//
//  EditListAccountsViewController.swift
//  Tusker
//
//  Created by Shadowfacts on 12/17/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import UIKit
import Pachyderm

class EditListAccountsViewController: EnhancedTableViewController {

    let list: List
    
    var dataSource: DataSource!
    
    var nextRange: RequestRange?
    
    var searchResultsController: SearchResultsViewController!
    var searchController: UISearchController!
    
    init(list: List) {
        self.list = list
        
        super.init(style: .plain)
        
        title = String(format: NSLocalizedString("Edit %@", comment: "edit list screen title"), list.title)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemeneted")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.register(UINib(nibName: "AccountTableViewCell", bundle: .main), forCellReuseIdentifier: "accountCell")
        
        tableView.rowHeight = UITableView.automaticDimension
        tableView.estimatedRowHeight = 66
        
        dataSource = DataSource(tableView: tableView, cellProvider: { (tableView, indexPath, item) -> UITableViewCell? in
            guard case let .account(id) = item else { fatalError() }
            
            let cell = tableView.dequeueReusableCell(withIdentifier: "accountCell", for: indexPath) as! AccountTableViewCell
            cell.updateUI(accountID: id)
            return cell
        })
        dataSource.editListAccountsController = self
        
        searchResultsController = SearchResultsViewController()
        searchResultsController.delegate = self
        searchResultsController.onlySections = [.accounts]
        searchController = UISearchController(searchResultsController: searchResultsController)
        searchController.hidesNavigationBarDuringPresentation = false
        searchController.searchResultsUpdater = searchResultsController
        searchController.searchBar.autocapitalizationType = .none
        searchController.searchBar.placeholder = NSLocalizedString("Search for accounts to add", comment: "edit list search field placeholder")
        searchController.searchBar.delegate = searchResultsController
        definesPresentationContext = true
        
        navigationItem.searchController = searchController
        navigationItem.hidesSearchBarWhenScrolling = false
        
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: NSLocalizedString("Rename", comment: "rename list button title"), style: .plain, target: self, action: #selector(renameButtonPressed))
        
        loadAccounts()
    }
    
    func loadAccounts() {
        let request = List.getAccounts(list)
        MastodonController.client.run(request) { (response) in
            guard case let .success(accounts, pagination) = response else {
                fatalError()
            }
            
            self.nextRange = pagination?.older
            
            MastodonCache.addAll(accounts: accounts)
            
            var snapshot = self.dataSource.snapshot()
            snapshot.deleteSections([.accounts])
            snapshot.appendSections([.accounts])
            snapshot.appendItems(accounts.map { .account(id: $0.id) })
            
            DispatchQueue.main.async {
                self.dataSource.apply(snapshot)
            }
        }
    }

    // MARK: - Table view delegate

    override func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
        return .delete
    }
    
    // MARK: - Interaction
    
    @objc func renameButtonPressed() {
        let alert = UIAlertController(title: NSLocalizedString("Rename List", comment: "rename list alert title"), message: nil, preferredStyle: .alert)
        alert.addTextField { (textField) in
            textField.text = self.list.title
        }
        alert.addAction(UIAlertAction(title: NSLocalizedString("Cancel", comment: "rename list alert cancel button"), style: .cancel, handler: nil))
        alert.addAction(UIAlertAction(title: NSLocalizedString("Rename", comment: "renaem list alert rename button"), style: .default, handler: { (_) in
            guard let text = alert.textFields?.first?.text else {
                fatalError()
            }
            let request = List.update(self.list, title: text)
            MastodonController.client.run(request) { (response) in
                guard case .success(_, _) = response else {
                    fatalError()
                }
                // todo: show success message somehow
            }
        }))
        present(alert, animated: true)
    }
    
}

extension EditListAccountsViewController {
    enum Section: Hashable {
        case accounts
    }
    enum Item: Hashable {
        case account(id: String)
    }
    
    class DataSource: UITableViewDiffableDataSource<Section, Item> {
        weak var editListAccountsController: EditListAccountsViewController?
        
        override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
            return true
        }
        
        override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
            guard editingStyle == .delete,
                case let .account(id) = itemIdentifier(for: indexPath) else {
                return
            }
            
            let request = List.remove(editListAccountsController!.list, accounts: [id])
            MastodonController.client.run(request) { (response) in
                guard case .success(_, _) = response else {
                    fatalError()
                }
                
                self.editListAccountsController?.loadAccounts()
            }
        }
    }
}

extension EditListAccountsViewController: SearchResultsViewControllerDelegate {
    func selectedSearchResult(account accountID: String) {
        let request = List.add(list, accounts: [accountID])
        MastodonController.client.run(request) { (response) in
            guard case .success(_, _) = response else {
                fatalError()
            }
            
            self.loadAccounts()
            DispatchQueue.main.async {
                self.searchController.isActive = false
            }
        }
    }
}