Aplysia

0.article.swift

class Neuron {
    var incomingNeurons: [Neuron] = []
    var outcomingNeurons: [Neuron] = []
    var releasableSynapticVesicles: Int = 1000
    private weak var timer: Timer?

    init() {
        Timer.scheduledTimer(withTimeInterval: 5, repeats: true, block: { _ in
            self.replenishSynapticVesicles()
        })
    }

    func excite(magnitude: Int) { fatalError("Needs to be overriden") }

    func consumeReleasableSynapticVesicles() {
        releasableSynapticVesicles = releasableSynapticVesicles * 3/4
    }

    @objc private func replenishSynapticVesicles() {
        print("replenishing vesicles ...")
        if self.releasableSynapticVesicles < 1000 {
            self.releasableSynapticVesicles += 100
        }
    }

}

class MotorNeuron: Neuron {
    override func excite(magnitude: Int) {
        print("Withdraw with magnitude \(magnitude)")
    }
}

class SensoryNeuron: Neuron {
    override func excite(magnitude: Int) {
        let outputMagnitude = magnitude * self.releasableSynapticVesicles
        print("Sensory neuron receives touch with magnitude \(magnitude) sends action potential with magnitude: \(outputMagnitude)")
        for neuron in outcomingNeurons {
            neuron.excite(magnitude: outputMagnitude)
        }
        consumeReleasableSynapticVesicles()
    }
}

class InterNeuron: Neuron {
    override func excite(magnitude: Int) {
        let outputMagnitude = magnitude * self.releasableSynapticVesicles
        print("Inter neuron receives action potential with magnitude \(magnitude) sends action potential with magnitude: \(outputMagnitude)")
        for neuron in outcomingNeurons {
            neuron.excite(magnitude: outputMagnitude)
        }
        consumeReleasableSynapticVesicles()
    }
}

protocol Organ {
    var neurons: [Neuron] { get }
}

class Siphon: Organ {
    var neurons = [Neuron]()
    func touch() {
        for neuron in neurons {
            neuron.excite(magnitude: 10)
        }
    }
}

class Gill: Organ {
    var neurons = [Neuron]()
}

class Aplysia {
    let siphon: Siphon
    let gill: Gill

    init(siphon: Siphon, gill: Gill) {
        self.siphon = siphon
        self.gill = gill
        grow()
    }

    private func grow() {
        print("Aplysia is growing up ...");
        // Wire up neurons in Aplysia, this is what happens when a baby Aplysia grows up :)
        let interNeuron = InterNeuron()
        self.siphon.neurons[0].outcomingNeurons.append(interNeuron);
        interNeuron.outcomingNeurons.append(self.gill.neurons[0]);

        print("Aplysia has grown up. Neural pathways are fully wired. :)");
        // siphon's sensory neuron --> interNeuron --> gill's motor neuron
    }

}