import Foundation
import UserNotifications
import WebKit

enum DashboardNotificationsRequest: String {
    case status
    case requestPermission = "request-permission"
    case sendTest = "send-test"
}

struct DashboardNotificationsSnapshot: Encodable, Equatable {
    let permission: String
    let test: TestNotificationOutcome?
}

@MainActor
final class DashboardNotificationsMessageHandler: NSObject, WKScriptMessageHandler {
    weak var owner: DashboardWindowController?

    func userContentController(_: WKUserContentController, didReceive message: WKScriptMessage) {
        self.owner?.receiveNotificationsMessage(message)
    }
}

extension DashboardWindowController {
    static let notificationsMessageHandlerName = "openclawNotifications"

    static func notificationsRequest(from body: Any) -> DashboardNotificationsRequest? {
        guard let payload = body as? [String: Any],
              let type = payload["type"] as? String
        else {
            return nil
        }
        return DashboardNotificationsRequest(rawValue: type)
    }

    static func notificationsPermissionLabel(for status: UNAuthorizationStatus) -> String {
        switch status {
        case .authorized, .provisional:
            "granted"
        case .denied:
            "denied"
        case .notDetermined:
            "notDetermined"
        default:
            // .ephemeral is unavailable by name on macOS and cannot occur here;
            // map it and future cases to notDetermined so the UI offers the
            // permission request instead of claiming access.
            "notDetermined"
        }
    }

    func receiveNotificationsMessage(_ message: WKScriptMessage) {
        guard message.name == Self.notificationsMessageHandlerName,
              message.webView === self.webView,
              message.frameInfo.isMainFrame,
              Self.isTrustedLinkSource(message.frameInfo.request.url, dashboardURL: self.currentURL)
        else {
            return
        }
        guard let request = Self.notificationsRequest(from: message.body) else { return }

        switch request {
        case .status:
            Task { await self.refreshNotificationsPermission() }
        case .requestPermission:
            Task {
                _ = await PermissionManager.ensure([.notifications], interactive: true)
                await self.refreshNotificationsPermission()
            }
        case .sendTest:
            Task {
                guard self.notificationTestOutcome != .pending else { return }
                self.notificationTestOutcome = .pending
                await self.publishNotificationsStatus()
                self.notificationTestOutcome = await TestNotificationAction.send()
                await self.publishNotificationsStatus()
            }
        }
    }

    static func notificationsSnapshot(
        permission: String,
        testOutcome: TestNotificationOutcome?) -> DashboardNotificationsSnapshot
    {
        DashboardNotificationsSnapshot(permission: permission, test: testOutcome)
    }

    private func refreshNotificationsPermission() async {
        guard PermissionManager.notificationCenterAvailable else { return }
        let settings = await UNUserNotificationCenter.current().notificationSettings()
        self.notificationPermission = Self.notificationsPermissionLabel(for: settings.authorizationStatus)
        await self.publishNotificationsStatus()
    }

    private func publishNotificationsStatus() async {
        // Honest absence beats a fabricated status when the process is unbundled.
        guard PermissionManager.notificationCenterAvailable else { return }
        let snapshot = Self.notificationsSnapshot(
            permission: self.notificationPermission,
            testOutcome: self.notificationTestOutcome)
        guard let data = try? JSONEncoder().encode(snapshot),
              let json = String(data: data, encoding: .utf8)
        else { return }
        // Keep a global snapshot so late subscribers can read status without a bridge round-trip.
        _ = try? await self.webView.evaluateJavaScript(
            """
            window.__OPENCLAW_NATIVE_NOTIFICATIONS__ = \(json);
            window.dispatchEvent(new CustomEvent('openclaw:native-notifications-status', \
            {detail:window.__OPENCLAW_NATIVE_NOTIFICATIONS__}));
            """)
    }
}