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.black.ignoresSafeArea())
        }
        .tint(IdP.tint)
        .preferredColorScheme(.dark)
        .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: 10) {
            WatchBadge(title: "PAIR · STEP 1", tone: .accent)

            Text("Link your watch")
                .font(.system(size: 15, weight: .semibold))
                .foregroundStyle(.white)

            Text("Use the shared demo passport so approvals stay visible on your wrist.")
                .font(.footnote)
                .foregroundStyle(Color.idpMutedForeground)
                .fixedSize(horizontal: false, vertical: true)

            Spacer(minLength: 4)

            Button("Use demo payload") {
                Task {
                    await model.signInWithSuggestedPayload()
                }
            }
            .buttonStyle(PrimaryActionStyle())
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .padding(8)
        .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 })
    }

    @ViewBuilder
    private func signInPrompt(handle: String) -> some View {
        var attributed = AttributedString("Sign in as \(handle)?")
        attributed.font = .system(size: 15, weight: .semibold)
        attributed.foregroundColor = .white
        if let range = attributed.range(of: handle) {
            attributed[range].foregroundColor = IdP.tint
        }
        return Text(attributed)
            .lineLimit(2)
            .minimumScaleFactor(0.8)
    }

    var body: some View {
        Group {
            if let request {
                VStack(alignment: .leading, spacing: 5) {
                    HStack(spacing: 5) {
                        MonogramAvatar(
                            title: request.watchAppDisplayName,
                            size: 18,
                            tint: BrandTint.color(for: request.watchAppDisplayName)
                        )
                        Text(request.watchAppDisplayName)
                            .font(.system(size: 11, weight: .medium))
                            .foregroundStyle(Color.idpMutedForeground)
                            .lineLimit(1)
                    }

                    signInPrompt(handle: model.profile?.handle ?? "@you")

                    HStack(spacing: 3) {
                        Image(systemName: "location.fill")
                            .font(.system(size: 8))
                        Text("\(request.watchLocationSummary) · now")
                    }
                    .font(.system(size: 10))
                    .foregroundStyle(Color.idpMutedForeground)

                    Spacer(minLength: 4)

                    GeometryReader { geo in
                        HStack(spacing: 5) {
                            Button {
                                Task {
                                    Haptics.warning()
                                    await model.reject(request)
                                }
                            } label: {
                                Image(systemName: "xmark")
                                    .font(.footnote.weight(.semibold))
                            }
                            .buttonStyle(SecondaryActionStyle())
                            .frame(width: (geo.size.width - 5) / 3)

                            WatchHoldToApproveButton(isBusy: model.activeRequestID == request.id) {
                                await model.approve(request)
                            }
                        }
                    }
                    .frame(height: 36)
                }
                .frame(maxWidth: .infinity, alignment: .leading)
                .padding(.horizontal, 8)
                .padding(.top, 4)
                .padding(.bottom, 6)
                .navigationBarTitleDisplayMode(.inline)
                .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 {
        ScrollView {
            VStack(alignment: .leading, spacing: 6) {
                Text("INBOX · \(model.requests.count)")
                    .font(.system(size: 10, weight: .bold))
                    .tracking(0.6)
                    .foregroundStyle(IdP.tint)
                    .padding(.horizontal, 4)
                    .padding(.top, 2)

                if model.requests.isEmpty {
                    WatchEmptyState(
                        title: "All clear",
                        message: "New sign-in requests appear here.",
                        systemImage: "shield"
                    )
                } else {
                    ForEach(model.requests) { request in
                        NavigationLink {
                            WatchRequestDetailView(model: model, requestID: request.id)
                        } label: {
                            WatchQueueRow(request: request)
                        }
                        .buttonStyle(.plain)
                    }
                }
            }
            .padding(.horizontal, 6)
            .padding(.bottom, 8)
        }
        .scrollIndicators(.hidden)
        .navigationTitle("Queue")
    }
}

private struct WatchQueueRow: View {
    let request: ApprovalRequest

    var body: some View {
        HStack(spacing: 6) {
            MonogramAvatar(
                title: request.watchAppDisplayName,
                size: 20,
                tint: BrandTint.color(for: request.watchAppDisplayName)
            )

            VStack(alignment: .leading, spacing: 0) {
                Text(request.watchAppDisplayName)
                    .font(.system(size: 11, weight: .semibold))
                    .foregroundStyle(.white)
                    .lineLimit(1)
                Text(request.kind.title)
                    .font(.system(size: 9))
                    .foregroundStyle(Color.idpMutedForeground)
                    .lineLimit(1)
            }

            Spacer(minLength: 4)

            Text(relativeTime)
                .font(.system(size: 9))
                .foregroundStyle(Color.idpMutedForeground)
        }
        .padding(6)
        .overlay(
            RoundedRectangle(cornerRadius: 7, style: .continuous)
                .stroke(Color.white.opacity(0.12), lineWidth: 1)
        )
    }

    private var relativeTime: String {
        let seconds = Int(Date.now.timeIntervalSince(request.createdAt))
        if seconds < 60 { return "now" }
        if seconds < 3600 { return "\(seconds / 60)m" }
        if seconds < 86_400 { return "\(seconds / 3600)h" }
        return "\(seconds / 86_400)d"
    }
}

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: 10) {
                        RequestHeroCard(request: request, handle: model.profile?.handle ?? "@you")

                        Text(request.watchTrustExplanation)
                            .font(.footnote)
                            .foregroundStyle(Color.idpMutedForeground)
                            .fixedSize(horizontal: false, vertical: true)

                        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(8)
                }
            } 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) : Color.idpPrimary)

            if isBusy {
                Text("Working…")
                    .font(.footnote.weight(.semibold))
                    .foregroundStyle(.white)
            } else {
                HStack(spacing: 4) {
                    Image(systemName: "checkmark")
                    Text("Approve")
                }
                .font(.footnote.weight(.semibold))
                .foregroundStyle(Color.idpPrimaryForeground)
            }

            RoundedRectangle(cornerRadius: IdP.controlRadius, style: .continuous)
                .trim(from: 0, to: progress)
                .stroke(IdP.tint, style: StrokeStyle(lineWidth: 2, lineCap: .round))
                .rotationEffect(.degrees(-90))
                .padding(1.5)
        }
        .frame(height: 36)
        .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"
    }
}

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

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            Image(systemName: systemImage)
                .font(.title3)
                .foregroundStyle(Color.idpMutedForeground)
            Text(title)
                .font(.system(size: 13, weight: .semibold))
                .foregroundStyle(.white)
            Text(message)
                .font(.footnote)
                .foregroundStyle(Color.idpMutedForeground)
                .fixedSize(horizontal: false, vertical: true)
        }
        .padding(8)
    }
}

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

#Preview("Watch Queue") {
    NavigationStack {
        WatchQueuePreviewHost()
    }
    .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)
    }
}

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

    var body: some View {
        WatchQueueView(model: model)
    }
}

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
        ),
        ApprovalRequest(
            title: "Lufthansa sign-in",
            subtitle: "Verify identity",
            source: "lufthansa.com",
            createdAt: .now.addingTimeInterval(-60 * 4),
            kind: .accessGrant,
            risk: .routine,
            scopes: ["profile"],
            status: .pending
        ),
        ApprovalRequest(
            title: "Hetzner",
            subtitle: "Console",
            source: "hetzner.cloud",
            createdAt: .now.addingTimeInterval(-60 * 8),
            kind: .elevatedAction,
            risk: .elevated,
            scopes: ["device"],
            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() {}
}