// Infectious Spread -- by John Clavin -- July 22, 2016

var restartFlag;
var counter;
var society;

function setup() {
  createCanvas(640, 680);
  background(235);
  restartFlag = false;
  counter = 0;
  society = new Society();
}

function draw() {
  counter++;
  society.runSociety();
  if(counter > 650) {
    restartFlag = true;
    noLoop();
  }
}

function mousePressed() {
  if(restartFlag === true) {
    society.resetSociety();
    restartFlag = false;
    loop();
  }
  return false;
}

Society = function() {
  this.people = [];
  var virusColor = color(0);
  var p = new Person(createVector(width/2, height + 6));
  this.people.push(p);
  
  this.resetSociety = function() {
    background(235);
    counter = 0;
    this.people = [];
    var pp = new Person(createVector(width/2, height + 6));
    this.people.push(pp);
  }

  this.runSociety = function() {
    var virusColor1 = color(random(200), random(100), random(20), 120);
    var virusColor2 = color(random(20), random(200), random(100), 120);
    var virusColor3 = color(random(20), random(100), random(200), 120);
    var virusColor4 = color(random(160), random(160), random(160), 120);
    if((counter % 61) == 1) {
      virusColor = virusColor1;
    } else if((counter % 61) == 16) {
      virusColor = virusColor2;
    } else if((counter % 61) == 31) {
      virusColor = virusColor3;
    } else if((counter % 61) == 46) {
      virusColor = virusColor4;
    }
    
    for (var i = 0; i < this.people.length; i++) {
      this.people[i].pointColor = virusColor;
      if(this.people[i].aliveFlag === true) {
        this.people[i].update();
        this.people[i].render();
        if(this.people[i].timeToSpread()) {
          if(this.people.length < 2048) {
            this.people.push(this.people[i].spreadInfection());
            this.people.push(this.people[i].spreadInfection());
          }
        }              
      } else {
        this.people.splice(i, 1);
      }
    }
  }
}

function Person(pos) {
  this.pointColor;
  this.position = pos;
  this.repelLocation = createVector(width/2, height + 24);
  this.attractLocation = createVector(width/2, 0);
  this.randomForce = createVector(0, 0);
  this.repelForce = createVector(0, 0);
  this.attractForce = createVector(0, 0);
  this.counter = 0;
  this.aliveFlag = true;
  
  this.update = function() {
    this.randomForce.x = random(-1,  1);
    this.randomForce.y = random(-0.3, 0.3);
    this.randomForce.normalize();
    var randomF = this.randomForce.mult(3.2);
    
    this.repelForce = p5.Vector.sub(this.position, this.repelLocation);
    this.repelForce.normalize();
    var repelF = this.repelForce.mult(1.2);
    
    this.attractForce = p5.Vector.sub(this.attractLocation, this.position);
    this.attractForce.normalize();
    var attractF = this.attractForce.mult(1);
    
    this.position.add(randomF);
    if(counter < 120) {
      this.position.add(attractF);  
    } else {
      this.position.add(repelF);
    }
  }
  
  this.spreadInfection = function() {
    return new Person(createVector(this.position.x, this.position.y));
  }
  
  this.timeToSpread = function() {
    this.counter++;
    if(this.counter == 16) {
      this.aliveFlag = false;
      return true;
    } else {
      return false;
    }
  }

  this.render = function() {
    strokeWeight(3);
    stroke(this.pointColor);
    point(this.position.x, this.position.y);
  }
}