// What the app tells the complication besides the credentials: whether it is in demo mode, and the
// last summary it saw, which the complication shows when it cannot reach the gateway. Both live in
// the shared Keychain group next to the device token, the one store the two processes share. `api`
// is the gateway the complication and its Allow and Deny buttons call.

import Foundation

enum SharedState {
    private static let demoAccount = "demo"
    private static let summaryAccount = "lastSummary"

    /// True while the app is in demo mode, so the complication shows the demo counts too.
    static var demo: Bool {
        get { DeviceStore.sharedData(demoAccount) == Data([1]) }
        set { DeviceStore.setSharedData(newValue ? Data([1]) : nil, account: demoAccount) }
    }

    /// The demo gateway in demo mode, the paired gateway otherwise, and nil when not paired.
    static var api: (any GatewayAPI)? {
        if demo { return DemoGateway.shared }
        return DeviceStore.load().map { GatewayClient(baseURL: $0.gatewayURL, token: $0.token) }
    }

    /// The last summary the app or the complication saw, or nil after signing out.
    static var lastSummary: Summary? {
        get { DeviceStore.sharedData(summaryAccount).flatMap { try? JSON.decoder().decode(Summary.self, from: $0) } }
        set { DeviceStore.setSharedData(newValue.flatMap { try? JSON.encoder().encode($0) }, account: summaryAccount) }
    }
}