/*
 * 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.foundation;

import org.gradle.api.Project;
import org.gradle.api.Task;
import org.gradle.api.logging.Logger;
import org.gradle.api.logging.Logging;

import java.util.*;

/**
 * This converts Gradle's projects into ProjectView objects. These can be safely reused unlike Gradle's projects.
 *
 * @author mhunsicker
 */
public class ProjectConverter {
    private List<ProjectView> rootLevelResultingProjects = new ArrayList<ProjectView>();
    private HashMap<Project, ProjectView> projectMap = new HashMap<Project, ProjectView>();
    private final Logger logger = Logging.getLogger(ProjectConverter.class);

    public ProjectConverter() {
    }

    /**
     * Call this to convert the projects.
     *
     * @param rootProject the root project.
     */
    public List<ProjectView> convertProjects(Project rootProject) {
        rootLevelResultingProjects.clear();
        projectMap.clear();

        addRootLevelProject(rootProject);

        buildDependencies();

        return rootLevelResultingProjects;
    }

    /**
     * This adds the specified poject as a root level projects. It then adds all tasks and recursively adds all sub
     * projects.
     *
     * @param rootLevelProject a root level project.
     */
    public void addRootLevelProject(Project rootLevelProject) {
        ProjectView rootLevelProjectView = new ProjectView(null, rootLevelProject.getName(), rootLevelProject.getBuildFile(), rootLevelProject.getDescription());
        projectMap.put(rootLevelProject, rootLevelProjectView);

        rootLevelResultingProjects.add(rootLevelProjectView);

        addSubProjects(rootLevelProject, rootLevelProjectView);

        addTasks(rootLevelProject, rootLevelProjectView);

        rootLevelProjectView.sortSubProjectsAndTasks();
    }

    /**
     * Adds all sub projects of the specified GradleProject.
     *
     * @param parentProject the source parent project. Where we get the sub projects from.
     * @param parentProjectView the destination of the sub projects from parentProject.
     */
    private void addSubProjects(Project parentProject, ProjectView parentProjectView) {
        Collection<Project> subProjects = parentProject.getChildProjects().values();
        for (Project subProject : subProjects) {
            ProjectView projectView = new ProjectView(parentProjectView, subProject.getName(), subProject.getBuildFile(), subProject.getDescription());
            projectMap.put(subProject, projectView);

            addTasks(subProject, projectView);

            projectView.sortSubProjectsAndTasks();

            addSubProjects(subProject, projectView);
        }
    }

    /**
     * Adds the tasks from the project to the GradleProject.
     *
     * @param project the source parent project. Where we get the sub projects from.
     * @param projectView the destination of the tasks from project.
     */
    private void addTasks(Project project, ProjectView projectView) {
        List<String> defaultTasks = project.getDefaultTasks();
        for (Task task : project.getTasks()) {
            String taskName = task.getName();

            boolean isDefault = defaultTasks.contains(taskName);

            projectView.createTask(taskName, task.getDescription(), isDefault);
        }
    }

    /**
     * This sets the dependencies on the ProjectViews. We ask the gradle projects for the dependencies and then convert
     * them to ProjectViews. Obviously, this must be done after converting all Projects to ProjectViews.
     */
    private void buildDependencies() {
        for (Project project : projectMap.keySet()) {
            ProjectView projectView = projectMap.get(project);

            List<ProjectView> projectViewList = getProjectViews(project.getDependsOnProjects());

            projectView.setDependsOnProjects(projectViewList);
        }
    }

    /**
     * Converts a set of projects to the existing project views. This does not actually instantiate new ProjectView
     * objects.
     */
    private List<ProjectView> getProjectViews(Set<Project> projects) {
        List<ProjectView> views = new ArrayList<ProjectView>();

        Iterator<Project> projectIterator = projects.iterator();
        while (projectIterator.hasNext()) {
            Project project = projectIterator.next();
            ProjectView projectView = projectMap.get(project);
            if (projectView == null) {
                logger.error("Missing project: " + project.getName());
            } else {
                views.add(projectView);
            }
        }

        return views;
    }
}