// Local notification handler for watchOS timer alerts

import Foundation
import UserNotifications
import os

@MainActor
final class WatchNotificationHandler: NSObject, ObservableObject {
    static let shared = WatchNotificationHandler()

    private let logger = Logger(subsystem: "com.chronomind.watch", category: "Notifications")
    private let center = UNUserNotificationCenter.current()

    static let timerFiredCategory = "CHRONOMIND_TIMER_FIRED"
    static let snoozeAction = "SNOOZE_ACTION"
    static let dismissAction = "DISMISS_ACTION"

    private override init() {
        super.init()
    }

    // MARK: - Setup

    func requestAuthorization() {
        center.requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
            Task { @MainActor in
                if let error = error {
                    self.logger.error("Notification auth error: \(error.localizedDescription)")
                    return
                }
                self.logger.info("Notification auth granted: \(granted)")
                self.registerCategories()
            }
        }
    }

    private func registerCategories() {
        let snooze = UNNotificationAction(
            identifier: Self.snoozeAction,
            title: "Snooze 5m",
            options: []
        )
        let dismiss = UNNotificationAction(
            identifier: Self.dismissAction,
            title: "Dismiss",
            options: [.destructive]
        )

        let category = UNNotificationCategory(
            identifier: Self.timerFiredCategory,
            actions: [snooze, dismiss],
            intentIdentifiers: [],
            options: []
        )

        center.setNotificationCategories([category])
        center.delegate = self
        logger.info("Notification categories registered")
    }

    // MARK: - Schedule

    func scheduleTimerNotification(id: String, label: String, targetTime: Date, urgency: UrgencyLevel) {
        let interval = targetTime.timeIntervalSinceNow
        guard interval > 0 else { return }

        let content = UNMutableNotificationContent()
        content.title = "Timer Fired"
        content.body = label
        content.sound = urgency == .critical ? .defaultCritical : .default
        content.categoryIdentifier = Self.timerFiredCategory
        content.userInfo = ["timerId": id, "urgency": urgency.rawValue]

        let trigger = UNTimeIntervalNotificationTrigger(timeInterval: interval, repeats: false)
        let request = UNNotificationRequest(identifier: "timer-\(id)", content: content, trigger: trigger)

        center.add(request) { error in
            Task { @MainActor in
                if let error = error {
                    self.logger.error("Failed to schedule notification: \(error.localizedDescription)")
                } else {
                    self.logger.info("Scheduled notification for timer \(id) in \(Int(interval))s")
                }
            }
        }
    }

    func cancelNotification(for timerId: String) {
        center.removePendingNotificationRequests(withIdentifiers: ["timer-\(timerId)"])
    }
}

// MARK: - UNUserNotificationCenterDelegate

extension WatchNotificationHandler: UNUserNotificationCenterDelegate {
    nonisolated func userNotificationCenter(
        _ center: UNUserNotificationCenter,
        didReceive response: UNNotificationResponse,
        withCompletionHandler completionHandler: @escaping () -> Void
    ) {
        let userInfo = response.notification.request.content.userInfo
        guard let timerId = userInfo["timerId"] as? String else {
            completionHandler()
            return
        }

        Task { @MainActor in
            let sessionManager = WatchSessionManager.shared
            switch response.actionIdentifier {
            case Self.snoozeAction:
                sessionManager.sendCommand(.snooze(id: timerId, minutes: 5))
                logger.info("Snooze action for timer \(timerId)")
            case Self.dismissAction:
                sessionManager.sendCommand(.dismiss(id: timerId))
                logger.info("Dismiss action for timer \(timerId)")
            default:
                break
            }
        }

        completionHandler()
    }

    nonisolated func userNotificationCenter(
        _ center: UNUserNotificationCenter,
        willPresent notification: UNNotification,
        withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void
    ) {
        completionHandler([.banner, .sound])
    }
}