// Copyright 2016 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.android;

import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.analysis.skylark.SkylarkApiProvider;
import com.google.devtools.build.lib.collect.nestedset.NestedSet;
import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
import com.google.devtools.build.lib.collect.nestedset.Order;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import com.google.devtools.build.lib.rules.java.JavaRuleOutputJarsProvider;
import com.google.devtools.build.lib.rules.java.JavaRuleOutputJarsProvider.OutputJar;
import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
import com.google.devtools.build.lib.skylarkinterface.SkylarkModuleCategory;
import java.util.function.Function;
import javax.annotation.Nullable;

/**
 * A class that exposes the Android providers to Skylark. It is intended to provide a simple and
 * stable interface for Skylark users.
 */
@SkylarkModule(
  name = "AndroidSkylarkApiProvider",
  title = "android",
  category = SkylarkModuleCategory.PROVIDER,
  doc =
      "Provides access to information about Android rules. Every Android-related target provides "
          + "this struct, accessible as a <code>android</code> field on a "
          + "<a href=\"Target.html\">target</a>."
)
@Immutable
public class AndroidSkylarkApiProvider extends SkylarkApiProvider {
  /** The name of the field in Skylark used to access this class. */
  public static final String NAME = "android";

  private final IdlInfo idlInfo = new IdlInfo();
  private final AndroidResourcesInfo resourceInfo;

  public AndroidSkylarkApiProvider(AndroidResourcesInfo resourceInfo) {
    this.resourceInfo = resourceInfo;
  }

  @SkylarkCallable(
    name = "apk",
    structField = true,
    allowReturnNones = true,
    doc = "Returns an APK produced by this target."
  )
  public Artifact getApk() {
    return getIdeInfoProvider().getSignedApk();
  }

  private AndroidIdeInfoProvider getIdeInfoProvider() {
    return getInfo().getProvider(AndroidIdeInfoProvider.class);
  }

  @SkylarkCallable(
    name = "java_package",
    structField = true,
    allowReturnNones = true,
    doc = "Returns a java package for this target."
  )
  public String getJavaPackage() {
    return getIdeInfoProvider().getJavaPackage();
  }

  @SkylarkCallable(
    name = "manifest",
    structField = true,
    allowReturnNones = true,
    doc = "Returns a manifest file for this target."
  )
  public Artifact getManifest() {
    return getIdeInfoProvider().getManifest();
  }

  @SkylarkCallable(
    name = "merged_manifest",
    structField = true,
    allowReturnNones = true,
    doc = "Returns a manifest file for this target after all processing, e.g.: merging, etc."
  )
  public Artifact getMergedManifest() {
    return getIdeInfoProvider().getGeneratedManifest();
  }

  @SkylarkCallable(
    name = "native_libs",
    structField = true,
    doc =
        "Returns the native libraries as a dictionary of the libraries' architecture as a string "
            + "to a set of the native library files, or the empty dictionary if there are no "
            + "native libraries."
  )
  public ImmutableMap<String, NestedSet<Artifact>> getNativeLibs() {
    return getIdeInfoProvider().getNativeLibs();
  }

  @SkylarkCallable(
    name = "resource_apk",
    structField = true,
    doc = "Returns the resources container for the target."
  )
  public Artifact getResourceApk() {
    return getIdeInfoProvider().getResourceApk();
  }

  @SkylarkCallable(
    name = "apks_under_test",
    structField = true,
    allowReturnNones = true,
    doc = "Returns a collection of APKs that this target tests."
  )
  public ImmutableCollection<Artifact> getApksUnderTest() {
    return getIdeInfoProvider().getApksUnderTest();
  }

  @SkylarkCallable(
    name = "defines_resources",
    structField = true,
    doc = "Returns <code>True</code> if the target defines any Android resources directly."
  )
  public boolean definesAndroidResources() {
    return getIdeInfoProvider().definesAndroidResources();
  }

  @SkylarkCallable(
    name = "idl",
    structField = true,
    doc = "Returns information about IDL files associated with this target."
  )
  public IdlInfo getIdlInfo() {
    return idlInfo;
  }

  @SkylarkCallable(
    name = "resources",
    structField = true,
    doc = "Returns resources defined by this target."
  )
  public NestedSet<Artifact> getResources() {
    return collectDirectArtifacts(ValidatedAndroidData::getResources);
  }

  @SkylarkCallable(
    name = "resource_jar",
    structField = true,
    allowReturnNones = true,
    doc = "Returns a jar file for classes generated from resources."
  )
  @Nullable
  public JavaRuleOutputJarsProvider.OutputJar getResourceJar() {
    return getIdeInfoProvider().getResourceJar();
  }

  @SkylarkCallable(
    name = "aar",
    structField = true,
    allowReturnNones = true,
    doc = "Returns the aar output of this target."
  )
  public Artifact getAar() {
    return getIdeInfoProvider().getAar();
  }

  private NestedSet<Artifact> collectDirectArtifacts(
      final Function<ValidatedAndroidData, Iterable<Artifact>> artifactFunction) {
    if (resourceInfo == null) {
      return NestedSetBuilder.emptySet(Order.STABLE_ORDER);
    }
    // This will iterate over all (direct) resources. If this turns out to be a performance
    // problem, {@link ResourceContainer#getArtifacts} can be changed to return NestedSets.
    return NestedSetBuilder.wrap(
        Order.STABLE_ORDER,
        Iterables.concat(
            Iterables.transform(
                resourceInfo.getDirectAndroidResources(), data -> artifactFunction.apply(data))));
  }

  /** Helper class to provide information about IDLs related to this rule. */
  @SkylarkModule(
    name = "AndroidSkylarkIdlInfo",
    category = SkylarkModuleCategory.NONE,
    doc = "Provides access to information about Android rules."
  )
  @Immutable
  public class IdlInfo {
    @SkylarkCallable(
      name = "import_root",
      structField = true,
      allowReturnNones = true,
      doc = "Returns the root of IDL packages if not the java root."
    )
    public String getImportRoot() {
      return getIdeInfoProvider().getIdlImportRoot();
    }

    @SkylarkCallable(name = "sources", structField = true, doc = "Returns a list of IDL files.")
    public ImmutableCollection<Artifact> getSources() {
      return getIdeInfoProvider().getIdlSrcs();
    }

    @SkylarkCallable(
      name = "generated_java_files",
      structField = true,
      doc = "Returns a list Java files generated from IDL sources."
    )
    public ImmutableCollection<Artifact> getIdlGeneratedJavaFiles() {
      return getIdeInfoProvider().getIdlGeneratedJavaFiles();
    }

    @SkylarkCallable(
      name = "output",
      structField = true,
      allowReturnNones = true,
      doc = "Returns a jar file for classes generated from IDL sources."
    )
    @Nullable
    public JavaRuleOutputJarsProvider.OutputJar getIdlOutput() {
      if (getIdeInfoProvider().getIdlClassJar() == null) {
        return null;
      }

      Artifact idlSourceJar = getIdeInfoProvider().getIdlSourceJar();
      return new OutputJar(
          getIdeInfoProvider().getIdlClassJar(),
          null,
          idlSourceJar == null ? ImmutableList.<Artifact>of() : ImmutableList.of(idlSourceJar));
    }
  }
}