//
//  PinxinTakeMeasurementScenario.swift
//  Harmonize
//
//  Created by Valerii Hvozdiev on 9/18/19.
//  Copyright © 2019 Harmonize. All rights reserved.
//

import Foundation
import SwiftyTimer

class PinxinTakeMeasurementScenario : ScenarioProtocol, SensorCommunicatorRouterSimpleDelegate {

    class Constants {
        static let weightLowerBound : Float = 20.0
        static let valuesInRowNeededForAccept = 4
        static let acceptTimeout = 5.0
    }

    var scenarioDelegate: ScenarioDelegate?
    var scenarioIsCompletedSuccessfully: Bool = false
    var measurementDelegate: WeightTakeMeasurementScenarioDelegate?

    private var peripheralController : PeripheralControllerProtocol!
    private var valueAcceptTimer : Timer?
    private var sameWeightInRowCount = 0
    private var lastWeightValue : Float = 0

    func start() {
        sameWeightInRowCount = 0
        valueAcceptTimer = nil
        lastWeightValue = 0

        measurementDelegate?.measurementBegan()
        peripheralController.setCharacteristicNotification(Devices.PinxinWeight.weightNotifyCharacteristic.identifier)
        peripheralController.writeCharacteristic(Devices.PinxinWeight.weightSettingCharacteristic.identifier, value: Data([1,1]))
    }

    func stop() {
        peripheralController.requestDeviceDisconnect()
    }

    func restart() {
        start()
    }

    func setController(_ controller: PeripheralControllerProtocol) {
        self.peripheralController = controller
    }

    func onReadCharacteristic(_ characteristic: SensorCharacteristicIdentifier) {
        guard let data = characteristic.value?.map({Int($0)}), data.count >= 13 else { return }
        let weightValue = Float(data[12] << 8 + data[11]) / 10.0
        receiveValue(weightLbs: weightValue)
    }

    private func receiveValue(weightLbs: Float) {
        // reject values lower then 20lbs
        if weightLbs < Constants.weightLowerBound {
            sameWeightInRowCount = 0
            return
        }

        print("same in row count \(sameWeightInRowCount) \(lastWeightValue)")
        // count how many equal weight values were received in row
        if weightLbs == lastWeightValue {
            sameWeightInRowCount += 1
        } else {
            sameWeightInRowCount = 0
            valueAcceptTimer?.invalidate()
            lastWeightValue = weightLbs
        }

        // start finisher timer if we have 5 measurements and new measurements
        // will not be received in next 5 seconds
        guard sameWeightInRowCount == Constants.valuesInRowNeededForAccept else { return }

        print("timer reset")
        valueAcceptTimer?.invalidate()
        valueAcceptTimer = Timer.after(Constants.acceptTimeout.seconds, { [weak self] in
            print("weight timer fired")
            self?.finishMeasurement()
        })
    }

    private func finishMeasurement() {
        scenarioIsCompletedSuccessfully = true
        peripheralController.requestDeviceDisconnect()
        measurementDelegate?.measurementFinished(weightLbs: lastWeightValue)
        scenarioDelegate?.scenarioExecutionFinished(scenario: self)
    }

    deinit {
        valueAcceptTimer?.invalidate()
        valueAcceptTimer = nil
    }

}