//

//  CBManagerState.swift

//  USB Meter

//

//  Created by Bogdan Timofte on 02/03/2020.

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

//

//import Foundation

import CoreBluetooth

import SwiftUI

//Manager States

//.poweredOff   A state that indicates Bluetooth is currently powered off.

//.poweredOn    A state that indicates Bluetooth is currently powered on and available to use.

//.resetting    A state that indicates the connection with the system service was momentarily lost.

//.unauthorized A state that indicates the application isn’t authorized to use the Bluetooth low energy role.

//.unknown      The manager’s state is unknown.

//.unsupported  A state that indicates this device doesn’t support the Bluetooth low energy central or client role.

extension CBManagerState {

    var description: String  {

        switch self {

        case .poweredOff:

            return "CBManagerState.poweredOff"

        case .poweredOn:

            return "CBManagerState.poweredOn"

        case .resetting:

            return "CBManagerState.resetting"

        case .unauthorized:

            return "CBManagerState.unauthorized"

        case .unknown:

            return "CBManagerState.unknown"

        case .unsupported:

            return "CBManagerState.unsupported"

        default:

            return "CBManagerState.other"

        }

    }

    var color: Color  {

        switch self {

        case .poweredOff:

            return Color.red

        case .poweredOn:

            return Color.blue

        case .resetting:

            return Color.green

        case .unauthorized:

            return Color.orange

        case .unknown:

            return Color.secondary

        case .unsupported:

            return Color.gray

        default:

            return Color.yellow

        }

    }

    var helpView: AnyView  {

        switch self {

        case .poweredOff:

            return AnyView(poweredOffHelperView())

        case .poweredOn:

            return AnyView(poweredOnHelperView())

        case .resetting:

            return AnyView(resettingHelperView())

        case .unauthorized:

            return AnyView(unauthorizedHelperView())

        case .unknown:

            return AnyView(unknownHelperView())

        case .unsupported:

            return AnyView(unsupportedHelperView())

        default:

            return AnyView(defaultHelperView())

        }

    }

    private struct poweredOffHelperView: View {

        var body: some View {

                title: "Bluetooth Off",

                detail: "Bluetooth is turned off on this device. You can enable it in Settings > Bluetooth.",

                tint: .red

            )

    }

    private struct poweredOnHelperView: View {

        var body: some View {

                title: "Bluetooth Ready",

                detail: "Bluetooth is powered on and ready for scanning.",

                tint: .blue

            )

    }

    private struct resettingHelperView: View {

        var body: some View {

                title: "Bluetooth Resetting",

                detail: "The Bluetooth stack is temporarily resetting. Wait a moment and try again.",

                tint: .green

            )

    }

    private struct unauthorizedHelperView: View {

        var body: some View {

                Text("Bluetooth Access Needed")

                    .font(.headline)

                Text("This application does not have permission to access Bluetooth. You can enable it in Settings.")

                    .font(.footnote)

                    .foregroundColor(.secondary)

                    Text("Settings")

                }

                .padding(.vertical, 10)

                .meterCard(tint: .orange, fillOpacity: 0.16, strokeOpacity: 0.22, cornerRadius: 14)

                .buttonStyle(.plain)

            .padding(20)

            .meterCard(tint: .orange, fillOpacity: 0.18, strokeOpacity: 0.24)

            .padding()

    }

    private struct unknownHelperView: View {

        var body: some View {

                title: "Unknown Bluetooth State",

                detail: "Bluetooth is reporting an unknown state. Wait a moment and check again.",

                tint: .secondary

            )

    }

    private struct unsupportedHelperView: View {

        var body: some View {

                title: "Bluetooth Unsupported",

                detail: "This device does not support the Bluetooth capabilities required by these USB meters.",

                tint: .gray

            )

    }

    private struct defaultHelperView: View {

        var body: some View {

                title: "Other Bluetooth State",

                detail: "Bluetooth is in an unexpected state. Try again, then contact the developer if it persists.",

                tint: .yellow

            )

        }

    }

    private struct BluetoothHelpCard: View {

        let title: String

        let detail: String

        let tint: Color

        var body: some View {

            ScrollView {

                VStack(alignment: .leading, spacing: 10) {

                    Text(title)

                        .font(.system(.title3, design: .rounded).weight(.bold))

                    Text(detail)

                        .font(.footnote)

                        .foregroundColor(.secondary)

                }

                .frame(maxWidth: .infinity, alignment: .leading)

                .padding(20)

                .meterCard(tint: tint, fillOpacity: 0.18, strokeOpacity: 0.24)

                .padding()

                LinearGradient(

                    colors: [tint.opacity(0.14), Color.clear],

                    startPoint: .topLeading,

                    endPoint: .bottomTrailing

                )

                .ignoresSafeArea()

            )

    }

}