/*

    Copyright (C) 2015 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    A SpriteKit node whose position is managed by a GameplayKit agent. Also provides the standard appearance for agents in this demo.

 */

#import "AAPLAgentNode.h"

@interface AAPLAgentNode ()

@property SKShapeNode *triangleShape;

@property SKEmitterNode *particles;

@property CGFloat defaultParticleRate;

@end

@implementation AAPLAgentNode

#pragma mark - Initialization

- (instancetype)initWithScene:(SKScene *)scene radius:(float)radius position:(CGPoint)position {

    self = [super init];

    if (self) {

        self.position = position;

        self.zPosition = 10;

        [scene addChild:self];

        // An agent to manage the movement of this node in a scene.

        _agent = [[GKAgent2D alloc] init];

        _agent.radius = radius;

        _agent.position = (vector_float2){position.x, position.y};

        _agent.delegate = self;

        _agent.maxSpeed = 100;

        _agent.maxAcceleration = 50;

        // A circle to represent the agent's radius in the agent simulation.

        SKShapeNode *circleShape = [SKShapeNode shapeNodeWithCircleOfRadius:radius];

        circleShape.lineWidth = 2.5;

        circleShape.fillColor = [SKColor grayColor];

        circleShape.zPosition = 1;

        [self addChild:circleShape];

        // A triangle to represent the agent's heading (rotation) in the agent simulation.

        CGPoint points[4];

        const static float triangleBackSideAngle = (135.0f / 360.0f) * (2 * M_PI);

        points[0] = CGPointMake(radius,0); // Tip.

        points[1] = CGPointMake(radius * cos(triangleBackSideAngle), radius * sin(triangleBackSideAngle)); // Back bottom.

        points[2] = CGPointMake(radius * cos(triangleBackSideAngle), -radius * sin(triangleBackSideAngle)); // Back top.

        points[3] = CGPointMake(radius, 0); // Back top.

        _triangleShape = [SKShapeNode shapeNodeWithPoints:points count:4];

        _triangleShape.lineWidth = 2.5;

        _triangleShape.zPosition = 1;

        [self addChild:_triangleShape];

        // A particle effect to leave a trail behind the agent as it moves through the scene.

        _particles = [SKEmitterNode nodeWithFileNamed:@"Trail.sks"];

        _defaultParticleRate = _particles.particleBirthRate;

        _particles.position = CGPointMake(-radius + 5, 0);

        _particles.targetNode = scene;

        _particles.zPosition = 0;

        [self addChild:_particles];

    }

    return self;

}

- (void)setColor:(SKColor *)color {

    self.triangleShape.strokeColor = color;

}

- (SKColor *)color {

    return self.triangleShape.strokeColor;

}

- (void)setDrawsTrail:(BOOL)drawsTrail {

    _drawsTrail = drawsTrail;

    if (_drawsTrail) {

        self.particles.particleBirthRate = self.defaultParticleRate;

    }

    else {

        self.particles.particleBirthRate = 0;

    }

}

#pragma mark - GKAgentDelegate

- (void)agentWillUpdate:(nonnull GKAgent *)agent {

    // All changes to agents in this app are driven by the agent system, so

    // there's no other changes to pass into the agent system in this method.

}

- (void)agentDidUpdate:(nonnull GKAgent2D *)agent {

    // Agent and sprite use the same coordinate system (in this app),

    // so just convert vector_float2 position to CGPoint.

    self.position = CGPointMake(agent.position.x, agent.position.y);

    self.zRotation = agent.rotation;

}

@end