// Copyright 2017 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.rules.java;

import static com.google.devtools.build.lib.util.Preconditions.checkNotNull;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.ParameterFile.ParameterFileType;
import com.google.devtools.build.lib.analysis.RuleContext;
import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
import com.google.devtools.build.lib.analysis.actions.CustomCommandLine.CustomMultiArgv;
import com.google.devtools.build.lib.analysis.actions.SpawnAction;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.rules.java.JavaConfiguration.OneVersionEnforcementLevel;
import com.google.devtools.build.lib.util.Preconditions;

/** Utility for generating a call to the one-version binary. */
public final class OneVersionCheckActionBuilder {

  private OneVersionCheckActionBuilder() {}

  private OneVersionEnforcementLevel enforcementLevel;
  private Artifact outputArtifact;
  private JavaToolchainProvider javaToolchain;
  private NestedSet<Artifact> jarsToCheck;

  public static OneVersionCheckActionBuilder newBuilder() {
    return new OneVersionCheckActionBuilder();
  }

  public OneVersionCheckActionBuilder useToolchain(JavaToolchainProvider toolchain) {
    javaToolchain = toolchain;
    return this;
  }

  public OneVersionCheckActionBuilder checkJars(NestedSet<Artifact> jarsToCheck) {
    this.jarsToCheck = jarsToCheck;
    return this;
  }

  public OneVersionCheckActionBuilder outputArtifact(Artifact outputArtifact) {
    this.outputArtifact = outputArtifact;
    return this;
  }

  public OneVersionCheckActionBuilder withEnforcementLevel(
      OneVersionEnforcementLevel enforcementLevel) {
    Preconditions.checkArgument(
        enforcementLevel != OneVersionEnforcementLevel.OFF,
        "one version enforcement actions shouldn't be built if the enforcement "
            + "level is set to off");
    this.enforcementLevel = enforcementLevel;
    return this;
  }

  public Artifact build(RuleContext ruleContext) {
    Preconditions.checkNotNull(enforcementLevel);
    Preconditions.checkNotNull(outputArtifact);
    Preconditions.checkNotNull(javaToolchain);
    Preconditions.checkNotNull(jarsToCheck);

    Artifact oneVersionTool = javaToolchain.getOneVersionBinary();
    Artifact oneVersionWhitelist = javaToolchain.getOneVersionWhitelist();
    if (oneVersionTool == null || oneVersionWhitelist == null) {
      ruleContext.ruleError(
          String.format(
              "one version enforcement was requested but it is not supported by the current "
                  + "Java toolchain '%s'; see the "
                  + "java_toolchain.oneversion and java_toolchain.oneversion_whitelist "
                  + "attributes",
              javaToolchain.getToolchainLabel()));
      return outputArtifact;
    }

    CustomCommandLine.Builder oneVersionArgsBuilder =
        CustomCommandLine.builder()
            .addExecPath("--output", outputArtifact)
            .addExecPath("--whitelist", oneVersionWhitelist);
    if (enforcementLevel == OneVersionEnforcementLevel.WARNING) {
      oneVersionArgsBuilder.add("--succeed_on_found_violations");
    }
    oneVersionArgsBuilder.add(new OneVersionJarMapArgv(jarsToCheck));
    CustomCommandLine oneVersionArgs = oneVersionArgsBuilder.build();
    ruleContext.registerAction(
        new SpawnAction.Builder()
            .addOutput(outputArtifact)
            .addInput(oneVersionWhitelist)
            .addTransitiveInputs(jarsToCheck)
            .setExecutable(oneVersionTool)
            .setCommandLine(oneVersionArgs)
            .alwaysUseParameterFile(ParameterFileType.SHELL_QUOTED)
            .setMnemonic("JavaOneVersion")
            .setProgressMessage("Checking for one-version violations in " + ruleContext.getLabel())
            .build(ruleContext));
    return outputArtifact;
  }

  private static class OneVersionJarMapArgv extends CustomMultiArgv {

    private static final Joiner COMMA_JOINER = Joiner.on(',');
    private final Iterable<Artifact> classPathJars;

    private OneVersionJarMapArgv(Iterable<Artifact> classPathJars) {
      this.classPathJars = classPathJars;
    }

    @Override
    public Iterable<String> argv() {
      ImmutableList.Builder<String> args = ImmutableList.builder();
      args.add("--inputs");
      for (Artifact classPathJar : classPathJars) {
        args.add(
            COMMA_JOINER.join(
                classPathJar.getExecPathString(), getArtifactOwnerGeneralizedLabel(classPathJar)));
      }
      return args.build();
    }

    private static String getArtifactOwnerGeneralizedLabel(Artifact artifact) {
      Label label = checkNotNull(artifact.getArtifactOwner(), artifact).getLabel();
      return
          label.getPackageIdentifier().getRepository().isDefault()
                  || label.getPackageIdentifier().getRepository().isMain()
              ? label.toString()
              // Escape '@' prefix for .params file.
              : "@" + label;
    }
  }
}
