/*

 Copyright (C) 2018 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 This is a simple behavior for enemies to chase the character when the player is detected.

 */

#import "AAPLPlayerComponent.h"

#import "AAPLChaserComponent.h"

#import "AAPLCharacter.h"

typedef enum

{

    Wander,

    Chase,

    Dead

} ChaserState;

@implementation AAPLChaserComponent

{

    ChaserState _state;

    AAPLPlayerComponent *_player;

    GKGoal *_chaseGoal;

    GKGoal *_wanderGoal;

    GKGoal *_centerGoal;

    float _speed;

    BOOL _hitting;

}

- (instancetype)initWithCoder:(NSCoder *)aDecoder{

    if (self = [super initWithCoder:aDecoder])

    {

        _speed = self.chaseSpeed;

    }

    return self;

}

- (AAPLPlayerComponent *)player

{

    return _player;

}

- (BOOL)isDead

{

    return _state == Dead;

}

- (void)startWandering

{

    self.agent.maxSpeed = self.wanderSpeed;

    [self.agent.behavior setWeight:1 forGoal:_wanderGoal];

    [self.agent.behavior setWeight:0 forGoal:_chaseGoal];

    [self.agent.behavior setWeight:.4 forGoal:_centerGoal];

    _state = Wander;

}

- (void)startChasing

{

    self.agent.maxSpeed = _speed;

    [self.agent.behavior setWeight:0 forGoal:_wanderGoal];

    [self.agent.behavior setWeight:1 forGoal:_chaseGoal];

    [self.agent.behavior setWeight:.1 forGoal:_centerGoal];

    _state = Chase;

}

- (void) setPlayer:(AAPLPlayerComponent *)player

{

    _player = player;

    self.agent.mass = self.mass;

    self.agent.maxAcceleration = self.maxAcceleration;

    _chaseGoal = [GKGoal goalToSeekAgent:self.player.agent];

    _wanderGoal = [GKGoal goalToWander:self.wanderSpeed];

    simd_float2 center[] = { {-1, 9}, {1, 9}, {1, 11}, {-1, 11} };

    GKPath * p = [GKPath pathWithPoints:center count:4 radius:.5 cyclical:YES];

    _centerGoal = [GKGoal goalToStayOnPath:p maxPredictionTime:1];

    self.agent.behavior = [GKBehavior behaviorWithGoals:@[_chaseGoal, _wanderGoal, _centerGoal]];

    [self startWandering];

}

- (void)updateWithDeltaTime:(NSTimeInterval)seconds

{

    if(_state == Dead){

        return;

    }

    GKSCNNodeComponent *playerComponent = (GKSCNNodeComponent *)[self.player.entity componentForClass:GKSCNNodeComponent.class];

    SCNNode *player = playerComponent.node;

    GKSCNNodeComponent *nodeComponent = (GKSCNNodeComponent *)[self.entity componentForClass:GKSCNNodeComponent.class];

    SCNNode *enemyNode = nodeComponent.node;

    vector_float3 direction = enemyNode.simdWorldPosition - player.simdWorldPosition;

    float distance = vector_length(direction);

    switch (_state)

    {

        case Wander:

        {

            if (distance < self.chaseDistance) {

                [self startChasing];

            }

        } break;

        case Chase:

        {

            if (distance > self.chaseDistance) {

                [self startWandering];

            }

        } break;

        case Dead:

            break;

    }

    //update speed

    _speed = MIN(self.chaseSpeed, distance);

    if (distance < self.hitDistance) {

        if(_player.character.isAttacking){

            //let's die

            _state = Dead;

            [_player.character didHitEnemy];

            SCNScene *explosionScene = [SCNScene sceneNamed:@"Art.scnassets/enemy/enemy_explosion.scn"];

            [SCNTransaction begin];

            [SCNTransaction setAnimationDuration:0.4];

            [SCNTransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];

            [SCNTransaction setCompletionBlock:^{

                [explosionScene.rootNode enumerateHierarchyUsingBlock:^(SCNNode * _Nonnull node, BOOL * _Nonnull stop) {

                    for(SCNParticleSystem *ps in node.particleSystems){

                        [enemyNode addParticleSystem:ps];

                    }

                }];

                //hide

                enemyNode.childNodes[0].opacity = 0.0;

            }];

            direction.y = 0;

            [enemyNode removeAllAnimations];

            enemyNode.eulerAngles = SCNVector3Make(enemyNode.eulerAngles.x,enemyNode.eulerAngles.y +  M_PI * 4.f, enemyNode.eulerAngles.z);

            enemyNode.simdWorldPosition = enemyNode.simdWorldPosition + vector_normalize(direction) * 1.5;

            [self positionAgentFromNode];

            [SCNTransaction commit];

        }

        else{

            [_player.character wasTouchedByEnemy];

        }

    }    

    [super updateWithDeltaTime:seconds];

}

@end