Gamification for adaptive courses

Podfile

@@ -53,6 +53,7 @@ def all_pods
     pod 'lottie-ios'
     pod 'Koloda', '4.3.1'
     pod 'SDWebImage/GIF'
+    pod 'Charts', '3.0.2'
 end
 
 def testing_pods

Stepic/AdaptiveRatingHelper.swift

@@ -0,0 +1,19 @@
+//
+//  AdaptiveRatingHelper.swift
+//  Stepic
+//
+//  Created by Vladislav Kiryukhin on 03.08.2017.
+//  Copyright © 2017 Alex Karpov. All rights reserved.
+//
+
+import Foundation
+
+class AdaptiveRatingHelper {
+    static func getLevel(for rating: Int) -> Int {
+        return rating < 5 ? 1 : 2 + Int(log(Double(rating) / 5.0) / log(2.0))
+    }
+
+    static func getRating(for level: Int) -> Int {
+        return level == 0 ? 0 : (level == 1 ? 5 : 5 * Int(pow(2.0, Double(level - 1))))
+    }
+}

Stepic/AdaptiveRatingManager.swift

@@ -0,0 +1,51 @@
+//
+//  AdaptiveRatingManager.swift
+//  Stepic
+//
+//  Created by Vladislav Kiryukhin on 12.07.2017.
+//  Copyright © 2017 Alex Karpov. All rights reserved.
+//
+
+import Foundation
+
+class AdaptiveRatingManager {
+
+    let courseId: Int
+
+    private lazy var ratingKey: String = {
+        "rating_\(self.courseId)"
+    }()
+
+    private lazy var streakKey: String = {
+        "streak_\(self.courseId)"
+    }()
+
+    let defaults = UserDefaults.standard
+
+    init(courseId: Int) {
+        self.courseId = courseId
+    }
+
+    var rating: Int {
+        get {
+            return defaults.integer(forKey: ratingKey)
+        }
+        set(newValue) {
+            updateValue(newValue, for: ratingKey)
+        }
+    }
+
+    var streak: Int {
+        get {
+            return max(1, defaults.integer(forKey: streakKey))
+        }
+        set(newValue) {
+            updateValue(newValue, for: streakKey)
+        }
+    }
+
+    private func updateValue(_ newValue: Int, for key: String) {
+        defaults.set(newValue, forKey: key)
+        defaults.synchronize()
+    }
+}

Stepic/AdaptiveRatingsAPI.swift

@@ -0,0 +1,80 @@
+//
+//  AdaptiveRatingsAPI.swift
+//  Stepic
+//
+//  Created by Vladislav Kiryukhin on 15.08.2017.
+//  Copyright © 2017 Alex Karpov. All rights reserved.
+//
+
+import Foundation
+import Alamofire
+import SwiftyJSON
+import PromiseKit
+
+class AdaptiveRatingsAPI: APIEndpoint {
+    override var name: String { return "rating" }
+
+    typealias RatingRecord = (userId: Int, exp: Int, rank: Int)
+    typealias Scoreboard = (allCount: Int, leaders: [RatingRecord])
+
+    func update(courseId: Int, exp: Int) -> Promise<Void> {
+        var params: Parameters = [
+            "course": courseId,
+            "exp": exp
+        ]
+
+        if let token = AuthInfo.shared.token?.accessToken {
+            params["token"] = token
+        }
+
+        return Promise { fulfill, reject in
+            manager.request("\(StepicApplicationsInfo.adaptiveRatingURL)/\(name)", method: .put, parameters: params, encoding: JSONEncoding.default, headers: nil).responseSwiftyJSON { response in
+                switch response.result {
+                case .failure(let error):
+                    reject(error)
+                case .success(_):
+                    switch response.response?.statusCode ?? 500 {
+                    case 200: fulfill()
+                    case 401: reject(RatingsAPIError.badRequest)
+                    default: reject(RatingsAPIError.serverError)
+                    }
+                }
+            }
+        }
+    }
+
+    func retrieve(courseId: Int, count: Int = 10, days: Int? = 7) -> Promise<Scoreboard> {
+        var params: Parameters = [
+            "course": courseId,
+            "count": count
+        ]
+
+        if let days = days {
+            params["days"] = days
+        }
+
+        if let userId = AuthInfo.shared.userId {
+            params["user"] = userId
+        }
+
+        return Promise { fulfill, reject in
+            manager.request("\(StepicApplicationsInfo.adaptiveRatingURL)/\(name)", method: .get, parameters: params, encoding: URLEncoding.default, headers: nil).responseSwiftyJSON { response in
+                switch response.result {
+                case .failure(let error):
+                    reject(error)
+                case .success(let json):
+                    if response.response?.statusCode == 200 {
+                        let leaders = json["users"].arrayValue.map { RatingRecord(userId: $0["user"].intValue, exp: $0["exp"].intValue, rank: $0["rank"].intValue) }
+                        fulfill(Scoreboard(allCount: json["count"].intValue, leaders: leaders))
+                    } else {
+                        reject(RatingsAPIError.serverError)
+                    }
+                }
+            }
+        }
+    }
+}
+
+enum RatingsAPIError: Error {
+    case badRequest, serverError, connectionError(error: String)
+}

Stepic/AdaptiveRatingsPresenter.swift

@@ -0,0 +1,129 @@
+//
+//  AdaptiveRatingsPresenter.swift
+//  Stepic
+//
+//  Created by Vladislav Kiryukhin on 15.08.2017.
+//  Copyright © 2017 Alex Karpov. All rights reserved.
+//
+
+import Foundation
+import Alamofire
+import PromiseKit
+
+protocol AdaptiveRatingsView: class {
+    func reload()
+    func setRatings(data: ScoreboardViewData)
+    func showError()
+}
+
+struct RatingViewData {
+    let position: Int
+    let exp: Int
+    let name: String
+    let me: Bool
+}
+
+struct ScoreboardViewData {
+    let allCount: Int
+    let leaders: [RatingViewData]
+}
+
+class AdaptiveRatingsPresenter {
+    weak var view: AdaptiveRatingsView?
+
+    fileprivate var ratingsAPI: AdaptiveRatingsAPI
+    fileprivate var ratingManager: AdaptiveRatingManager
+
+    private var scoreboard: [Int: ScoreboardViewData] = [:]
+
+    // Names (word + grammatical gender)
+    private var nouns: [(String, String)] = []
+    private var adjs: [(String, String)] = []
+
+    init(ratingsAPI: AdaptiveRatingsAPI, ratingManager: AdaptiveRatingManager, view: AdaptiveRatingsView) {
+        self.view = view
+        self.ratingManager = ratingManager
+        self.ratingsAPI = ratingsAPI
+
+        loadNamesFromFiles()
+    }
+
+    func reloadData(days: Int? = nil, force: Bool = false) {
+        // Send rating first, then get rating
+        ratingsAPI.cancelAllTasks()
+        ratingsAPI.update(courseId: ratingManager.courseId, exp: ratingManager.rating).then { _ -> Promise<ScoreboardViewData> in
+            print("adaptive ratings: remote rating updated -> reload rating")
+            let downloadedScoreboard = self.scoreboard[days ?? 0] // 0 when 'days' == nil
+            if downloadedScoreboard == nil || force {
+                return self.reloadRating(days: days, force: force)
+            } else {
+                return Promise(value: downloadedScoreboard!)
+            }
+        }.then { scoreboard -> Void in
+            self.scoreboard[days ?? 0] = scoreboard
+            self.view?.setRatings(data: scoreboard)
+            self.view?.reload()
+        }.catch { error in
+            switch error {
+            case RatingsAPIError.serverError:
+                print("adaptive ratings: remote rating update failed: server error")
+                AnalyticsReporter.reportEvent(AnalyticsEvents.Errors.adaptiveRatingServer)
+            default:
+                print("adaptive ratings: remote rating update failed: \(error)")
+            }
+            self.view?.showError()
+        }
+    }
+
+    fileprivate func reloadRating(days: Int? = nil, force: Bool = false) -> Promise<ScoreboardViewData> {
+        return Promise { fulfill, reject in
+            let currentUser = AuthInfo.shared.userId
+
+            ratingsAPI.cancelAllTasks()
+            ratingsAPI.retrieve(courseId: ratingManager.courseId, count: 10, days: days).then { scoreboard -> Void in
+                var curLeaders: [RatingViewData] = []
+                scoreboard.leaders.forEach { record in
+                    curLeaders.append(RatingViewData(position: record.rank, exp: record.exp, name: self.generateNameBy(userId: record.userId), me: currentUser == record.userId))
+                }
+
+                let curScoreboard = ScoreboardViewData(allCount: scoreboard.allCount, leaders: curLeaders)
+                fulfill(curScoreboard)
+            }.catch { error in
+                reject(error)
+            }
+        }
+    }
+
+    fileprivate func loadNamesFromFiles() {
+        func readFile(name: String) -> [String] {
+            if let path = Bundle.main.path(forResource: name, ofType: "plist"),
+                let words = NSArray(contentsOfFile: path) as? [String] {
+                return words
+            }
+            return []
+        }
+
+        readFile(name: "adjectives_m").forEach { adjs.append(($0, "m")) }
+        readFile(name: "adjectives_f").forEach { adjs.append(($0, "f")) }
+        readFile(name: "nouns_m").forEach { nouns.append(($0, "m")) }
+        readFile(name: "nouns_f").forEach { nouns.append(($0, "f")) }
+
+        assert(adjs.count % 2 == 0)
+    }
+
+    fileprivate func generateNameBy(userId: Int) -> String {
+        func hash(_ id: Int) -> Int {
+            var x = id
+            x = ((x >> 16) ^ x) &* 0x45d9f3b
+            x = ((x >> 16) ^ x) &* 0x45d9f3b
+            x = (x >> 16) ^ x
+            return x % (nouns.count * (adjs.count / 2))
+        }
+
+        let noun = nouns[hash(userId) % nouns.count]
+        let adjsByGender = adjs.flatMap { noun.1 == $0.1 ? $0 : nil }
+        let adjNum = hash(userId) / nouns.count
+
+        return "\(adjsByGender[adjNum].0.capitalized) \(noun.0)"
+    }
+}