//
//  TimerModule.swift
//  Werkout_ios
//
//  Created by Trey Tartt on 6/14/23.
//

import Foundation
import WatchConnectivity

enum WatchActions: Codable {
    case nextExercise
    case workoutComplete(Data)
}

class BridgeModule: NSObject, ObservableObject {
    private let kMessageKey = "message"

    static let shared = BridgeModule()
    @Published var isShowingOnExternalDisplay = false
    
    private var timer: Timer?
    @Published var timeLeft: Int = 0
    
    @Published var currentExercise: ExerciseElement?
    var currentWorkout: Workout?
    var currentExerciseIdx: Int = -1
    
    var workoutStartDate: Date?
    
    // workoutEndDate ties into WatchPackageModel.workoutEndDate which
    // tells the watch app to stop the workout
    var workoutEndDate: Date?
    @Published var currentWorkoutRunTimeInSeconds: Int = -1
    private var currentWorkoutRunTimer: Timer?
    
    @Published var isInWorkout = false
    var completedWorkoutFromWatch: (() -> Void)?
    var totalCaloire: Float?
    var heartRates: [Int]?
    
    func start(workout: Workout, atExerciseIndex: Int = 0) {
        self.currentWorkout = workout
        currentWorkoutRunTimeInSeconds = 0
        currentWorkoutRunTimer?.invalidate()
        currentWorkoutRunTimer = nil
        
        currentExerciseIdx = 0
        let exercise = workout.exercises[currentExerciseIdx]
        updateCurrent(exercise: exercise)
        startWorkoutTimer()
        workoutStartDate = Date()
        isInWorkout = true
        
        if WCSession.isSupported() {
            WCSession.default.delegate = self
            WCSession.default.activate()
        }
    }
    
    func resetCurrentWorkout() {
        currentWorkoutRunTimeInSeconds = 0
        currentWorkoutRunTimer?.invalidate()
        currentWorkoutRunTimer = nil
        
        currentWorkoutRunTimer?.invalidate()
        currentWorkoutRunTimer = nil
        
        currentWorkoutRunTimeInSeconds = -1
        currentExerciseIdx = -1
        
        currentExercise = nil
        currentWorkout = nil
 
        isInWorkout = false
        workoutStartDate = nil
        workoutEndDate = nil
        
        let watchModel = WatchPackageModel(currentExerciseName: "", currentTimeLeft: -100, workoutStartDate: Date())
        let data = try! JSONEncoder().encode(watchModel)
        send(data)
    }
    
    private func startWorkoutTimer() {
        currentWorkoutRunTimer?.invalidate()
        currentWorkoutRunTimer = nil
        currentWorkoutRunTimer = Timer.scheduledTimer(timeInterval: 1,
                                     target: self,
                                     selector: #selector(addOneToWorkoutRunTime),
                                     userInfo: nil,
                                     repeats: true)
        currentWorkoutRunTimer?.fire()
    }
    
    private func startTimerWith(duration: Int) {
        timer?.invalidate()
        timer = nil
        timeLeft = duration
        timer = Timer.scheduledTimer(timeInterval: 1,
                                     target: self,
                                     selector: #selector(updateCounter),
                                     userInfo: nil,
                                     repeats: true)
        timer?.fire()
    }
    
    @objc func updateCounter() {
        if timeLeft > 0 {
            timeLeft -= 1
            
            let watchModel = WatchPackageModel(currentExerciseName: currentExercise?.exercise.name ?? "-", currentTimeLeft: timeLeft, workoutStartDate: workoutStartDate ?? Date())
            let data = try! JSONEncoder().encode(watchModel)
            send(data)
            
        } else {
            timer?.invalidate()
            timer = nil
            
            nextExercise()
        }
    }
    
    func nextExercise() {
        currentExerciseIdx += 1
        if let currentWorkout = currentWorkout {
            if currentExerciseIdx < currentWorkout.exercises.count {
                let nextExercise = currentWorkout.exercises[currentExerciseIdx]
                updateCurrent(exercise: nextExercise)
            } else {
                
            }
        }
    }
    
    @objc func addOneToWorkoutRunTime() {
        currentWorkoutRunTimeInSeconds += 1
    }
    
    func updateCurrent(exercise: ExerciseElement) {
        self.currentExercise = exercise

        if let duration = exercise.duration {
            startTimerWith(duration: duration)
        }
    }
}

extension BridgeModule: WCSessionDelegate {
    func sendWorkoutCompleteToWatch() {
        let watchModel = WatchPackageModel(currentExerciseName: currentExercise?.exercise.name ?? "-", currentTimeLeft: timeLeft, workoutStartDate: workoutStartDate ?? Date(), workoutEndDate: Date())
        let data = try! JSONEncoder().encode(watchModel)
        send(data)
    }
    
    func session(_ session: WCSession, didReceiveMessageData messageData: Data) {
        if let model = try? JSONDecoder().decode(WatchActions.self, from: messageData) {
            switch model {
            case .nextExercise:
                nextExercise()
            case .workoutComplete(let data):
                let model = try! JSONDecoder().decode(WatchFinishWorkoutModel.self, from: data)
                totalCaloire = Float(model.totalBurnedEnergery)
                heartRates = model.allHeartRates
                completedWorkoutFromWatch?()
            }
        }
    }

    
    func session(_ session: WCSession,
                 activationDidCompleteWith activationState: WCSessionActivationState,
                 error: Error?) {}
    
#if os(iOS)
    func sessionDidBecomeInactive(_ session: WCSession) {}
    func sessionDidDeactivate(_ session: WCSession) {
        session.activate()
    }
#endif
    
    
    func send(_ data: Data) {
        guard WCSession.default.activationState == .activated else {
            return
        }
#if os(iOS)
        guard WCSession.default.isWatchAppInstalled else {
            return
        }
#else
        guard WCSession.default.isCompanionAppInstalled else {
            return
        }
#endif
        WCSession.default.sendMessageData(data, replyHandler: nil)
        { error in
            print("Cannot send message: \(String(describing: error))")
        }
    }
}