//
//  RecipientsViewModel.swift
//  GME Remit
//
//  Created by InKwon James Kim on 08/08/2019.
//  Copyright © 2019 Gobal Money Express Co. Ltd. All rights reserved.
//

import RxSwift
import RxCocoa

class RecipientsViewModel: ViewModelType {
  var presenter: RecipientsModuleInterface?
  
  struct Input {
    let fetchTrigger: Driver<Void>
    let refreshTrigger: Driver<Void>
    let addTrigger: Driver<Void>
    let selectTrigger: Driver<IndexPath>
    let editTrigger: Driver<Recipient>
    let deleteTrigger: Driver<Recipient>
    let needEditTrigger: Driver<Void>
    let filterText: Driver<String?>
  }
  
  struct Output {
    let recipients: Driver<[Recipient]>
    let isNeedEdit: Driver<Void>
    let isPartnerChanged: Driver<Void>
    let isError: Driver<Error>
    let isProgress: Driver<Bool>
  }
  
  private let disposeBag = DisposeBag()
  private var selectedRecipientID: String?
  
  private let recipientsLinker = BehaviorSubject<[Recipient]>(value: [])
  private let filteredRecipientLinker = BehaviorSubject<[Recipient]>(value: [])
  
  private let accountsLinker = BehaviorSubject<[Account]>(value: [])
  
  private let editLinker = PublishSubject<Recipient>()
  private let deleteLinker = PublishSubject<Recipient>()
  
  private let progressLinker = PublishSubject<Bool>()
  private let errorLinker = PublishSubject<Error>()
  
  private var selectedRecipient: Recipient?
  
  private var isNeedEditRecipient = PublishSubject<Void>()
  private var isPartnerChanged = PublishSubject<Void>()
  
  func transform(input: Input) -> Output {
    input
      .fetchTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.presenter?.fetchRecipients(isRefresh: false)
      })
      .disposed(by: disposeBag)
    
    input
      .refreshTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.presenter?.fetchRecipients(isRefresh: true)
      })
      .disposed(by: disposeBag)
    
    let recipients = Observable.combineLatest(
      recipientsLinker, input.filterText.asObservable()
    ) { recipients, searchText -> [Recipient] in
      guard let searchText = searchText, searchText != "" else {
        return  recipients
      }
      return recipients.filter {( $0.fullName?.lowercased().contains(searchText.lowercased()) ?? false )}
    }.asDriverOnErrorJustComplete()
    
    input.selectTrigger
      .withLatestFrom(recipients) { (indexPath, recipients) -> Recipient in
        return recipients[indexPath.row]
      }
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.selectedRecipient = $0
        
        guard let paymentMode = self.selectedRecipient?.paymentMethod else {
          self.isNeedEditRecipient.onNext(())
          return
        }
        
        if paymentMode.id == nil {
          self.isNeedEditRecipient.onNext(())
          return
        }
        
        if self.selectedRecipient?.isPartnerChanged == "1" {
          self.isPartnerChanged.onNext(())
          return
        }
        
        let accounts = try? self.accountsLinker.value()
        self.presenter?.openSelectAccount(with: accounts ?? [])
      })
      .disposed(by: disposeBag)
    
    input.editTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.presenter?.openEditRecipient(who: $0, with: self)
      })
      .disposed(by: disposeBag)
    
    input.deleteTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.presenter?.deleteRecipient(who: $0)
      })
      .disposed(by: disposeBag)
    
    input.addTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        self.presenter?.openAddRecipient(with: self)
      })
      .disposed(by: disposeBag)
    
    input.needEditTrigger
      .drive(onNext: { [weak self] in guard let `self` = self else { return }
        guard let recipient = self.selectedRecipient else {return}
        self.presenter?.openEditRecipient(who: recipient, with: self)
      })
      .disposed(by: disposeBag)
    
    return Output(
      recipients: recipients,
      isNeedEdit: isNeedEditRecipient.asDriverOnErrorJustComplete(),
      isPartnerChanged: isPartnerChanged.asDriverOnErrorJustComplete(),
      isError: errorLinker.asDriverOnErrorJustComplete(),
      isProgress: progressLinker.asDriverOnErrorJustComplete()
    )
  }
}

// MARK: - RecipientsViewModelInterface
extension RecipientsViewModel: RecipientsViewModelInterface {
  func setSelectedAccount(_ account: Account) {
    guard let recipient = selectedRecipient else { return }
    
    presenter?.goNextStep(who: recipient, with: account)
  }
  
  func setRecipients(using model: [Recipient]) {
    recipientsLinker.onNext(model)
    
    guard let selectedID = selectedRecipientID else {
      return
    }
    
    selectedRecipient = model.filter({$0.receiverID == selectedID}).first
    
    let accounts = try? self.accountsLinker.value()
    presenter?.openSelectAccount(with: accounts ?? [])
    
    selectedRecipientID = nil
  }
  
  func setAccounts(using model: [Account]) {
    accountsLinker.onNext(model)
  }
  
  func setError(with error: Error) {
    errorLinker.onNext(error)
  }
  
  func progress(isShow: Bool) {
    progressLinker.onNext(isShow)
  }
}

extension RecipientsViewModel: SetupRecipientDelegate {
  func setupRecieient(_ viewController: SetupRecipientViewController, didSelectRecipientID: String?) {
    selectedRecipientID = didSelectRecipientID
    presenter?.fetchRecipients(isRefresh: true)
  }
}