//
//  WatchConnectivityManager.swift
//  Feels
//
//  Central coordinator for Watch Connectivity.
//  iOS app is the hub - all mood logging flows through here.
//

import Foundation
import WatchConnectivity
import WidgetKit
import os.log

/// Manages Watch Connectivity between iOS and watchOS
/// iOS app acts as the central coordinator for all mood logging
final class WatchConnectivityManager: NSObject, ObservableObject {

    static let shared = WatchConnectivityManager()

    private static let logger = Logger(subsystem: "com.tt.feels", category: "WatchConnectivity")

    private var session: WCSession?

    /// Whether the paired device is currently reachable for immediate messaging
    var isReachable: Bool {
        session?.isReachable ?? false
    }

    private override init() {
        super.init()

        if WCSession.isSupported() {
            session = WCSession.default
            session?.delegate = self
            session?.activate()
            Self.logger.info("WCSession activated")
        } else {
            Self.logger.warning("WCSession not supported on this device")
        }
    }

    // MARK: - iOS → Watch

    #if os(iOS)
    /// Notify watch to reload its complications
    func notifyWatchToReload() {
        guard let session = session,
              session.activationState == .activated,
              session.isWatchAppInstalled else {
            return
        }

        let message = ["action": "reloadWidgets"]
        session.transferUserInfo(message)
        Self.logger.info("Sent reload notification to watch")
    }
    #endif

    // MARK: - Watch → iOS

    #if os(watchOS)
    /// Send mood to iOS app for centralized logging
    /// Returns true if message was sent, false if fallback to local storage is needed
    func sendMoodToPhone(mood: Int, date: Date) -> Bool {
        guard let session = session,
              session.activationState == .activated else {
            Self.logger.warning("WCSession not ready")
            return false
        }

        let message: [String: Any] = [
            "action": "logMood",
            "mood": mood,
            "date": date.timeIntervalSince1970
        ]

        // Use transferUserInfo for guaranteed delivery
        session.transferUserInfo(message)
        Self.logger.info("Sent mood \(mood) to iPhone for logging")
        return true
    }
    #endif
}

// MARK: - WCSessionDelegate

extension WatchConnectivityManager: WCSessionDelegate {

    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
        if let error = error {
            Self.logger.error("WCSession activation failed: \(error.localizedDescription)")
        } else {
            Self.logger.info("WCSession activation completed: \(activationState.rawValue)")
        }
    }

    #if os(iOS)
    func sessionDidBecomeInactive(_ session: WCSession) {
        Self.logger.info("WCSession became inactive")
    }

    func sessionDidDeactivate(_ session: WCSession) {
        Self.logger.info("WCSession deactivated, reactivating...")
        session.activate()
    }

    // iOS receives mood from watch and logs it centrally
    func session(_ session: WCSession, didReceiveUserInfo userInfo: [String: Any] = [:]) {
        handleReceivedMessage(userInfo)
    }

    func session(_ session: WCSession, didReceiveMessage message: [String: Any]) {
        handleReceivedMessage(message)
    }

    private func handleReceivedMessage(_ message: [String: Any]) {
        guard let action = message["action"] as? String else { return }

        switch action {
        case "logMood":
            guard let moodRaw = message["mood"] as? Int,
                  let mood = Mood(rawValue: moodRaw),
                  let timestamp = message["date"] as? TimeInterval else {
                Self.logger.error("Invalid mood message format")
                return
            }

            let date = Date(timeIntervalSince1970: timestamp)
            Self.logger.info("Received mood \(moodRaw) from watch, logging centrally")

            Task { @MainActor in
                // Use MoodLogger for centralized logging with all side effects
                MoodLogger.shared.logMood(mood, for: date, entryType: .watch)
            }

        case "reloadWidgets":
            Task { @MainActor in
                WidgetCenter.shared.reloadAllTimelines()
            }

        default:
            break
        }
    }
    #endif

    #if os(watchOS)
    // Watch receives reload notification from iOS
    func session(_ session: WCSession, didReceiveUserInfo userInfo: [String: Any] = [:]) {
        if userInfo["action"] as? String == "reloadWidgets" {
            Self.logger.info("Received reload notification from iPhone")
            Task { @MainActor in
                WidgetCenter.shared.reloadAllTimelines()
            }
        }
    }

    func session(_ session: WCSession, didReceiveMessage message: [String: Any]) {
        if message["action"] as? String == "reloadWidgets" {
            Task { @MainActor in
                WidgetCenter.shared.reloadAllTimelines()
            }
        }
    }
    #endif
}