ContactsViewController.swift

//
//  ContactsViewController.swift
//  ContactsApp
//
//  Created by User on 3/13/20.
//  Copyright © 2020 jheisecke. All rights reserved.
//

import UIKit
import ContactsUI

class ContactsViewController: UIViewController {
    
    @IBOutlet weak var contactsTable: UITableView!
    var contactStructArray = [ContactStruct]()
    var contactStruct : ContactStruct?
    let contactStore = CNContactStore()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        contactsTable.register(UINib(nibName: "ContactSection", bundle: nil), forHeaderFooterViewReuseIdentifier: "headerId")
        importContacts()
        contactsTable.tableFooterView = UIView(frame: .zero)
    }
    
    func importContacts() {
        
        let keys = [CNContactFormatter.descriptorForRequiredKeys(for: .fullName), CNContactEmailAddressesKey, CNContactPhoneNumbersKey, CNContactImageDataKey] as [Any]
        let request = CNContactFetchRequest( keysToFetch: keys as! [CNKeyDescriptor])
        request.sortOrder = CNContactSortOrder.givenName
        do {
            var auxLetter = ""
            var contacts = [CNContact]()
            var isNotTheFirst = false
            try self.contactStore.enumerateContacts(with: request) {
                (contact, stop) in
                if contact.givenName.prefix(1) == auxLetter {
                    contacts.append(contact)
                } else {
                    if isNotTheFirst {
                        let contactsExpandables = ContactStruct(isExpanded: true, contacts: contacts, letter: auxLetter)
                        self.contactStructArray.append(contactsExpandables) //guardamos el contacto expandible anterior
                        auxLetter = String(contact.givenName.prefix(1)) //guardamos la nueva letra
                        contacts = [CNContact]() //inicializamos nuevamente el array de contactos
                        contacts.append(contact) //guardamos el nuevo contacto
                    } else {
                        contacts.append(contact)
                        auxLetter = String(contact.givenName.prefix(1)) //auxLetter tiene la primera letra del nombre
                        isNotTheFirst = true //la siguiente vez que las letras no sean iguales guardara en el array
                    }

                }
            }
            self.contactStructArray.append(ContactStruct(isExpanded: true, contacts: contacts, letter: auxLetter)) //agregamos el ultimo nombre
        }
        catch {
            print("unable to fetch contacts")
        }
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let singleContactVC = segue.destination as? SingleContactViewController {
            if let selectedCnt = sender as? CNContact {
                singleContactVC.selectedContact = selectedCnt
            }
        }
    }
}
extension ContactsViewController: UITableViewDelegate, UITableViewDataSource {
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return contactStructArray.count
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if !contactStructArray[section].isExpanded {
            return 0
        }
        
        return contactStructArray[section].contacts.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {        
        let cell = tableView.dequeueReusableCell(withIdentifier: "contactName")!
        let contactCell = contactStructArray[indexPath.section].contacts[indexPath.row]
        
        let givenName = "\(contactCell.givenName) "
        let familyName: NSMutableAttributedString = NSMutableAttributedString(string: contactCell.familyName)
        
        let attributes: [NSAttributedString.Key: Any] = [
            .font: UIFont.boldSystemFont(ofSize: 15)
        ]
        let fullName = NSMutableAttributedString(string: givenName, attributes: attributes)
        fullName.append(familyName)
        
        cell.textLabel?.attributedText = fullName
        
        return cell
    }
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let selectedContact = contactStructArray[indexPath.section].contacts[indexPath.row]
        performSegue(withIdentifier: "gotocontact", sender: selectedContact)
    }
    
    func tableView(_ tableView: UITableView, estimatedHeightForHeaderInSection section: Int) -> CGFloat {
        return 40
    }
    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let header = contactsTable.dequeueReusableHeaderFooterView(withIdentifier: "headerId") as! ContactSectionView
        header.contentView.backgroundColor = .systemGray4
        header.labelExpandable.setTitle("Λ", for: .normal)
        header.labelExpandable.setTitleColor(.black, for: .normal)
        header.labelExpandable.titleLabel?.font = UIFont.boldSystemFont(ofSize: 15)
        header.labelExpandable.addTarget(self, action: #selector(interactSection), for: .touchUpInside)
        header.labelExpandable.tag = section
        header.labelLetter.text = contactStructArray[section].letter
        return header//ʌΛ
    }
    
    @objc func interactSection(button : UIButton) {
        //contactsBackup = contacts
        let section = button.tag
        
        var indexPaths = [IndexPath]()
        for row in contactStructArray[section].contacts.indices {
            let indexPath = IndexPath(row: row, section: section)
            indexPaths.append(indexPath)
        }

        let isExpanded = contactStructArray[section].isExpanded
        contactStructArray[section].isExpanded = !isExpanded
        
        button.setTitle(isExpanded ? "V" : "Λ", for: .normal)
        
        if isExpanded {
            contactsTable.deleteRows(at: indexPaths, with: .top)
        } else {
            contactsTable.insertRows(at: indexPaths, with: .bottom)
        }
        
    }
}