Detecting shake of playdate device

Shaker.swift

//
//  Shaker.swift
//
//
//  Created by Rico Becker on 30.03.24.
//
import PlaydateKit

struct Shaker {
    let gravity: Float = 9.80665

    enum Sensitivity: CInt {
        case low = 10
        case medium = 15
        case high = 20
    }

    let threshold: Float
    let sensitivity: Shaker.Sensitivity
    let sampleSize: UInt32
    var samples: [Float]

    private var index: UInt32 = 0

    var isTriggering = false

    init(threshold: Float = 0.75, sensitivity: Shaker.Sensitivity = .medium, sampleSize: UInt32 = 20) {
        self.threshold = threshold
        self.sensitivity = sensitivity
        self.sampleSize = sampleSize

        samples = Array(repeating: 0, count: Int(sampleSize))
        reset()

        System.accelerometerIsEnabled = true
    }

    mutating func reset() {
        isTriggering = false
        index = 0
        samples = Array(repeating: 0, count: Int(sampleSize))
    }

    mutating func sample() {
        var (x, y, z) = System.accelerometer

        x *= gravity
        y *= gravity
        z *= gravity

        let acceleration = x * x + y * y + z * z
        let sensitivityValue = Float(sensitivity.rawValue)
        let isAccelerating = acceleration > (sensitivityValue * sensitivityValue)

        index = (index + 1) % sampleSize
        samples[Int(index)] = isAccelerating ? 1 : 0

        test()
    }

    mutating func test() {
        let avg = samples.reduce(0, +) / Float(sampleSize)
        if avg > threshold {
            System.log("Trigger shake")
            isTriggering = true
        }
    }
}