ChatListSearchTableController.swift

import UIKit
import Shared
import Combine
import AppResources
import Dependencies
import AppNavigation

class ChatSearchListTableViewDiffableDataSource: UITableViewDiffableDataSource<SearchSection, SearchItem> {
  override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    switch snapshot().sectionIdentifiers[section] {
    case .chats:
      return "CHATS"
    case .connections:
      return "CONNECTIONS"
    }
  }
}

final class ChatSearchTableController: UITableViewController {
  @Dependency(\.navigator) var navigator

  private let viewModel: ChatListViewModel
  private let cellHeight: CGFloat = 83.0
  private var cancellables = Set<AnyCancellable>()
  private var tableDataSource: ChatSearchListTableViewDiffableDataSource?
  
  init(_ viewModel: ChatListViewModel) {
    self.viewModel = viewModel
    super.init(style: .grouped)
    
    tableDataSource = ChatSearchListTableViewDiffableDataSource(
      tableView: tableView
    ) { table, indexPath, item in
      let cell = table.dequeueReusableCell(forIndexPath: indexPath, ofType: ChatListCell.self)
      switch item {
      case .chat(let info):
        switch info {
        case .group(let group):
          cell.setupGroup(
            name: group.name,
            date: group.createdAt,
            preview: nil,
            unreadCount: 0
          )
          
        case .groupChat(let groupChatInfo):
          cell.setupGroup(
            name: groupChatInfo.group.name,
            date: groupChatInfo.lastMessage.date,
            preview: groupChatInfo.lastMessage.text,
            unreadCount: groupChatInfo.unreadCount
          )
          
        case .contactChat(let contactChatInfo):
          cell.setupContact(
            name: (contactChatInfo.contact.nickname ?? contactChatInfo.contact.username) ?? "",
            image: contactChatInfo.contact.photo,
            date: contactChatInfo.lastMessage.date,
            unreadCount: contactChatInfo.unreadCount,
            preview: contactChatInfo.lastMessage.text
          )
        }
        
      case .connection(let contact):
        cell.setupContact(
          name: (contact.nickname ?? contact.username) ?? "",
          image: contact.photo,
          date: nil,
          unreadCount: 0,
          preview: contact.username ?? ""
        )
      }
      
      return cell
    }
  }
  
  required init?(coder: NSCoder) { nil }
  
  override func viewDidLoad() {
    super.viewDidLoad()
    
    tableView.separatorStyle = .none
    tableView.tableFooterView = UIView()
    tableView.sectionIndexColor = .blue
    tableView.register(ChatListCell.self)
    tableView.dataSource = tableDataSource
    view.backgroundColor = Asset.neutralWhite.color
    
    viewModel.searchPublisher
      .receive(on: DispatchQueue.main)
      .sink { [unowned self] in tableDataSource?.apply($0, animatingDifferences: false) }
      .store(in: &cancellables)
  }
}

extension ChatSearchTableController {
  override func tableView(
    _ tableView: UITableView,
    heightForRowAt: IndexPath
  ) -> CGFloat {
    return cellHeight
  }
  
  override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    if let item = tableDataSource?.itemIdentifier(for: indexPath) {
      switch item {
      case .chat(let chatInfo):
        switch chatInfo {
        case .group(let group):
          if let groupInfo = viewModel.groupInfo(from: group) {
            navigator.perform(PresentGroupChat(groupInfo: groupInfo, on: navigationController!))
          }
        case .groupChat(let info):
          if let groupInfo = viewModel.groupInfo(from: info.group) {
            navigator.perform(PresentGroupChat(groupInfo: groupInfo, on: navigationController!))
          }
        case .contactChat(let info):
          guard info.contact.authStatus == .friend else { return }
          navigator.perform(PresentChat(contact: info.contact, on: navigationController!))
        }
      case .connection(let contact):
        navigator.perform(PresentContact(contact: contact, on: navigationController!))
      }
    }
  }
}