/*
 * Copyright (C) 2020 The Dagger Authors.
 *
 * 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 dagger.hilt.processor.internal.uninstallmodules;

import static dagger.internal.codegen.extension.DaggerStreams.toImmutableList;
import static net.ltgt.gradle.incap.IncrementalAnnotationProcessorType.ISOLATING;

import com.google.auto.common.MoreElements;
import com.google.auto.service.AutoService;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.squareup.javapoet.ClassName;
import dagger.hilt.processor.internal.BaseProcessor;
import dagger.hilt.processor.internal.ClassNames;
import dagger.hilt.processor.internal.ProcessorErrors;
import dagger.hilt.processor.internal.Processors;
import java.util.Set;
import javax.annotation.processing.Processor;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import net.ltgt.gradle.incap.IncrementalAnnotationProcessor;

/** Validates {@link dagger.hilt.android.testing.UninstallModules} usages. */
@IncrementalAnnotationProcessor(ISOLATING)
@AutoService(Processor.class)
public final class UninstallModulesProcessor extends BaseProcessor {

  @Override
  public Set<String> getSupportedAnnotationTypes() {
    return ImmutableSet.of(ClassNames.UNINSTALL_MODULES.toString());
  }

  @Override
  public void processEach(TypeElement annotation, Element element) throws Exception {
    // TODO(bcorso): Consider using RootType to check this?
    // TODO(bcorso): Loosen this restriction to allow defining sets of ignored modules in libraries.
    ProcessorErrors.checkState(
        MoreElements.isType(element)
            && Processors.hasAnnotation(element, ClassNames.HILT_ANDROID_TEST),
        element,
        "@%s should only be used on test classes annotated with @%s, but found: %s",
        annotation.getSimpleName(),
        ClassNames.HILT_ANDROID_TEST.simpleName(),
        element);

    TypeElement testElement = MoreElements.asType(element);
    ImmutableList<TypeElement> uninstallModules =
        Processors.getAnnotationClassValues(
            getElementUtils(),
            Processors.getAnnotationMirror(testElement, ClassNames.UNINSTALL_MODULES),
            "value");

    checkModulesHaveInstallIn(testElement, uninstallModules);
    checkModulesDontOriginateFromTest(testElement, uninstallModules);

    new AggregatedUninstallModulesGenerator(testElement, uninstallModules, getProcessingEnv())
        .generate();
  }

  private void checkModulesHaveInstallIn(
      TypeElement testElement, ImmutableList<TypeElement> uninstallModules) {
    ImmutableList<TypeElement> invalidModules =
        uninstallModules.stream()
            .filter(
                module ->
                    !(Processors.hasAnnotation(module, ClassNames.MODULE)
                        && Processors.hasAnnotation(module, ClassNames.INSTALL_IN)))
            .collect(toImmutableList());

    ProcessorErrors.checkState(
        invalidModules.isEmpty(),
        // TODO(b/152801981): Point to the annotation value rather than the annotated element.
        testElement,
        "@UninstallModules should only include modules annotated with both @Module and @InstallIn, "
            + "but found: %s.",
        invalidModules);
  }

  private void checkModulesDontOriginateFromTest(
      TypeElement testElement, ImmutableList<TypeElement> uninstallModules) {
    ImmutableList<ClassName> invalidModules =
        uninstallModules.stream()
            .filter(
                module ->
                    Processors.getOriginatingTestElement(module, getElementUtils()).isPresent())
            .map(ClassName::get)
            .collect(toImmutableList());

    ProcessorErrors.checkState(
        invalidModules.isEmpty(),
        // TODO(b/152801981): Point to the annotation value rather than the annotated element.
        testElement,
        "@UninstallModules should not contain test modules, but found: %s",
        invalidModules);
  }
}