// 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 static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.base.Strings;
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.MoveInput;
import com.google.gerrit.extensions.api.changes.NotifyHandling;
import com.google.gerrit.extensions.api.changes.RestoreInput;
import com.google.gerrit.extensions.api.changes.ReviewInput;
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.server.OutputFormat;
import com.google.gerrit.server.config.AllProjectsName;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.project.ProjectCache;
import com.google.gerrit.server.project.ProjectControl;
import com.google.gerrit.server.project.ProjectState;
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 java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.Option;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@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(String token) {
    try {
      PatchSet ps = psParser.parsePatchSet(token, 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 = "--move", usage = "move the specified change(s)", metaVar = "BRANCH")
  private String moveToBranch;

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

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

  @Option(
      name = "--tag",
      aliases = "-t",
      usage = "applies a tag to the given review",
      metaVar = "TAG")
  private String changeTag;

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

  @Inject private ProjectCache projectCache;

  @Inject private AllProjectsName allProjects;

  @Inject private GerritApi gApi;

  @Inject private PatchSetParser psParser;

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

  @Override
  protected void run() throws UnloggedFailure {
    if (abandonChange) {
      if (restoreChange) {
        throw die("abandon and restore actions are mutually exclusive");
      }
      if (submitChange) {
        throw die("abandon and submit actions are mutually exclusive");
      }
      if (rebaseChange) {
        throw die("abandon and rebase actions are mutually exclusive");
      }
      if (moveToBranch != null) {
        throw die("abandon and move actions are mutually exclusive");
      }
    }
    if (json) {
      if (restoreChange) {
        throw die("json and restore actions are mutually exclusive");
      }
      if (submitChange) {
        throw die("json and submit actions are mutually exclusive");
      }
      if (abandonChange) {
        throw die("json and abandon actions are mutually exclusive");
      }
      if (changeComment != null) {
        throw die("json and message are mutually exclusive");
      }
      if (rebaseChange) {
        throw die("json and rebase actions are mutually exclusive");
      }
      if (moveToBranch != null) {
        throw die("json and move actions are mutually exclusive");
      }
      if (changeTag != null) {
        throw die("json and tag actions are mutually exclusive");
      }
    }
    if (rebaseChange) {
      if (submitChange) {
        throw die("rebase and submit actions are mutually exclusive");
      }
    }

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

    for (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("error", "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 die("one or more reviews failed; review output above");
    }
  }

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

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

  private void reviewPatchSet(PatchSet patchSet) throws Exception {

    ReviewInput review = new ReviewInput();
    review.message = Strings.emptyToNull(changeComment);
    review.tag = Strings.emptyToNull(changeTag);
    review.notify = notify;
    review.labels = new TreeMap<>();
    review.drafts = ReviewInput.DraftHandling.PUBLISH;
    for (ApproveOption ao : optionList) {
      Short v = ao.value();
      if (v != null) {
        review.labels.put(ao.getLabelName(), v);
      }
    }
    review.labels.putAll(customLabels);

    // We don't need to add the review comment when abandoning/restoring.
    if (abandonChange || restoreChange || moveToBranch != null) {
      review.message = null;
    }

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

      if (moveToBranch != null) {
        MoveInput moveInput = new MoveInput();
        moveInput.destinationBranch = moveToBranch;
        moveInput.message = Strings.emptyToNull(changeComment);
        changeApi(patchSet).move(moveInput);
      }

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

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

    } catch (IllegalStateException | RestApiException e) {
      throw die(e);
    }
  }

  private ChangeApi changeApi(PatchSet patchSet) throws RestApiException {
    return gApi.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 = new HashMap<>();

    ProjectState allProjectsState;
    try {
      allProjectsState = projectCache.checkedGet(allProjects);
    } catch (IOException e) {
      throw die("missing " + allProjects.get());
    }

    for (LabelType type : allProjectsState.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();
  }
}