/*
 * Copyright 2009 the original author or 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 org.gradle.api.tasks.compile;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import org.gradle.api.Incubating;
import org.gradle.api.InvalidUserDataException;
import org.gradle.api.JavaVersion;
import org.gradle.api.file.FileCollection;
import org.gradle.api.file.FileTree;
import org.gradle.api.internal.file.FileResolver;
import org.gradle.api.internal.project.ProjectInternal;
import org.gradle.api.internal.tasks.JavaToolChainFactory;
import org.gradle.api.internal.tasks.compile.processing.AnnotationProcessorPathFactory;
import org.gradle.api.internal.tasks.compile.CleaningGroovyCompiler;
import org.gradle.api.internal.tasks.compile.CompilerForkUtils;
import org.gradle.api.internal.tasks.compile.DefaultGroovyJavaJointCompileSpec;
import org.gradle.api.internal.tasks.compile.DefaultGroovyJavaJointCompileSpecFactory;
import org.gradle.api.internal.tasks.compile.GroovyCompilerFactory;
import org.gradle.api.internal.tasks.compile.GroovyJavaJointCompileSpec;
import org.gradle.api.model.ObjectFactory;
import org.gradle.api.tasks.CacheableTask;
import org.gradle.api.tasks.Classpath;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.Nested;
import org.gradle.api.tasks.PathSensitive;
import org.gradle.api.tasks.PathSensitivity;
import org.gradle.api.tasks.TaskAction;
import org.gradle.api.tasks.WorkResult;
import org.gradle.jvm.toolchain.JavaToolChain;
import org.gradle.language.base.internal.compile.Compiler;
import org.gradle.util.GFileUtils;
import org.gradle.workers.internal.IsolatedClassloaderWorkerFactory;
import org.gradle.workers.internal.WorkerDaemonFactory;

import javax.inject.Inject;
import java.io.File;
import java.util.List;

/**
 * Compiles Groovy source files, and optionally, Java source files.
 */
@CacheableTask
public class GroovyCompile extends AbstractCompile {
    private Compiler<GroovyJavaJointCompileSpec> compiler;
    private FileCollection groovyClasspath;
    private final CompileOptions compileOptions;
    private final GroovyCompileOptions groovyCompileOptions = new GroovyCompileOptions();

    public GroovyCompile() {
        CompileOptions compileOptions = getServices().get(ObjectFactory.class).newInstance(CompileOptions.class);
        this.compileOptions = compileOptions;
        CompilerForkUtils.doNotCacheIfForkingViaExecutable(compileOptions, getOutputs());
    }

    @Override
    @TaskAction
    protected void compile() {
        checkGroovyClasspathIsNonEmpty();
        DefaultGroovyJavaJointCompileSpec spec = createSpec();
        WorkResult result = getCompiler(spec).execute(spec);
        setDidWork(result.getDidWork());
    }

    private Compiler<GroovyJavaJointCompileSpec> getCompiler(GroovyJavaJointCompileSpec spec) {
        if (compiler == null) {
            ProjectInternal projectInternal = (ProjectInternal) getProject();
            WorkerDaemonFactory workerDaemonFactory = getServices().get(WorkerDaemonFactory.class);
            IsolatedClassloaderWorkerFactory inProcessWorkerFactory = getServices().get(IsolatedClassloaderWorkerFactory.class);
            FileResolver fileResolver = getServices().get(FileResolver.class);
            GroovyCompilerFactory groovyCompilerFactory = new GroovyCompilerFactory(projectInternal, workerDaemonFactory, inProcessWorkerFactory, fileResolver);
            Compiler<GroovyJavaJointCompileSpec> delegatingCompiler = groovyCompilerFactory.newCompiler(spec);
            compiler = new CleaningGroovyCompiler(delegatingCompiler, getOutputs());
        }
        return compiler;
    }

    private DefaultGroovyJavaJointCompileSpec createSpec() {
        DefaultGroovyJavaJointCompileSpec spec = new DefaultGroovyJavaJointCompileSpecFactory(compileOptions).create();
        spec.setSource(getSource());
        spec.setDestinationDir(getDestinationDir());
        spec.setWorkingDir(getProject().getProjectDir());
        spec.setTempDir(getTemporaryDir());
        spec.setCompileClasspath(ImmutableList.copyOf(getClasspath()));
        spec.setSourceCompatibility(getSourceCompatibility());
        spec.setTargetCompatibility(getTargetCompatibility());
        spec.setAnnotationProcessorPath(calculateAnnotationProcessorClasspath());
        spec.setGroovyClasspath(Lists.newArrayList(getGroovyClasspath()));
        spec.setCompileOptions(compileOptions);
        spec.setGroovyCompileOptions(groovyCompileOptions);
        if (spec.getGroovyCompileOptions().getStubDir() == null) {
            File dir = new File(getTemporaryDir(), "groovy-java-stubs");
            GFileUtils.mkdirs(dir);
            spec.getGroovyCompileOptions().setStubDir(dir);
        }
        return spec;
    }

    private List<File> calculateAnnotationProcessorClasspath() {
        AnnotationProcessorPathFactory annotationProcessorPathFactory = getServices().get(AnnotationProcessorPathFactory.class);
        FileCollection processorClasspath = annotationProcessorPathFactory.getEffectiveAnnotationProcessorClasspath(compileOptions, getClasspath());
        return Lists.newArrayList(processorClasspath);
    }

    private void checkGroovyClasspathIsNonEmpty() {
        if (getGroovyClasspath().isEmpty()) {
            throw new InvalidUserDataException("'" + getName() + ".groovyClasspath' must not be empty. If a Groovy compile dependency is provided, "
                    + "the 'groovy-base' plugin will attempt to configure 'groovyClasspath' automatically. Alternatively, you may configure 'groovyClasspath' explicitly.");
        }
    }

    /**
     * We need to track the Java version of the JVM the Groovy compiler is running on, since the Groovy compiler produces different results depending on it.
     *
     * This should be replaced by a property on the Groovy toolchain as soon as we model these.
     *
     * @since 4.0
     */
    @Incubating
    @Input
    protected String getGroovyCompilerJvmVersion() {
        return JavaVersion.current().getMajorVersion();
    }

    /**
     * We need to track the toolchain used by the Groovy compiler to compile Java sources.
     *
     * @since 4.0
     */
    @Nested
    @Incubating
    protected JavaToolChain getJavaToolChain() {
        return getJavaToolChainFactory().forCompileOptions(getOptions());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @PathSensitive(PathSensitivity.NAME_ONLY) // Java source files are supported, too. Therefore we should care about the names.
    public FileTree getSource() {
        return super.getSource();
    }

    /**
     * Gets the options for the Groovy compilation. To set specific options for the nested Java compilation, use {@link
     * #getOptions()}.
     *
     * @return The Groovy compile options. Never returns null.
     */
    @Nested
    public GroovyCompileOptions getGroovyOptions() {
        return groovyCompileOptions;
    }

    /**
     * Returns the options for Java compilation.
     *
     * @return The Java compile options. Never returns null.
     */
    @Nested
    public CompileOptions getOptions() {
        return compileOptions;
    }

    /**
     * Returns the classpath containing the version of Groovy to use for compilation.
     *
     * @return The classpath.
     */
    @Classpath
    public FileCollection getGroovyClasspath() {
        return groovyClasspath;
    }

    /**
     * Sets the classpath containing the version of Groovy to use for compilation.
     *
     * @param groovyClasspath The classpath. Must not be null.
     */
    public void setGroovyClasspath(FileCollection groovyClasspath) {
        this.groovyClasspath = groovyClasspath;
    }

    @Internal
    public Compiler<GroovyJavaJointCompileSpec> getCompiler() {
        return getCompiler(createSpec());
    }

    public void setCompiler(Compiler<GroovyJavaJointCompileSpec> compiler) {
        this.compiler = compiler;
    }

    @Inject
    protected JavaToolChainFactory getJavaToolChainFactory() {
        throw new UnsupportedOperationException();
    }
}
