FloatTable data;
float dataMin, dataMax;

float plotX1, plotY1;
float plotX2, plotY2;

int rowCount;
int columnCount;
int currentColumn = 0;

int yearMin, yearMax;
int[] years;

int yearInterval = 10;

PFont plotFont; 


void setup() {
  size(720, 405);
  
  data = new FloatTable("milk-tea-coffee.tsv");
  rowCount = data.getRowCount();
  columnCount = data.getColumnCount();
  
  years = int(data.getRowNames());
  yearMin = years[0];
  yearMax = years[years.length - 1];
  
  dataMin = 0;
  dataMax = data.getTableMax();

  // Corners of the plotted time series
  plotX1 = 50; 
  plotX2 = width - plotX1;
  plotY1 = 60;
  plotY2 = height - plotY1;  
  
  plotFont = createFont("SansSerif", 20);
  textFont(plotFont);

  smooth();
}


void draw() {
  background(224);
  
  // Show the plot area as a white box  
  fill(255);
  rectMode(CORNERS);
  noStroke();
  rect(plotX1, plotY1, plotX2, plotY2);

  drawTitle();
  drawYearLabels();

  stroke(#5679C1);
  strokeWeight(5);
  drawDataPoints(currentColumn);
}


void drawTitle() {
  fill(0);
  textSize(20);
  textAlign(LEFT);
  String title = data.getColumnName(currentColumn);
  text(title, plotX1, plotY1 - 10);
}


void drawYearLabels() {
  fill(0);
  textSize(10);
  textAlign(CENTER, TOP);
  
  // Use thin, gray lines to draw the grid
  stroke(224);
  strokeWeight(1);
  
  for (int row = 0; row < rowCount; row++) {
    if (years[row] % yearInterval == 0) {
      float x = map(years[row], yearMin, yearMax, plotX1, plotX2);
      text(years[row], x, plotY2 + 5);
    }
  }
}


void drawDataPoints(int col) {
  for (int row = 0; row < rowCount; row++) {
    if (data.isValid(row, col)) {
      float value = data.getFloat(row, col);
      float x = map(years[row], yearMin, yearMax, plotX1, plotX2);
      float y = map(value, dataMin, dataMax, plotY2, plotY1);
      point(x, y);
    }
  }
}


void keyPressed() {
  if (key == '[') {
    currentColumn--;
    if (currentColumn < 0) {
      currentColumn = columnCount - 1;
    }
  } else if (key == ']') {
    currentColumn++;
    if (currentColumn == columnCount) {
      currentColumn = 0;
    }
  }
}