import Foundation

/// Single decode target for anything that can deep-link into the app — push
/// notification taps today (docs/api/push-notifications-integration-guide.md
/// §6), in-app promo/discount banner taps tomorrow (same shape: a string-keyed
/// dictionary naming a screen + its params). Adding a new destination means
/// adding one case here + one branch in `ContentView.route(to:)` — never a new
/// `NotificationCenter` name, `AppState` field, or observer pair.
enum DeepLinkDestination: Equatable {
    /// `type: "order_status"` — the only push type Atomenta fixes today
    /// (§6), so it gets its own case instead of routing through `targetScreen`.
    case orderTracking(orderId: String, shortId: String?)

    /// Everything else, keyed by `targetScreen` — our own convention (§6
    /// leaves this to us). Once a real screen exists for a given name (e.g.
    /// future promo/coupon "list of participating stores/products"), give it
    /// its own case; until then this carries the raw params so nothing is
    /// silently dropped.
    case screen(name: String, params: [String: String])
}

/// Resolves the *navigation* half of a tapped push's payload. Pure and
/// side-effect-free on purpose: easy to unit test, and reusable as-is for
/// in-app banner taps once those exist. Campaign-open reporting (§6a) is a
/// separate side effect, not a navigation target, and is not decided here —
/// see `PushNotificationCoordinator.handleTap`.
struct PushDeepLinkParser {
    static func parse(_ userInfo: [AnyHashable: Any]) -> DeepLinkDestination? {
        if let type = userInfo["type"] as? String, type == "order_status" {
            // Atomenta's real order-status push (PushNotificationService.
            // notifyOrderStatusUpdate) sends only `shortId`, never `orderId` —
            // `GET /api/public/orders/:orderId` accepts either as the lookup
            // key server-side, so `shortId` doubles as the id here too.
            let shortId = userInfo["shortId"] as? String
            guard let orderId = (userInfo["orderId"] as? String) ?? shortId else { return nil }
            return .orderTracking(orderId: orderId, shortId: shortId)
        }

        guard let targetScreen = userInfo["targetScreen"] as? String else { return nil }
        var params: [String: String] = [:]
        for (key, value) in userInfo {
            guard let key = key as? String, key != "type", key != "targetScreen" else { continue }
            if let stringValue = value as? String {
                params[key] = stringValue
            }
        }
        return .screen(name: targetScreen, params: params)
    }
}