CurrentGlucoseView.swift

import SwiftUI

struct CurrentGlucoseView: View {
    @Binding var recentGlucose: BloodGlucose?
    @Binding var timerDate: Date
    @Binding var delta: Int?
    @Binding var units: GlucoseUnits
    @Binding var alarm: GlucoseAlarm?
    @Binding var lowGlucose: Decimal
    @Binding var highGlucose: Decimal
    @Binding var cgmAvailable: Bool

    private var glucoseFormatter: NumberFormatter {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.maximumFractionDigits = 0
        if units == .mmolL {
            formatter.minimumFractionDigits = 1
            formatter.maximumFractionDigits = 1
        }
        formatter.roundingMode = .halfUp
        return formatter
    }

    private var deltaFormatter: NumberFormatter {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.maximumFractionDigits = 1
        formatter.positivePrefix = "  +"
        formatter.negativePrefix = "  -"
        return formatter
    }

    private var timaAgoFormatter: NumberFormatter {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.maximumFractionDigits = 0
        formatter.negativePrefix = ""
        return formatter
    }

    private var dateFormatter: DateFormatter {
        let formatter = DateFormatter()
        formatter.timeStyle = .short
        return formatter
    }

    var body: some View {
        if cgmAvailable {
            VStack(alignment: .center) {
                HStack {
                    Text(
                        (recentGlucose?.glucose ?? 100) == 400 ? "HIGH" : recentGlucose?.glucose
                            .map {
                                glucoseFormatter
                                    .string(from: Double(units == .mmolL ? $0.asMmolL : Decimal($0)) as NSNumber)! }
                            ?? "--"
                    )
                    .font(.title).fontWeight(.bold)
                    .foregroundColor(alarm == nil ? colorOfGlucose : .loopRed)

                    image
                }
                HStack {
                    let minutesAgo = -1 * (recentGlucose?.dateString.timeIntervalSinceNow ?? 0) / 60
                    let text = timaAgoFormatter.string(for: Double(minutesAgo)) ?? ""
                    Text(
                        minutesAgo <= 1 ? "< 1 " + NSLocalizedString("min", comment: "Short form for minutes") : (
                            text + " " +
                                NSLocalizedString("min", comment: "Short form for minutes") + " "
                        )
                    )
                    .font(.caption2).foregroundColor(.secondary)

                    Text(
                        delta
                            .map {
                                deltaFormatter.string(from: Double(units == .mmolL ? $0.asMmolL : Decimal($0)) as NSNumber)!
                            } ?? "--"
                    )
                    .font(.caption2).foregroundColor(.secondary)
                }.frame(alignment: .top)
            }
        } else {
            VStack(alignment: .center, spacing: 12) {
                HStack
                    {
                        // no cgm defined so display a generic CGM
                        Image(systemName: "sensor.tag.radiowaves.forward.fill").font(.body).imageScale(.large)
                    }
                HStack {
                    Text("Add CGM").font(.caption).bold()
                }
            }.frame(alignment: .top)
        }
    }

    var image: Image {
        guard let direction = recentGlucose?.direction else {
            return Image(systemName: "arrow.left.and.right")
        }

        switch direction {
        case .doubleUp,
             .singleUp,
             .tripleUp:
            return Image(systemName: "arrow.up")
        case .fortyFiveUp:
            return Image(systemName: "arrow.up.right")
        case .flat:
            return Image(systemName: "arrow.forward")
        case .fortyFiveDown:
            return Image(systemName: "arrow.down.forward")
        case .doubleDown,
             .singleDown,
             .tripleDown:
            return Image(systemName: "arrow.down")

        case .none,
             .notComputable,
             .rateOutOfRange:
            return Image(systemName: "arrow.left.and.right")
        }
    }

    var colorOfGlucose: Color {
        let whichGlucose = recentGlucose?.glucose ?? 0

        guard lowGlucose < highGlucose else { return .primary }

        switch whichGlucose {
        case 0 ..< Int(lowGlucose):
            return .loopRed
        case Int(lowGlucose) ..< Int(highGlucose):
            return .loopGreen
        case Int(highGlucose)...:
            return .loopYellow
        default:
            return .loopYellow
        }
    }
}