GenreTableViewController.swift

//
//  GenreTableViewController.swift
//  MyFavoriteMovies
//
//  Created by Jarrod Parkes on 1/23/15.
//  Copyright (c) 2015 Udacity. All rights reserved.
//

import UIKit

// MARK: GenreTableViewController: UITableViewController

class GenreTableViewController: UITableViewController {
    
    // MARK: Properties
    
    var appDelegate: AppDelegate!
    var session: NSURLSession!
    
    var movies: [Movie] = [Movie]()
    var genreID: Int? = nil
    
    // MARK: Life Cycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        /* Get the app delegate */
        appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        
        /* Get the shared URL session */
        session = NSURLSession.sharedSession()
        
        /* Get the correct genre id */
        genreID = getGenreIDFromItemTag(self.tabBarItem.tag)
        
        /* Create and set the logout button */        
        self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Reply, target: self, action: "logoutButtonTouchUp")
    }
    
    override func viewWillAppear(animated: Bool) {
        
        super.viewWillAppear(animated)

        /* TASK: Get movies by a genre id, then populate the table */
        
        /* 1. Set the parameters */
        let methodParameters = [
            "api_key": appDelegate.apiKey,
        ]
        
        /* 2. Build the URL */        
        let urlString = appDelegate.baseURLSecureString + "genre/\(genreID!)/movies" + appDelegate.escapedParameters(methodParameters)
        let url = NSURL(string: urlString)!
        
        /* 3. Configure the request */        
        let request = NSMutableURLRequest(URL: url)
        request.addValue("application/json", forHTTPHeaderField: "Accept")
        
        /* 4. Make the request */
        let task = session.dataTaskWithRequest(request) { (data, response, error) in
            
            /* GUARD: Was there an error? */
            guard (error == nil) else {
                print("There was an error with your request: \(error)")
                return
            }
            
            /* GUARD: Did we get a successful 2XX response? */
            guard let statusCode = (response as? NSHTTPURLResponse)?.statusCode where statusCode >= 200 && statusCode <= 299 else {
                if let response = response as? NSHTTPURLResponse {
                    print("Your request returned an invalid response! Status code: \(response.statusCode)!")
                } else if let response = response {
                    print("Your request returned an invalid response! Response: \(response)!")
                } else {
                    print("Your request returned an invalid response!")
                }
                return
            }
            
            /* GUARD: Was there any data returned? */
            guard let data = data else {
                print("No data was returned by the request!")
                return
            }
            
            /* 5. Parse the data */
            let parsedResult: AnyObject!
            do {
                parsedResult = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments)
            } catch {
                parsedResult = nil
                print("Could not parse the data as JSON: '\(data)'")
                return
            }
            
            /* GUARD: Did TheMovieDB return an error? */
            guard (parsedResult.objectForKey("status_code") == nil) else {
                print("TheMovieDB returned an error. See the status_code and status_message in \(parsedResult)")
                return
            }
                    
            /* GUARD: Is the "results" key in parsedResult? */
            guard let results = parsedResult["results"] as? [[String : AnyObject]] else {
                print("Cannot find key 'results' in \(parsedResult)")
                return
            }
            
            /* 6. Use the data! */
            self.movies = Movie.moviesFromResults(results)
            dispatch_async(dispatch_get_main_queue()) {
                self.tableView.reloadData()
            }
        }
        
        /* 7. Start the request */
        task.resume()
    }
    
    // MARK: UITableViewController
    
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        
        /* Get cell type */        
        let cellReuseIdentifier = "MovieTableViewCell"
        let movie = movies[indexPath.row]
        let cell = tableView.dequeueReusableCellWithIdentifier(cellReuseIdentifier) as UITableViewCell!
        
        /* Set cell defaults */
        cell.textLabel!.text = movie.title
        cell.imageView!.image = UIImage(named: "Film Icon")
        cell.imageView!.contentMode = UIViewContentMode.ScaleAspectFit
        
        /* TASK: Get the poster image, then populate the image view */
        if let posterPath = movie.posterPath {
            
            /* 1. Set the parameters */
            // There are none...
            
            /* 2. Build the URL */
            let baseURL = NSURL(string: appDelegate.config.baseImageURLString)!
            let url = baseURL.URLByAppendingPathComponent("w154").URLByAppendingPathComponent(posterPath)
            
            /* 3. Configure the request */
            let request = NSURLRequest(URL: url)
            
            /* 4. Make the request */
            let task = session.dataTaskWithRequest(request) { (data, response, error) in
                
                /* GUARD: Was there an error? */
                guard (error == nil) else {
                    print("There was an error with your request: \(error)")
                    return
                }
                
                /* GUARD: Did we get a successful 2XX response? */
                guard let statusCode = (response as? NSHTTPURLResponse)?.statusCode where statusCode >= 200 && statusCode <= 299 else {
                    if let response = response as? NSHTTPURLResponse {
                        print("Your request returned an invalid response! Status code: \(response.statusCode)!")
                    } else if let response = response {
                        print("Your request returned an invalid response! Response: \(response)!")
                    } else {
                        print("Your request returned an invalid response!")
                    }
                    return
                }
                
                /* GUARD: Was there any data returned? */
                guard let data = data else {
                    print("No data was returned by the request!")
                    return
                }
                
                /* 5. Parse the data */
                // No need, the data is already raw image data.
                
                /* 6. Use the data! */
                if let image = UIImage(data: data) {
                    dispatch_async(dispatch_get_main_queue()) {
                        cell.imageView!.image = image
                    }
                } else {
                    print("Could not create image from \(data)")
                }
            }
            
            /* 7. Start the request */            
            task.resume()
        }
        
        return cell
    }
    
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return movies.count
    }
    
    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        
        /* Push the movie detail view */
        let controller = self.storyboard!.instantiateViewControllerWithIdentifier("MovieDetailViewController") as! MovieDetailViewController
        controller.movie = movies[indexPath.row]
        self.navigationController!.pushViewController(controller, animated: true)
    }

    // MARK: Logout
    
    func logoutButtonTouchUp() {
        self.dismissViewControllerAnimated(true, completion: nil)
    }
}

// MARK: - Genre Map

extension GenreTableViewController {
    
    /* Helper function: Uses the tab bar item tag to return the correct genre id */
    func getGenreIDFromItemTag(itemTag: Int) -> Int {
        
        let genres: [String] = [
            "Sci-Fi",
            "Comedy",
            "Action"
        ]
        
        let genreMap: [String:Int] = [
            "Action": 28,
            "Sci-Fi": 878,
            "Comedy": 35
        ]
        
        return genreMap[genres[itemTag]]!
    }
    
}