[iOS/#369] Timezone 동기화 및 Timer bug fix (#371)

* fix: 24시간제 대응

* fix: Polling 할 때마다 Timer 중복 실행되던 이슈 해결

* feat: GMT로 변경하여 시간대 동기화

iOS/FlipMate/FlipMate/Presentation/Utils/Extensions/Date++Extension.swift

@@ -10,14 +10,12 @@ import Foundation
 extension Date {
     enum FMDateFormmat: String {
         case yyyyMMdd = "yyyy-MM-dd"
-        case yyyyMMddhhmmss = "yyyy-MM-dd hh:mm:ss"
+        case yyyyMMddhhmmss = "yyyy-MM-dd HH:mm:ssZZZZZ"
     }
 
     /// 파라미터로 전달받은 format의 타입으로 Date을 문자열로 변환하여 리턴합니다.
     func dateToString(format: FMDateFormmat) -> String {
         let formatter = DateFormatter()
-        formatter.locale = Locale(identifier: "ko_KR")
-        formatter.timeZone = TimeZone(identifier: "Asia/Seoul")
         formatter.dateFormat = format.rawValue
         return formatter.string(from: self)
     }
@@ -27,10 +25,6 @@ extension DateFormatter {
     static func FMDateFormat(dateFormat: Date.FMDateFormmat) -> DateFormatter {
         let formatter = DateFormatter()
         formatter.dateFormat = dateFormat.rawValue
-        /// locale & timezone
-        formatter.locale = Locale(identifier: "ko_KR")
-        formatter.timeZone = TimeZone(identifier: "Asia/Seoul")
-        print(Locale.current.identifier, TimeZone.current.identifier)
         return formatter
     }
 }

iOS/FlipMate/FlipMate/Presentation/Utils/FriendStatusPollingManager/FriendStatusPollingManager.swift

@@ -60,7 +60,7 @@ final class FriendStatusPollingManager: FriendStatusPollingManageable {
             guard let friend = friendsStatus.filter({ $0.id == id }).first else { return }
             guard let startedTime = friend.startedTime else { continue }
             guard let date = startedTime.stringToDate(.yyyyMMddhhmmss) else { continue }
-            let currentLearningTime = Int(Date().timeIntervalSince(date))
+            let currentLearningTime = Int(Date().timeIntervalSince(date)) - 1
             updateFriendArray.append(UpdateFriend(id: friend.id, currentLearningTime: currentLearningTime))
         }
         startTimer()
@@ -72,7 +72,7 @@ final class FriendStatusPollingManager: FriendStatusPollingManageable {
             guard let friend = friendsStatus.filter({ $0.id == id }).first else { return }
             guard let startedTime = friend.startedTime else { continue }
             guard let date = startedTime.stringToDate(.yyyyMMddhhmmss) else { continue }
-            let currentLearningTime = Int(Date().timeIntervalSince(date))
+            let currentLearningTime = Int(Date().timeIntervalSince(date)) - 1
             updateFriendArray.append(UpdateFriend(id: friend.id, currentLearningTime: currentLearningTime))
         }
     }
@@ -153,10 +153,13 @@ final class FriendStatusPollingManager: FriendStatusPollingManageable {
 
     private func startTimer() {
         if updateFriendArray.isEmpty { return }
+        if timerState == .resumed { return }
         timerManager.start(completion: increaseLearningTime)
+        timerState = .resumed
     }
 
     private func stopTimer() {
         timerManager.cancel()
+        timerState = .cancled
     }
 }