import SwiftUI

struct WatchRootView: View {
    @ObservedObject var model: AppViewModel
    @State private var showsQueue = false

    var body: some View {
        NavigationStack {
            Group {
                if model.session == nil {
                    WatchPairingView(model: model)
                } else {
                    if showsQueue {
                        WatchQueueView(model: model)
                    } else {
                        WatchHomeView(model: model)
                    }
                }
            }
            .background(Color.idpGroupedBackground.ignoresSafeArea())
        }
        .tint(IdP.tint)
        .onOpenURL { url in
            if (url.host ?? url.lastPathComponent).lowercased() == "inbox" {
                showsQueue = true
            }
        }
    }
}

private struct WatchPairingView: View {
    @ObservedObject var model: AppViewModel

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Link your watch")
                .font(.headline)
                .foregroundStyle(.white)

            Text("Use the shared demo passport so approvals stay visible on your wrist.")
                .font(.footnote)
                .foregroundStyle(.white.opacity(0.72))

            Button("Use demo payload") {
                Task {
                    await model.signInWithSuggestedPayload()
                }
            }
            .buttonStyle(PrimaryActionStyle())
        }
        .approvalCard(highlighted: true)
        .padding(10)
        .navigationTitle("idp.global")
    }
}

private struct WatchHomeView: View {
    @ObservedObject var model: AppViewModel

    var body: some View {
        Group {
            if let request = model.pendingRequests.first {
                WatchApprovalView(model: model, requestID: request.id)
            } else {
                WatchQueueView(model: model)
            }
        }
    }
}

struct WatchApprovalView: View {
    @ObservedObject var model: AppViewModel
    let requestID: ApprovalRequest.ID

    private var request: ApprovalRequest? {
        model.requests.first(where: { $0.id == requestID })
    }

    var body: some View {
        Group {
            if let request {
                ScrollView {
                    VStack(alignment: .leading, spacing: 12) {
                        MonogramAvatar(title: request.watchAppDisplayName, size: 42)

                        Text("Sign in as \(model.profile?.handle ?? "@you")?")
                            .font(.headline)
                            .foregroundStyle(.white)

                        Text(request.watchLocationSummary)
                            .font(.footnote)
                            .foregroundStyle(.white.opacity(0.72))

                        HStack(spacing: 8) {
                            Button {
                                Task {
                                    Haptics.warning()
                                    await model.reject(request)
                                }
                            } label: {
                                Image(systemName: "xmark")
                                    .frame(maxWidth: .infinity)
                            }
                            .buttonStyle(SecondaryActionStyle())
                            .frame(maxWidth: .infinity)

                            WatchHoldToApproveButton(isBusy: model.activeRequestID == request.id) {
                                await model.approve(request)
                            }
                            .frame(maxWidth: .infinity)
                        }
                    }
                    .approvalCard(highlighted: true)
                    .padding(10)
                }
                .navigationTitle("Approve")
                .toolbar {
                    ToolbarItem(placement: .bottomBar) {
                        NavigationLink("Queue") {
                            WatchQueueView(model: model)
                        }
                    }
                }
            } else {
                WatchEmptyState(
                    title: "No request",
                    message: "This sign-in is no longer pending.",
                    systemImage: "checkmark.circle"
                )
            }
        }
    }
}

private struct WatchQueueView: View {
    @ObservedObject var model: AppViewModel

    var body: some View {
        List {
            if model.requests.isEmpty {
                WatchEmptyState(
                    title: "All clear",
                    message: "New sign-in requests will appear on your watch here.",
                    systemImage: "shield"
                )
            } else {
                ForEach(model.requests) { request in
                    NavigationLink {
                        WatchRequestDetailView(model: model, requestID: request.id)
                    } label: {
                        WatchQueueRow(request: request)
                    }
                }
            }
        }
        .navigationTitle("Queue")
    }
}

private struct WatchQueueRow: View {
    let request: ApprovalRequest

    var body: some View {
        HStack(spacing: 8) {
            MonogramAvatar(title: request.watchAppDisplayName, size: 22)

            VStack(alignment: .leading, spacing: 2) {
                Text(request.watchAppDisplayName)
                    .font(.footnote.weight(.semibold))
                    .foregroundStyle(.white)
                Text(request.createdAt, style: .time)
                    .font(.caption2)
                    .foregroundStyle(.white.opacity(0.68))
            }
        }
        .padding(.vertical, 2)
    }
}

private struct WatchRequestDetailView: View {
    @ObservedObject var model: AppViewModel
    let requestID: ApprovalRequest.ID

    private var request: ApprovalRequest? {
        model.requests.first(where: { $0.id == requestID })
    }

    var body: some View {
        Group {
            if let request {
                ScrollView {
                    VStack(alignment: .leading, spacing: 12) {
                        RequestHeroCard(request: request, handle: model.profile?.handle ?? "@you")

                        Text(request.watchTrustExplanation)
                            .font(.footnote)
                            .foregroundStyle(.white.opacity(0.72))

                        if request.status == .pending {
                            WatchHoldToApproveButton(isBusy: model.activeRequestID == request.id) {
                                await model.approve(request)
                            }

                            Button("Deny") {
                                Task {
                                    Haptics.warning()
                                    await model.reject(request)
                                }
                            }
                            .buttonStyle(SecondaryActionStyle())
                        }
                    }
                    .padding(10)
                }
            } else {
                WatchEmptyState(
                    title: "No request",
                    message: "This sign-in is no longer pending.",
                    systemImage: "shield"
                )
            }
        }
        .navigationTitle("Details")
    }
}

private struct WatchHoldToApproveButton: View {
    var isBusy = false
    let action: () async -> Void

    @State private var progress: CGFloat = 0

    var body: some View {
        ZStack {
            RoundedRectangle(cornerRadius: IdP.controlRadius, style: .continuous)
                .fill(isBusy ? Color.white.opacity(0.18) : IdP.tint)

            RoundedRectangle(cornerRadius: IdP.controlRadius, style: .continuous)
                .stroke(Color.white.opacity(0.16), lineWidth: 1)

            Text(isBusy ? "Working…" : "Approve")
                .font(.headline)
                .foregroundStyle(.white)
                .padding(.vertical, 12)

            RoundedRectangle(cornerRadius: IdP.controlRadius, style: .continuous)
                .trim(from: 0, to: progress)
                .stroke(Color.white.opacity(0.88), style: StrokeStyle(lineWidth: 2.5, lineCap: .round))
                .rotationEffect(.degrees(-90))
                .padding(2)
        }
        .contentShape(RoundedRectangle(cornerRadius: IdP.controlRadius, style: .continuous))
        .onLongPressGesture(minimumDuration: 0.6, maximumDistance: 18, pressing: updateProgress) {
            guard !isBusy else { return }
            Task {
                Haptics.success()
                await action()
                progress = 0
            }
        }
        .watchPrimaryActionGesture()
        .accessibilityAddTraits(.isButton)
        .accessibilityHint("Press and hold to approve the sign-in request.")
    }

    private func updateProgress(_ isPressing: Bool) {
        guard !isBusy else { return }
        withAnimation(.linear(duration: isPressing ? 0.6 : 0.15)) {
            progress = isPressing ? 1 : 0
        }
    }
}

private extension View {
    @ViewBuilder
    func watchPrimaryActionGesture() -> some View {
        if #available(watchOS 11.0, *) {
            self.handGestureShortcut(.primaryAction)
        } else {
            self
        }
    }
}

private extension ApprovalRequest {
    var watchAppDisplayName: String {
        source.replacingOccurrences(of: "auth.", with: "")
    }

    var watchTrustExplanation: String {
        risk == .elevated
            ? "This request needs a higher-assurance proof before it can continue."
            : "This request matches a familiar device and sign-in pattern."
    }

    var watchLocationSummary: String {
        "Berlin, DE"
    }
}

private struct WatchEmptyState: View {
    let title: String
    let message: String
    let systemImage: String

    var body: some View {
        ContentUnavailableView {
            Label(title, systemImage: systemImage)
        } description: {
            Text(message)
        }
    }
}

#Preview("Watch Approval Light") {
    WatchApprovalPreviewHost()
}

#Preview("Watch Approval Dark") {
    WatchApprovalPreviewHost()
        .preferredColorScheme(.dark)
}

@MainActor
private struct WatchApprovalPreviewHost: View {
    @State private var model = WatchPreviewFixtures.model()

    var body: some View {
        WatchApprovalView(model: model, requestID: WatchPreviewFixtures.requests[0].id)
    }
}

private enum WatchPreviewFixtures {
    static let profile = MemberProfile(
        name: "Jurgen Meyer",
        handle: "@jurgen",
        organization: "idp.global",
        deviceCount: 3,
        recoverySummary: "Recovery kit healthy."
    )

    static let session = AuthSession(
        deviceName: "Apple Watch",
        originHost: "github.com",
        pairedAt: .now.addingTimeInterval(-60 * 45),
        tokenPreview: "berlin",
        pairingCode: "idp.global://pair?token=swiftapp-demo-berlin&origin=github.com&device=Apple%20Watch",
        pairingTransport: .preview
    )

    static let requests: [ApprovalRequest] = [
        ApprovalRequest(
            title: "GitHub sign-in",
            subtitle: "A sign-in request is waiting on your iPhone.",
            source: "github.com",
            createdAt: .now.addingTimeInterval(-60 * 2),
            kind: .signIn,
            risk: .routine,
            scopes: ["profile", "email"],
            status: .pending
        )
    ]

    @MainActor
    static func model() -> AppViewModel {
        let model = AppViewModel(
            service: MockIDPService.shared,
            notificationCoordinator: WatchPreviewCoordinator(),
            appStateStore: WatchPreviewStore(),
            launchArguments: []
        )
        model.session = session
        model.profile = profile
        model.requests = requests
        model.notifications = []
        model.notificationPermission = .allowed
        return model
    }
}

private struct WatchPreviewCoordinator: NotificationCoordinating {
    func authorizationStatus() async -> NotificationPermissionState { .allowed }
    func requestAuthorization() async throws -> NotificationPermissionState { .allowed }
    func scheduleTestNotification(title: String, body: String) async throws {}
}

private struct WatchPreviewStore: AppStateStoring {
    func load() -> PersistedAppState? { nil }
    func save(_ state: PersistedAppState) {}
    func clear() {}
}