InfoCell.swift

//
//  InfoCell.swift
//  FeedReader
//
//  Created by Mitchell Cooper on 2/1/15.
//  Copyright (c) 2015 Mitchell Cooper. All rights reserved.
//

import UIKit


class InfoCell: UITableViewCell {
    @IBOutlet var unreadBox: UIView!
    @IBOutlet var totalBox:  UIView!
    @IBOutlet var savedBox:  UIView!
    
    // info for the buttons, as returned by delegate methods
    typealias ButtonInfo = (title: String, articles: [Article])
    var totalInfo:  ButtonInfo?
    var unreadInfo: ButtonInfo?
    var savedInfo:  ButtonInfo?
    
    // upon setting the delegate, get the info we need
    private weak var _dataSource: InfoCellDataSource?
    var dataSource: InfoCellDataSource? {
        get {
            return _dataSource
        }
        set {
            _dataSource = newValue
            totalInfo   = _dataSource?.infoCellTotalArticles (self)
            unreadInfo  = _dataSource?.infoCellUnreadArticles(self)
            savedInfo   = _dataSource?.infoCellSavedArticles (self)
            updateArticleCounts()
        }
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()

        // add gesture recognizers
        for box in [unreadBox, totalBox, savedBox] {
            let tap = UITapGestureRecognizer(target: self, action: "handleTap:")
            box.addGestureRecognizer(tap)
        }
        
    }
    
    // button box view map to button info
    // this is a lazy var because it will only be computed after
    // the info properties are present
    lazy var boxToInfoMap: [UIView: ButtonInfo!] = {
       return [
            self.unreadBox: self.unreadInfo,
            self.totalBox:  self.totalInfo,
            self.savedBox:  self.savedInfo
        ]
    }()
    
    // callback for all gesture recognizers
    func handleTap(sender: UITapGestureRecognizer) {
        let box = sender.view!
        updateBackground(box)
        pushCollection(boxToInfoMap[box]!)
    }
    
    // make the background the cell selected background color
    // after half a second, return to transparent background
    func updateBackground(box: UIView) {
        box.backgroundColor = Colors.cellSelectedBackgroundColor
        after(0.5) { box.backgroundColor = nil }
    }
    
    // update the article counts in the buttons
    func updateArticleCounts() {
        for (box, info) in boxToInfoMap {
            (box.subviews.first as? UILabel)?.text = "\(info.articles.count)"
        }
    }
    
    // push a collection of articles with a generic article collection
    func pushCollection(info: ButtonInfo) {
        let collection = GenericArticleCollection(title: info.title, articles: info.articles)
        let articleVC  = ArticleListVC(collection: collection)
        rss.navigationController.pushViewController(articleVC, animated: true)
    }
    
}

// protocol for article collection data source
// defined as a class protocol so that data source can be weak
protocol InfoCellDataSource: class {
    func infoCellTotalArticles (cell: InfoCell) -> InfoCell.ButtonInfo
    func infoCellUnreadArticles(cell: InfoCell) -> InfoCell.ButtonInfo
    func infoCellSavedArticles (cell: InfoCell) -> InfoCell.ButtonInfo
}