var Collider = function(type, params) {

  PIXI.Container.call(this);

  this.group = params.group || "main";
  this.type = type;
  this.radius;
  this.active = true;
  this.id = Collider.count++;
  this.scalable = params.scalable || true;

  this.x = params.x || 0;
  this.y = params.y || 0;
  this.w = params.w || 0;
  this.h = params.h || 0;

  switch(type) {
    case "circle":
      this.radius = params.r || 1;
    break;
    case "rect":

    break;
    default: return;
  }

  this.makeDebugGraphics = function() {
    this.debug = new PIXI.Graphics();
    this.addChild(this.debug);
    switch(type) {
      case "circle":
        var color = 0x00ff00;
        this.debug.lineStyle(1, color, 1);
        this.debug.beginFill(color, 0.4);
        this.debug.drawCircle(0, 0,this.radius);
        this.debug.endFill();
        break;
      case "rect":
        var color = 0x00ff00;
        this.debug.lineStyle(1, color, 1);
        this.debug.beginFill(color, 0.4);
        this.debug.drawRect(-this.w / 2, -this.h / 2, this.w, this.h);
        this.debug.endFill();
        break;
      }
  }

  Collisions.add(this);

}

Collider.count = 0;
Collider.prototype = Object.create(PIXI.Container.prototype);

var Collisions = (function() {
  var debug = true;
  var groups = [];
  var handlers = [];
  var contacts = [];

  function update() {
    for (var i = 0; i < handlers.length; i++) {
      var h = handlers[i];
      var g1 = groups[h.group1];
      var g2 = groups[h.group2];

      if (!g1 || !g2) continue;

      for (var m = 0; m < g1.length; m++) {
        for (var n = 0; n < g2.length; n++) {
          if (g1[m] !== g2[n]) {
            var event = _collide(g1[m], g2[n]);
            if (event) {
              h.f(event);
            }
          }
        }
      }
    }
  }

  function add(c) {
    if (!(c.group in groups)) groups[c.group] = [];
    groups[c.group].push(c);

    if (debug) {
      c.makeDebugGraphics();
    }
  }

  function on(group1, group2, f) {
    handlers.push({
      group1: group1,
      group2: group2,
      f: f
    });
  }

  function _collide(c1, c2) {

    var collided = false;
    var hash = c1.id + "#" + c2.id;

    if (c1.type === "rect" && c2.type === "rect") {
      //console.log(c1, c2)
      var wt1 = c1.worldTransform;
      var wt2 = c2.worldTransform;

      var r1 = {
        left: wt1.tx - (c1.w * 0.5) * wt1.a,
        right: wt1.tx + (c1.w * 0.5) * wt1.a,
        top: wt1.ty - (c1.h * 0.5) * wt1.d,
        bottom: wt1.ty + (c1.h * 0.5) * wt1.d,
      }

      var r2 = {
        left: wt2.tx - (c2.w * 0.5) * wt2.a,
        right: wt2.tx + (c2.w * 0.5) * wt2.a,
        top: wt2.ty - (c2.h * 0.5) * wt2.d,
        bottom: wt2.ty + (c2.h * 0.5) * wt2.d,
      }



      collided = _intersectRect(r1, r2);
    }

    if (hash in contacts) {
      if (collided && !contacts[hash]) {
        contacts[hash] = true;
        return {
          event: "start", c1: c1, c2: c2
        }
      }
      if (!collided && contacts[hash]) {
        contacts[hash] = false;
        return {
          event: "end", c1: c1, c2: c2
        }
      }
      return null;
    } else {
      contacts[hash] = true;
      return {
        event: "start", c1: c1, c2: c2
      }
    }
  }

  function _intersectRect(r1, r2) {
    return !(r2.left > r1.right ||
             r2.right < r1.left ||
             r2.top > r1.bottom ||
             r2.bottom < r1.top);
  }

  return {
    update: update,
    add: add,
    on: on
  }
})();




// Test app //////////////////////////////////////////////////
//////////////////////////////////////////////////////////////

var app = new PIXI.Application(innerWidth, innerHeight, {backgroundColor : 0x000000});
document.body.appendChild(app.view);

// create a new Sprite from an image path
var bunny = PIXI.Sprite.fromImage('https://pixijs.github.io/examples/required/assets/basics/bunny.png')
var bunny2 = PIXI.Sprite.fromImage('https://pixijs.github.io/examples/required/assets/basics/bunny.png')
var text = new PIXI.Text("Collision", {fill: 0xffffff});
text.x = 50;
text.y = 20;
text.visible = false;

// center the sprite's anchor point
bunny.anchor.set(0.5);
bunny2.anchor.set(0.5);

// move the sprite to the center of the screen
bunny.x = app.renderer.width / 2;
bunny.y = app.renderer.height / 2;
bunny2.x = app.renderer.width / 2;
bunny2.y = app.renderer.height / 2;

//bunny.addChild(new Collider("circle", {x: 0, y: -10, r: 15}));
bunny.addChild(new Collider("rect", {x: 0, y: 0, w: 15, h: 30, group: "b1"}));
//bunny2.addChild(new Collider("circle", {x: 0, y: -10, r: 15}));
bunny2.addChild(new Collider("rect", {x: 0, y: 0, w: 15, h: 30, group: "b2"}));

bunny.scale.set(2,2);
bunny2.scale.set(2,2);

app.stage.addChild(bunny);
app.stage.addChild(bunny2);
app.stage.addChild(text);

Collisions.on("b1", "b2", function(e) {
  if (e.event === "start") {
    text.visible = true;
  }
   if (e.event === "end") {
    text.visible = false;
  }
})

// Listen for animate update
app.ticker.add(function(delta) {
    // just for fun, let's rotate mr rabbit a little
    // delta is 1 if running at 100% performance
    // creates frame-independent tranformation
   // bunny.rotation += 0.01 * delta;
    //bunny2.rotation -= 0.01 * delta;

    bunny2.x = app.renderer.width /2 + Math.sin(Date.now() / 2000) * 50;
    Collisions.update();
});