PasswordGenerationPromptView.swift

//
//  PasswordGenerationPromptView.swift
//  DuckDuckGo
//
//  Copyright © 2023 DuckDuckGo. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

import SwiftUI
import DesignResourcesKit

struct PasswordGenerationPromptView: View {

    @State var frame: CGSize = .zero
    @ObservedObject var viewModel: PasswordGenerationPromptViewModel
    @Environment(\.horizontalSizeClass) var horizontalSizeClass
    @Environment(\.verticalSizeClass) var verticalSizeClass

    var body: some View {
        GeometryReader { geometry in
            makeBodyView(geometry)
        }
    }

    private func makeBodyView(_ geometry: GeometryProxy) -> some View {
        DispatchQueue.main.async { self.frame = geometry.size }

        return ZStack {
            AutofillViews.CloseButtonHeader(action: viewModel.cancelButtonPressed)
                .offset(x: AutofillViews.isIPhonePortrait(verticalSizeClass, horizontalSizeClass) ? Const.Size.closeButtonOffsetPortrait
                                                                                                  : Const.Size.closeButtonOffset)
                .zIndex(1)

                VStack {
                    AutofillViews.Headline(title: UserText.autofillPasswordGenerationPromptTitle)
                        .padding(.top, Const.Size.topPadding)
                    if #available(iOS 16.0, *) {
                        passwordView
                            .padding([.top, .bottom], passwordVerticalPadding)
                    } else {
                        AutofillViews.LegacySpacerView()
                        passwordView
                        AutofillViews.LegacySpacerView()
                    }
                    AutofillViews.Description(text: UserText.autofillPasswordGenerationPromptSubtitle)
                    contentViewSpacer
                    ctaView
                        .padding(.bottom, AutofillViews.isIPad(verticalSizeClass, horizontalSizeClass) ? Const.Size.bottomPaddingIPad
                                                                                                       : Const.Size.bottomPadding)
                }
                .background(GeometryReader { proxy -> Color in
                    DispatchQueue.main.async { viewModel.contentHeight = proxy.size.height }
                    return Color.clear
                })
                .useScrollView(shouldUseScrollView(), minHeight: frame.height)

        }
        .padding(.horizontal, AutofillViews.isIPhonePortrait(verticalSizeClass, horizontalSizeClass) ? Const.Size.closeButtonOffsetPortrait
                                                                                                     : Const.Size.closeButtonOffset)

    }

    private func shouldUseScrollView() -> Bool {
        var useScrollView: Bool = false

        if #available(iOS 16.0, *) {
            useScrollView = AutofillViews.contentHeightExceedsScreenHeight(viewModel.contentHeight)
        } else {
            useScrollView = viewModel.contentHeight > frame.height + Const.Size.ios15scrollOffset
        }

        return useScrollView
    }

    private func presentCopyConfirmation(message: String) {
        DispatchQueue.main.async {
            ActionMessageView.present(message: message,
                                      actionTitle: "",
                                      onAction: {})
        }
    }

    private var passwordVerticalPadding: CGFloat {
        if AutofillViews.isIPhoneLandscape(verticalSizeClass) {
            return Const.Size.passwordPaddingHeightLandscape
        } else {
            return Const.Size.passwordPaddingHeight
        }
    }

    private var passwordView: some View {
        HStack(spacing: Const.Size.passwordButtonSpacing) {
            Text(viewModel.generatedPassword)
                .textSelectionEnabled()
                .multilineTextAlignment(.center)
                .fixedSize(horizontal: false, vertical: true)
                .setKerning(0)
                .font(Const.Fonts.password)
                .foregroundColor(Color(designSystemColor: .textSecondary))
            Button {
                UIPasteboard.general.string = viewModel.generatedPassword
                presentCopyConfirmation(message: UserText.autofillCopyToastPasswordCopied)
            } label: {
                Image.copy
                    .foregroundColor(Color(designSystemColor: .textSecondary))
            }
            .buttonStyle(.plain) // Prevent taps from being forwarded to the container view
        }
    }

    private var contentViewSpacer: some View {
        VStack {
            if AutofillViews.isIPhoneLandscape(verticalSizeClass) {
                AutofillViews.LegacySpacerView(height: Const.Size.contentSpacerHeightLandscape)
            } else {
                AutofillViews.LegacySpacerView(height: Const.Size.contentSpacerHeight)
            }
        }
    }

    private var ctaView: some View {
        VStack(spacing: Const.Size.ctaVerticalSpacing) {
            AutofillViews.PrimaryButton(title: UserText.autofillPasswordGenerationPromptUseGeneratedPasswordCTA,
                                        action: viewModel.useGeneratedPasswordPressed)

            AutofillViews.TertiaryButton(title: UserText.autofillPasswordGenerationPromptUseOwnPasswordCTA,
                                         action: viewModel.cancelButtonPressed)
        }
    }
}

// MARK: - View Helpers

private extension View {

    @ViewBuilder
    func setKerning(_ kerning: CGFloat) -> some View {
        if #available(iOS 16.0, *) {
            self.kerning(kerning)
        } else {
            self
        }
    }

    @ViewBuilder
    func textSelectionEnabled() -> some View {
        if #available(iOS 15.0, *) {
            self.textSelection(.enabled)
        } else {
            self
        }
    }
}

// MARK: - Constants

private enum Const {
    enum Fonts {
        static let password = Font.system(.callout, design: .monospaced)
    }

    enum Size {
        static let closeButtonOffset: CGFloat = 48.0
        static let closeButtonOffsetPortrait: CGFloat = 44.0
        static let topPadding: CGFloat = 56.0
        static let ios15scrollOffset: CGFloat = 80.0
        static let passwordButtonSpacing: CGFloat = 10.0
        static let passwordPaddingHeight: CGFloat = 28.0
        static let passwordPaddingHeightLandscape: CGFloat = 42.0
        static let contentSpacerHeight: CGFloat = 24.0
        static let contentSpacerHeightLandscape: CGFloat = 30.0
        static let ctaVerticalSpacing: CGFloat = 8.0
        static let bottomPadding: CGFloat = 12.0
        static let bottomPaddingIPad: CGFloat = 24.0
    }

}

private extension Image {
    static let copy = Image("Copy-24")
}

// MARK: - Preview

struct PasswordGenerationPromptView_Previews: PreviewProvider {
    static var previews: some View {
        let viewModel = PasswordGenerationPromptViewModel(generatedPassword: "GeNeRaTeD-pAsSwOrD")
        PasswordGenerationPromptView(viewModel: viewModel)
    }
}