/*
 * Copyright 2016 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.buildinit.tasks;

import org.gradle.api.DefaultTask;
import org.gradle.api.GradleException;
import org.gradle.api.file.Directory;
import org.gradle.api.internal.tasks.userinput.UserInputHandler;
import org.gradle.api.provider.Property;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.Optional;
import org.gradle.api.tasks.TaskAction;
import org.gradle.api.tasks.options.Option;
import org.gradle.api.tasks.options.OptionValues;
import org.gradle.buildinit.InsecureProtocolOption;
import org.gradle.buildinit.plugins.internal.BuildConverter;
import org.gradle.buildinit.plugins.internal.BuildInitializer;
import org.gradle.buildinit.plugins.internal.InitSettings;
import org.gradle.buildinit.plugins.internal.ProjectLayoutSetupRegistry;
import org.gradle.buildinit.plugins.internal.modifiers.BuildInitDsl;
import org.gradle.buildinit.plugins.internal.modifiers.BuildInitTestFramework;
import org.gradle.buildinit.plugins.internal.modifiers.ComponentType;
import org.gradle.buildinit.plugins.internal.modifiers.Language;
import org.gradle.buildinit.plugins.internal.modifiers.ModularizationOption;
import org.gradle.internal.jvm.Jvm;
import org.gradle.internal.logging.text.TreeFormatter;
import org.gradle.jvm.toolchain.JavaLanguageVersion;
import org.gradle.work.DisableCachingByDefault;

import javax.annotation.Nullable;
import javax.lang.model.SourceVersion;
import java.util.List;
import java.util.Locale;

import static com.google.common.base.Strings.isNullOrEmpty;
import static java.util.Optional.empty;
import static java.util.Optional.of;
import static org.gradle.buildinit.plugins.internal.PackageNameBuilder.toPackageName;

/**
 * Generates a Gradle project structure.
 */
@DisableCachingByDefault(because = "Not worth caching")
public abstract class InitBuild extends DefaultTask {
    private static final int MINIMUM_VERSION_SUPPORTED_BY_FOOJAY_API = 7;
    private final Directory projectDir = getProject().getLayout().getProjectDirectory();
    private String type;
    private final Property<Boolean> splitProject = getProject().getObjects().property(Boolean.class);
    private String dsl;
    private final Property<Boolean> useIncubatingAPIs = getProject().getObjects().property(Boolean.class);
    private String testFramework;
    private String projectName;
    private String packageName;
    private final Property<InsecureProtocolOption> insecureProtocol = getProject().getObjects().property(InsecureProtocolOption.class);

    @Internal
    private ProjectLayoutSetupRegistry projectLayoutRegistry;

    /**
     * The desired type of project to generate, defaults to 'pom' if a 'pom.xml' is found in the project root and if no 'pom.xml' is found, it defaults to 'basic'.
     *
     * This property can be set via command-line option '--type'.
     */
    @Input
    public String getType() {
        return isNullOrEmpty(type) ? detectType() : type;
    }

    /**
     * Should the build be split into multiple subprojects?
     *
     * This property can be set via the command-line options '--split-project'
     * and '--no-split-project'.
     *
     * @since 6.7
     */
    @Input
    @Optional
    @Option(option = "split-project", description = "Split functionality across multiple subprojects?")
    public Property<Boolean> getSplitProject() {
        return splitProject;
    }

    /**
     * The desired DSL of build scripts to create, defaults to 'kotlin'.
     *
     * This property can be set via command-line option '--dsl'.
     *
     * @since 4.5
     */
    @Optional
    @Input
    public String getDsl() {
        return isNullOrEmpty(dsl) ? BuildInitDsl.KOTLIN.getId() : dsl;
    }

    /**
     * Can the generated build use new and unstable features?
     *
     * When enabled, the generated build will use new patterns, APIs or features that
     * may be unstable between minor releases. Use this if you'd like to try out the
     * latest features of Gradle.
     *
     * By default, init will generate a build that uses stable features and behavior.
     *
     * @since 7.3
     */
    @Input
    @Optional
    @Option(option = "incubating", description = "Allow the generated build to use new features and APIs")
    public Property<Boolean> getUseIncubating() {
        return useIncubatingAPIs;
    }

    /**
     * The name of the generated project, defaults to the name of the directory the project is generated in.
     *
     * This property can be set via command-line option '--project-name'.
     *
     * @since 5.0
     */
    @Input
    public String getProjectName() {
        return projectName == null ? projectDir.getAsFile().getName() : projectName;
    }

    /**
     * The name of the package to use for generated source.
     *
     * This property can be set via command-line option '--package'.
     *
     * @since 5.0
     */
    @Input
    public String getPackageName() {
        return packageName == null ? "" : packageName;
    }

    /**
     * The test framework to be used in the generated project.
     *
     * This property can be set via command-line option '--test-framework'
     */
    @Nullable
    @Optional
    @Input
    public String getTestFramework() {
        return testFramework;
    }

    /**
     * How to handle insecure (http) URLs used for Maven Repositories.
     *
     * This property can be set via command-line option '--insecure-protocol'.  The default value is 'warn'.
     *
     * @since 7.3
     */
    @Input
    @Option(option = "insecure-protocol", description = "How to handle insecure URLs used for Maven Repositories.")
    public Property<InsecureProtocolOption> getInsecureProtocol() {
        return insecureProtocol;
    }

    public ProjectLayoutSetupRegistry getProjectLayoutRegistry() {
        if (projectLayoutRegistry == null) {
            projectLayoutRegistry = getServices().get(ProjectLayoutSetupRegistry.class);
        }

        return projectLayoutRegistry;
    }

    @TaskAction
    public void setupProjectLayout() {
        UserInputHandler inputHandler = getServices().get(UserInputHandler.class);
        ProjectLayoutSetupRegistry projectLayoutRegistry = getProjectLayoutRegistry();

        BuildInitializer initDescriptor = getBuildInitializer(inputHandler, projectLayoutRegistry);

        ModularizationOption modularizationOption = getModularizationOption(inputHandler, initDescriptor);

        BuildInitDsl dsl = getBuildInitDsl(inputHandler, initDescriptor);

        BuildInitTestFramework testFramework = getBuildInitTestFramework(inputHandler, initDescriptor, modularizationOption);

        String projectName = getProjectName(inputHandler, initDescriptor);

        String packageName = getPackageName(inputHandler, initDescriptor, projectName);

        validatePackageName(packageName);

        java.util.Optional<JavaLanguageVersion> toolChainVersion = getJavaLanguageVersion(inputHandler, initDescriptor);

        boolean useIncubatingAPIs = shouldUseIncubatingAPIs(inputHandler);

        List<String> subprojectNames = initDescriptor.getComponentType().getDefaultProjectNames();
        InitSettings settings = new InitSettings(
            projectName,
            useIncubatingAPIs,
            subprojectNames,
            modularizationOption,
            dsl,
            packageName,
            testFramework,
            insecureProtocol.get(),
            projectDir,
            toolChainVersion);
        initDescriptor.generate(settings);

        initDescriptor.getFurtherReading(settings)
            .ifPresent(link -> getLogger().lifecycle(link));
    }

    private static void validatePackageName(String packageName) {
        if (!isNullOrEmpty(packageName) && !SourceVersion.isName(packageName)) {
            throw new GradleException("Package name: '" + packageName + "' is not valid - it may contain invalid characters or reserved words.");
        }
    }

    java.util.Optional<JavaLanguageVersion> getJavaLanguageVersion(UserInputHandler inputHandler, BuildInitializer initDescriptor) {
        if (!initDescriptor.supportsJavaTargets()) {
            return empty();
        }

        JavaLanguageVersion current = JavaLanguageVersion.of(Jvm.current().getJavaVersion().getMajorVersion());
        String version = inputHandler.askQuestion("Enter target version of Java (min. " + MINIMUM_VERSION_SUPPORTED_BY_FOOJAY_API + ")", current.toString());
        try {
            int parsedVersion = Integer.parseInt(version);
            if (parsedVersion < MINIMUM_VERSION_SUPPORTED_BY_FOOJAY_API) {
                throw new GradleException("Java target version: '" + version + "' is not a supported target version. It must be equal to or greater than " + MINIMUM_VERSION_SUPPORTED_BY_FOOJAY_API);
            }
            return of(JavaLanguageVersion.of(parsedVersion));
        } catch (NumberFormatException e) {
            throw new GradleException("Invalid Java target version '" + version + "'. The version must be an integer.", e);
        }
    }

    private BuildInitDsl getBuildInitDsl(UserInputHandler inputHandler, BuildInitializer initDescriptor) {
        BuildInitDsl dsl;
        if (isNullOrEmpty(this.dsl)) {
            dsl = initDescriptor.getDefaultDsl();
            if (initDescriptor.getDsls().size() > 1) {
                dsl = inputHandler.selectOption("Select build script DSL", initDescriptor.getDsls(), dsl);
            }
        } else {
            dsl = BuildInitDsl.fromName(getDsl());
            if (!initDescriptor.getDsls().contains(dsl)) {
                throw new GradleException("The requested DSL '" + getDsl() + "' is not supported for '" + initDescriptor.getId() + "' build type");
            }
        }
        return dsl;
    }

    private ModularizationOption getModularizationOption(UserInputHandler inputHandler, BuildInitializer initDescriptor) {
        if (splitProject.isPresent()) {
            return splitProject.get() ? ModularizationOption.WITH_LIBRARY_PROJECTS : ModularizationOption.SINGLE_PROJECT;
        }
        if (initDescriptor.getModularizationOptions().size() == 1) {
            return initDescriptor.getModularizationOptions().iterator().next();
        }
        if (!isNullOrEmpty(type)) {
            return ModularizationOption.SINGLE_PROJECT;
        }
        boolean multipleSubprojects = inputHandler.askYesNoQuestion("Generate multiple subprojects for application?", false);
        return multipleSubprojects ? ModularizationOption.WITH_LIBRARY_PROJECTS : ModularizationOption.SINGLE_PROJECT;
    }

    private boolean shouldUseIncubatingAPIs(UserInputHandler inputHandler) {
        if (this.useIncubatingAPIs.isPresent()) {
            return this.useIncubatingAPIs.get();
        }
        return inputHandler.askYesNoQuestion("Generate build using new APIs and behavior (some features may change in the next minor release)?", false);
    }

    private BuildInitTestFramework getBuildInitTestFramework(UserInputHandler inputHandler, BuildInitializer initDescriptor, ModularizationOption modularizationOption) {
        if (modularizationOption == ModularizationOption.WITH_LIBRARY_PROJECTS) {
            // currently we only support JUnit5 tests for this combination
            return BuildInitTestFramework.JUNIT_JUPITER;
        }

        if (!isNullOrEmpty(this.testFramework)) {
            return initDescriptor.getTestFrameworks().stream()
                .filter(candidate -> this.testFramework.equals(candidate.getId()))
                .findFirst()
                .orElseThrow(() -> createNotSupportedTestFrameWorkException(initDescriptor));
        }

        BuildInitTestFramework testFramework = initDescriptor.getDefaultTestFramework();
        if (initDescriptor.getTestFrameworks().size() > 1) {
            return inputHandler.selectOption("Select test framework", initDescriptor.getTestFrameworks(), testFramework);
        }
        return testFramework;
    }

    private GradleException createNotSupportedTestFrameWorkException(BuildInitializer initDescriptor) {
        TreeFormatter formatter = new TreeFormatter();
        formatter.node("The requested test framework '" + getTestFramework() + "' is not supported for '" + initDescriptor.getId() + "' build type. Supported frameworks");
        formatter.startChildren();
        for (BuildInitTestFramework framework : initDescriptor.getTestFrameworks()) {
            formatter.node("'" + framework.getId() + "'");
        }
        formatter.endChildren();
        return new GradleException(formatter.toString());
    }

    String getProjectName(UserInputHandler inputHandler, BuildInitializer initDescriptor) {
        String projectName = this.projectName;
        if (initDescriptor.supportsProjectName()) {
            if (isNullOrEmpty(projectName)) {
                return inputHandler.askQuestion("Project name", getProjectName());
            }
        } else if (!isNullOrEmpty(projectName)) {
            throw new GradleException("Project name is not supported for '" + initDescriptor.getId() + "' build type.");
        }
        return projectName;
    }

    String getPackageName(UserInputHandler inputHandler, BuildInitializer initDescriptor, String projectName) {
        String packageName = this.packageName;
        if (initDescriptor.supportsPackage()) {
            if (isNullOrEmpty(packageName)) {
                return inputHandler.askQuestion("Source package", toPackageName(projectName).toLowerCase(Locale.US));
            }
        } else if (!isNullOrEmpty(packageName)) {
            throw new GradleException("Package name is not supported for '" + initDescriptor.getId() + "' build type.");
        }
        return packageName;
    }

    private BuildInitializer getBuildInitializer(UserInputHandler inputHandler, ProjectLayoutSetupRegistry projectLayoutRegistry) {
        if (!isNullOrEmpty(type)) {
            return projectLayoutRegistry.get(type);
        }

        BuildConverter converter = projectLayoutRegistry.getBuildConverter();
        if (converter.canApplyToCurrentDirectory(projectDir)) {
            if (inputHandler.askYesNoQuestion("Found a " + converter.getSourceBuildDescription() + " build. Generate a Gradle build from this?", true)) {
                return converter;
            }
        }
        return selectTypeOfProject(inputHandler, projectLayoutRegistry);
    }

    private static BuildInitializer selectTypeOfProject(UserInputHandler inputHandler, ProjectLayoutSetupRegistry projectLayoutRegistry) {
        ComponentType componentType = inputHandler.selectOption("Select type of project to generate", projectLayoutRegistry.getComponentTypes(), projectLayoutRegistry.getDefault().getComponentType());
        List<Language> languages = projectLayoutRegistry.getLanguagesFor(componentType);
        if (languages.size() == 1) {
            return projectLayoutRegistry.get(componentType, languages.get(0));
        }
        if (!languages.contains(Language.JAVA)) {
            // Not yet implemented
            throw new UnsupportedOperationException();
        }
        Language language = inputHandler.selectOption("Select implementation language", languages, Language.JAVA);
        return projectLayoutRegistry.get(componentType, language);
    }

    @Option(option = "type", description = "Set the type of project to generate.")
    public void setType(String type) {
        this.type = type;
    }

    @OptionValues("type")
    public List<String> getAvailableBuildTypes() {
        return getProjectLayoutRegistry().getAllTypes();
    }

    /**
     * Set the build script DSL to be used.
     *
     * @since 4.5
     */
    @Option(option = "dsl", description = "Set the build script DSL to be used in generated scripts.")
    public void setDsl(String dsl) {
        this.dsl = dsl;
    }

    /**
     * Available build script DSLs to be used.
     *
     * @since 4.5
     */
    @OptionValues("dsl")
    public List<String> getAvailableDSLs() {
        return BuildInitDsl.listSupported();
    }

    /**
     * Set the test framework to be used.
     */
    @Option(option = "test-framework", description = "Set the test framework to be used.")
    public void setTestFramework(@Nullable String testFramework) {
        this.testFramework = testFramework;
    }

    /**
     * Available test frameworks.
     */
    @OptionValues("test-framework")
    public List<String> getAvailableTestFrameworks() {
        return BuildInitTestFramework.listSupported();
    }

    /**
     * Set the project name.
     *
     * @since 5.0
     */
    @Option(option = "project-name", description = "Set the project name.")
    public void setProjectName(String projectName) {
        this.projectName = projectName;
    }

    /**
     * Set the package name.
     *
     * @since 5.0
     */
    @Option(option = "package", description = "Set the package for source files.")
    public void setPackageName(String packageName) {
        this.packageName = packageName;
    }

    void setProjectLayoutRegistry(ProjectLayoutSetupRegistry projectLayoutRegistry) {
        this.projectLayoutRegistry = projectLayoutRegistry;
    }

    private String detectType() {
        ProjectLayoutSetupRegistry projectLayoutRegistry = getProjectLayoutRegistry();
        BuildConverter buildConverter = projectLayoutRegistry.getBuildConverter();
        if (buildConverter.canApplyToCurrentDirectory(projectDir)) {
            return buildConverter.getId();
        }
        return projectLayoutRegistry.getDefault().getId();
    }
}