AppDetailController.swift

//
//  AppDetailController.swift
//  AppStore
//
//  Created by Tihomir Videnov on 11/9/16.
//  Copyright © 2016 Tihomir Videnov. All rights reserved.
//

import UIKit

class AppDetailViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
    
    var app: App? {
        
        didSet {
            
            if app?.screenshots != nil {
                return
            }
            
            if let id = app?.id {
                
                ApiService.sharedInstance.fetchAppDetails(id: Int(id), completionHandler: { (appDetail) in
                    
                    self.app = appDetail
                    self.collectionView?.reloadData()
                })
            }
            
        }
    }
    
    fileprivate let headerId = "headerId"
    fileprivate let cellId = "cellId"
    fileprivate let descriptionCell = "descriptionId"
    fileprivate let moreInfoCell = "moreInfoCell"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        collectionView?.alwaysBounceVertical = true
        
        collectionView?.backgroundColor = .white
        collectionView?.register(AppDetailHeader.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader , withReuseIdentifier: headerId)
        collectionView?.register(ScreenshotsCell.self, forCellWithReuseIdentifier: cellId)
        collectionView?.register(AppDetailDescription.self, forCellWithReuseIdentifier: descriptionCell)
        collectionView?.register(AppMoreInformation.self, forCellWithReuseIdentifier: moreInfoCell)
    }
    
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        
        if indexPath.item == 1 {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: descriptionCell, for: indexPath) as! AppDetailDescription
            cell.textView.attributedText = descriptionAttributedText()
            return cell
        }
        
        if indexPath.item == 2 {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: moreInfoCell, for: indexPath) as! AppMoreInformation
            return cell
        }
        
        let cell =  collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! ScreenshotsCell

        cell.app = app
        return cell
    }
    
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 3
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        
        if indexPath.item == 1 {
            
            let dummySize = CGSize(width: view.frame.width - 8 - 8, height: 1000)
            let options = NSStringDrawingOptions.usesFontLeading.union(NSStringDrawingOptions.usesLineFragmentOrigin)
            let rect = descriptionAttributedText().boundingRect(with: dummySize, options: options, context: nil)
            
            return CGSize(width: view.frame.width, height: rect.height + 30)
        }
        
        return CGSize(width: view.frame.width, height: 170)
    }
    
    
    override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: headerId, for: indexPath) as! AppDetailHeader
        header.app = app
        return header
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return CGSize(width: view.frame.width, height: 170)
    }
    
    fileprivate func descriptionAttributedText() -> NSAttributedString {
        let attributedText = NSMutableAttributedString(string: "Description\n", attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 14)])
        
        let style = NSMutableParagraphStyle()
        style.lineSpacing = 10
        let range = NSMakeRange(0, attributedText.string.characters.count)
        attributedText.addAttribute(NSParagraphStyleAttributeName, value: style, range: range)
        
        if let desc = app?.desc {
            attributedText.append(NSAttributedString(string: desc, attributes: [NSFontAttributeName:UIFont.systemFont(ofSize: 11), NSForegroundColorAttributeName: UIColor.darkGray]))
        }
        
        return attributedText
    }
}