class_lesson.py

class Flight:
    ''' A flight with a particular passenger aircraft'''

    def __init__(self, number, aircraft):
        if not number[:2].isalpha():
            raise ValueError("No airline code in '{}'".format(number))
        if not number[:2].isupper():
            raise ValueError("Invalid airline code in '{}'".format(number))
        if not number[2:].isdigit() and int(number[2:] <= 9999):
            raise ValueError("Invalid route number '{}'".format(number))

        self._number = number
        self._aircraft = aircraft

        rows, seats = self.aircraft_seating_plan()
        self._seating = [None] + [{letter: None for letter in seats} for _ in rows]

    def number(self):
        return self._number

    def airline(self):
        return self._number[:2]

    def aircraft_model(self):
        return self._aircraft.model()

    def _parse_seat(self, seat):
        rows, seat_letters = self._aircraft.seating_plan()

        letter = seat[-1]
        if letter not in seat_letters:
            raise ValueError("Invalid seat letter {}".format(letter))

        row_text = seat[:-1]
        try:
            row = int(row_text)
        except:
            raise ValueError("Invalid seat row {}".format(row_text))

        if row not in rows:
            raise ValueError("Invalid row number {}".format(row))

        return row, letter


    def allocate_seat(self, seat, passenger):
        """Allocate a seat to a passenger
        
        Args:
            seat: A seat designator such as '12c' or '21f'.
            passenger: the passenger name.
            
        Raises:
            ValueError: if the seat is unavailable.
        
        """
        row, letter = self._parse_seat(seat)
        if self._seating[row][letter] is not None:
            raise ValueError("Seat {} already occupied".format(seat))

        self._seating[row][letter] = passenger

    def relocate_passenger(self, from_seat, to_seat):

        from_row, from_letter = self._parse_seat(from_seat)
        if self._seating[from_row][from_letter] is None:
            raise ValueError("No passenger to relocate in seat {}".format(from_seat))

        to_row, to_letter = self._parse_seat(to_seat)
        if self._seating[to_row][to_letter] is not None:
            raise ValueError("Seat {} is already occupied".format(to_seat))

        self._seating[to_row][to_letter], self._seating[from_row][from_letter] = self._seating[from_row][from_letter], None

    def aircraft_seating_plan(self):
        return self._aircraft.seating_plan()

    def num_available_seats(self):
        return sum(sum(1 for s in row.values() if s is None)
                   for row in self._seating
                   if row is not None)

    def make_boarding_cards(self, card_printer):
        for passenger, seat in sorted(self._passenger_seats()):
            card_printer(passenger, seat, self.number(), self.aircraft_model())

    def _passenger_seats(self):
        """An iterable series of passenger seating allocations."""
        row_numbers, seat_letters = self._aircraft.seating_plan()
        for row in row_numbers:
            for letter in seat_letters:
                passenger = self._seating[row][letter]
                if passenger is not None:
                    yield(passenger, "{}{}".format(row, letter))


class Aircraft:
    def __init__(self, registration):
        self._registration = registration

    def registration(self):
        return self._registration

    def num_seats(self):
        rows, row_seats = self.seating_plan()
        return len(rows) * len(row_seats)


class AirbusA319(Aircraft):

    def model(self):
        return "Airbus A319"

    def seating_plan(self):
        return range(1,23), "ABCDEF"


class Boeing777(Aircraft):

    def model(self):
        return "Boeing 777"

    def seating_plan(self):
        return range(1,56), "ABCDEGHJK"


def make_flight():
    f = Flight("BA758", Aircraft("G-EUPT", "Airbus A319", num_rows=22, num_seats_per_row=6))
    f.allocate_seat("12A", "David Beltran")
    f.allocate_seat("21B", "Fred Wilson")
    f.allocate_seat("12B", "Gema Beltran")
    f.allocate_seat("12C", "Leonardito Hernandez")
    return f


def console_card_printer(passenger, seat, flight_number, aircraft):
    output = "| Name: {0} "   \
             " Flight: {1}"   \
             " Seat: {2}  "   \
             " Aircraft: {3}" \
             " |".format(passenger, flight_number, seat, aircraft)
    banner = '+' + '-' * (len(output) - 2) + '+'
    border = '|' + ' ' * (len(output) - 2) + '|'
    lines = [banner, border, output, border, banner]
    card = '\n'.join(lines)
    print(card)
    print()