using MySql.Data.MySqlClient;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HanvonF710XAttendanceService
{
    internal class AttendanceMachineUserDAO
    {
        public AttendanceMachineUserDAO() { }
        public void Add(AttendanceMachineUser attendanceMachineUser, MySqlConnection connection)
        {
            // Ensure synced users are active and clear any pending deletion request.
            const string query =
                "REPLACE INTO `hrms`.`attendance_machine_user` " +
                "(`machine_id`, `serial_number`, `employee_name`, `is_deletion_requested`, `is_deleted`, `updated_by`, `updated_at`) " +
                "VALUES (@MachineId, @SerialNumber, @EmployeeName, 0, 0, @UpdatedBy, @UpdatedAt)";

            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.Parameters.AddWithValue("@MachineId", attendanceMachineUser.MachineId);
                cmd.Parameters.AddWithValue("@SerialNumber", attendanceMachineUser.SerialNumber);
                cmd.Parameters.AddWithValue("@EmployeeName", attendanceMachineUser.EmployeeName);
                cmd.Parameters.AddWithValue("@UpdatedBy", "SERVICE");
                cmd.Parameters.AddWithValue("@UpdatedAt", DateTime.Now);
                cmd.ExecuteNonQuery();
            }

        }

        public List<AttendanceMachineUser> getActiveEmployees(MySqlConnection connection)
        {
            const string query =
                "SELECT machine_id, serial_number, employee_name " +
                "FROM hrms.attendance_machine_user " +
                "WHERE is_deleted = 0";
            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.CommandTimeout = 120;
                using (var reader = cmd.ExecuteReader())
                {
                    return getDBUsers(reader);
                }
            }
        }

        public List<string> GetDeletionRequestedSerials(MySqlConnection connection, string machineId)
        {
            var serials = new List<string>();
            const string query =
                "SELECT serial_number " +
                "FROM hrms.attendance_machine_user " +
                "WHERE machine_id = @MachineId AND is_deletion_requested = 1 AND is_deleted = 0";
            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.CommandTimeout = 60;
                cmd.Parameters.AddWithValue("@MachineId", machineId);
                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        if (!reader.IsDBNull(0))
                        {
                            var s = reader.GetString(0);
                            if (!string.IsNullOrWhiteSpace(s))
                                serials.Add(s.Trim());
                        }
                    }
                }
            }
            return serials;
        }

        public int MarkUserDeleted(MySqlConnection connection, string machineId, string serialNumber)
        {
            const string query =
                "UPDATE hrms.attendance_machine_user " +
                "SET is_deleted = 1, is_deletion_requested = 0, updated_by = @UpdatedBy, updated_at = @UpdatedAt " +
                "WHERE machine_id = @MachineId AND serial_number = @SerialNumber AND is_deleted = 0";
            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.CommandTimeout = 60;
                cmd.Parameters.AddWithValue("@UpdatedBy", "SERVICE");
                cmd.Parameters.AddWithValue("@UpdatedAt", DateTime.Now);
                cmd.Parameters.AddWithValue("@MachineId", machineId);
                cmd.Parameters.AddWithValue("@SerialNumber", serialNumber);
                return cmd.ExecuteNonQuery();
            }
        }


        public List<AttendanceMachineUser> getAllEmployees(MySqlConnection connection)
        {
            string query = "SELECT machine_id, serial_number, employee_name FROM hrms.attendance_machine_user";
            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.CommandTimeout = 120;
                using (var reader = cmd.ExecuteReader())
                {
                    return getDBUsers(reader);
                }
            }
        }

        public string GetEmployeeNameForMachine(MySqlConnection connection, string machineId, string serialNumber)
        {
            if (string.IsNullOrWhiteSpace(machineId) || string.IsNullOrWhiteSpace(serialNumber)) return null;
            const string query =
                "SELECT employee_name FROM hrms.attendance_machine_user " +
                "WHERE machine_id = @MachineId AND serial_number = @SerialNumber AND is_deleted = 0 LIMIT 1";
            using (var cmd = new MySqlCommand(query, connection))
            {
                cmd.CommandTimeout = 60;
                cmd.Parameters.AddWithValue("@MachineId", machineId);
                cmd.Parameters.AddWithValue("@SerialNumber", serialNumber.Trim());
                var result = cmd.ExecuteScalar();
                if (result == null || result == DBNull.Value) return null;
                var name = result.ToString()?.Trim();
                return string.IsNullOrWhiteSpace(name) ? null : name;
            }
        }

        private List<AttendanceMachineUser> getDBUsers(MySqlDataReader reader)
        {
            List<AttendanceMachineUser> DbUsers = new List<AttendanceMachineUser>();
            while (reader.Read())
            {
                DbUsers.Add(GetDbUsers(reader));
            }
            return DbUsers;
        }


        private AttendanceMachineUser GetDbUsers(MySqlDataReader reader)
        {
            return new AttendanceMachineUser(
                    reader.IsDBNull(0) ? "" : reader.GetString("machine_id"),                
                    reader.IsDBNull(1) ? "" : reader.GetString("serial_number"),
                    reader.IsDBNull(1) ? "" : reader.GetString("serial_number")

                );
        }
    }
}