/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    An `SKSpriteNode` subclass that displays a `PlayerBot`'s remaining charge.

*/

import SpriteKit

class ChargeBar: SKSpriteNode {

    // MARK: Static Properties

    struct Configuration {

        /// The size of the complete bar (back and level indicator).

        static let size = CGSize(width: 74.0, height: 10.0)

        /// The size of the colored level bar.

        static let chargeLevelNodeSize = CGSize(width: 70.0, height: 6.0)

        /// The duration used for actions to update the level indicator.

        static let levelUpdateDuration: TimeInterval = 0.1

        /// The background color.

        static let backgroundColor = SKColor.black

        /// The charge level node color.

        static let chargeLevelColor = SKColor.green

    }

    // MARK: Properties

    var level: Double = 1.0 {

        didSet {

            // Scale the level bar node based on the current health level.

            let action = SKAction.scaleX(to: CGFloat(level), duration: Configuration.levelUpdateDuration)

            action.timingMode = .easeInEaseOut

            chargeLevelNode.run(action)

        }

    }

    /// A node representing the charge level.

    let chargeLevelNode = SKSpriteNode(color: Configuration.chargeLevelColor, size: Configuration.chargeLevelNodeSize)

    // MARK: Initializers

    init() {

        super.init(texture: nil, color: Configuration.backgroundColor, size: Configuration.size)

        addChild(chargeLevelNode)

        // Constrain the position of the `chargeLevelNode`.

        let xRange = SKRange(constantValue: chargeLevelNode.size.width / -2.0)

        let yRange = SKRange(constantValue: 0.0)

        let constraint = SKConstraint.positionX(xRange, y: yRange)

        constraint.referenceNode = self

        chargeLevelNode.anchorPoint = CGPoint(x: 0.0, y: 0.5)

        chargeLevelNode.constraints = [constraint]

    }

    required init?(coder aDecoder: NSCoder) {

        fatalError("init(coder:) has not been implemented")

    }

}