscore)
    return label.replace(':', '_').replace('\r', '_').replace('\n', '_');
  }

  private Settings createSettings(final VcsRoot root) throws VcsException {
    Settings settings = new Settings(myDefaultWorkFolderParent, root);
    String customClonePath = root.getProperty(Constants.SERVER_CLONE_PATH_PROP);
    if (!StringUtil.isEmptyOrSpaces(customClonePath) && !myDefaultWorkFolderParent.equals(new File(customClonePath).getAbsoluteFile())) {
      File parentDir = new File(customClonePath);
      createClonedRepositoryParentDir(parentDir);

      // take last part of repository path
      String repPath = settings.getRepositoryUrl();
      String[] splitted = repPath.split("[/\\\\]");
      if (splitted.length > 0) {
        repPath = splitted[splitted.length-1];
      }

      File customWorkingDir = new File(parentDir, repPath);
      settings.setWorkingDir(customWorkingDir);
    } else {
      createClonedRepositoryParentDir(myDefaultWorkFolderParent);
    }
    return settings;
  }

  private void createClonedRepositoryParentDir(final File parentDir) throws VcsException {
    if (!parentDir.exists() && !parentDir.mkdirs()) {
      throw new VcsException("Failed to create parent directory for cloned repository: " + parentDir.getAbsolutePath());
    }
  }

  public boolean isAgentSideCheckoutAvailable() {
    return true;
  }
}