var speed = 3.0;
var rotationSpeed = 5.0;
var shootRange = 15.0;
var attackRange = 30.0;
var shootAngle = 4.0;
var dontComeCloserRange = 5.0;
var delayShootTime = 0.35;
var pickNextWaypointDistance = 2.0;
var target : Transform;

private var lastShot = -10.0;

// Make sure there is always a character controller
@script RequireComponent (CharacterController)

function Start () {
  // Auto setup player as target through tags
  if (target == null && GameObject.FindWithTag("Player"))
   target = GameObject.FindWithTag("Player").transform;

  Patrol();
}

function Patrol () {
  var curWayPoint = AutoWayPoint.FindClosest(transform.position);
  while (true) {
   var waypointPosition = curWayPoint.transform.position;
   // Are we close to a waypoint? -> pick the next one!
   if (Vector3.Distance(waypointPosition, transform.position) < pickNextWaypointDistance)
    curWayPoint = PickNextWaypoint (curWayPoint);

   // Attack the player and wait until
   // - player is killed
   // - player is out of sight   
   if (CanSeeTarget ())
    yield StartCoroutine("AttackPlayer");
    
   // Move towards our target
   MoveTowards(waypointPosition);
    
   yield;
  }
}

function CanSeeTarget () : boolean {
  if (Vector3.Distance(transform.position, target.position) > attackRange)
   return false;
    
  var hit : RaycastHit;
  if (Physics.Linecast (transform.position, target.position, hit))
   return hit.transform == target;

  return false;
}

function Shoot () {
  // Start shoot animation
  animation.CrossFade("shoot", 0.3);

  // Wait until half the animation has played
  yield WaitForSeconds(delayShootTime);
   
  // Fire gun
  BroadcastMessage("Fire");
   
  // Wait for the rest of the animation to finish
  yield WaitForSeconds(animation["shoot"].length - delayShootTime);
}

function AttackPlayer () {
  var lastVisiblePlayerPosition = target.position;
  while (true) {
   if (CanSeeTarget ()) {
    // Target is dead - stop hunting
    if (target == null)
     return;

    // Target is too far away - give up  
    var distance = Vector3.Distance(transform.position, target.position);
    if (distance > shootRange * 3)
     return;
     
    lastVisiblePlayerPosition = target.position;
    if (distance > dontComeCloserRange)
     MoveTowards (lastVisiblePlayerPosition);
    else
     RotateTowards(lastVisiblePlayerPosition);

    var forward = transform.TransformDirection(Vector3.forward);
    var targetDirection = lastVisiblePlayerPosition - transform.position;
    targetDirection.y = 0;

    var angle = Vector3.Angle(targetDirection, forward);

    // Start shooting if close and play is in sight
    if (distance < shootRange && angle < shootAngle)
     yield StartCoroutine("Shoot");
   } else {
    yield StartCoroutine("SearchPlayer", lastVisiblePlayerPosition);
    // Player not visible anymore - stop attacking
    if (!CanSeeTarget ())
     return;
   }

   yield;
  }
}

function SearchPlayer (position : Vector3) {
  // Run towards the player but after 3 seconds timeout and go back to Patroling
  var timeout = 3.0;
  while (timeout > 0.0) {
   MoveTowards(position);

   // We found the player
   if (CanSeeTarget ())
    return;

   timeout -= Time.deltaTime;
   yield;
  }
}

function RotateTowards (position : Vector3) {
  SendMessage("SetSpeed", 0.0);
   
  var direction = position - transform.position;
  direction.y = 0;
  if (direction.magnitude < 0.1)
   return;
   
  // Rotate towards the target
  transform.rotation = Quaternion.Slerp (transform.rotation, Quaternion.LookRotation(direction), rotationSpeed * Time.deltaTime);
  transform.eulerAngles = Vector3(0, transform.eulerAngles.y, 0);
}

function MoveTowards (position : Vector3) {
  var direction = position - transform.position;
  direction.y = 0;
  if (direction.magnitude < 0.5) {
   SendMessage("SetSpeed", 0.0);
   return;
  }
   
  // Rotate towards the target
  transform.rotation = Quaternion.Slerp (transform.rotation, Quaternion.LookRotation(direction), rotationSpeed * Time.deltaTime);
  transform.eulerAngles = Vector3(0, transform.eulerAngles.y, 0);

  // Modify speed so we slow down when we are not facing the target
  var forward = transform.TransformDirection(Vector3.forward);
  var speedModifier = Vector3.Dot(forward, direction.normalized);
  speedModifier = Mathf.Clamp01(speedModifier);

  // Move the character
  direction = forward * speed * speedModifier;
  GetComponent (CharacterController).SimpleMove(direction);
   
  SendMessage("SetSpeed", speed * speedModifier, SendMessageOptions.DontRequireReceiver);
}

function PickNextWaypoint (currentWaypoint : AutoWayPoint) {
  // We want to find the waypoint where the character has to turn the least

  // The direction in which we are walking
  var forward = transform.TransformDirection(Vector3.forward);

  // The closer two vectors, the larger the dot product will be.
  var best = currentWaypoint;
  var bestDot = -10.0;
  for (var cur : AutoWayPoint in currentWaypoint.connected) {
   var direction = Vector3.Normalize(cur.transform.position - transform.position);
   var dot = Vector3.Dot(direction, forward);
   if (dot > bestDot && cur != currentWaypoint) {
    bestDot = dot;
    best = cur;
   }
  }
   
  return best;
}