// The watch face complication: how many threads are waiting on you, from `GET /v1/summary`. It
// reads the device token from the shared Keychain group and the demo flag from the App Group, and
// the app reloads it whenever its own feed or a notification changes the counts.

import SwiftUI
import WidgetKit

@main
struct WristCodeWidgets: WidgetBundle {
    var body: some Widget {
        WaitingWidget()
    }
}

struct WaitingWidget: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "WaitingCount", provider: WaitingProvider()) { entry in
            WaitingView(entry: entry)
        }
        .configurationDisplayName("Waiting on you")
        .description("Threads waiting for your approval or answer.")
        .supportedFamilies([.accessoryCircular, .accessoryRectangular, .accessoryInline, .accessoryCorner])
    }
}

struct WaitingEntry: TimelineEntry {
    enum Content: Equatable {
        /// Counts from the gateway. `stale` when they are the last ones seen because the gateway
        /// could not be reached.
        case counts(Summary, stale: Bool)
        case notPaired
        /// The gateway could not be reached and there is nothing saved to show.
        case unavailable
    }

    var date: Date
    var content: Content

    /// Ranks the complication higher in the Smart Stack while something waits.
    var relevance: TimelineEntryRelevance? {
        guard case let .counts(summary, _) = content, summary.needsYou > 0 else { return nil }
        return TimelineEntryRelevance(score: Float(summary.needsYou))
    }

    static let sample = WaitingEntry(date: .now, content: .counts(Summary(
        needsYou: 2, working: 3,
        next: .init(hostId: "mac-mini", threadId: "t-ocr", title: "Receipt OCR", hostLabel: "Mac mini"),
        hostsOffline: 0), stale: false))
}

struct WaitingProvider: TimelineProvider {
    /// How long until WidgetKit asks again. The app reloads sooner when it learns something.
    static let refreshInterval: TimeInterval = 15 * 60

    func placeholder(in context: Context) -> WaitingEntry {
        .sample
    }

    func getSnapshot(in context: Context, completion: @escaping @Sendable (WaitingEntry) -> Void) {
        if context.isPreview {
            completion(.sample)
            return
        }
        Task { completion(await Self.load()) }
    }

    func getTimeline(in context: Context, completion: @escaping @Sendable (Timeline<WaitingEntry>) -> Void) {
        Task {
            let entry = await Self.load()
            completion(Timeline(entries: [entry], policy: .after(entry.date.addingTimeInterval(Self.refreshInterval))))
        }
    }

    static func load() async -> WaitingEntry {
        let api: any GatewayAPI
        if SharedState.demo {
            api = DemoGateway.shared
        } else if let credentials = DeviceStore.load() {
            api = GatewayClient(baseURL: credentials.gatewayURL, token: credentials.token)
        } else {
            return WaitingEntry(date: .now, content: .notPaired)
        }
        do {
            let summary = try await api.summary()
            SharedState.lastSummary = summary
            return WaitingEntry(date: .now, content: .counts(summary, stale: false))
        } catch GatewayError.unauthorized {
            return WaitingEntry(date: .now, content: .notPaired)
        } catch {
            guard let last = SharedState.lastSummary else { return WaitingEntry(date: .now, content: .unavailable) }
            return WaitingEntry(date: .now, content: .counts(last, stale: true))
        }
    }
}