//
// Copyright 2025 Element Creations Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//

import Compound
import SwiftUI

struct AuthenticationClassicAppAccountView: View {
    @Bindable var context: AuthenticationStartScreenViewModel.Context
    
    let classicAppAccount: ClassicAppAccount
    
    var isLoadingAccount: Bool {
        classicAppAccount.state.isServerSupported == nil || classicAppAccount.state.availableSecrets == nil
    }
    
    var body: some View {
        FullscreenDialog(topPadding: 25, background: .gradient) {
            VStack(spacing: 38) {
                header
                    .padding(.bottom, 20)
                
                profile
                
                buttons
            }
        } bottomContent: {
            // Buttons are intentionally shown inline on this screen.
        }
        .navigationBarTitleDisplayMode(.inline)
        .alert(item: $context.alertInfo)
        .sheet(isPresented: $context.showClassicAppBackupInstructions) {
            AuthenticationClassicAppBackupInstructionsView(classicAppAccount: classicAppAccount) {
                context.send(viewAction: .openClassicApp)
            }
        }
        .introspect(.window, on: .supportedVersions) { window in
            context.send(viewAction: .updateWindow(window))
        }
    }
    
    var header: some View {
        VStack(spacing: 8) {
            AuthenticationStartLogo(size: 54, hideBrandChrome: false, isOnGradient: false)
            
            Text(L10n.screenOnboardingWelcomeTitle)
                .font(.compound.headingMDBold)
                .foregroundStyle(.compound.textPrimary)
                .multilineTextAlignment(.center)
        }
    }
    
    var profile: some View {
        VStack(spacing: 16) {
            LoadableAvatarImage(url: classicAppAccount.avatarURL,
                                name: classicAppAccount.displayName,
                                contentID: classicAppAccount.userID,
                                avatarSize: .user(on: .classicAppAccount),
                                mediaProvider: context.mediaProvider)
            
            VStack(spacing: 0) {
                Text(L10n.screenOnboardingWelcomeBack)
                    .font(.compound.bodyMD)
                    .foregroundStyle(.compound.textSecondary)
                    .multilineTextAlignment(.center)
                
                Text(classicAppAccount.displayableName)
                    .font(.compound.headingLGBold)
                    .foregroundStyle(.compound.textPrimary)
                    .multilineTextAlignment(.center)
            }
            
            Text(classicAppAccount.userID)
                .font(.compound.bodyLGSemibold)
                .foregroundStyle(.compound.textPrimary)
                .multilineTextAlignment(.center)
        }
    }
    
    var buttons: some View {
        VStack(spacing: 16) {
            if isLoadingAccount {
                Button {
                    context.send(viewAction: .continueWithClassic(classicAppAccount))
                } label: {
                    Label {
                        Text(L10n.screenOnboardingCheckingAccount)
                    } icon: {
                        ProgressView()
                            .tint(.compound.iconOnSolidPrimary)
                    }
                }
                .buttonStyle(.compound(.primary))
                .disabled(true)
            } else {
                Button(L10n.actionContinue) {
                    context.send(viewAction: .continueWithClassic(classicAppAccount))
                }
                .buttonStyle(.compound(.primary))
                
                Button(L10n.commonOtherOptions) {
                    context.send(viewAction: .otherOptions(classicAppAccount))
                }
                .buttonStyle(.compound(.secondary))
            }
        }
    }
}

private extension ClassicAppAccount {
    var displayableName: String {
        if let displayName, !displayName.isEmpty {
            displayName
        } else if let localPart = userID.dropFirst().split(separator: ":").first, !localPart.isEmpty {
            String(localPart)
        } else {
            userID
        }
    }
}

// MARK: - Previews

struct AuthenticationClassicAppAccountView_Previews: PreviewProvider { // Not Testable – snapshots generated by main screen.
    static let viewModel = makeViewModel()
    static let classicAppAccount = {
        let account = ClassicAppAccount.mockDan
        account.state.isServerSupported = true
        account.state.availableSecrets = .complete
        return account
    }()
    
    static var previews: some View {
        ElementNavigationStack {
            AuthenticationClassicAppAccountView(context: viewModel.context, classicAppAccount: classicAppAccount)
        }
        .previewDisplayName("Ready")
        
        ElementNavigationStack {
            AuthenticationClassicAppAccountView(context: viewModel.context, classicAppAccount: .mockDan)
        }
        .previewDisplayName("Loading")
    }
    
    static func makeViewModel() -> AuthenticationStartScreenViewModel {
        AuthenticationStartScreenViewModel(authenticationService: AuthenticationService.mock,
                                           provisioningParameters: nil,
                                           isBugReportServiceEnabled: false,
                                           appMediator: AppMediatorMock(),
                                           appSettings: ServiceLocator.shared.settings,
                                           mediaProvider: MediaProviderMock(configuration: .init()),
                                           userIndicatorController: UserIndicatorControllerMock())
    }
}