/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    A state used by `LevelScene` to indicate that the game is actively being played. This state updates the current time of the level's countdown timer.

*/

import SpriteKit

import GameplayKit

class LevelSceneActiveState: GKState {

    // MARK: Properties

    unowned let levelScene: LevelScene

    var timeRemaining: TimeInterval = 0.0

    /*

        A formatter for individual date components used to provide an appropriate

        display value for the timer.

    */

    let timeRemainingFormatter: DateComponentsFormatter = {

        let formatter = DateComponentsFormatter()

        formatter.zeroFormattingBehavior = .pad

        formatter.allowedUnits = [.minute, .second]

        return formatter

    }()

    // The formatted string representing the time remaining.

    var timeRemainingString: String {

        let components = NSDateComponents()

        components.second = Int(max(0.0, timeRemaining))

        return timeRemainingFormatter.string(from: components as DateComponents)!

    }

    // MARK: Initializers

    init(levelScene: LevelScene) {

        self.levelScene = levelScene

        timeRemaining = levelScene.levelConfiguration.timeLimit

    }

    // MARK: GKState Life Cycle

    override func didEnter(from previousState: GKState?) {

        super.didEnter(from: previousState)

        levelScene.timerNode.text = timeRemainingString

    }

    override func update(deltaTime seconds: TimeInterval) {

        super.update(deltaTime: seconds)

        // Subtract the elapsed time from the remaining time.

        timeRemaining -= seconds

        // Update the displayed time remaining.

        levelScene.timerNode.text = timeRemainingString

        // Check if the `levelScene` contains any bad `TaskBot`s.

        let allTaskBotsAreGood = !levelScene.entities.contains { entity in

            if let taskBot = entity as? TaskBot {

                return !taskBot.isGood

            }

            return false

        }

        if allTaskBotsAreGood {

            // If all the TaskBots are good, the player has completed the level.

            stateMachine?.enter(LevelSceneSuccessState.self)

        }

        else if timeRemaining <= 0.0 {

            // If there is no time remaining, the player has failed to complete the level.

            stateMachine?.enter(LevelSceneFailState.self)

        }

    }

    override func isValidNextState(_ stateClass: AnyClass) -> Bool {

        switch stateClass {

            case is LevelScenePauseState.Type, is LevelSceneFailState.Type, is LevelSceneSuccessState.Type:

                return true

            default:

                return false

        }

    }

}