"""Heading-recursive chunker tests. No corpus, no Chroma."""
from __future__ import annotations

import unittest

import rag.chunk as chunk


META = {"bundle_id": "Admin.10.0", "title": "Admin Guide"}


def _bodies(text: str) -> list[str]:
    return [c["text"] for c in chunk.chunks_from_page(text, "Page", META)]


class ChunkTests(unittest.TestCase):
    def setUp(self) -> None:
        self._saved = chunk.TARGET_CHARS

    def tearDown(self) -> None:
        chunk.TARGET_CHARS = self._saved

    def test_chunk0_always_has_title_on_short_page(self) -> None:
        page = "# Install\n\nJust one short paragraph about installing."
        chunks = list(chunk.chunks_from_page(page, "Install", META))
        self.assertGreaterEqual(len(chunks), 1)
        self.assertEqual(chunks[0]["metadata"]["ordinal"], 0)
        self.assertIn("# Admin Guide", chunks[0]["text"])

    def test_sibling_h2_sections_do_not_mix(self) -> None:
        chunk.TARGET_CHARS = 80
        page = (
            "# A\n\n"
            "intro text for A\n\n"
            "## A.1\n\n"
            "alpha content lives here only\n\n"
            "## A.2\n\n"
            "beta content lives here only\n"
        )
        bodies = _bodies(page)
        self.assertTrue(any("alpha content" in b and "beta content" not in b for b in bodies[1:]),
                        bodies)
        self.assertTrue(any("beta content" in b and "alpha content" not in b for b in bodies[1:]),
                        bodies)

    def test_giant_section_splits_on_paragraphs(self) -> None:
        chunk.TARGET_CHARS = 40
        paras = [f"Paragraph number {i} with enough words." for i in range(8)]
        page = "# Giant\n\n" + "\n\n".join(paras)
        bodies = _bodies(page)
        # skip chunk 0
        for b in bodies[1:]:
            # may exceed by at most one paragraph (the one that filled the buf)
            self.assertLessEqual(len(b), chunk.TARGET_CHARS + len(paras[0]) + 2, b)

    def test_fenced_code_never_sliced(self) -> None:
        chunk.TARGET_CHARS = 30
        fence = "```\n" + ("x" * 80) + "\n```"
        page = "# Code\n\nBefore.\n\n" + fence + "\n\nAfter."
        bodies = _bodies(page)
        joined = "\n".join(bodies)
        self.assertIn(fence, joined)
        # no body chunk should contain a half-fence
        for b in bodies:
            if "```" in b:
                self.assertTrue(b.strip().startswith("```") or "```\n" in b)
                self.assertGreaterEqual(b.count("```"), 2, b)


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