BookingStateUpdate.swift

private func updateState() {
		// Make sure all the information is available
		guard let rentalState = rentalState else {
			self.state.value = .Unknown
			return
		}
        
        let isPaymentInProgress = (paymentInProgress ?? false)
        
        // Save whether address details should be shown before updating state
        let showAddressDetailsBeforeUpdatingState = showAddressDetails()
		
		// Translate RentalState together with variables into BookingState
		switch rentalState {
            
		case .NotSend:
			if isRenter {
				self.state.value = .RequestNotSent
			} else {
				// Owner should never see bookings that have not been sent (should never happen)
				self.state.value = .Unknown
			}
			
		case .Requested:
			self.state.value = .Requested
			
		case .Denied:
			self.state.value = .Declined
			
		case .Cancelled:
			self.state.value = .Cancelled
			
		case .PaymentCancelled:
			self.state.value = .Unknown
			
		case .Accepted:
			if isRenter && isPaymentInProgress {
                // Only the renter sees whether the payment is processing
				self.state.value = .PaymentProcessing
			} else {
				self.state.value = .Accepted
			}
			
		case .PaymentAuthorized:
            if let canCheckIn = checkInCanStart, let isCheckInStarted = checkInStarted, let isCheckInCompleted = checkInCompleted, let isCheckOutStarted = checkOutStarted, let isCheckOutCompleted = checkOutCompleted {
                if isCheckOutCompleted {
                    // Mark the booking as finished if it was checked out already
                    self.state.value = .Finished
                } else if isCheckOutStarted {
                    // Mark the booking as check-out started if the user started but did not finish the check-out
                    self.state.value = .CheckOutStarted
                } else if isCheckInCompleted {
                    // Mark the booking as started if it was checked in but not checked out yet
                    self.state.value = .Started
                } else if isCheckInStarted {
                    // Mark the booking as check-in started if the user started but did not finish the check-in
                    self.state.value = .CheckInStarted
                } else if canCheckIn {
                    // Mark the booking as needing check-in if it can be checked in
                    self.state.value = .CanCheckIn
                } else {
                    // Mark the booking as paid if it cannot be checked in yet
                    self.state.value = .Paid
                }
            } else {
                // Check-in/out status not available, mark as paid
                self.state.value = .Paid
            }
			
		case .RentalStarted:
            guard let isCheckInStarted = checkInStarted, let isCheckInCompleted = checkInCompleted, let isCheckOutStarted = checkOutStarted, let isCheckOutCompleted = checkOutCompleted else {
                // Check-in/out status is mandatory when booking has started to prevent showing the wrong state
				self.state.value = .Unknown
				return
			}
			
            if isCheckOutCompleted {
                // Mark the booking as finished if it was checked out already
                self.state.value = .Finished
            } else if isCheckOutStarted {
                // Mark the booking as check-out started if the user started but did not finish the check-out
                self.state.value = .CheckOutStarted
            } else if isCheckInCompleted {
                // Mark the booking as started if it was checked in but not checked out yet
                self.state.value = .Started
            } else if isCheckInStarted {
                // Mark the booking as check-in started if the user started but did not finish the check-in
                self.state.value = .CheckInStarted
            } else {
                // Mark the booking as needing check-in if it has started but was not checked in yet
                self.state.value = .CanCheckIn
            }
			
		case .RentalEnded:
            guard let canCheckIn = checkInCanStart, let isCheckInStarted = checkInStarted, let isCheckInCompleted = checkInCompleted, let canCheckOut = checkOutCanStart, let isCheckOutStarted = checkOutStarted, let isCheckOutCompleted = checkOutCompleted else {
                // Check-in/out status is mandatory when booking has ended to prevent showing the wrong state
                self.state.value = .Unknown
                return
            }
            
            if isCheckOutCompleted {
                // Mark the booking as finished if it was checked out
                self.state.value = .Finished
            } else if isCheckInCompleted {
                if canCheckOut {
                    if isCheckOutStarted {
                        // Mark the booking as check-out started if the user started but did not finish the check-out, and can still be checked out
                        self.state.value = .CheckOutStarted
                    } else {
                        // Mark the booking as needing check-out if it was checked in and not checked out yet, and can still be checked out
                        self.state.value = .NeedsCheckOut
                    }
                } else {
                    // Mark the booking as finished if it was checked in and not checked out yet, and cannot be checked out anymore
                    self.state.value = .Finished
                }
            } else if canCheckIn {
                if isCheckInStarted {
                    // Mark the booking as check-in started if it has ended and the user started the check-in and can still finish it
                    self.state.value = .CheckInStarted
                } else {
                    // Mark the booking as needing check-in if it has ended and was never checked in, but can still be checked in
                    self.state.value = .CanCheckIn
                }
            } else {
                // Mark the booking as finished if it has ended and was never checked in, and cannot be checked in anymore
                self.state.value = .Finished
            }
            
		case .TransactionDone:
			if isRenter {
                // The renter doesn't see whether the owner has been paid out or not
				self.state.value = .Finished
			} else {
				self.state.value = .PaidOut
			}
			
		case .DeclinedBySystem:
			self.state.value = .CancelledBySystem
			
		case .Overdue:
			self.state.value = .Expired
			
		case .Unknown:
			// Should never happen
			self.state.value = .Unknown
		}
		
		// Store last update timestamp
		lastUpdated = Date()
		
		// Update address if necessary
        if showAddressDetailsBeforeUpdatingState != showAddressDetails() {
            updateAddress()
        }
	}