package com.jetbrains.edu.kotlin;

import com.intellij.openapi.actionSystem.DefaultActionGroup;
import com.intellij.openapi.fileEditor.FileEditorManager;
import com.intellij.openapi.fileEditor.FileEditorManagerEvent;
import com.intellij.openapi.fileEditor.FileEditorManagerListener;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.util.containers.HashMap;
import com.jetbrains.edu.courseFormat.Course;
import com.jetbrains.edu.courseFormat.Task;
import com.jetbrains.edu.courseFormat.TaskFile;
import com.jetbrains.edu.learning.StudyTaskManager;
import com.jetbrains.edu.learning.StudyToolWindowConfigurator;
import com.jetbrains.edu.learning.StudyUtils;
import com.jetbrains.edu.learning.actions.*;
import com.jetbrains.edu.learning.ui.StudyToolWindow;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import javax.swing.*;

public class KotlinStudyToolWindowConfigurator implements StudyToolWindowConfigurator {
    @NotNull
    @Override
    public DefaultActionGroup getActionGroup(Project project) {
        final DefaultActionGroup group = new DefaultActionGroup();
        group.add(new KotlinStudyCheckAction());
        group.add(new StudyPreviousStudyTaskAction());
        group.add(new StudyNextStudyTaskAction());
        group.add(new StudyRefreshTaskFileAction());
        group.add(new StudyShowHintAction());
        group.add(new StudyRunAction());
        group.add(new StudyEditInputAction());
        
        return group;
    }

    @NotNull
    @Override
    public HashMap<String, JPanel> getAdditionalPanels(Project project) {
        return new HashMap<String, JPanel>();
    }

    @NotNull
    @Override
    public FileEditorManagerListener getFileEditorManagerListener(@NotNull final Project project, 
                                                                  @NotNull final StudyToolWindow studyToolWindow) {

        return new FileEditorManagerListener() {

            private static final String EMPTY_TASK_TEXT = "Please, open any task Ыto see task description";

            @Override
            public void fileOpened(@NotNull FileEditorManager source, @NotNull VirtualFile file) {
                Task task = getTask(file);
                setTaskText(task, file.getParent());
            }

            @Override
            public void fileClosed(@NotNull FileEditorManager source, @NotNull VirtualFile file) {
                studyToolWindow.setTaskText(EMPTY_TASK_TEXT);
            }

            @Override
            public void selectionChanged(@NotNull FileEditorManagerEvent event) {
                VirtualFile file = event.getNewFile();
                if (file != null) {
                    Task task = getTask(file);
                    setTaskText(task, file.getParent());
                }
            }

            @Nullable
            private Task getTask(@NotNull VirtualFile file) {
                TaskFile taskFile = StudyUtils.getTaskFile(project, file);
                if (taskFile != null) {
                    return taskFile.getTask();
                }
                else {
                    return null;
                }
            }

            private void setTaskText(@Nullable final Task task, @Nullable final VirtualFile taskDirectory) {
                String text = StudyUtils.getTaskTextFromTask(task, taskDirectory);
                if (text == null) {
                    studyToolWindow.setTaskText(EMPTY_TASK_TEXT);
                    return;
                }
                studyToolWindow.setTaskText(text);
            }
        };
    }

    @NotNull
    @Override
    public String getDefaultHighlightingMode() {
        return "text/x-java";
    }

    @Override
    public boolean accept(@NotNull Project project) {
        Course course = StudyTaskManager.getInstance(project).getCourse();
        return course != null && "PyCharm".equals(course.getCourseType()) && "kotlin".equals(course.getLanguage());
    }
}

Add KotlinStudyToolWindowConfigurator to provide custom action group and code highlighting settings in task description