/*

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

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    A struct that wraps saving and restoring `Workout`s from shared user defaults.

*/

import Foundation

public struct WorkoutHistory {

    var workouts: [Workout]

    public var count: Int {

        return workouts.count

    }

    public subscript(index: Int) -> Workout {

        get {

            return workouts[index]

        }

        set(newValue) {

            workouts[index] = newValue

        }

    }

    public var last: Workout? {

        return workouts.last

    }

    // MARK: Initialization

    private init(workouts: [Workout]) {

        self.workouts = workouts

    }

    // MARK: Load and save

    public static func load() -> WorkoutHistory {

        var workouts = [Workout]()

        let defaults = WorkoutHistory.makeUserDefaults()

        if let savedWorkouts = defaults.object(forKey: "workouts") as? [[String: AnyObject]] {

            for dictionary in savedWorkouts {

                if let workout = Workout(dictionaryRepresentation: dictionary) {

                    workouts.append(workout)

                }

            }

        }

        return WorkoutHistory(workouts: workouts)

    }

    func save() {

        let workoutDictionaries: [[String: AnyObject]] = workouts.map { $0.dictionaryRepresentation }

        let defaults = WorkoutHistory.makeUserDefaults()

        defaults.set(workoutDictionaries as AnyObject, forKey: "workouts")

    }

    // MARK: Convenience

    private static func makeUserDefaults() -> UserDefaults {

        guard let defaults = UserDefaults(suiteName: "group.com.example.apple-samplecode.Ascent") else { fatalError("Unable to create user defaults object") }

        return defaults

    }

}

extension WorkoutHistory: Sequence {

    public typealias Iterator = AnyIterator<Workout>

    public func makeIterator() -> Iterator {

        var index = 0

        return Iterator {

            guard index < self.workouts.count else { return nil }

            let workout = self.workouts[index]

            index += 1

            return workout

        }

    }

}

extension WorkoutHistory: Equatable {}

public func ==(lhs: WorkoutHistory, rhs: WorkoutHistory) -> Bool {

    return lhs.workouts == rhs.workouts

}