import unittest
from textbook.extract_section import extract_section, labeled_statements

FIXTURE = """\
1.6. Divisibility in the Integers
intro text

Proposition 1.6.1.
body

Theorem 1.6.6. There are infinitely many prime numbers.
Proof. blah
36                          1. ALGEBRAIC THEMES


Theorem 1.6.6. There are infinitely many prime numbers.
Proof continues after a page break, repeats the label.

1.7. Modular Arithmetic
next section text
"""


class ExtractSectionTests(unittest.TestCase):
    def test_extract_section_slices_between_headings(self):
        section = extract_section(FIXTURE, '1.6. Divisibility in the Integers', '1.7. Modular Arithmetic')
        self.assertIn('Theorem 1.6.6', section)
        self.assertNotIn('next section text', section)

    def test_extract_section_missing_heading_raises(self):
        with self.assertRaises(ValueError):
            extract_section(FIXTURE, '1.6. Divisibility in the Integers', '9.9. Does Not Exist')

    def test_labeled_statements_dedupes_and_orders(self):
        section = extract_section(FIXTURE, '1.6. Divisibility in the Integers', '1.7. Modular Arithmetic')
        items = labeled_statements(section, '1.6.')
        labels = [item['label'] for item in items]
        # Theorem 1.6.6 appears twice (page-break repeat) but must be kept once, and
        # book order (1.6.1 before 1.6.6) must be preserved.
        self.assertEqual(labels, ['1.6.1', '1.6.6'])

    def test_labeled_statements_filters_by_prefix(self):
        section = extract_section(FIXTURE, '1.6. Divisibility in the Integers', '1.7. Modular Arithmetic')
        items = labeled_statements(section, '1.7.')
        self.assertEqual(items, [])


if __name__ == '__main__':
    unittest.main()