Tusker/Tusker/Screens/Profile/ProfileTableViewController.swift

//
//  ProfileTableViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 8/27/18.
//  Copyright © 2018 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm
import SafariServices

class ProfileTableViewController: EnhancedTableViewController {
    
    var accountID: String! {
        didSet {
            if shouldLoadOnAccountIDSet {
                DispatchQueue.main.async {
                    self.updateAccountUI()
                }
            }
        }
    }
    
    var statusIDs: [String] = [] {
        didSet {
            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        }
    }
    
    var older: RequestRange?
    var newer: RequestRange?
    
    var shouldLoadOnAccountIDSet = false
    var loadingVC: LoadingViewController? = nil
    
    init(accountID: String?) {
        self.accountID = accountID
        
        super.init(style: .plain)
        
        self.refreshControl = UIRefreshControl()
        refreshControl!.addTarget(self, action: #selector(refreshStatuses(_:)), for: .valueChanged)
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .compose, target: self, action: #selector(composePressed(_:)))
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemeneted")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.rowHeight = UITableView.automaticDimension
        tableView.estimatedRowHeight = 140
        
        tableView.register(UINib(nibName: "StatusTableViewCell", bundle: nil), forCellReuseIdentifier: "statusCell")
        tableView.register(UINib(nibName: "ProfileHeaderTableViewCell", bundle: nil), forCellReuseIdentifier: "headerCell")
        
        tableView.prefetchDataSource = self
        
        if let accountID = accountID {
            if MastodonCache.account(for: accountID) != nil {
                updateAccountUI()
            } else {
                loadingVC = LoadingViewController()
                embedChild(loadingVC!)
                MastodonCache.account(for: accountID) { (account) in
                    guard account != nil else {
                        let alert = UIAlertController(title: "Something Went Wrong", message: "Couldn't load the selected account", preferredStyle: .alert)
                        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { (_) in
                            self.navigationController!.popViewController(animated: true)
                        }))
                        DispatchQueue.main.async {
                            self.present(alert, animated: true)
                        }
                        return
                    }
                    DispatchQueue.main.async {
                        self.updateAccountUI()
                        self.tableView.reloadData()
                    }
                }
            }
        } else {
            loadingVC = LoadingViewController()
            embedChild(loadingVC!)
            shouldLoadOnAccountIDSet = true
        }
        
        NotificationCenter.default.addObserver(self, selector: #selector(updateUIForPreferences), name: .preferencesChanged, object: nil)
    }

    override var previewActionItems: [UIPreviewActionItem] {
        var actions = [UIPreviewActionItem]()
        if let account = MastodonCache.account(for: accountID) {
            actions.append(UIPreviewAction(title: "Open in Safari", style: .default, handler: { (_, _) in
                let vc = SFSafariViewController(url: account.url)
                UIApplication.shared.delegate!.window!!.rootViewController!.present(vc, animated: true)
                // TODO: kill this ^ with fire
            }))
            actions.append(UIPreviewAction(title: "Share", style: .default, handler: { (_, _) in
                let vc = UIActivityViewController(activityItems: [account.url], applicationActivities: nil)
                UIApplication.shared.delegate!.window!!.rootViewController!.present(vc, animated: true)
            }))
            actions.append(UIPreviewAction(title: "Send Message", style: .default, handler: { (_, _) in
                let vc = UINavigationController(rootViewController: ComposeViewController(mentioningAcct: account.acct))
                UIApplication.shared.delegate!.window!!.rootViewController!.present(vc, animated: true)
            }))
        }
        return actions
    }
    
    func updateAccountUI() {
        loadingVC?.removeViewAndController()
        
        updateUIForPreferences()
        
        getStatuses() { response in
            guard case let .success(statuses, pagination) = response else { fatalError() }
            MastodonCache.addAll(statuses: statuses)
            self.statusIDs = statuses.map { $0.id }
            self.older = pagination?.older
            self.newer = pagination?.newer
        }
    }
    
    @objc func updateUIForPreferences() {
        guard let account = MastodonCache.account(for: accountID) else { fatalError("Missing cached account \(accountID!)") }
        navigationItem.title = account.realDisplayName
    }
    
    func getStatuses(for range: RequestRange = .default, completion: @escaping Client.Callback<[Status]>) {
        let request = Account.getStatuses(accountID, range: range, onlyMedia: false, pinned: false, excludeReplies: !Preferences.shared.showRepliesInProfiles)
        MastodonController.client.run(request, completion: completion)
    }
    
    func sendMessageMentioning() {
        guard let account = MastodonCache.account(for: accountID) else { fatalError("Missing cached account \(accountID!)") }
        let vc = UINavigationController(rootViewController: ComposeViewController(mentioningAcct: account.acct))
        present(vc, animated: true)
    }
    
    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        return 2
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        switch section {
        case 0:
            return accountID == nil || MastodonCache.account(for: accountID) == nil ? 0 : 1
        case 1:
            return statusIDs.count
        default:
            return 0
        }
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        switch indexPath.section {
        case 0:
            guard let cell = tableView.dequeueReusableCell(withIdentifier: "headerCell", for: indexPath) as? ProfileHeaderTableViewCell else { fatalError() }
            cell.selectionStyle = .none
            cell.delegate = self
            cell.updateUI(for: accountID)
            return cell
        case 1:
            guard let cell = tableView.dequeueReusableCell(withIdentifier: "statusCell", for: indexPath) as? StatusTableViewCell else { fatalError() }
            cell.updateUI(statusID: statusIDs[indexPath.row])
            cell.delegate = self
            return cell
        default:
            fatalError("Invalid section \(indexPath.section) for profile VC")
        }
    }
    
    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
        if indexPath.section == 1 && indexPath.row == statusIDs.count - 1 {
            guard let older = older else { return }
            
            getStatuses(for: older) { response in
                guard case let .success(newStatuses, pagination) = response else { fatalError() }
                self.older = pagination?.older
                MastodonCache.addAll(statuses: newStatuses)
                self.statusIDs.append(contentsOf: newStatuses.map { $0.id })
            }
        }
    }

    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }
    
    override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
    }
    
    override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
    }
    
    @objc func refreshStatuses(_ sender: Any) {
        guard let newer = newer else { return }
        
        getStatuses(for: newer) { response in
            guard case let .success(newStatuses, pagination) = response else { fatalError() }
            self.newer = pagination?.newer
            MastodonCache.addAll(statuses: newStatuses)
            self.statusIDs.insert(contentsOf: newStatuses.map { $0.id }, at: 0)
            DispatchQueue.main.async {
                self.refreshControl?.endRefreshing()
            }
        }
    }
    
    @objc func composePressed(_ sender: Any) {
        sendMessageMentioning()
    }
    
}

extension ProfileTableViewController: StatusTableViewCellDelegate {}
extension ProfileTableViewController: ProfileHeaderTableViewCellDelegate {
    func showMoreOptions() {
        let account = MastodonCache.account(for: accountID)!
        
        let alert = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
        alert.addAction(UIAlertAction(title: "Open in Safari", style: .default, handler: { _ in
            let vc = SFSafariViewController(url: account.url)
            self.present(vc, animated: true)
        }))
        alert.addAction(UIAlertAction(title: "Share", style: .default, handler: { _ in
            let vc = UIActivityViewController(activityItems: [account.url], applicationActivities: nil)
            self.present(vc, animated: true)
        }))
        alert.addAction(UIAlertAction(title: "Send Message", style: .default, handler: { _ in
            self.sendMessageMentioning()
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

        MastodonCache.relationship(for: account.id) { (relationship) in
            guard let relationship = relationship else {
                DispatchQueue.main.async {
                    self.present(alert, animated: true)
                }
                return
            }
            let title = relationship.following ? "Unfollow": "Follow"
            DispatchQueue.main.async {
                alert.addAction(UIAlertAction(title: title, style: .default, handler: { (_) in
                    UIImpactFeedbackGenerator(style: .medium).impactOccurred()
                    let request = (relationship.following ? Account.unfollow : Account.follow)(account.id)
                    MastodonController.client.run(request, completion: { (response) in
                        if case let .success(relationship, _) = response {
                            MastodonCache.add(relationship: relationship)
                        } else {
                            // todo: display error message
                            UINotificationFeedbackGenerator().notificationOccurred(.error)
                            fatalError()
                        }
                    })
                }))
                self.present(alert, animated: true)
            }
        }
    }
}

extension ProfileTableViewController: UITableViewDataSourcePrefetching {
    func tableView(_ tableView: UITableView, prefetchRowsAt indexPaths: [IndexPath]) {
        for indexPath in indexPaths {
            guard indexPath.section == 1,
                let status = MastodonCache.status(for: statusIDs[indexPath.row]) else { continue }
            ImageCache.avatars.get(status.account.avatar, completion: nil)
            for attachment in status.attachments {
                ImageCache.attachments.get(attachment.url, completion: nil)
            }
        }
    }
    
    func tableView(_ tableView: UITableView, cancelPrefetchingForRowsAt indexPaths: [IndexPath]) {
        for indexPath in indexPaths {
            guard indexPath.section == 1,
                let status = MastodonCache.status(for: statusIDs[indexPath.row]) else { continue }
            ImageCache.avatars.cancel(status.account.avatar)
            for attachment in status.attachments {
                ImageCache.attachments.cancel(attachment.url)
            }
        }
    }
}