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

    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 {
        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(.system(size: 40, weight: .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)
        }
        .overlay(
            TrendShape(color: colorOfGlucose)
        )
    }

    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
        }
    }
}

struct Triangle: Shape {
    func path(in rect: CGRect) -> Path {
        var path = Path()

        path.move(to: CGPoint(x: rect.midX, y: rect.minY))
        path.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY))
        path.addLine(to: CGPoint(x: rect.minX, y: rect.maxY))
        path.closeSubpath()

        return path
    }
}

struct TrendShape: View {
    let color: Color

    var body: some View {
        HStack(alignment: .center, spacing: -4) {
            CircleShape(color: color)
            TriangleShape(color: color)
        }
    }
}

struct CircleShape: View {
    let color: Color

    var body: some View {
        Circle()
            .stroke(color, lineWidth: 10)
            .frame(width: 100, height: 100)
            .offset(x: 13)
    }
}

struct TriangleShape: View {
    let color: Color

    var body: some View {
        Triangle()
            .fill(color)
            .frame(width: 30, height: 30)
            .rotationEffect(.degrees(90))
            .offset(x: 13)
    }
}