/**
 *  Implementation of a ProjectEvaluationListener that sets the
 *  tasks mustRunAfter according to the sub project ordering in
 *  the file setting.gradle
 */
class SubProjectOrderListener implements org.gradle.api.ProjectEvaluationListener {
  private static final Logger LOG = Logging.getLogger(SubProjectOrderListener.class);


  void  afterEvaluate(Project project, ProjectState state) {
    if(project.getSubprojects().isEmpty()) {
      return;
    }
    LOG.lifecycle("Order tasks for sub projects of project " + project.name + " per sub project definition in settings.gradle");


    File settingsFile = new File(project.getProjectDir(), "settings.gradle");
    if(settingsFile.exists() == false) {
      LOG.error("No settings.gradle found in project directory " + project.getProjectDir());
      return;
    }


    /*
     * Determine ordered list of sub projects according to the entries in file setting.gradle
     */
    List<String> orderedSubProjects = new ArrayList<String>();
    BufferedReader br = new BufferedReader(new FileReader(settingsFile));
    try {
      String line;
      while ((line = br.readLine()) != null) {
        if(line.startsWith("include")) {
          String[] splitLine = line.substring("include".length()).split(",");
          LOG.debug("Found ordered sub projects list");
          for(String tmp : splitLine) {
            int b = tmp.indexOf("\"")+1;
            int e = tmp.indexOf("\"",b);
            String subProject = tmp.substring(b, e);
            if(subProject.contains(':')) {
              throw new RuntimeException("No sub sub projects supported");
            }
            LOG.debug(subProject);
            orderedSubProjects.add(subProject);
          }
          break;
        }
      }
    }
    finally {
      br.close();
    }


    if(orderedSubProjects.isEmpty()) {
      LOG.error("No sub projects included in settings.gradle");
      return;
    }


    Map<String, Set<Task>> name2Task = new HashMap<String, Set<Task>>();
    LOG.debug("Found tasks:");
    for(Set<Task> tasks: project.getAllTasks(true).values()) {
      for(Task task : tasks) {
        String taskName = task.getName();
        LOG.debug(task.getProject().getName() + ":" + task.getName());
        if(!name2Task.containsKey(taskName)) {
          name2Task.put(taskName, new HashSet<Task>());
        }
        name2Task.get(taskName).add(task);
      }
    }


    /*
     * Visit all tasks and set mustRunAfter according to sub project ordering
     */
    for(Set<Task> tasksWithSameName : name2Task.values()) {

      for(Task task : tasksWithSameName) {
        int pos = orderedSubProjects.indexOf(task.getProject().getName());
        Set<Task> tasksToRunBefore = task.getMustRunAfter().getDependencies(task);

        String taskLogName = task.getProject().getName() + ":" + task.getName();
        LOG.info("Process task " + taskLogName);

        for(Task runBeforeTask : tasksWithSameName) {
          int runBeforePos = orderedSubProjects.indexOf(runBeforeTask.getProject().getName());


          if(runBeforePos < pos) {
            tasksToRunBefore.add(runBeforeTask);

            String runBeforeLogName = runBeforeTask.getProject().getName() + ":" + runBeforeTask.getName();
            LOG.info("   added  " + runBeforeLogName);
          }

          task.setMustRunAfter(tasksToRunBefore);
        }
      }
    }
  }

  void  beforeEvaluate(Project project) {
  }
}



/**
 * This is how you attach the listener in your root projects build.gradle
 */
gradle.addProjectEvaluationListener(new SubProjectOrderListener())