import pytest
import parser
from pathlib import Path

# Happy path
def test_validFile(tmp_path):
    file_contents = """

FRONT


Foo

Bar

BACK


Fizz

Buzz



FRONT

Another card

BACK

Another back


        """
    expected = {
        ("Foo\n\nBar", "Fizz\n\nBuzz"),
        ("Another card", "Another back")
    }
    
    path = tmp_path / "valid_file.fcard"
    with open(path, "w") as f:
        f.write(file_contents)

    cards = parser.parse(path)

    assert expected == set(cards.values())

# Edge cases
def test_emptyFile(tmp_path):
    path = tmp_path / "empty.fcard"
    with open(path, "w") as f:
        f.write("")

    cards = parser.parse(path)
    assert cards == {}

def test_missingFile(tmp_path):
    cards = parser.parse(tmp_path / "missing_file.fcard")
    assert cards == {}

def checkException(tmp_path, file_contents):
    path = tmp_path / "invalid_file.fcard"
    with open(path, "w") as f:
        f.write(file_contents)

    with pytest.raises(Exception):
        cards = parser.parse(path)

def test_doesNotStartWithFront(tmp_path):
    checkException(tmp_path, "BACK\noops")

def test_frontTwiceInARow(tmp_path):
    checkException(tmp_path, "FRONT\noops\nFRONT\nbad")

def test_doesNotEndWithBack(tmp_path):
    checkException(tmp_path, "FRONT\ntest\nBACK\ntest\nFRONT\noops")