class NoSuchStudentException(Exception):
    """Raised when plants are requested for a student not assigned a plot."""


DEFAULT_STUDENTS = (
    "Alena",
    "Boris",
    "Cyril",
    "Daniel",
    "Eva",
    "František",
    "Gitka",
    "Helena",
    "Ivana",
    "Jozef",
    "Karol",
    "Ladislav",
)

PLANT_NAMES = {
    "G": "Tráva",
    "C": "Ďatelina",
    "R": "Reďkovky",
    "V": "Fialky",
}


class Garden:
    def __init__(self, diagram, students=None):
        self.rows = diagram.splitlines()
        self.students = sorted(DEFAULT_STUDENTS if students is None else students)

    def plants(self, student):
        try:
            index = self.students.index(student)
        except ValueError:
            raise NoSuchStudentException(
                f"Žiak '{student}' nemá pridelený záhon."
            ) from None

        start = index * 2
        return [
            PLANT_NAMES[code] for row in self.rows for code in row[start : start + 2]
        ]