Untested async JSON request/unmarshalling for next version of APO app

APODirectory-iOS.playground

//
//  Directory.swift
//  APO-DZ
//
//  Created by Ronald Martin on 9/21/14.
//  Copyright (c) 2014 Alpha Phi Omega, Delta Zeta Chapter. All rights reserved.
//

import Foundation

typealias Json = AnyObject
typealias JsonObject = [String: Json]
typealias JsonArray = [JsonObject]

struct Brother {
    
    let json: JsonObject
    
    // mark: readonly computed properties
    var name: String {
        get {
            let nameKey  = "First_and_Last_Name"
            return json[nameKey] as Json? as String
        }
    }
    
    var pledgeClass: String {
        get {
            let classKey = "Pledge_Class"
            return json[classKey] as Json? as String
        }
    }
    var year: Int {
        get {
            let yearKey  = "Graduation_Year"
            return json[yearKey] as Json? as Int
        }
    }
    
    var major: String {
        get {
            let majorKey = "Major"
            return json[majorKey] as Json? as String
        }
    }
    var email: String {
        get {
            let emailKey = "Email_Address"
            return json[emailKey] as Json? as String
        }
    }
    var phone: String {
        get {
            let phoneKey = "Phone_Number"
            return json[phoneKey] as Json? as String
        }
    }
}

struct Directory {
    
    // mark: constants
    let BrotherDirName = "Brothers"
    let PledgeDirName  = "Pledges"
    let AlumniDirName  = "Alumni"
    
    // mark: properties
    var brothers: JsonArray?, pledges: JsonArray?, alumni: JsonArray?
    
    // mark: initialization
    init(callback: (Directory) -> ()) {
        if let (broDir, pledgeDir, alumDir) = retrieveDirectories() {
            self.brothers = broDir
            self.pledges  = pledgeDir
            self.alumni   = alumDir
            
            callback(self)
        } else {
            downloadDirectory(callback)
        }
    }
    
    func retrieveDirectories() -> (JsonArray, JsonArray, JsonArray)? {
        let prefs = NSUserDefaults.standardUserDefaults()
        let brothers = prefs.objectForKey(BrotherDirName) as? JsonArray
        let pledges  = prefs.objectForKey(PledgeDirName)  as? JsonArray
        let alumni   = prefs.objectForKey(AlumniDirName)  as? JsonArray
        
        if brothers != nil && pledges != nil && alumni != nil {
            return (brothers!, pledges!, alumni!)
        } else {
            return nil
        }
    }
    
    mutating func downloadDirectory(callback: (Directory) -> ()) {
        // GET data from sheet and deserialize the response, populating the table if successful.
        let requestManager = AFHTTPSessionManager()
        let url = URLs.directoryUrlWithSheetName("All")
        requestManager.responseSerializer = AFJSONResponseSerializer()
        requestManager.GET(url,
            parameters:nil,
            success: { (task: NSURLSessionDataTask!, responseObject: Json!) in
                println("Directory async response: \(responseObject)")
                
                self.brothers = responseObject[self.BrotherDirName] as? JsonArray
                self.pledges  = responseObject[self.PledgeDirName] as? JsonArray
                self.alumni   = responseObject[self.AlumniDirName] as? JsonArray
                
                callback(self)
            },
            failure: { (task: NSURLSessionDataTask!, error: NSError!) in
                println("Directory HTTPRequest Error: " + error.localizedDescription)
            }
        )
    }
    
    func brotherAtIndexPath(index: NSIndexPath) -> Brother? {
        var subdirectory: [JsonObject]?
        switch index.section {
        case 0:
            subdirectory = self.brothers
        case 1:
            subdirectory = self.pledges
        case 2:
            subdirectory = self.alumni
        default:
            subdirectory = nil
        }
        
        if let jsonForBrother = subdirectory?[index.row] {
            return Brother(json: jsonForBrother)
        } else {
            return nil
        }
    }
}