elpha-ios/elpha-ios/InstancesTableViewController.swift

//
//  InstancesTableViewController.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 8/29/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import CoreData
import UIKit

struct Instance {
    var id: String?
    var name: String?
    var addedAt: String?
    var updatedAt: String?
    var checkedAt: String?
    var uptime: Int?
    var up: Bool?
    var dead: Bool?
    var version: String?
    var ipv6: Bool?
    var httpsScore: Int?
    var httpsRank: String?
    var users: String?
    var statuses: String?
    var connections: Int?
    var openRegistrations: Bool?
    var thumbnail: String?
    var thumbnailProxy: String?
    var activeUsers: Int?
    var shortDescription: String?
    var fullDescription: String?
    var topic: String?
    var languages: [String]?
    var categories: [String]?
}

class InstancesTableViewController: UITableViewController, UIViewControllerPreviewingDelegate {
    @IBOutlet var mainNavigationItem: UINavigationItem!
    
    let instanceRequestCount = 20
    var instances: [Instance] = []
    var nextID: String? = nil
    var finished: Bool = false
    
    var loading: Bool = false {
        didSet {
            DispatchQueue.main.async {
                if self.loading {
                    UIApplication.shared.isNetworkActivityIndicatorVisible = true
                    self.refreshControl?.beginRefreshing()
                } else {
                    UIApplication.shared.isNetworkActivityIndicatorVisible = false
                    self.refreshControl?.endRefreshing()
                }
            }
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        UINavigationBar.appearance().titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
        
        mainNavigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(done))
        
        registerForPreviewing(with: self, sourceView: tableView)
        refreshControl?.addTarget(self, action: #selector(self.reloadInstances), for: .valueChanged)
        
        loadInstances()
    }
    
    @objc func done() {
        dismiss(animated: true, completion: nil)
    }
    
    @objc func reloadInstances() {
        self.nextID = nil
        self.finished = false
        
        loadInstances()
    }
    
    func loadInstances() {
        loading = true
        
        var params = [
            "count=\(instanceRequestCount)",
            "sort_by=users",
            "sort_order=desc",
            "include_closed=true",
            "include_down=false",
        ]
        
        if let nextID = nextID {
            params.append("min_id=\(nextID)")
        } else {
            instances = []

            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        }
        
        let requestURL = "\(Config.instancesServiceUrl)\(Config.instancesServiceEndpoint)?\(params.joined(separator: "&"))"
        
        print("loading instances: requestURL: \(requestURL)")
        
        var request = URLRequest(url: URL(string: requestURL)!)
        request.addValue("Bearer \(Config.instancesServiceSecret)", forHTTPHeaderField: "Authorization")
        
        let dataTask = URLSession.shared.dataTask(with: request) { data, response, error in
            guard error == nil else {
                return
            }
            
            defer {
                self.loading = false
            }
            
            if let response = response as? HTTPURLResponse {
                switch response.statusCode {
                case 200..<300:
                    if let data = data {
                        do {
                            let instancesResult = try JSONSerialization.jsonObject(with: data) as! [String: Any]
                            
                            if let pagination = instancesResult["pagination"] as? [String: Any] {
                                if let nextID = pagination["next_id"] as? String {
                                    self.nextID = nextID
                                } else {
                                    self.nextID = nil
                                    self.finished = true
                                }
                            }
                            
                            if let instances = instancesResult["instances"] as? [Any] {
                                for case let instance as [String: Any] in instances {
                                    var i = Instance()
                                    i.id = instance["id"] as? String
                                    i.name = instance["name"] as? String
                                    i.addedAt = instance["added_at"] as? String
                                    i.updatedAt = instance["updated_at"] as? String
                                    i.checkedAt = instance["checked_at"] as? String
                                    i.uptime = instance["uptime"] as? Int
                                    i.up = instance["up"] as? Bool
                                    i.dead = instance["dead"] as? Bool
                                    i.version = instance["version"] as? String
                                    i.ipv6 = instance["ipv6"] as? Bool
                                    i.httpsScore = instance["https_score"] as? Int
                                    i.httpsRank = instance["https_rank"] as? String
                                    i.users = instance["users"] as? String
                                    i.statuses = instance["statuses"] as? String
                                    i.connections = instance["connections"] as? Int
                                    i.openRegistrations = instance["open_registrations"] as? Bool
                                    i.thumbnail = instance["thumbnail"] as? String
                                    i.thumbnailProxy = instance["thumbnail_proxy"] as? String
                                    i.activeUsers = instance["active_users"] as? Int
                                    
                                    let info = instance["info"] as? [String: Any]
                                    if let info = info {
                                        i.shortDescription = info["short_description"] as? String
                                        i.fullDescription = info["full_description"] as? String
                                        i.topic = info["topic"] as? String
                                        i.languages = info["languages"] as? [String]
                                        i.categories = info["categories"] as? [String]
                                    }
                                    
                                    self.instances.append(i)
                                }
                                
                                DispatchQueue.main.async {
                                    self.tableView.reloadData()
                                }
                            }
                        } catch let error {
                            print(error)
                            return
                        }
                    }
                case 400:
                    print("instances.social: 400")
                default:
                    return
                }
            }
        }
        
        dataTask.resume()
    }
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return instances.count
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "InstancesTableViewCell", for: indexPath) as? InstancesTableViewCell else {
            fatalError("Unable to find reusable cell")
        }
        
        let instance = instances[indexPath.row]
        cell.instanceNameLabel.text = instance.name
        
        if let statuses = instance.statuses {
            cell.statusesLabel.text = NumberFormatter.localizedString(from: NSNumber(value: Int64(statuses)!), number: .decimal)
        }
        
        if let users = instance.users {
            cell.usersLabel.text = NumberFormatter.localizedString(from: NSNumber(value: Int64(users)!), number: .decimal)
        }
        
        if let thumbnail = instance.thumbnail {
            cell.thumbnailURL = thumbnail
        }
        
        if indexPath.row == instances.count - 1 && !loading && !finished {
            loadInstances()
        }
        
        return cell
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "InstanceDetailSegue", let cell = segue.destination as? InstanceViewController {
            if let row = tableView.indexPathForSelectedRow?.row {
                cell.instance = instances[row]
            }
        }
    }
    
    public func previewingContext(_ previewingContext: UIViewControllerPreviewing, viewControllerForLocation location: CGPoint) -> UIViewController? {
        guard let indexPath = tableView.indexPathForRow(at: location) else {
            return nil
        }
        
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        if let detailViewController = storyboard.instantiateViewController(withIdentifier: "InstanceViewController") as? InstanceViewController {
            detailViewController.instance = instances[indexPath.row]
            return detailViewController
        } else {
            return nil
        }
    }
    
    public func previewingContext(_ previewingContext: UIViewControllerPreviewing, commit viewControllerToCommit: UIViewController) {
        navigationController?.pushViewController(viewControllerToCommit, animated: true)
    }
}