The Tricky Tracker

robot.js

//FightCode can only understand your robot
//if its class is called Robot
var Robot = function(robot) {
    
};

var D = {
    enemyIds: [],
    enemyPositions: {}
};

function addEnemy(robot) {
    var i;
    var exists = false;
    for (i = 0; i < D.enemyIds && !exists; i++) {
	exists = D.enemyIds[i] === robot.id;
    }
    if (!exists) {
      robot.log("id: " + robot.id);
	D.enemyIds.push(robot.id);
	D.enemyPositions[robot.id] = [];
    }
}

Robot.prototype.onIdle = function(ev) {
    var robot = ev.robot;
    robot.ahead(200);
    robot.turn(90);

    adjustCannon(robot);
};

Robot.prototype.onScannedRobot = function(ev) {
    var robot = ev.robot;
    var enemy = ev.scannedRobot;
    addEnemy(enemy);
    updateEnemyPosition(enemy.id, enemy.position);
    robot.fire();
    adjustCannon(robot);
};

function updateEnemyPosition(id, position) {
    if (D.enemyPositions[id].length > 1) {
	D.enemyPositions[id].pop();
    }
    D.enemyPositions[id].push(position);
}

function predictEnemyPosition(id) {
    // Stupid implementation
    var positions = D.enemyPositions[id];
    return positions[positions.length - 1];
}

function adjustCannon(robot) {
    var i, dx, dy, angle, pos, deltaAngle;
    var bestDeltaAngle = 360;
	robot.log(D.enemyIds);
  for (i = 0; i < D.enemyIds.length; i++) {
	pos = predictEnemyPosition(D.enemyIds[i]);
	dx = pos.x - robot.position.x;
	dy = pos.y - robot.position.y;
	angle = Math.atan2(dy, dx) * 180 / Math.PI;
	deltaAngle = robot.cannonAbsoluteAngle - angle;
	if (Math.abs(deltaAngle) < Math.abs(bestDeltaAngle)) {
	    bestDeltaAngle = deltaAngle;
	}
    }
  robot.rotateCannon(bestDeltaAngle);
}