/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */
package org.elasticsearch.gradle.internal.test.rest;

import org.gradle.api.Plugin;
import org.gradle.api.Project;
import org.gradle.api.artifacts.Configuration;
import org.gradle.api.artifacts.Dependency;
import org.gradle.api.attributes.Usage;
import org.gradle.api.provider.Provider;
import org.gradle.api.tasks.SourceSet;
import org.gradle.api.tasks.SourceSetContainer;

import java.util.Map;

import static org.gradle.api.tasks.SourceSet.TEST_SOURCE_SET_NAME;

/**
 * <p>
 * Gradle plugin to help configure {@link CopyRestApiTask}'s and {@link CopyRestTestsTask} that copies the artifacts needed for the Rest API
 * spec and YAML based rest tests.
 * </p>
 * <strong>Rest API specification:</strong> <br>
 * When the {@link RestResourcesPlugin} has been applied the {@link CopyRestApiTask} will automatically copy the core Rest API specification
 * if there are any Rest YAML tests present in source, or copied from {@link CopyRestTestsTask} output. X-pack specs must be explicitly
 * declared to be copied.
 * <br>
 * <i>For example:</i>
 * <pre>
 * restResources {
 *   restApi {
 *     includeXpack 'enrich'
 *   }
 * }
 * </pre>
 * Will copy the entire core Rest API specifications (assuming the project has tests) and any of the X-pack specs starting with enrich*.
 * It is recommended (but not required) to also explicitly declare which core specs your project depends on to help optimize the caching
 * behavior.
 * <i>For example:</i>
 * <pre>
 * restResources {
 *   restApi {
 *     includeCore 'index', 'cat'
 *     includeXpack 'enrich'
 *   }
 * }
 * </pre>
 * <br>
 * <strong>Rest YAML tests :</strong> <br>
 * When the {@link RestResourcesPlugin} has been applied the {@link CopyRestTestsTask} will copy the Rest YAML tests if explicitly
 * configured with `includeCore` or `includeXpack` through the `restResources.restTests` extension.
 * <i>For example:</i>
 * <pre>
 * restResources {
 *  restApi {
 *      includeXpack 'graph'
 *   }
 *   restTests {
 *     includeXpack 'graph'
 *   }
 * }
 * </pre>
 * Will copy any of the x-pack tests that start with graph, and will copy the X-pack graph specification, as well as the full core
 * Rest API specification.
 * <p>
 * Additionally you can specify which sourceSetName resources should be copied to. The default is the yamlRestTest source set.
 *
 * @see CopyRestApiTask
 * @see CopyRestTestsTask
 */
public class RestResourcesPlugin implements Plugin<Project> {

    public static final String COPY_YAML_TESTS_TASK = "copyYamlTestsTask";
    public static final String COPY_REST_API_SPECS_TASK = "copyRestApiSpecsTask";
    public static final String YAML_TESTS_USAGE = "yaml-tests";
    public static final String YAML_XPACK_TESTS_USAGE = "yaml-xpack-tests";
    public static final String YAML_SPEC_USAGE = "yaml-spec";
    private static final String EXTENSION_NAME = "restResources";

    @Override
    public void apply(Project project) {
        RestResourcesExtension extension = project.getExtensions().create(EXTENSION_NAME, RestResourcesExtension.class);

        SourceSetContainer sourceSets = project.getExtensions().getByType(SourceSetContainer.class);
        SourceSet defaultSourceSet = sourceSets.maybeCreate(TEST_SOURCE_SET_NAME);

        // tests
        Configuration testConfig = project.getConfigurations().create("restTestConfig", config -> {
            config.setCanBeConsumed(false);
            config.getAttributes().attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_TESTS_USAGE));
        });
        Configuration xpackTestConfig = project.getConfigurations().create("restXpackTestConfig", config -> {
            config.setCanBeConsumed(false);
            config.getAttributes().attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_XPACK_TESTS_USAGE));
        });
        // core
        // we guard this reference to :rest-api-spec with a find to make testing easier
        var restApiSpecProjectAvailable = project.findProject(":rest-api-spec") != null;
        if (restApiSpecProjectAvailable) {
            Dependency restTestdependency = project.getDependencies()
                .project(Map.of("path", ":rest-api-spec", "configuration", "restTests"));
            project.getDependencies().add(testConfig.getName(), restTestdependency);
        }

        // x-pack
        var restXpackTests = project.findProject(":x-pack:plugin") != null;
        if (restXpackTests) {
            Dependency restXPackTestdependency = project.getDependencies()
                .project(Map.of("path", ":x-pack:plugin", "configuration", "restXpackTests"));
            project.getDependencies().add(xpackTestConfig.getName(), restXPackTestdependency);
        }
        project.getConfigurations()
            .create(
                "restTests",
                config -> config.getAttributes().attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_TESTS_USAGE))
            );
        project.getConfigurations()
            .create(
                "restXpackTests",
                config -> config.getAttributes()
                    .attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_XPACK_TESTS_USAGE))
            );

        Provider<CopyRestTestsTask> copyRestYamlTestTask = project.getTasks()
            .register(COPY_YAML_TESTS_TASK, CopyRestTestsTask.class, task -> {
                task.dependsOn(testConfig, xpackTestConfig);
                task.setCoreConfig(testConfig);
                task.setXpackConfig(xpackTestConfig);
                // If this is the rest spec project, don't copy the tests again
                if (project.getPath().equals(":rest-api-spec") == false) {
                    task.getIncludeCore().set(extension.getRestTests().getIncludeCore());
                }
                task.getIncludeXpack().set(extension.getRestTests().getIncludeXpack());
                task.getOutputResourceDir().set(project.getLayout().getBuildDirectory().dir("restResources/yamlTests"));
            });

        // api
        Configuration specConfig = project.getConfigurations()
            .create(
                "restSpec", // name chosen for passivity
                config -> {
                    config.setCanBeConsumed(false);
                    config.getAttributes().attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_SPEC_USAGE));
                }
            );
        if (restApiSpecProjectAvailable) {
            Dependency restSpecDependency = project.getDependencies()
                .project(Map.of("path", ":rest-api-spec", "configuration", "restSpecs"));
            project.getDependencies().add(specConfig.getName(), restSpecDependency);
        }
        project.getConfigurations()
            .create(
                "restSpecs",
                config -> config.getAttributes().attribute(Usage.USAGE_ATTRIBUTE, project.getObjects().named(Usage.class, YAML_SPEC_USAGE))
            );

        Provider<CopyRestApiTask> copyRestYamlApiTask = project.getTasks()
            .register(COPY_REST_API_SPECS_TASK, CopyRestApiTask.class, task -> {
                task.dependsOn(copyRestYamlTestTask);
                task.getInclude().set(extension.getRestApi().getInclude());
                task.setConfig(specConfig);
                task.getOutputResourceDir().set(project.getLayout().getBuildDirectory().dir("restResources/yamlSpecs"));
                task.getAdditionalYamlTestsDir().set(copyRestYamlTestTask.flatMap(CopyRestTestsTask::getOutputResourceDir));
                task.setSourceResourceDir(
                    defaultSourceSet.getResources()
                        .getSrcDirs()
                        .stream()
                        .filter(f -> f.isDirectory() && f.getName().equals("resources"))
                        .findFirst()
                        .orElse(null)
                );
            });

        defaultSourceSet.getOutput().dir(copyRestYamlApiTask.map(CopyRestApiTask::getOutputResourceDir));
        defaultSourceSet.getOutput().dir(copyRestYamlTestTask.map(CopyRestTestsTask::getOutputResourceDir));
    }
}