import CryptoKit
import Foundation

enum AppSection: String, CaseIterable, Identifiable, Hashable, Codable {
    case inbox
    case notifications
    case devices
    case identity
    case settings

    var id: String { rawValue }

    var title: String {
        switch self {
        case .inbox: "Inbox"
        case .notifications: "Notifications"
        case .devices: "Devices"
        case .identity: "Identity"
        case .settings: "Settings"
        }
    }

    var systemImage: String {
        switch self {
        case .inbox: "tray.full.fill"
        case .notifications: "bell.badge.fill"
        case .devices: "desktopcomputer"
        case .identity: "person.crop.rectangle.stack.fill"
        case .settings: "gearshape.fill"
        }
    }
}

enum NotificationPermissionState: String, CaseIterable, Identifiable, Codable {
    case unknown
    case allowed
    case provisional
    case denied

    var id: String { rawValue }

    var title: String {
        switch self {
        case .unknown: "Not Asked Yet"
        case .allowed: "Enabled"
        case .provisional: "Delivered Quietly"
        case .denied: "Disabled"
        }
    }

    var systemImage: String {
        switch self {
        case .unknown: "bell"
        case .allowed: "bell.badge.fill"
        case .provisional: "bell.badge"
        case .denied: "bell.slash.fill"
        }
    }

    var summary: String {
        switch self {
        case .unknown:
            "The app has not asked for notification delivery yet."
        case .allowed:
            "Identity proof alerts can break through immediately when a check arrives."
        case .provisional:
            "Identity proof alerts can be delivered quietly until the user promotes them."
        case .denied:
            "Identity proof events stay in-app until the user re-enables notifications."
        }
    }
}

struct BootstrapContext {
    let suggestedPairingPayload: String
}

enum PairingTransport: String, Hashable, Codable {
    case qr
    case nfc
    case manual
    case preview

    var title: String {
        switch self {
        case .qr:
            "QR"
        case .nfc:
            "NFC"
        case .manual:
            "Manual"
        case .preview:
            "Preview"
        }
    }
}

struct PairingAuthenticationRequest: Hashable {
    let pairingPayload: String
    let transport: PairingTransport
    let signedGPSPosition: SignedGPSPosition?
}

struct SignedGPSPosition: Hashable, Codable {
    let latitude: Double
    let longitude: Double
    let horizontalAccuracyMeters: Double
    let capturedAt: Date
    let signatureBase64: String
    let publicKeyBase64: String

    init(
        latitude: Double,
        longitude: Double,
        horizontalAccuracyMeters: Double,
        capturedAt: Date,
        signatureBase64: String = "",
        publicKeyBase64: String = ""
    ) {
        self.latitude = latitude
        self.longitude = longitude
        self.horizontalAccuracyMeters = horizontalAccuracyMeters
        self.capturedAt = capturedAt
        self.signatureBase64 = signatureBase64
        self.publicKeyBase64 = publicKeyBase64
    }

    var coordinateSummary: String {
        "\(Self.normalized(latitude, precision: 5)), \(Self.normalized(longitude, precision: 5))"
    }

    var accuracySummary: String {
        "±\(Int(horizontalAccuracyMeters.rounded())) m"
    }

    func signingPayload(for pairingPayload: String) -> Data {
        let lines = [
            "payload=\(pairingPayload)",
            "latitude=\(Self.normalized(latitude, precision: 6))",
            "longitude=\(Self.normalized(longitude, precision: 6))",
            "accuracy=\(Self.normalized(horizontalAccuracyMeters, precision: 2))",
            "captured_at=\(Self.timestampFormatter.string(from: capturedAt))"
        ]
        return Data(lines.joined(separator: "\n").utf8)
    }

    func verified(for pairingPayload: String) -> Bool {
        guard let signatureData = Data(base64Encoded: signatureBase64),
              let publicKeyData = Data(base64Encoded: publicKeyBase64),
              let publicKey = try? P256.Signing.PublicKey(x963Representation: publicKeyData),
              let signature = try? P256.Signing.ECDSASignature(derRepresentation: signatureData) else {
            return false
        }

        return publicKey.isValidSignature(signature, for: signingPayload(for: pairingPayload))
    }

    func signed(signatureData: Data, publicKeyData: Data) -> SignedGPSPosition {
        SignedGPSPosition(
            latitude: latitude,
            longitude: longitude,
            horizontalAccuracyMeters: horizontalAccuracyMeters,
            capturedAt: capturedAt,
            signatureBase64: signatureData.base64EncodedString(),
            publicKeyBase64: publicKeyData.base64EncodedString()
        )
    }

    private static let timestampFormatter: ISO8601DateFormatter = {
        let formatter = ISO8601DateFormatter()
        formatter.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
        return formatter
    }()

    private static func normalized(_ value: Double, precision: Int) -> String {
        String(format: "%.\(precision)f", locale: Locale(identifier: "en_US_POSIX"), value)
    }
}

struct DashboardSnapshot {
    let profile: MemberProfile
    let requests: [ApprovalRequest]
    let notifications: [AppNotification]
    let devices: [PassportDeviceRecord]

    init(
        profile: MemberProfile,
        requests: [ApprovalRequest],
        notifications: [AppNotification],
        devices: [PassportDeviceRecord] = []
    ) {
        self.profile = profile
        self.requests = requests
        self.notifications = notifications
        self.devices = devices
    }
}

struct SignInResult {
    let session: AuthSession
    let snapshot: DashboardSnapshot
}

struct MemberProfile: Identifiable, Hashable, Codable {
    let id: UUID
    let name: String
    let handle: String
    let organization: String
    let deviceCount: Int
    let recoverySummary: String

    init(
        id: UUID = UUID(),
        name: String,
        handle: String,
        organization: String,
        deviceCount: Int,
        recoverySummary: String
    ) {
        self.id = id
        self.name = name
        self.handle = handle
        self.organization = organization
        self.deviceCount = deviceCount
        self.recoverySummary = recoverySummary
    }
}

struct AuthSession: Identifiable, Hashable, Codable {
    let id: UUID
    let deviceName: String
    let originHost: String
    let serverURL: String
    let passportDeviceID: String
    let pairedAt: Date
    let tokenPreview: String
    let pairingCode: String
    let pairingTransport: PairingTransport
    let signedGPSPosition: SignedGPSPosition?

    init(
        id: UUID = UUID(),
        deviceName: String,
        originHost: String,
        serverURL: String = "",
        passportDeviceID: String = "",
        pairedAt: Date,
        tokenPreview: String,
        pairingCode: String,
        pairingTransport: PairingTransport = .manual,
        signedGPSPosition: SignedGPSPosition? = nil
    ) {
        self.id = id
        self.deviceName = deviceName
        self.originHost = originHost
        self.serverURL = serverURL
        self.passportDeviceID = passportDeviceID
        self.pairedAt = pairedAt
        self.tokenPreview = tokenPreview
        self.pairingCode = pairingCode
        self.pairingTransport = pairingTransport
        self.signedGPSPosition = signedGPSPosition
    }

    private enum CodingKeys: String, CodingKey {
        case id
        case deviceName
        case originHost
        case serverURL
        case passportDeviceID
        case pairedAt
        case tokenPreview
        case pairingCode
        case pairingTransport
        case signedGPSPosition
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        id = try container.decodeIfPresent(UUID.self, forKey: .id) ?? UUID()
        deviceName = try container.decode(String.self, forKey: .deviceName)
        originHost = try container.decode(String.self, forKey: .originHost)
        serverURL = try container.decodeIfPresent(String.self, forKey: .serverURL) ?? "https://\(originHost)"
        passportDeviceID = try container.decodeIfPresent(String.self, forKey: .passportDeviceID) ?? ""
        pairedAt = try container.decode(Date.self, forKey: .pairedAt)
        tokenPreview = try container.decode(String.self, forKey: .tokenPreview)
        pairingCode = try container.decode(String.self, forKey: .pairingCode)
        pairingTransport = try container.decodeIfPresent(PairingTransport.self, forKey: .pairingTransport) ?? .manual
        signedGPSPosition = try container.decodeIfPresent(SignedGPSPosition.self, forKey: .signedGPSPosition)
    }
}

enum ApprovalRequestKind: String, CaseIterable, Hashable, Codable {
    case signIn
    case accessGrant
    case elevatedAction

    var title: String {
        switch self {
        case .signIn: "Identity Check"
        case .accessGrant: "Strong Proof"
        case .elevatedAction: "Sensitive Proof"
        }
    }

    var systemImage: String {
        switch self {
        case .signIn: "qrcode.viewfinder"
        case .accessGrant: "person.badge.shield.checkmark.fill"
        case .elevatedAction: "shield.checkered"
        }
    }
}

enum ApprovalRisk: String, Hashable, Codable {
    case routine
    case elevated

    var title: String {
        switch self {
        case .routine: "Routine"
        case .elevated: "Elevated"
        }
    }

    var summary: String {
        switch self {
        case .routine:
            "A familiar identity proof for a normal sign-in or check."
        case .elevated:
            "A higher-assurance identity proof for a sensitive check."
        }
    }

    var guidance: String {
        switch self {
        case .routine:
            "Review the origin and continue only if it matches the proof you started."
        case .elevated:
            "Only continue if you initiated this proof and trust the origin asking for it."
        }
    }
}

enum ApprovalStatus: String, Hashable, Codable {
    case pending
    case approved
    case rejected

    var title: String {
        switch self {
        case .pending: "Pending"
        case .approved: "Approved"
        case .rejected: "Denied"
        }
    }

    var systemImage: String {
        switch self {
        case .pending: "clock.badge"
        case .approved: "checkmark.circle.fill"
        case .rejected: "xmark.circle.fill"
        }
    }
}

struct ApprovalRequest: Identifiable, Hashable, Codable {
    let id: UUID
    let serverID: String
    let hintID: String
    let title: String
    let subtitle: String
    let source: String
    let createdAt: Date
    let kind: ApprovalRequestKind
    let risk: ApprovalRisk
    let scopes: [String]
    let requiresLocation: Bool
    let challenge: String?
    let signingPayload: String?
    let deviceSummaryText: String?
    let locationSummaryText: String?
    let networkSummaryText: String?
    let ipSummaryText: String?
    let expiresAtDate: Date?
    var status: ApprovalStatus

    init(
        id: UUID = UUID(),
        serverID: String = UUID().uuidString,
        hintID: String = UUID().uuidString,
        title: String,
        subtitle: String,
        source: String,
        createdAt: Date,
        kind: ApprovalRequestKind,
        risk: ApprovalRisk,
        scopes: [String],
        requiresLocation: Bool = false,
        challenge: String? = nil,
        signingPayload: String? = nil,
        deviceSummaryText: String? = nil,
        locationSummaryText: String? = nil,
        networkSummaryText: String? = nil,
        ipSummaryText: String? = nil,
        expiresAtDate: Date? = nil,
        status: ApprovalStatus
    ) {
        self.id = id
        self.serverID = serverID
        self.hintID = hintID
        self.title = title
        self.subtitle = subtitle
        self.source = source
        self.createdAt = createdAt
        self.kind = kind
        self.risk = risk
        self.scopes = scopes
        self.requiresLocation = requiresLocation
        self.challenge = challenge
        self.signingPayload = signingPayload
        self.deviceSummaryText = deviceSummaryText
        self.locationSummaryText = locationSummaryText
        self.networkSummaryText = networkSummaryText
        self.ipSummaryText = ipSummaryText
        self.expiresAtDate = expiresAtDate
        self.status = status
    }

    private enum CodingKeys: String, CodingKey {
        case id
        case serverID
        case hintID
        case title
        case subtitle
        case source
        case createdAt
        case kind
        case risk
        case scopes
        case requiresLocation
        case challenge
        case signingPayload
        case deviceSummaryText
        case locationSummaryText
        case networkSummaryText
        case ipSummaryText
        case expiresAtDate
        case status
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        id = try container.decodeIfPresent(UUID.self, forKey: .id) ?? UUID()
        serverID = try container.decodeIfPresent(String.self, forKey: .serverID) ?? id.uuidString
        hintID = try container.decodeIfPresent(String.self, forKey: .hintID) ?? serverID
        title = try container.decode(String.self, forKey: .title)
        subtitle = try container.decode(String.self, forKey: .subtitle)
        source = try container.decode(String.self, forKey: .source)
        createdAt = try container.decode(Date.self, forKey: .createdAt)
        kind = try container.decode(ApprovalRequestKind.self, forKey: .kind)
        risk = try container.decode(ApprovalRisk.self, forKey: .risk)
        scopes = try container.decode([String].self, forKey: .scopes)
        requiresLocation = try container.decodeIfPresent(Bool.self, forKey: .requiresLocation) ?? false
        challenge = try container.decodeIfPresent(String.self, forKey: .challenge)
        signingPayload = try container.decodeIfPresent(String.self, forKey: .signingPayload)
        deviceSummaryText = try container.decodeIfPresent(String.self, forKey: .deviceSummaryText)
        locationSummaryText = try container.decodeIfPresent(String.self, forKey: .locationSummaryText)
        networkSummaryText = try container.decodeIfPresent(String.self, forKey: .networkSummaryText)
        ipSummaryText = try container.decodeIfPresent(String.self, forKey: .ipSummaryText)
        expiresAtDate = try container.decodeIfPresent(Date.self, forKey: .expiresAtDate)
        status = try container.decode(ApprovalStatus.self, forKey: .status)
    }

    var scopeSummary: String {
        if scopes.isEmpty {
            return "No proof details listed"
        }

        let suffix = scopes.count == 1 ? "" : "s"
        return "\(scopes.count) proof detail\(suffix)"
    }

    var trustHeadline: String {
        switch (kind, risk) {
        case (.signIn, .routine):
            "Standard identity proof"
        case (.signIn, .elevated):
            "High-assurance sign-in proof"
        case (.accessGrant, _):
            "Cross-device identity proof"
        case (.elevatedAction, _):
            "Sensitive identity proof"
        }
    }

    var trustDetail: String {
        switch kind {
        case .signIn:
            "This request proves that the person at the browser, CLI, or device is really you."
        case .accessGrant:
            "This request asks for a stronger proof so the relying party can trust the session with higher confidence."
        case .elevatedAction:
            "This request asks for the highest confidence proof before continuing with a sensitive flow."
        }
    }
}

enum AppNotificationKind: String, Hashable, Codable {
    case approval
    case security
    case system

    var title: String {
        switch self {
        case .approval: "Proof"
        case .security: "Security"
        case .system: "System"
        }
    }

    var systemImage: String {
        switch self {
        case .approval: "checkmark.seal.fill"
        case .security: "shield.fill"
        case .system: "sparkles"
        }
    }

    var summary: String {
        switch self {
        case .approval:
            "Identity proof activity"
        case .security:
            "Passport and security posture updates"
        case .system:
            "Product and environment status messages"
        }
    }
}

struct AppNotification: Identifiable, Hashable, Codable {
    let id: UUID
    let serverID: String
    let hintID: String
    let title: String
    let message: String
    let sentAt: Date
    let kind: AppNotificationKind
    var isUnread: Bool

    init(
        id: UUID = UUID(),
        serverID: String = UUID().uuidString,
        hintID: String = UUID().uuidString,
        title: String,
        message: String,
        sentAt: Date,
        kind: AppNotificationKind,
        isUnread: Bool
    ) {
        self.id = id
        self.serverID = serverID
        self.hintID = hintID
        self.title = title
        self.message = message
        self.sentAt = sentAt
        self.kind = kind
        self.isUnread = isUnread
    }

    private enum CodingKeys: String, CodingKey {
        case id
        case serverID
        case hintID
        case title
        case message
        case sentAt
        case kind
        case isUnread
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        id = try container.decodeIfPresent(UUID.self, forKey: .id) ?? UUID()
        serverID = try container.decodeIfPresent(String.self, forKey: .serverID) ?? id.uuidString
        hintID = try container.decodeIfPresent(String.self, forKey: .hintID) ?? serverID
        title = try container.decode(String.self, forKey: .title)
        message = try container.decode(String.self, forKey: .message)
        sentAt = try container.decode(Date.self, forKey: .sentAt)
        kind = try container.decode(AppNotificationKind.self, forKey: .kind)
        isUnread = try container.decode(Bool.self, forKey: .isUnread)
    }
}

struct PassportDeviceRecord: Identifiable, Hashable, Codable {
    let id: String
    let label: String
    let platform: String
    let lastSeenAt: Date?
    let isCurrent: Bool
}

enum AppError: LocalizedError, Equatable {
    case invalidPairingPayload
    case missingSignedGPSPosition
    case invalidSignedGPSPosition
    case locationPermissionDenied
    case locationUnavailable
    case requestNotFound

    var errorDescription: String? {
        switch self {
        case .invalidPairingPayload:
            "That idp.global payload is not valid for this action."
        case .missingSignedGPSPosition:
            "Tap NFC requires a signed GPS position."
        case .invalidSignedGPSPosition:
            "The signed GPS position attached to this NFC proof could not be verified."
        case .locationPermissionDenied:
            "Location access is required so Tap NFC can attach a signed GPS position."
        case .locationUnavailable:
            "Unable to determine the current GPS position for Tap NFC."
        case .requestNotFound:
            "The selected identity check could not be found."
        }
    }
}