import ActivityKit
import Foundation

extension Notification.Name {
    static let liveActivityDismissed = Notification.Name("liveActivityDismissed")
}

@MainActor
final class LiveActivityManager {
    static let shared = LiveActivityManager()
    private init() {}

    private var currentActivity: Activity<SessionActivityAttributes>?
    private var healthCheckTimer: Timer?
    private var lastHealthCheck: Date = Date()

    deinit {
        healthCheckTimer?.invalidate()
    }

    /// Check if there's an active session and restart Live Activity if needed
    func restartLiveActivityIfNeeded(activeSession: ClimbSession?, gymName: String?) async {
        // If we have an active session but no Live Activity, restart it
        guard let activeSession = activeSession,
            let gymName = gymName,
            activeSession.status == .active
        else {
            return
        }

        // Check if we have a tracked Live Activity that's still actually running
        if let currentActivity = currentActivity {
            let activities = Activity<SessionActivityAttributes>.activities
            let isStillActive = activities.contains { $0.id == currentActivity.id }

            if isStillActive {
                print("ℹ️ Live Activity still running: \(currentActivity.id)")
                return
            } else {
                print(
                    "⚠️ Tracked Live Activity \(currentActivity.id) was dismissed, clearing reference"
                )
                self.currentActivity = nil
            }
        }

        // Check if there are ANY active Live Activities for this session
        let existingActivities = Activity<SessionActivityAttributes>.activities
        if let existingActivity = existingActivities.first {
            print("ℹ️ Found existing Live Activity: \(existingActivity.id), using it")
            self.currentActivity = existingActivity
            return
        }

        print("🔄 No Live Activity found, restarting for existing session")
        await startLiveActivity(for: activeSession, gymName: gymName)
    }

    /// Call this when a ClimbSession starts to begin a Live Activity
    func startLiveActivity(for session: ClimbSession, gymName: String) async {
        print("🔴 Starting Live Activity for gym: \(gymName)")

        await endLiveActivity()

        // Start health checks once we have an active session
        startHealthChecks()

        // Calculate elapsed time if session already started
        let startTime = session.startTime ?? session.date
        let elapsed = Date().timeIntervalSince(startTime)

        let attributes = SessionActivityAttributes(
            gymName: gymName, startTime: startTime)
        let initialContentState = SessionActivityAttributes.ContentState(
            elapsed: elapsed,
            totalAttempts: 0,
            completedProblems: 0
        )

        do {
            let activity = try Activity<SessionActivityAttributes>.request(
                attributes: attributes,
                content: .init(state: initialContentState, staleDate: nil),
                pushType: nil
            )
            self.currentActivity = activity
            print("✅ Live Activity started successfully: \(activity.id)")
        } catch {
            print("❌ Failed to start live activity: \(error)")
            print("Error details: \(error.localizedDescription)")

            // Check specific error types
            if error.localizedDescription.contains("authorization") {
                print("Authorization error - check Live Activity permissions in Settings")
            } else if error.localizedDescription.contains("content") {
                print("Content error - check ActivityAttributes structure")
            } else if error.localizedDescription.contains("frequencyLimited") {
                print("Frequency limited - too many Live Activities started recently")
            }
        }
    }

    /// Call this to update the Live Activity with new session progress
    func updateLiveActivity(elapsed: TimeInterval, totalAttempts: Int, completedProblems: Int) async
    {
        guard let currentActivity = currentActivity else {
            print("⚠️ No current activity to update")
            return
        }

        // Verify the activity is still valid before updating
        let activities = Activity<SessionActivityAttributes>.activities
        let isStillActive = activities.contains { $0.id == currentActivity.id }

        if !isStillActive {
            print(
                "⚠️ Tracked Live Activity \(currentActivity.id) is no longer active, clearing reference"
            )
            self.currentActivity = nil
            return
        }

        print(
            "🔄 Updating Live Activity - Attempts: \(totalAttempts), Completed: \(completedProblems)"
        )

        let updatedContentState = SessionActivityAttributes.ContentState(
            elapsed: elapsed,
            totalAttempts: totalAttempts,
            completedProblems: completedProblems
        )

        await currentActivity.update(.init(state: updatedContentState, staleDate: nil))
        print("✅ Live Activity updated successfully")
    }

    /// Call this when a ClimbSession ends to end the Live Activity
    func endLiveActivity() async {
        // Stop health checks first
        stopHealthChecks()

        // First end the tracked activity if it exists
        if let currentActivity {
            print("🔴 Ending tracked Live Activity: \(currentActivity.id)")
            await currentActivity.end(nil, dismissalPolicy: .immediate)
            self.currentActivity = nil
            print("✅ Tracked Live Activity ended successfully")
        }

        // Force end ALL active activities of our type to ensure cleanup
        print("🔍 Checking for any remaining active activities...")
        let activities = Activity<SessionActivityAttributes>.activities

        if activities.isEmpty {
            print("ℹ️ No additional activities found")
        } else {
            print("🔴 Found \(activities.count) additional active activities, ending them...")
            for activity in activities {
                print("🔴 Force ending activity: \(activity.id)")
                await activity.end(nil, dismissalPolicy: .immediate)
            }
            print("✅ All Live Activities ended successfully")
        }
    }

    /// Check if Live Activities are available and authorized
    func checkLiveActivityAvailability() -> String {
        let authorizationInfo = ActivityAuthorizationInfo()
        let status = authorizationInfo.areActivitiesEnabled
        let allActivities = Activity<SessionActivityAttributes>.activities

        let message = """
            Live Activity Status:
            • Enabled: \(status)
            • Authorization: \(authorizationInfo.areActivitiesEnabled ? "Granted" : "Denied/Unknown")
            • Tracked Activity: \(currentActivity?.id.description ?? "None")
            • All Active Activities: \(allActivities.count)
            """

        print(message)
        return message
    }

    /// Force check and cleanup dismissed Live Activities
    func cleanupDismissedActivities() async {
        let activities = Activity<SessionActivityAttributes>.activities

        if let currentActivity = currentActivity {
            let isStillActive = activities.contains { $0.id == currentActivity.id }
            if !isStillActive {
                print("🧹 Cleaning up dismissed Live Activity: \(currentActivity.id)")
                self.currentActivity = nil
            }
        }
    }

    /// Start periodic health checks for Live Activity
    func startHealthChecks() {
        stopHealthChecks()  // Stop any existing timer

        print("🩺 Starting Live Activity health checks")
        healthCheckTimer = Timer.scheduledTimer(withTimeInterval: 30.0, repeats: true) {
            [weak self] _ in
            Task { @MainActor in
                await self?.performHealthCheck()
            }
        }
    }

    /// Stop periodic health checks
    func stopHealthChecks() {
        healthCheckTimer?.invalidate()
        healthCheckTimer = nil
        print("🛑 Stopped Live Activity health checks")
    }

    /// Perform a health check on the current Live Activity
    private func performHealthCheck() async {
        guard let currentActivity = currentActivity else { return }

        let now = Date()
        let timeSinceLastCheck = now.timeIntervalSince(lastHealthCheck)

        // Only perform health check if it's been at least 25 seconds
        guard timeSinceLastCheck >= 25 else { return }

        print("🩺 Performing Live Activity health check")
        lastHealthCheck = now

        let activities = Activity<SessionActivityAttributes>.activities
        let isStillActive = activities.contains { $0.id == currentActivity.id }

        if !isStillActive {
            print("💔 Health check failed - Live Activity was dismissed")
            self.currentActivity = nil

            // Notify that we need to restart
            NotificationCenter.default.post(
                name: .liveActivityDismissed,
                object: nil
            )
        } else {
            print("✅ Live Activity health check passed")
        }
    }

    /// Get the current activity status for debugging
    func getCurrentActivityStatus() -> String {
        let activities = Activity<SessionActivityAttributes>.activities
        let trackedStatus = currentActivity != nil ? "Tracked" : "None"
        let actualCount = activities.count

        return "Status: \(trackedStatus) | Active Count: \(actualCount)"
    }

    /// Start periodic updates for Live Activity
    func startPeriodicUpdates(for session: ClimbSession, totalAttempts: Int, completedProblems: Int)
    {
        guard currentActivity != nil else { return }

        Task {
            while currentActivity != nil {
                let elapsed = Date().timeIntervalSince(session.startTime ?? session.date)
                await updateLiveActivity(
                    elapsed: elapsed,
                    totalAttempts: totalAttempts,
                    completedProblems: completedProblems
                )

                // Wait 30 seconds before next update
                try? await Task.sleep(nanoseconds: 30_000_000_000)
            }
        }
    }
}