Senior Review

SpotifyClone/Core/Configuration/AppConfiguration.swift

@@ -0,0 +1,69 @@
+//
+//  AppConfiguration.swift
+//  SpotifyClone
+//
+//  Created for code improvements
+//
+
+import Foundation
+
+/// Centralized configuration for the application
+enum AppConfiguration {
+    /// Spotify API configuration
+    enum Spotify {
+        static let baseURL = "https://api.spotify.com/v1"
+        static let authURL = "https://accounts.spotify.com"
+        static var tokenURL: String {
+            return "\(authURL)/api/token"
+        }
+
+        static var clientID: String {
+            guard let path = Bundle.main.path(forResource: "Config", ofType: "plist"),
+                  let plist = NSDictionary(contentsOfFile: path) as? [String: Any],
+                  let id = plist["SpotifyClientID"] as? String, !id.isEmpty else {
+                fatalError("SpotifyClientID not found in Config.plist")
+            }
+            return id
+        }
+
+        static var clientSecret: String {
+            guard let path = Bundle.main.path(forResource: "Config", ofType: "plist"),
+                  let plist = NSDictionary(contentsOfFile: path) as? [String: Any],
+                  let secret = plist["SpotifyClientSecret"] as? String, !secret.isEmpty else {
+                fatalError("SpotifyClientSecret not found in Config.plist")
+            }
+            return secret
+        }
+
+        static var redirectURI: String {
+            guard let path = Bundle.main.path(forResource: "Config", ofType: "plist"),
+                  let plist = NSDictionary(contentsOfFile: path) as? [String: Any],
+                  let uri = plist["SpotifyRedirectURI"] as? String else {
+                return "http://localhost:3000/callback"
+            }
+            return uri
+        }
+    }
+
+    /// UserDefaults keys
+    enum UserDefaultsKeys {
+        static let accessToken = "access_token"
+        static let refreshToken = "refresh_token"
+        static let expirationDate = "expiration_date"
+    }
+
+    /// Cache configuration
+    enum Cache {
+        static let maxMemorySize = 50 * 1024 * 1024 // 50MB
+        static let maxDiskSize = 200 * 1024 * 1024 // 200MB
+        static let expirationInterval: TimeInterval = 3600 // 1 hour
+    }
+
+    /// Network configuration
+    enum Network {
+        static let timeoutInterval: TimeInterval = 30
+        static let maxRetries = 3
+        static let retryBaseDelay: TimeInterval = 1.0
+    }
+}
+

SpotifyClone/Core/Error/ApiError.swift

@@ -21,7 +21,7 @@ enum ApiError: LocalizedError {
     case apiError(String)
     case decodingError(String)
     case unknownError(String)
-    case rateLimitExceeded
+    case rateLimitExceeded(retryAfter: String? = nil)
     case jsonSerializationFailed
     case jsonParsingFailed
 
@@ -59,4 +59,68 @@ enum ApiError: LocalizedError {
             return "JSON parsing failed"
         }
     }
+
+    /// User-friendly error message for display in UI
+    var userMessage: String {
+        switch self {
+        case .code:
+            return "Authentication failed. Please try logging in again."
+        case .tokenNotFound:
+            return "Your session has expired. Please log in again."
+        case .invalidInput:
+            return "Invalid input. Please check your search and try again."
+        case .invalidURL:
+            return "Something went wrong. Please try again."
+        case .failedToGetData:
+            return "Unable to load data. Please check your internet connection."
+        case .decodeError, .decodingError:
+            return "Unable to process the response. Please try again."
+        case .rateLimitExceeded(let retryAfter):
+            if let retryAfter = retryAfter, let seconds = Int(retryAfter) {
+                return "Too many requests. Please wait \(seconds) seconds and try again."
+            }
+            return "Too many requests. Please wait a moment and try again."
+        case .invalidResponse(let statusCode):
+            switch statusCode {
+            case 401:
+                return "Your session has expired. Please log in again."
+            case 403:
+                return "You don't have permission to access this."
+            case 404:
+                return "The requested item was not found."
+            case 429:
+                return "Too many requests. Please wait a moment."
+            case 500...599:
+                return "Server error. Please try again later."
+            default:
+                return "Something went wrong. Please try again."
+            }
+        case .noGenresAvailable:
+            return "No genres are currently available."
+        case .apiError(let message):
+            return "Error: \(message)"
+        case .encodingError(let message):
+            return "Encoding error: \(message)"
+        case .unknownError(let message):
+            return "An unexpected error occurred: \(message)"
+        case .jsonSerializationFailed, .jsonParsingFailed:
+            return "Unable to process the data. Please try again."
+        }
+    }
+
+    /// Suggested recovery action for the error
+    var recoveryAction: String? {
+        switch self {
+        case .tokenNotFound, .code:
+            return "Log In"
+        case .failedToGetData:
+            return "Retry"
+        case .rateLimitExceeded:
+            return "Wait"
+        case .invalidResponse(let statusCode) where statusCode == 401:
+            return "Log In"
+        default:
+            return nil
+        }
+    }
 }

SpotifyClone/Core/Logging/Logger.swift

@@ -0,0 +1,126 @@
+//
+//  Logger.swift
+//  SpotifyClone
+//
+//  Created for centralized logging
+//
+
+import Foundation
+import os.log
+
+/// Log levels for different types of messages
+enum LogLevel {
+    case debug
+    case info
+    case warning
+    case error
+
+    var osLogType: OSLogType {
+        switch self {
+        case .debug: return .debug
+        case .info: return .info
+        case .warning: return .default
+        case .error: return .error
+        }
+    }
+
+    var prefix: String {
+        switch self {
+        case .debug: return "🔍 DEBUG"
+        case .info: return "ℹ️ INFO"
+        case .warning: return "⚠️ WARNING"
+        case .error: return "❌ ERROR"
+        }
+    }
+}
+
+/// Centralized logging utility
+final class Logger {
+    static let shared = Logger()
+
+    private let subsystem: String
+    private let category = "SpotifyClone"
+    private let log: OSLog
+
+    #if DEBUG
+    private let isDebugMode = true
+    #else
+    private let isDebugMode = false
+    #endif
+
+    private init() {
+        subsystem = Bundle.main.bundleIdentifier ?? "com.spotifyclone"
+        log = OSLog(subsystem: subsystem, category: category)
+    }
+
+    /// Log a message with specified level
+    func log(
+        _ message: String,
+        level: LogLevel = .info,
+        file: String = #file,
+        function: String = #function,
+        line: Int = #line
+    ) {
+        let fileName = (file as NSString).lastPathComponent
+        let logMessage = "[\(fileName):\(line)] \(function) - \(message)"
+
+        // Skip debug logs in release builds
+        if level == .debug && !isDebugMode {
+            return
+        }
+
+        // Log to OSLog (visible in Console.app)
+        os_log("%{public}@", log: log, type: level.osLogType, logMessage)
+
+        #if DEBUG
+        // Print to console in debug mode
+        print("\(level.prefix) - \(logMessage)")
+        #endif
+    }
+
+    /// Log a debug message
+    func debug(
+        _ message: String,
+        file: String = #file,
+        function: String = #function,
+        line: Int = #line
+    ) {
+        log(message, level: .debug, file: file, function: function, line: line)
+    }
+
+    /// Log an info message
+    func info(
+        _ message: String,
+        file: String = #file,
+        function: String = #function,
+        line: Int = #line
+    ) {
+        log(message, level: .info, file: file, function: function, line: line)
+    }
+
+    /// Log a warning message
+    func warning(
+        _ message: String,
+        file: String = #file,
+        function: String = #function,
+        line: Int = #line
+    ) {
+        log(message, level: .warning, file: file, function: function, line: line)
+    }
+
+    /// Log an error message
+    func error(
+        _ message: String,
+        error: Error? = nil,
+        file: String = #file,
+        function: String = #function,
+        line: Int = #line
+    ) {
+        var fullMessage = message
+        if let error = error {
+            fullMessage += " - Error: \(error.localizedDescription)"
+        }
+        log(fullMessage, level: .error, file: file, function: function, line: line)
+    }
+}
+

SpotifyClone/Core/Networking/NetworkMonitor.swift

@@ -0,0 +1,59 @@
+//
+//  NetworkMonitor.swift
+//  SpotifyClone
+//
+//  Created for network reachability monitoring
+//
+
+import Foundation
+import Network
+
+/// Delegate protocol for network status changes
+protocol NetworkMonitorDelegate: AnyObject {
+    func networkStatusChanged(isConnected: Bool)
+}
+
+/// Monitors network connectivity status
+final class NetworkMonitor {
+    static let shared = NetworkMonitor()
+
+    private let monitor = NWPathMonitor()
+    private let queue = DispatchQueue(label: "com.spotifyclone.networkmonitor")
+
+    /// Current network connection status
+    private(set) var isConnected: Bool = false
+
+    /// Delegate to notify about network status changes
+    weak var delegate: NetworkMonitorDelegate?
+
+    private init() {
+        startMonitoring()
+    }
+
+    /// Start monitoring network connectivity
+    func startMonitoring() {
+        monitor.pathUpdateHandler = { [weak self] path in
+            let wasConnected = self?.isConnected ?? false
+            self?.isConnected = path.status == .satisfied
+
+            // Notify delegate if status changed
+            if wasConnected != self?.isConnected {
+                DispatchQueue.main.async {
+                    self?.delegate?.networkStatusChanged(isConnected: self?.isConnected ?? false)
+                }
+            }
+        }
+        monitor.start(queue: queue)
+    }
+
+    /// Stop monitoring network connectivity
+    func stopMonitoring() {
+        monitor.cancel()
+    }
+
+    /// Check if network is currently available
+    func checkConnectivity() -> Bool {
+        return isConnected
+    }
+}
+

SpotifyClone/Extensions/UIViewController+ErrorDisplay.swift

@@ -0,0 +1,46 @@
+//
+//  UIViewController+ErrorDisplay.swift
+//  SpotifyClone
+//
+//  Created for error display utilities
+//
+
+import UIKit
+
+extension UIViewController {
+    /// Display an error alert with user-friendly message
+    func showError(_ error: Error, title: String = "Error", completion: (() -> Void)? = nil) {
+        let message: String
+        let recoveryAction: String?
+
+        if let apiError = error as? ApiError {
+            message = apiError.userMessage
+            recoveryAction = apiError.recoveryAction
+        } else {
+            message = error.localizedDescription
+            recoveryAction = nil
+        }
+
+        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
+
+        if let recoveryAction = recoveryAction {
+            alert.addAction(UIAlertAction(title: recoveryAction, style: .default) { _ in
+                completion?()
+            })
+        } else {
+            alert.addAction(UIAlertAction(title: "OK", style: .default) { _ in
+                completion?()
+            })
+        }
+
+        present(alert, animated: true)
+    }
+
+    /// Display a success message
+    func showSuccess(_ message: String, title: String = "Success") {
+        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
+        alert.addAction(UIAlertAction(title: "OK", style: .default))
+        present(alert, animated: true)
+    }
+}
+