// Imports / Requirements
var Geometry = Geometry || global.Geometry;
var MovingObject = MovingObject || global.MovingObject;
var RenderablePolygon = RenderablePolygon || global.RenderablePolygon;



var ObjectTypes = {SHIP: 0, ASTEROID: 1, BULLET: 2, EXPLOSION: 3};
var SHOT_TIMEOUT = 750; // 1/2 second
var SHOT_SPEED = 500; // must be larger than ship max speed.

/*
A bullet that is fired from a ship. The ship is used for initial position and velocity.
This velocity doesn't change.
This augments the given movingObj with bullet functionality, or creates a new bullet if
no moving obj is given.

args expects shipParent
*/
function Bullet(movingObj, args){
  // MobileObject Inheritance
  var shot = movingObj || new MovingObject(null, args);
  var t = args.t || 0;
  
  var parent_move = shot.move; //inherited method;
  var parent_toObj = shot.toObject;

  // RenderablePolygon Inheritance
  args.polyCoords = [[2, 0], [-1.4, -1.4], [-1.4, 1.4]];
  RenderablePolygon(shot, args);


  var move = function(delta){
    parent_move(delta);
    
    t += delta;
  }
  
  
  
  var toObject = function(){
    var obj = parent_toObj();
    obj.t = t;
    
    return obj;
  };



  shot.move = move;
  shot.toObject = toObject;
  shot.hasExpired = function(){ return t >= SHOT_TIMEOUT; };
  shot.getObjectType = function(){ return ObjectTypes.BULLET; };

  return shot;
}






/*
An explosion for when things blow up.

args expects movingParent, numParticles, maxRadius
*/
function Explosion(movingObj, args){
  var EXPLOSION_TIMEOUT = 750; // 3/4 second
  var EXPLOSION_SPEED = 500; // arbitrary

  var movingParent = args.movingParent;
  var numParticles = args.numParticles;
  var maxRadius = args.maxRadius;

  // MobileObject Inheritance
  var expl = movingObj || new MovingObject(null, args);
  var t = args.t || 0;

  var particlePoints = args.particlePoints || (function(){
    var arr = [];
    for(var i = 0; i < numParticles; i++){
      arr[i] = [];
      arr[i][0] = expl.getX();
      arr[i][1] = expl.getY();
    }
    return arr; })();
  
  var parent_move = expl.move; //inherited method;
  var parent_toObj = expl.toObject;



  var render = function(context){
    for(var i = 0; i < particlePoints.length; i++){
      var p = particlePoints[i];
      context.rect(p[0], p[1], 1, 1);
      context.closePath();
      context.lineWidth = 2;
      context.stroke();
    }
  };



  var move = function(delta){
    parent_move(delta);
    
    var length = maxRadius * delta / EXPLOSION_TIMEOUT;
    var angleDiff = 2 * Math.PI / particlePoints.length;
    
    for(var i = 0; i < particlePoints.length; i++){
      particlePoints[i][0] += length * Math.cos(i * angleDiff);
      particlePoints[i][1] -= length * Math.sin(i * angleDiff);
    }
    
    t += delta;
  }
  
  
  
  var toObject = function(){
    var obj = parent_toObj();
    
    obj.maxRadius = maxRadius;
    obj.numParticles = numParticles;
    obj.t = t;
    obj.particlePoints = particlePoints;
    
    return obj;
  };



  expl.render = render;
  expl.move = move;
  expl.toObject = toObject;
  expl.hasExpired = function(){ return t >= EXPLOSION_TIMEOUT; };
  expl.getObjectType = function(){ return ObjectTypes.EXPLOSION; };

  return expl;
}






/*
Asteroid object.

args expects rockSize, and movingObject
*/
function Asteroid(movingObj, args){
  var MAX_ROCK_SPEED = 80;

  var rockSize = args.rockSize;

  // MovingObject Inheritance
  args.maxSpeed = args.maxSpeed ? Math.min(args.maxSpeed, MAX_ROCK_SPEED)
                  : MAX_ROCK_SPEED;
  args.speed = args.speed || Math.floor(Math.random() * MAX_ROCK_SPEED / 2) + MAX_ROCK_SPEED / 2; // 1/2 max < speed < max
  args.angle = args.angle || Math.random() * Math.PI * 2; //random angle
  var rock = movingObj || new MovingObject(null, args);

  // RenderablePolygon Inheritance
  args.polyCoords = args.polyCoords || makeAsteroidPolygon(rockSize, rockSize * 5);
  RenderablePolygon(rock, args);
  
  var parent_toObj = rock.toObject;
  
  
  
  var toObject = function(){
    var obj = parent_toObj();
    obj.rockSize = rockSize;
    
    return obj;
  }



  rock.toObject = toObject;
  rock.getObjectType = function(){ return ObjectTypes.ASTEROID; };
  rock.getRockSize = function(){ return rockSize; };

  return rock;
}






/*
Creates a new Spaceship, or augments a moving object with Spaceship functionality.

Can shoot bullets.

args may have the arguments of moving object.
*/
function SpaceShip(movingObj, args){

  var SPEED_DECAY_RATE = 0.1; // Proportion of speed lost per second.
  var MAX_SHIP_SPEED = 150;
  var SHOT_DELAY = 2000; //1 second between shots.

  // MovingObject Inheritance
  args.maxSpeed = args.maxSpeed ? Math.min(args.maxSpeed, MAX_SHIP_SPEED)
                  : MAX_SHIP_SPEED;
  var ship = movingObj || new MovingObject(null, args);

  // RenderablePolygon Inheritance
  args.polyCoords = [ [15, 0],
            [Math.cos(Math.PI * 2/3) * 10, - Math.sin(Math.PI * 2/3) * 10],
            [-2, 0],
            [Math.cos(Math.PI * 4/3) * 10, - Math.sin(Math.PI * 4/3) * 10]];
  RenderablePolygon(ship, args);

  var shot_timeout = 0;
  
  
  var parent_toObj = ship.toObject;
  var parent_move = ship.move; // Inherited method.



  var makeShot = function(){
    if(shot_timeout <= 0){
      var bullet_args = {x: ship.getX(),
                         y: ship.getY(),
                         angle: ship.getViewAngle(),
                         speed: SHOT_SPEED};
      var shot = new Bullet(null, bullet_args);
      shot_timeout = SHOT_DELAY;
      return shot;
    } else {
      return false;
    }
  }



  // Move the ship, decay speed, check when we can shoot or not.
  var move = function(delta){
    parent_move(delta);
    //console.log("child move");
    
    //Slow down. Approximate speed loss.
    var currSpeed = ship.getSpeed();
    var speedLost = currSpeed * SPEED_DECAY_RATE * delta / 1000;
    ship.setSpeed(currSpeed - speedLost);
    if(ship.getSpeed() < 1){
      //speed = 0;
    }
    
    if(shot_timeout > 0){
      shot_timeout -= delta;
    }
  }
  
  
  
  var toObject = function(){
    var obj = parent_toObj();
    obj.shot_timeout = shot_timeout;
    
    return obj;
  }



  ship.move = move;
  ship.toObject = toObject;
  ship.shoot = makeShot;
  ship.canShoot = function(){ return shot_timeout <= 0; };
  ship.getObjectType = function(){ return ObjectTypes.SHIP; };

  return ship;
}






global.ObjectTypes = ObjectTypes;

global.Bullet = Bullet;
global.Asteroid = Asteroid;
global.Explosion = Explosion;
global.SpaceShip = SpaceShip;