// Copyright 2014 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 com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.events.Event;
import com.google.devtools.build.lib.packages.Target;
import com.google.devtools.build.lib.pkgcache.PackageCacheOptions;
import com.google.devtools.build.lib.query2.AbstractBlazeQueryEnvironment;
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.engine.QueryException;
import com.google.devtools.build.lib.query2.engine.QueryExpression;
import com.google.devtools.build.lib.query2.engine.QueryUtil;
import com.google.devtools.build.lib.query2.engine.QueryUtil.AggregateAllOutputFormatterCallback;
import com.google.devtools.build.lib.query2.engine.ThreadSafeOutputFormatterCallback;
import com.google.devtools.build.lib.query2.output.OutputFormatter;
import com.google.devtools.build.lib.query2.output.OutputFormatter.StreamedFormatter;
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.BlazeCommandResult;
import com.google.devtools.build.lib.runtime.Command;
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.util.Either;
import com.google.devtools.build.lib.util.ExitCode;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.channels.ClosedByInterruptException;
import java.util.Set;

/** Command line wrapper for executing a query with blaze. */
@Command(
    name = "query",
    options = {
      PackageCacheOptions.class,
      QueryOptions.class,
      KeepGoingOption.class,
      LoadingPhaseThreadsOption.class
    },
    help = "resource:query.txt",
    shortDescription = "Executes a dependency graph query.",
    allowResidue = true,
    binaryStdOut = true,
    completion = "label",
    canRunInOutputDirectory = true)
public final class QueryCommand extends QueryEnvironmentBasedCommand {

  @Override
  protected Either<BlazeCommandResult, QueryEvalResult> doQuery(
      String query,
      CommandEnvironment env,
      QueryOptions queryOptions,
      boolean streamResults,
      OutputFormatter formatter,
      AbstractBlazeQueryEnvironment<Target> queryEnv,
      QueryRuntimeHelper queryRuntimeHelper) {
    QueryExpression expr;
    try {
      expr = QueryExpression.parse(query, queryEnv);
    } catch (QueryException e) {
      env.getReporter()
          .handle(Event.error(null, "Error while parsing '" + query + "': " + e.getMessage()));
      return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR));
    }

    try {
      formatter.verifyCompatible(queryEnv, expr);
    } catch (QueryException e) {
      env.getReporter().handle(Event.error(e.getMessage()));
      return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.COMMAND_LINE_ERROR));
    }

    expr = queryEnv.transformParsedQuery(expr);

    OutputStream out;
    if (formatter.canBeBuffered()) {
      // There is no particular reason for the 16384 constant here, except its a multiple of the
      // gRPC buffer size. We mainly don't want to send each label individually because the output
      // stream is connected to gRPC, and every write gets converted to one gRPC call.
      out = new BufferedOutputStream(queryRuntimeHelper.getOutputStreamForQueryOutput(), 16384);
    } else {
      out = queryRuntimeHelper.getOutputStreamForQueryOutput();
    }

    ThreadSafeOutputFormatterCallback<Target> callback;
    if (streamResults) {
      disableAnsiCharactersFiltering(env);
      StreamedFormatter streamedFormatter = ((StreamedFormatter) formatter);
      streamedFormatter.setOptions(
          queryOptions,
          queryOptions.aspectDeps.createResolver(env.getPackageManager(), env.getReporter()));
      callback = streamedFormatter.createStreamCallback(out, queryOptions, queryEnv);
    } else {
      callback = QueryUtil.newOrderedAggregateAllOutputFormatterCallback(queryEnv);
    }

    QueryEvalResult result;
    boolean catastrophe = true;
    try {
      result = queryEnv.evaluateQuery(expr, callback);
      catastrophe = false;
    } catch (QueryException e) {
      catastrophe = false;
      // Keep consistent with reportBuildFileError()
      env.getReporter()
          // TODO(bazel-team): this is a kludge to fix a bug observed in the wild. We should make
          // sure no null error messages ever get in.
          .handle(Event.error(e.getMessage() == null ? e.toString() : e.getMessage()));
      return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.ANALYSIS_FAILURE));
    } catch (InterruptedException e) {
      catastrophe = false;
      IOException ioException = callback.getIoException();
      if (ioException == null || ioException instanceof ClosedByInterruptException) {
        env.getReporter().handle(Event.error("query interrupted"));
        return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.INTERRUPTED));
      } else {
        env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
        return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR));
      }
    } catch (IOException e) {
      catastrophe = false;
      env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
      return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR));
    } finally {
      if (!catastrophe) {
        try {
          out.flush();
        } catch (IOException e) {
          env.getReporter()
              .handle(Event.error("Failed to flush query results: " + e.getMessage()));
          return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR));
        }
      }
    }
    if (!streamResults) {
      disableAnsiCharactersFiltering(env);
      try {
        Set<Target> targets =
            ((AggregateAllOutputFormatterCallback<Target, ?>) callback).getResult();
        QueryOutputUtils.output(
            queryOptions,
            result,
            targets,
            formatter,
            out,
            queryOptions.aspectDeps.createResolver(env.getPackageManager(), env.getReporter()));
      } catch (ClosedByInterruptException | InterruptedException e) {
        env.getReporter().handle(Event.error("query interrupted"));
        return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.INTERRUPTED));
      } catch (IOException e) {
        env.getReporter().handle(Event.error("I/O error: " + e.getMessage()));
        return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR));
      } finally {
        try {
          out.flush();
        } catch (IOException e) {
          env.getReporter()
              .handle(Event.error("Failed to flush query results: " + e.getMessage()));
          return Either.ofLeft(BlazeCommandResult.exitCode(ExitCode.LOCAL_ENVIRONMENTAL_ERROR));
        }
      }
    }

    return Either.ofRight(result);
  }

  /**
   * When Blaze is used with --color=no or not in a tty a ansi characters filter is set so that
   * we don't print fancy colors in non-supporting terminal outputs. But query output, specifically
   * the binary formatters, can print actual data that contain ansi bytes/chars. Because of that
   * we need to remove the filtering before printing any query result.
   */
  private static void disableAnsiCharactersFiltering(CommandEnvironment env) {
    env.getReporter().switchToAnsiAllowingHandler();
  }

  @VisibleForTesting // for com.google.devtools.deps.gquery.test.QueryResultTestUtil
  public static AbstractBlazeQueryEnvironment<Target> newQueryEnvironment(CommandEnvironment env,
      boolean keepGoing, boolean orderedResults, int loadingPhaseThreads,
      Set<Setting> settings) {
    return newQueryEnvironment(env, keepGoing, orderedResults, ImmutableList.<String>of(),
        loadingPhaseThreads, settings);
  }
}