ViewController.swift

//
//  ViewController.swift
//  P07 WhiteHousePetitions
//
//  Created by Julian Moorhouse on 04/08/2019.
//  Copyright © 2019 Mindwarp Consultancy Ltd. All rights reserved.
//

import UIKit

class ViewController: UITableViewController {
    var petitions = [Petition]()
    var filteredPetitions = [Petition]()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Credits", style: .plain, target: self, action: #selector(credits))
        
        let filter = UIBarButtonItem(barButtonSystemItem: .search, target: self, action: #selector(showFilter))

        let reset = UIBarButtonItem(barButtonSystemItem: .trash, target: self, action: #selector(resetList))
        
        navigationItem.rightBarButtonItems = [filter, reset]
        
        //Beware - this code will lock up the app while data is downloaded, but it's ok for example purposes here
        let urlString: String
            
        if navigationController?.tabBarItem.tag == 0 {
            // urlString = "https://api.whitehouse.gov/v1/petitions.json?limit=100"
            urlString = "https://www.hackingwithswift.com/samples/petitions-1.json"
        } else {
            // urlString = "https://api.whitehouse.gov/v1/petitions.json?signatureCountFloor=10000&limit=100"
            urlString = "https://www.hackingwithswift.com/samples/petitions-2.json"
        }

        if let url = URL(string: urlString) {
            if let data = try? Data(contentsOf: url) {
                parse(json: data)
                return
            }
        }
        
        showError()
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return filteredPetitions.count
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        
        let petition = filteredPetitions[indexPath.row]
        cell.textLabel?.text = petition.title
        cell.detailTextLabel?.text = petition.body
        return cell
    }
    
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        let vc = DetailViewController()
        vc.detailItem = filteredPetitions[indexPath.row]
        navigationController?.pushViewController(vc, animated: true)
    }
    
    func parse(json: Data) {
        let decoder = JSONDecoder()
        
        if let jsonPetitions = try? decoder.decode(Petitions.self, from: json) {
            petitions = jsonPetitions.results
            filteredPetitions = petitions
            tableView.reloadData()
        }
    }
    
    func showError() {
        let ac = UIAlertController(title: "Loading error", message: "There was a problem loading the feed, please check your connection and try again.", preferredStyle: .alert)
        ac.addAction(UIAlertAction(title: "OK", style: .default))
        present(ac, animated: true)
    }
    
    @objc func credits() {
        let ac = UIAlertController(title: "Credits", message: "Data from We The People API of the Whitehouse", preferredStyle: .alert)
        
        ac.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        present(ac, animated: true)
    }
    
    @objc func showFilter() {
        let ac = UIAlertController(title: "Enter filter text", message: nil, preferredStyle: .alert)
        ac.addTextField()
        
        let submitAction = UIAlertAction(title: "Search", style: .default) {
            [weak self, weak ac] action in
            
            guard let filter = ac?.textFields?[0].text else { return }
            
            self?.filterResults(filter)
        }
        ac.addAction(submitAction)
        present(ac, animated: true)
    }
    
    @objc func filterResults(_ filter: String) {
        
        filteredPetitions.removeAll(keepingCapacity: true)

        for petition in petitions {
            if petition.title.contains(filter) || petition.body.contains(filter) {
                filteredPetitions.append(petition);
            }
        }
        tableView.reloadData()
    }
    
    @objc func resetList() {
        filteredPetitions = petitions
        tableView.reloadData()
    }
}