//

//  Measurements.swift

//  USB Meter

//

//  Created by Bogdan Timofte on 07/05/2020.

//  Copyright © 2020 Bogdan Timofte. All rights reserved.

//

import Foundation

import CoreGraphics

class Measurements : ObservableObject {

    class Measurement : ObservableObject {

        struct Point : Identifiable , Hashable {

                case sample

                case discontinuity

            }

            var timestamp: Date

            var value: Double

            var isSample: Bool {

                kind == .sample

            }

            var isDiscontinuity: Bool {

                kind == .discontinuity

            }

                return CGPoint(x: timestamp.timeIntervalSince1970, y: value)

            }

        }

        var points: [Point] = []

        var context = ChartContext()

            points.filter { $0.isSample }

        }

        private func rebuildContext() {

            context.reset()

            for point in points where point.isSample {

                context.include(point: point.point())

            }

        }

        private func appendPoint(timestamp: Date, value: Double, kind: Point.Kind) {

            let newPoint = Measurement.Point(id: points.count, timestamp: timestamp, value: value, kind: kind)

            points.append(newPoint)

            if newPoint.isSample {

                context.include(point: newPoint.point())

            }

            self.objectWillChange.send()

        }

            points.remove(at: index)

                points[index].id = index

        }

        func addPoint(timestamp: Date, value: Double) {

        }

        func addDiscontinuity(timestamp: Date) {

            guard !points.isEmpty else { return }

            guard points.last?.isDiscontinuity == false else { return }

            appendPoint(timestamp: timestamp, value: points.last?.value ?? 0, kind: .discontinuity)

            context.reset()

            self.objectWillChange.send()

        }

        func trim(before cutoff: Date) {

            points = points

                .filter { $0.timestamp >= cutoff }

                .enumerated()

                .map { index, point in

        }

    @Published var power = Measurement()

    @Published var voltage = Measurement()

    @Published var current = Measurement()

    @Published var rssi = Measurement()

    let averagePowerSampleOptions: [Int] = [5, 10, 20, 50, 100, 250]

    private var pendingBucketTimestamp: Date?

    private var itemsInSum: Double = 0

    private var powerSum: Double = 0

    private var voltageSum: Double = 0

    private var currentSum: Double = 0

    private var rssiSum: Double = 0

        pendingBucketSecond = nil

        pendingBucketTimestamp = nil

        powerSum = 0

        voltageSum = 0

        currentSum = 0

        rssiSum = 0

    private func flushPendingValues() {

        guard let pendingBucketTimestamp, itemsInSum > 0 else { return }

        self.power.addPoint(timestamp: pendingBucketTimestamp, value: powerSum / itemsInSum)

        self.voltage.addPoint(timestamp: pendingBucketTimestamp, value: voltageSum / itemsInSum)

        self.current.addPoint(timestamp: pendingBucketTimestamp, value: currentSum / itemsInSum)

        self.rssi.addPoint(timestamp: pendingBucketTimestamp, value: rssiSum / itemsInSum)

    }

    func resetSeries() {

        power.resetSeries()

        voltage.resetSeries()

        current.resetSeries()

        rssi.resetSeries()

        self.objectWillChange.send()

    }

    func reset() {

        resetSeries()

    }

    func remove(at idx: Int) {

        power.removeValue(index: idx)

        voltage.removeValue(index: idx)

        current.removeValue(index: idx)

        rssi.removeValue(index: idx)

    }

        voltage.trim(before: cutoff)

        current.trim(before: cutoff)

        rssi.trim(before: cutoff)

    }

        if pendingBucketSecond == valuesTimestamp {

            pendingBucketTimestamp = timestamp

            currentSum += current

            rssiSum += rssi

        flushPendingValues()

        pendingBucketSecond = valuesTimestamp

        pendingBucketTimestamp = timestamp

        itemsInSum = 1

        powerSum = power

        voltageSum = voltage

        currentSum = current

        rssiSum = rssi

    func markDiscontinuity(at timestamp: Date) {

        flushPendingValues()

        power.addDiscontinuity(timestamp: timestamp)

        voltage.addDiscontinuity(timestamp: timestamp)

        current.addDiscontinuity(timestamp: timestamp)

        rssi.addDiscontinuity(timestamp: timestamp)

    func powerSampleCount(flushPendingValues shouldFlushPendingValues: Bool = true) -> Int {

        if shouldFlushPendingValues {

            flushPendingValues()

        }

        return power.samplePoints.count

    }

    func recentPowerPoints(limit: Int, flushPendingValues shouldFlushPendingValues: Bool = true) -> [Measurement.Point] {

        if shouldFlushPendingValues {

            flushPendingValues()

        }

        let samplePoints = power.samplePoints

        guard limit > 0, samplePoints.count > limit else {

            return samplePoints

        }

        return Array(samplePoints.suffix(limit))

    }

    func averagePower(forRecentSampleCount sampleCount: Int, flushPendingValues shouldFlushPendingValues: Bool = true) -> Double? {

        let points = recentPowerPoints(limit: sampleCount, flushPendingValues: shouldFlushPendingValues)

        guard !points.isEmpty else { return nil }

        let sum = points.reduce(0) { partialResult, point in

            partialResult + point.value

        }

        return sum / Double(points.count)

    }