// Copyright 2019 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.runtime.commands;

import static com.google.devtools.build.lib.packages.Rule.ALL_LABELS;

import com.google.common.base.Joiner;
import com.google.devtools.build.lib.analysis.NoBuildEvent;
import com.google.devtools.build.lib.analysis.NoBuildRequestFinishedEvent;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.query2.AbstractBlazeQueryEnvironment;
import com.google.devtools.build.lib.query2.engine.QueryEnvironment;
import com.google.devtools.build.lib.query2.engine.QueryEnvironment.Setting;
import com.google.devtools.build.lib.query2.engine.QueryEvalResult;
import com.google.devtools.build.lib.query2.output.OutputFormatter;
import com.google.devtools.build.lib.query2.output.QueryOptions;
import com.google.devtools.build.lib.query2.output.QueryOutputUtils;
import com.google.devtools.build.lib.runtime.BlazeCommand;
import com.google.devtools.build.lib.runtime.BlazeCommandResult;
import com.google.devtools.build.lib.runtime.BlazeRuntime;
import com.google.devtools.build.lib.runtime.CommandEnvironment;
import com.google.devtools.build.lib.runtime.KeepGoingOption;
import com.google.devtools.build.lib.runtime.LoadingPhaseThreadsOption;
import com.google.devtools.build.lib.runtime.QueryRuntimeHelper;
import com.google.devtools.build.lib.runtime.QueryRuntimeHelper.Factory.CommandLineException;
import com.google.devtools.build.lib.runtime.TargetProviderForQueryEnvironment;
import com.google.devtools.build.lib.skyframe.LoadingPhaseStartedEvent;
import com.google.devtools.build.lib.skyframe.PackageProgressReceiver;
import com.google.devtools.build.lib.skyframe.SkyframeExecutorWrappingWalkableGraph;
import com.google.devtools.build.lib.util.AbruptExitException;
import com.google.devtools.build.lib.util.Either;
import com.google.devtools.build.lib.util.ExitCode;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import com.google.devtools.build.skyframe.WalkableGraph;
import com.google.devtools.common.options.OptionsParser;
import com.google.devtools.common.options.OptionsParsingResult;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Set;
import java.util.function.Function;

/**
 * Common methods and utils to set up Blaze Runtime environments for {@link BlazeCommand} which
 * requires {@link QueryEnvironment}
 */
public abstract class QueryEnvironmentBasedCommand implements BlazeCommand {

  @Override
  public void editOptions(OptionsParser optionsParser) { }

  /**
   * Exit codes:
   *   0   on successful evaluation.
   *   1   if query evaluation did not complete.
   *   2   if query parsing failed.
   *   3   if errors were reported but evaluation produced a partial result
   *        (only when --keep_going is in effect.)
   */
  @Override
  public BlazeCommandResult exec(CommandEnvironment env, OptionsParsingResult options) {
    env.getEventBus()
        .post(
            new NoBuildEvent(
                env.getCommandName(),
                env.getCommandStartTime(),
                /* separateFinishedEvent= */ true,
                /* showProgress= */ true,
                /* id= */ null));
    BlazeCommandResult result = execInternal(env, options);
    env.getEventBus()
        .post(
            new NoBuildRequestFinishedEvent(
                result.getExitCode(), env.getRuntime().getClock().currentTimeMillis()));
    return result;
  }

  private BlazeCommandResult execInternal(CommandEnvironment env, OptionsParsingResult options) {
    BlazeRuntime runtime = env.getRuntime();
    QueryOptions queryOptions = options.getOptions(QueryOptions.class);

    try {
      env.setupPackageCache(options);
    } catch (InterruptedException e) {
      env.getReporter().handle(Event.error("query interrupted"));
      return BlazeCommandResult.exitCode(ExitCode.INTERRUPTED);
    } catch (AbruptExitException e) {
      env.getReporter().handle(Event.error(null, "Unknown error: " + e.getMessage()));
      return BlazeCommandResult.exitCode(e.getExitCode());
    }

    String query;
    if (!options.getResidue().isEmpty()) {
      if (!queryOptions.queryFile.isEmpty()) {
        env.getReporter()
            .handle(Event.error("Command-line query and --query_file cannot both be specified"));
        return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
      }
      query = Joiner.on(' ').join(options.getResidue());
    } else if (!queryOptions.queryFile.isEmpty()) {
      // Works for absolute or relative query file.
      Path residuePath = env.getWorkingDirectory().getRelative(queryOptions.queryFile);
      try {
        query = new String(FileSystemUtils.readContent(residuePath), StandardCharsets.UTF_8);
      } catch (IOException e) {
        env.getReporter()
            .handle(Event.error("I/O error reading from " + residuePath.getPathString()));
        return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
      }
    } else {
      env.getReporter().handle(Event.error(String.format(
          "missing query expression. Type '%s help query' for syntax and help",
          runtime.getProductName())));
      return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
    }

    Iterable<OutputFormatter> formatters = runtime.getQueryOutputFormatters();
    OutputFormatter formatter =
        OutputFormatter.getFormatter(formatters, queryOptions.outputFormat);
    if (formatter == null) {
      env.getReporter().handle(Event.error(
          String.format("Invalid output format '%s'. Valid values are: %s",
              queryOptions.outputFormat, OutputFormatter.formatterNames(formatters))));
      return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
    }

    Set<Setting> settings = queryOptions.toSettings();
    boolean streamResults = QueryOutputUtils.shouldStreamResults(queryOptions, formatter);

    try (QueryRuntimeHelper queryRuntimeHelper =
        env.getRuntime().getQueryRuntimeHelperFactory().create(env)) {
      Either<BlazeCommandResult, QueryEvalResult> result;
      try (AbstractBlazeQueryEnvironment<Target> queryEnv =
          newQueryEnvironment(
              env,
              options.getOptions(KeepGoingOption.class).keepGoing,
              !streamResults,
              queryOptions.universeScope,
              options.getOptions(LoadingPhaseThreadsOption.class).threads,
              settings)) {
        result =
            doQuery(
                query, env, queryOptions, streamResults, formatter, queryEnv, queryRuntimeHelper);
      }
      return result.map(
          Function.identity(),
          queryEvalResult -> {
            if (queryEvalResult.isEmpty()) {
              env.getReporter().handle(Event.info("Empty results"));
            }
            try {
              queryRuntimeHelper.afterQueryOutputIsWritten();
            } catch (IOException e) {
              env.getReporter().handle(Event.error("I/O error:" + e.getMessage()));
              return BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR);
            } catch (InterruptedException e) {
              env.getReporter().handle(Event.error("query interrupted"));
              return BlazeCommandResult.exitCode(ExitCode.INTERRUPTED);
            }
            ExitCode exitCode =
                queryEvalResult.getSuccess() ? ExitCode.SUCCESS : ExitCode.PARTIAL_ANALYSIS_FAILURE;
            return BlazeCommandResult.exitCode(exitCode);
          });
    } catch (IOException e) {
      env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
      return BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR);
    } catch (CommandLineException e) {
      env.getReporter().handle(Event.error("Commandline error: " + e.getMessage()));
      return BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR);
    }
  }

  protected abstract Either<BlazeCommandResult, QueryEvalResult> doQuery(
      String query,
      CommandEnvironment env,
      QueryOptions queryOptions,
      boolean streamResults,
      OutputFormatter formatter,
      AbstractBlazeQueryEnvironment<Target> queryEnv,
      QueryRuntimeHelper queryRuntimeHelper);

  public static AbstractBlazeQueryEnvironment<Target> newQueryEnvironment(CommandEnvironment env,
      boolean keepGoing, boolean orderedResults, List<String> universeScope,
      int loadingPhaseThreads, Set<Setting> settings) {

    WalkableGraph walkableGraph =
        SkyframeExecutorWrappingWalkableGraph.of(env.getSkyframeExecutor());

    TargetProviderForQueryEnvironment targetProviderForQueryEnvironment =
        new TargetProviderForQueryEnvironment(walkableGraph, env.getPackageManager());

    PackageProgressReceiver progressReceiver =
        env.getSkyframeExecutor().getPackageProgressReceiver();
    if (progressReceiver != null) {
      progressReceiver.reset();
      env.getReporter().post(new LoadingPhaseStartedEvent(progressReceiver));
    }

    return env.getRuntime()
        .getQueryEnvironmentFactory()
        .create(
            env.getPackageManager().newTransitiveLoader(),
            env.getSkyframeExecutor(),
            targetProviderForQueryEnvironment,
            env.getPackageManager(),
            env.newTargetPatternPreloader(),
            env.getRelativeWorkingDirectory(),
            keepGoing,
            /*strictScope=*/ true,
            orderedResults,
            universeScope,
            loadingPhaseThreads,
            /*labelFilter=*/ ALL_LABELS,
            env.getReporter(),
            settings,
            env.getRuntime().getQueryFunctions(),
            env.getPackageManager().getPackagePath(),
            /*blockUniverseEvaluationErrors=*/ false);
  }
}