package app.controllers;

import java.net.URL;
import java.util.Collection;
import java.util.ResourceBundle;

import com.google.common.eventbus.EventBus;
import com.google.common.eventbus.Subscribe;

import org.fxmisc.richtext.CodeArea;
import org.fxmisc.richtext.LineNumberFactory;
import org.fxmisc.richtext.model.StyleSpans;
import org.fxmisc.richtext.model.TwoDimensional.Bias;
import org.fxmisc.richtext.model.TwoDimensional.Position;

import app.events.EditorChangedEvent;
import app.events.LanguageChangedEvent;
import app.events.ToggleCommentEvent;
import app.events.ToggleWrapTextEvent;
import app.events.FileSaveStateChangedEvent;
import app.model.Model;
import app.service.LanguageOperations;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;

public class EditorController implements Initializable, Controller {

  @FXML
  private CodeArea editor;

  private EventBus eventBus;

  /**
   * Initializes the controller, and binds the event of change in editor content
   * to {@link #editorChanged() editorChanged}
   */
  @Override
  public void initialize(URL url, ResourceBundle resourceBundle) {
    editor.setParagraphGraphicFactory(LineNumberFactory.get(editor));

    editor
      .textProperty()
      .addListener((obs, oldV, newV) -> this.editorChanged());
  }

  @Override
  public void setEventBus(EventBus eventBus) {
    this.eventBus = eventBus;
    this.eventBus.register(this);
  }

  /**
   * Applies highlighting to the editor.
   * 
   * @param highlighting highlighting data
   */
  private void setHighlighting(StyleSpans<Collection<String>> highlighting) {
    this.editor.setStyleSpans(0, highlighting);
  }

  /**
   * Recalculates and refreshes the syntax highlighting of the editor.
   */
  private void refreshHighlighting() {
    this.setHighlighting(LanguageOperations.syntaxHighlight(this.editor.getText(), Model.getLanguage()));
  }

  /**
   * Uses Model.language to determine whether the current line/selection
   * is commented or not, and toggles the comment.
   */
  private void toggleComment() {
    if (editor.getSelectedText().equals("")) {
      String currentLine = editor.getText(editor.getCurrentParagraph());

      String newText;
      if (Model.getLanguage().isCommentedLine(currentLine))
        newText = Model.getLanguage().unCommentLine(currentLine);
      else
        newText = Model.getLanguage().commentLine(currentLine);

      editor.replaceText(
        editor.getCurrentParagraph(),
        0,
        editor.getCurrentParagraph(),
        currentLine.length(),
        newText
      );

    } else { // Comment selection

      String newText;
      if (Model.getLanguage().isCommentedSelection(editor.getSelectedText()))
        newText = Model.getLanguage().unCommentSelection(editor.getSelectedText());
      else
        newText = Model.getLanguage().commentSelection(editor.getSelectedText());

      editor.replaceSelection(newText);

    }
  }

  private void setWrapText(boolean isWrapText)  {
    this.editor.setWrapText(isWrapText);
  }

  /**
   * Handles the event whenever the content of the editor is changed.
   */
  private void editorChanged() {
    int offset = this.editor.getCaretPosition();
    Position pos = this.editor.offsetToPosition(offset, Bias.Forward);
    this.eventBus.post(new EditorChangedEvent(pos.getMajor() + 1, pos.getMinor()));

    if (Model.getFileIsSaved())
      this.eventBus.post(new FileSaveStateChangedEvent(false));

    this.refreshHighlighting();
  }

  /**
   * Refreshes the editor whenever the language is changed.
   * @param event
   */
  @Subscribe
  private void handle(LanguageChangedEvent event) {
    this.refreshHighlighting();
  }

  /**
   * Toggles a language specific comment of the line/selection
   * @param event
   */
  @Subscribe
  private void handle(ToggleCommentEvent event) {
    this.toggleComment();
  }

  @Subscribe
  private void handle(ToggleWrapTextEvent event) {
    this.setWrapText(event.getIsWrapped());
  }

}