// Copyright (C) 2009 The Android Open Source Project
//
// 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 com.google.gerrit.sshd.commands;

import com.google.common.base.Strings;
import com.google.common.collect.Maps;
import com.google.common.io.CharStreams;
import com.google.gerrit.common.data.LabelType;
import com.google.gerrit.common.data.LabelValue;
import com.google.gerrit.extensions.api.GerritApi;
import com.google.gerrit.extensions.api.changes.AbandonInput;
import com.google.gerrit.extensions.api.changes.ChangeApi;
import com.google.gerrit.extensions.api.changes.RestoreInput;
import com.google.gerrit.extensions.api.changes.ReviewInput;
import com.google.gerrit.extensions.api.changes.ReviewInput.NotifyHandling;
import com.google.gerrit.extensions.api.changes.RevisionApi;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.server.ReviewDb;
import com.google.gerrit.server.OutputFormat;
import com.google.gerrit.server.config.AllProjectsName;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.project.NoSuchProjectException;
import com.google.gerrit.server.project.ProjectControl;
import com.google.gerrit.server.util.LabelVote;
import com.google.gerrit.sshd.CommandMetaData;
import com.google.gerrit.sshd.SshCommand;
import com.google.gerrit.util.cli.CmdLineParser;
import com.google.gson.JsonSyntaxException;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;

import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.Option;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

@CommandMetaData(name = "review", description = "Apply reviews to one or more patch sets")
public class ReviewCommand extends SshCommand {
  private static final Logger log =
      LoggerFactory.getLogger(ReviewCommand.class);

  @Override
  protected final CmdLineParser newCmdLineParser(Object options) {
    final CmdLineParser parser = super.newCmdLineParser(options);
    for (ApproveOption c : optionList) {
      parser.addOption(c, c);
    }
    return parser;
  }

  private final Set<PatchSet> patchSets = new HashSet<>();

  @Argument(index = 0, required = true, multiValued = true, metaVar = "{COMMIT | CHANGE,PATCHSET}", usage = "list of commits or patch sets to review")
  void addPatchSetId(final String token) {
    try {
      PatchSet ps = CommandUtils.parsePatchSet(token, db, projectControl,
          branch);
      patchSets.add(ps);
    } catch (UnloggedFailure e) {
      throw new IllegalArgumentException(e.getMessage(), e);
    } catch (OrmException e) {
      throw new IllegalArgumentException("database error", e);
    }
  }

  @Option(name = "--project", aliases = "-p", usage = "project containing the specified patch set(s)")
  private ProjectControl projectControl;

  @Option(name = "--branch", aliases = "-b", usage = "branch containing the specified patch set(s)")
  private String branch;

  @Option(name = "--message", aliases = "-m", usage = "cover message to publish on change(s)", metaVar = "MESSAGE")
  private String changeComment;

  @Option(name = "--notify", aliases = "-n", usage = "Who to send email notifications to after the review is stored.", metaVar = "NOTIFYHANDLING")
  private NotifyHandling notify;

  @Option(name = "--abandon", usage = "abandon the specified change(s)")
  private boolean abandonChange;

  @Option(name = "--restore", usage = "restore the specified abandoned change(s)")
  private boolean restoreChange;

  @Option(name = "--rebase", usage = "rebase the specified change(s)")
  private boolean rebaseChange;

  @Option(name = "--submit", aliases = "-s", usage = "submit the specified patch set(s)")
  private boolean submitChange;

  @Option(name = "--publish", usage = "publish the specified draft patch set(s)")
  private boolean publishPatchSet;

  @Option(name = "--delete", usage = "delete the specified draft patch set(s)")
  private boolean deleteDraftPatchSet;

  @Option(name = "--json", aliases = "-j", usage = "read review input json from stdin")
  private boolean json;

  @Option(name = "--label", aliases = "-l", usage = "custom label(s) to assign", metaVar = "LABEL=VALUE")
  void addLabel(final String token) {
    LabelVote v = LabelVote.parseWithEquals(token);
    LabelType.checkName(v.label()); // Disallow SUBM.
    customLabels.put(v.label(), v.value());
  }

  @Inject
  private ReviewDb db;

  @Inject
  private ProjectControl.Factory projectControlFactory;

  @Inject
  private AllProjectsName allProjects;

  @Inject
  private Provider<GerritApi> gApi;

  private List<ApproveOption> optionList;
  private Map<String, Short> customLabels;

  @Override
  protected void run() throws UnloggedFailure {
    if (abandonChange) {
      if (restoreChange) {
        throw error("abandon and restore actions are mutually exclusive");
      }
      if (submitChange) {
        throw error("abandon and submit actions are mutually exclusive");
      }
      if (publishPatchSet) {
        throw error("abandon and publish actions are mutually exclusive");
      }
      if (deleteDraftPatchSet) {
        throw error("abandon and delete actions are mutually exclusive");
      }
      if (rebaseChange) {
        throw error("abandon and rebase actions are mutually exclusive");
      }
    }
    if (publishPatchSet) {
      if (restoreChange) {
        throw error("publish and restore actions are mutually exclusive");
      }
      if (submitChange) {
        throw error("publish and submit actions are mutually exclusive");
      }
      if (deleteDraftPatchSet) {
        throw error("publish and delete actions are mutually exclusive");
      }
    }
    if (json) {
      if (restoreChange) {
        throw error("json and restore actions are mutually exclusive");
      }
      if (submitChange) {
        throw error("json and submit actions are mutually exclusive");
      }
      if (deleteDraftPatchSet) {
        throw error("json and delete actions are mutually exclusive");
      }
      if (publishPatchSet) {
        throw error("json and publish actions are mutually exclusive");
      }
      if (abandonChange) {
        throw error("json and abandon actions are mutually exclusive");
      }
      if (changeComment != null) {
        throw error("json and message are mutually exclusive");
      }
      if (rebaseChange) {
        throw error("json and rebase actions are mutually exclusive");
      }
    }
    if (rebaseChange) {
      if (deleteDraftPatchSet) {
        throw error("rebase and delete actions are mutually exclusive");
      }
      if (submitChange) {
        throw error("rebase and submit actions are mutually exclusive");
      }
    }
    if (deleteDraftPatchSet && submitChange) {
      throw error("delete and submit actions are mutually exclusive");
    }

    boolean ok = true;
    ReviewInput input = null;
    if (json) {
      input = reviewFromJson();
    }

    for (final PatchSet patchSet : patchSets) {
      try {
        if (input != null) {
          applyReview(patchSet, input);
        } else {
          reviewPatchSet(patchSet);
        }
      } catch (RestApiException | UnloggedFailure e) {
        ok = false;
        writeError("error: " + e.getMessage() + "\n");
      } catch (NoSuchChangeException e) {
        ok = false;
        writeError("no such change " + patchSet.getId().getParentKey().get());
      } catch (Exception e) {
        ok = false;
        writeError("fatal: internal server error while reviewing "
            + patchSet.getId() + "\n");
        log.error("internal error while reviewing " + patchSet.getId(), e);
      }
    }

    if (!ok) {
      throw error("one or more reviews failed; review output above");
    }
  }

  private void applyReview(PatchSet patchSet,
      final ReviewInput review) throws RestApiException {
    gApi.get().changes()
        .id(patchSet.getId().getParentKey().get())
        .revision(patchSet.getRevision().get())
        .review(review);
  }

  private ReviewInput reviewFromJson() throws UnloggedFailure {
    try (InputStreamReader r =
          new InputStreamReader(in, StandardCharsets.UTF_8)) {
      return OutputFormat.JSON.newGson().
          fromJson(CharStreams.toString(r), ReviewInput.class);
    } catch (IOException | JsonSyntaxException e) {
      writeError(e.getMessage() + '\n');
      throw error("internal error while reading review input");
    }
  }

  private void reviewPatchSet(final PatchSet patchSet) throws Exception {
    if (changeComment == null) {
      changeComment = "";
    }
    if (notify == null) {
      notify = NotifyHandling.ALL;
    }

    ReviewInput review = new ReviewInput();
    review.message = Strings.emptyToNull(changeComment);
    review.notify = notify;
    review.labels = Maps.newTreeMap();
    review.drafts = ReviewInput.DraftHandling.PUBLISH;
    review.strictLabels = false;
    for (ApproveOption ao : optionList) {
      Short v = ao.value();
      if (v != null) {
        review.labels.put(ao.getLabelName(), v);
      }
    }
    review.labels.putAll(customLabels);

    // If review labels are being applied, the comment will be included
    // on the review note. We don't need to add it again on the abandon
    // or restore comment.
    if (!review.labels.isEmpty() && (abandonChange || restoreChange)) {
      changeComment = null;
    }

    try {
      if (abandonChange) {
        AbandonInput input = new AbandonInput();
        input.message = changeComment;
        applyReview(patchSet, review);
        changeApi(patchSet).abandon(input);
      } else if (restoreChange) {
        RestoreInput input = new RestoreInput();
        input.message = changeComment;
        changeApi(patchSet).restore(input);
        applyReview(patchSet, review);
      } else {
        applyReview(patchSet, review);
      }

      if (rebaseChange){
        revisionApi(patchSet).rebase();
      }

      if (submitChange) {
        revisionApi(patchSet).submit();
      }

      if (publishPatchSet) {
        revisionApi(patchSet).publish();
      } else if (deleteDraftPatchSet) {
        revisionApi(patchSet).delete();
      }
    } catch (IllegalStateException | RestApiException e) {
      throw error(e.getMessage());
    }
  }

  private ChangeApi changeApi(PatchSet patchSet) throws RestApiException {
    return gApi.get().changes().id(patchSet.getId().getParentKey().get());
  }

  private RevisionApi revisionApi(PatchSet patchSet) throws RestApiException {
    return changeApi(patchSet).revision(patchSet.getRevision().get());
  }

  @Override
  protected void parseCommandLine() throws UnloggedFailure {
    optionList = new ArrayList<>();
    customLabels = Maps.newHashMap();

    ProjectControl allProjectsControl;
    try {
      allProjectsControl = projectControlFactory.controlFor(allProjects);
    } catch (NoSuchProjectException e) {
      throw new UnloggedFailure("missing " + allProjects.get());
    }

    for (LabelType type : allProjectsControl.getLabelTypes().getLabelTypes()) {
      StringBuilder usage = new StringBuilder("score for ")
        .append(type.getName())
        .append("\n");

      for (LabelValue v : type.getValues()) {
        usage.append(v.format()).append("\n");
      }

      final String name = "--" + type.getName().toLowerCase();
      optionList.add(new ApproveOption(name, usage.toString(), type));
    }

    super.parseCommandLine();
  }

  private void writeError(final String msg) {
    try {
      err.write(msg.getBytes(ENC));
    } catch (IOException e) {
    }
  }

  private static UnloggedFailure error(final String msg) {
    return new UnloggedFailure(1, msg);
  }
}