/**
 * @author Rodrigo
 * https://gist.github.com/roooodcastro/6325153
 */
sclass GraphPanel extends JPanel {
  int width = 800;
  int heigth = 400;
  int padding = 25;
  int labelPadding = 25;
  Color lineColor = new Color(44, 102, 230, 180);
  Color pointColor = new Color(100, 100, 100, 180);
  Color gridColor = new Color(200, 200, 200, 200);
  static final Stroke GRAPH_STROKE = new BasicStroke(2f);
  int pointWidth = 4;
  int numberYDivisions = 10;
  List<Double> scores;

  public GraphPanel(List<Double> scores) {
      this.scores = scores;
  }

  @Override
  protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

      double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (scores.size() - 1);
      double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

      List<Point> graphPoints = new ArrayList<>();
      for (int i = 0; i < scores.size(); i++) {
          int x1 = (int) (i * xScale + padding + labelPadding);
          int y1 = (int) ((getMaxScore() - scores.get(i)) * yScale + padding);
          graphPoints.add(new Point(x1, y1));
      }

      // draw white background
      g2.setColor(Color.WHITE);
      g2.fillRect(padding + labelPadding, padding, getWidth() - (2 * padding) - labelPadding, getHeight() - 2 * padding - labelPadding);
      g2.setColor(Color.BLACK);

      // create hatch marks and grid lines for y axis.
      for (int i = 0; i < numberYDivisions + 1; i++) {
          int x0 = padding + labelPadding;
          int x1 = pointWidth + padding + labelPadding;
          int y0 = getHeight() - ((i * (getHeight() - padding * 2 - labelPadding)) / numberYDivisions + padding + labelPadding);
          int y1 = y0;
          if (scores.size() > 0) {
              g2.setColor(gridColor);
              g2.drawLine(padding + labelPadding + 1 + pointWidth, y0, getWidth() - padding, y1);
              g2.setColor(Color.BLACK);
              String yLabel = ((int) ((getMinScore() + (getMaxScore() - getMinScore()) * ((i * 1.0) / numberYDivisions)) * 100)) / 100.0 + "";
              FontMetrics metrics = g2.getFontMetrics();
              int labelWidth = metrics.stringWidth(yLabel);
              g2.drawString(yLabel, x0 - labelWidth - 5, y0 + (metrics.getHeight() / 2) - 3);
          }
          g2.drawLine(x0, y0, x1, y1);
      }

      // and for x axis
      for (int i = 0; i < scores.size(); i++) {
          if (scores.size() > 1) {
              int x0 = i * (getWidth() - padding * 2 - labelPadding) / (scores.size() - 1) + padding + labelPadding;
              int x1 = x0;
              int y0 = getHeight() - padding - labelPadding;
              int y1 = y0 - pointWidth;
              if ((i % ((int) ((scores.size() / 20.0)) + 1)) == 0) {
                  g2.setColor(gridColor);
                  g2.drawLine(x0, getHeight() - padding - labelPadding - 1 - pointWidth, x1, padding);
                  g2.setColor(Color.BLACK);
                  String xLabel = i + "";
                  FontMetrics metrics = g2.getFontMetrics();
                  int labelWidth = metrics.stringWidth(xLabel);
                  g2.drawString(xLabel, x0 - labelWidth / 2, y0 + metrics.getHeight() + 3);
              }
              g2.drawLine(x0, y0, x1, y1);
          }
      }

      // create x and y axes 
      g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, padding + labelPadding, padding);
      g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, getWidth() - padding, getHeight() - padding - labelPadding);

      Stroke oldStroke = g2.getStroke();
      g2.setColor(lineColor);
      g2.setStroke(GRAPH_STROKE);
      for (int i = 0; i < graphPoints.size() - 1; i++) {
          int x1 = graphPoints.get(i).x;
          int y1 = graphPoints.get(i).y;
          int x2 = graphPoints.get(i + 1).x;
          int y2 = graphPoints.get(i + 1).y;
          g2.drawLine(x1, y1, x2, y2);
      }

      g2.setStroke(oldStroke);
      g2.setColor(pointColor);
      for (int i = 0; i < graphPoints.size(); i++) {
          int x = graphPoints.get(i).x - pointWidth / 2;
          int y = graphPoints.get(i).y - pointWidth / 2;
          int ovalW = pointWidth;
          int ovalH = pointWidth;
          g2.fillOval(x, y, ovalW, ovalH);
      }
  }

//    @Override
//    public Dimension getPreferredSize() {
//        return new Dimension(width, heigth);
//    }

  double getMinScore() {
      double minScore = Double.MAX_VALUE;
      for (Double score : scores) {
          minScore = Math.min(minScore, score);
      }
      return minScore;
  }

  double getMaxScore() {
      double maxScore = Double.MIN_VALUE;
      for (Double score : scores) {
          maxScore = Math.max(maxScore, score);
      }
      return maxScore;
  }

  public void setScores(List<Double> scores) {
      this.scores = scores;
      invalidate();
      repaint();
  }

  public List<Double> getScores() { return scores; }
}