import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;

public class EmployeeSource {
  Database datbase;
  public EmployeeSource(Database database) {
    this.datbase = database;
  }

  public ArrayList<Employee> getEmployees() {
    try {
      return tryGetEmployees();
    } catch (SQLException e) {
      System.err.println("Hiba! A lekérdezés sikertelen！");
      System.err.println(e.getMessage());
      return null;
    }
  }

  public ArrayList<Employee> tryGetEmployees() throws SQLException {
    Connection conn = datbase.connect();
    String sql = "select * from employees";
    ArrayList<Employee> employees = new ArrayList<Employee>();
    Statement stmt = conn.createStatement();
    ResultSet rs = stmt.executeQuery(sql);
    while (rs.next()) {
      Employee employee = new Employee();
      employee.id = rs.getInt("id");
      employee.name = rs.getString("name");
      employee.city = rs.getString("city");
      employee.salary = rs.getDouble("salary");
      employees.add(employee);
    }
    return employees;    
  }

  public Employee addEmployee(Employee employee) {
    try {
      return tryAddEmployee(employee);
    } catch (SQLException e) {
      System.err.println("Hiba! A hozzáadás sikertelen！");
      System.err.println(e.getMessage());
      return null;
    }
  }

  public Employee tryAddEmployee(Employee employee) throws SQLException {
    Connection conn = datbase.connect();
    String sql = """
    insert into employees 
    (name, city, salary) 
    values 
    (?, ?, ?)
    """;
    PreparedStatement pstmt = conn.prepareStatement(sql);
    pstmt.setString(1, employee.name);
    pstmt.setString(2, employee.city);
    pstmt.setDouble(3, employee.salary);
    pstmt.executeUpdate();
    return employee;
  }
}