package httpapi

import (
	"errors"
	"fmt"

	"calllinesystem/server/internal/model"
)

var errTicketPhoneUnavailable = errors.New("ticket phone data is unavailable")

func cloneStringPointer(value *string) *string {
	if value == nil {
		return nil
	}
	copy := *value
	return &copy
}

func stringPointer(value string) *string {
	return &value
}

func (s *Server) decryptTicketPersonal(ticket model.QueueTicket) (string, string, error) {
	phone, err := s.decryptTicketPhone(ticket)
	if err != nil {
		return "", "", err
	}
	lastName, err := s.decryptTicketLastName(ticket)
	if err != nil {
		return "", "", err
	}
	return phone, lastName, nil
}

func (s *Server) decryptTicketPhone(ticket model.QueueTicket) (string, error) {
	if ticket.PhoneHMAC == nil || len(ticket.PhoneCiphertext) == 0 || len(ticket.PhoneNonce) == 0 {
		return "", errTicketPhoneUnavailable
	}
	phone, err := s.cipher.Decrypt(ticket.PhoneCiphertext, ticket.PhoneNonce, []byte("phone:"+ticket.ProjectID))
	if err != nil {
		return "", fmt.Errorf("decrypt ticket phone: %w", err)
	}
	return phone, nil
}

func (s *Server) decryptTicketLastName(ticket model.QueueTicket) (string, error) {
	if len(ticket.LastNameCiphertext) == 0 && len(ticket.LastNameNonce) == 0 {
		return "", nil
	}
	if len(ticket.LastNameCiphertext) == 0 || len(ticket.LastNameNonce) == 0 {
		return "", errors.New("ticket last name data is incomplete")
	}
	lastName, err := s.cipher.Decrypt(ticket.LastNameCiphertext, ticket.LastNameNonce, []byte("last_name:"+ticket.ProjectID))
	if err != nil {
		return "", fmt.Errorf("decrypt ticket last name: %w", err)
	}
	return lastName, nil
}

func (s *Server) ticketPhoneLast4(ticket model.QueueTicket) (string, error) {
	phone, err := s.decryptTicketPhone(ticket)
	if err != nil {
		if errors.Is(err, errTicketPhoneUnavailable) {
			return "", nil
		}
		return "", err
	}
	return phoneLast4(phone)
}

func phoneLast4(phone string) (string, error) {
	digits := make([]byte, 0, len(phone))
	for i := 0; i < len(phone); i++ {
		if phone[i] >= '0' && phone[i] <= '9' {
			digits = append(digits, phone[i])
		}
	}
	if len(digits) < 4 {
		return "", errors.New("ticket phone has fewer than four digits")
	}
	return string(digits[len(digits)-4:]), nil
}