/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * 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.android.modules.targetprep;

import static android.compat.testing.Classpaths.ClasspathType.BOOTCLASSPATH;
import static android.compat.testing.Classpaths.ClasspathType.SYSTEMSERVERCLASSPATH;

import android.compat.testing.Classpaths;
import android.compat.testing.Classpaths.ClasspathType;

import com.android.modules.proto.ClasspathClasses.Classpath;
import com.android.modules.proto.ClasspathClasses.ClasspathClassesDump;
import com.android.modules.proto.ClasspathClasses.ClasspathEntry;
import com.android.modules.proto.ClasspathClasses.Jar;

import com.android.tradefed.config.Option;
import com.android.tradefed.device.DeviceNotAvailableException;
import com.android.tradefed.device.INativeDevice;
import com.android.tradefed.device.ITestDevice;
import com.android.tradefed.invoker.TestInformation;
import com.android.tradefed.log.LogUtil.CLog;
import com.android.tradefed.targetprep.BaseTargetPreparer;
import com.android.tradefed.targetprep.TargetSetupError;
import com.android.tradefed.util.RunUtil;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Objects;

import org.jf.dexlib2.iface.ClassDef;

/*
 * Target preparer that fetches classpath relevant artifacts for a test in a 'reentrant' manner.
 *
 * <p>The preparer will fetch all <b>BOOTCLASSPATH</b>, <b>SYSTEMSERVERCLASSPATH</b> and shared
 * libraries from the device, parse their contents and dump the classnames into a temporary
 * directory.</p>
 *
 * <p>Additionally, the preparer <i>can</i> fetch, parse and dump data for module specific artifacts
 * (i.e. apk-in-apex) if specified.</p>
 *
 * <p>Nested runs of the artifact fetcher (i.e. in the case of a top-level test config xml and a
 * child test xml) will only fetch non-common elements, and remove temporary class dumps fetched
 * during that particular preparer run.</p>
 *
 * <p>Each module's conformance framework test config xml must run the preparer (with module
 * specific parameters) before the entrypoint test jar, and the top-level conformance framework
 * config xml must also run it before any other module xml.</p>
 *
 * <p>The upshot is that when running all conformance framework tests for all modules, the shared
 * artifacts are fetched and processed only once.</p>
 */
public class ClasspathFetcher extends BaseTargetPreparer {

    public static final String DEVICE_JAR_ARTIFACTS_TAG = "device-jar-artifacts";
    public static final String BCP_CLASSES_FILE = "bcp.pb";
    public static final String SSCP_CLASSES_FILE = "sscp.pb";

    // TODO(andreionea): also fetch classes for standalone system server jars, apk-in-apex and
    // shared libraries. They require more mocking on the test side.

    public static final String APEX_PKG_TAG = "apex-package";
    // Special case for fetching only non-updatable platform.
    public static final String PLATFORM_PACKAGE = "platform";

    @Option(name = "apex-package",
            description = "The package name of the apex under test.")
    private String mApexPackage;

    private boolean mFetchedArtifacts = false;

    @Override
    public void setUp(TestInformation testInfo)
            throws TargetSetupError, DeviceNotAvailableException {
        Objects.requireNonNull(testInfo.getDevice());
        if (mApexPackage != null) {
            testInfo.properties().put(APEX_PKG_TAG, mApexPackage);
        }
        // The artifacts have been fetched already, no need to do anything else.
        if (testInfo.properties().containsKey(DEVICE_JAR_ARTIFACTS_TAG)) {
            return;
        }
        try {
            final Path tmpDir = Files.createTempDirectory("device_artifacts");
            testInfo.properties().put(DEVICE_JAR_ARTIFACTS_TAG,
                tmpDir.toAbsolutePath().toString());

            getClassesInClasspath(testInfo.getDevice(), BOOTCLASSPATH)
                .writeTo(new FileOutputStream(new File(tmpDir.toFile(), BCP_CLASSES_FILE)));
            getClassesInClasspath(testInfo.getDevice(), SYSTEMSERVERCLASSPATH)
                .writeTo(new FileOutputStream(new File(tmpDir.toFile(), SSCP_CLASSES_FILE)));

            mFetchedArtifacts = true;
        } catch(IOException e) {
            throw new RuntimeException("Could not create temp artifacts dir!", e);
        }
    }

    @Override
    public void tearDown(TestInformation testInfo, Throwable e) {
        if (mFetchedArtifacts) {
            try {
                final String path = testInfo.properties().get(DEVICE_JAR_ARTIFACTS_TAG);
                if (path == null) {
                    throw new IllegalStateException("Target preparer has previously fetched"
                            + " artifacts, but the DEVICE_JAR_ARTIFACTS_TAG property was removed");
                }
                final File jarArtifactsDir = new File(path);
                deleteDirectory(jarArtifactsDir);
            } finally {
                testInfo.properties().remove(DEVICE_JAR_ARTIFACTS_TAG);
            }
        }
    }

    private Classpath classpathTypeToClasspathEnum(ClasspathType t) {
        switch(t) {
            case BOOTCLASSPATH:
                return Classpath.valueOf(Classpath.BOOTCLASSPATH_VALUE);
            case SYSTEMSERVERCLASSPATH:
                return Classpath.valueOf(Classpath.SYSTEMSERVERCLASSPATH_VALUE);
            default:
                throw new RuntimeException("Unknown classpath type " + t);
        }
    }

    private ImmutableSet<String> getClassesInFile(INativeDevice device, String file)
            throws DeviceNotAvailableException, IOException {
        final File jar = device.pullFile(file);
        if (jar == null) {
            throw new IllegalStateException("could not pull remote file " + file);
        }
        return Classpaths.getClassDefsFromJar(jar)
                .stream()
                .map(ClassDef::getType)
                .collect(ImmutableSet.toImmutableSet());
    }

    private ClasspathClassesDump getClassesInClasspath(INativeDevice device, ClasspathType type)
            throws DeviceNotAvailableException, IOException {
        ClasspathClassesDump.Builder builder = ClasspathClassesDump.newBuilder();
        final ImmutableList<String> jars = Classpaths.getJarsOnClasspath(device, type);
        for (String jar : jars) {
            ClasspathEntry.Builder entryBuilder = ClasspathEntry.newBuilder();
            Jar.Builder jarBuilder = Jar.newBuilder();
            jarBuilder.setClasspath(classpathTypeToClasspathEnum(type));
            jarBuilder.setPath(jar);
            entryBuilder.setJar(jarBuilder.build());
            entryBuilder.addAllClasses(getClassesInFile(device, jar));
            builder.addEntries(entryBuilder.build());
        }
        return builder.build();
    }


    /**
     * Deletes a directory and its contents recursively
     *
     * @param directory to delete
     */
    private static void deleteDirectory(File directory) {
        File[] files = directory.listFiles();
        if (files != null) {
            for (File file : files) {
                if (!file.isDirectory()) {
                    file.delete();
                } else {
                    deleteDirectory(file);
                }
            }
        }
        directory.delete();
    }

}