"""Tests for text chunking."""

import unittest

from converter import config
from converter.chunking import split_into_chunks


class ChunkSizeDefaultTests(unittest.TestCase):
    """Guard the default chunk size: each API call is one model generation,
    and long single generations lose prosody, can turn garbled, and are
    truncated at the model's token limit (text past it is never spoken)."""

    def test_default_chunk_size_within_single_generation_budget(self):
        self.assertLessEqual(config.CHUNK_SIZE_WORDS, 60)


class SplitIntoChunksTests(unittest.TestCase):
    def test_empty_input(self):
        self.assertEqual(split_into_chunks(""), [])
        self.assertEqual(split_into_chunks("   \n  "), [])

    def test_short_text_single_chunk(self):
        self.assertEqual(split_into_chunks("One short sentence."), ["One short sentence."])

    def test_respects_word_limit_across_sentences(self):
        # 10 sentences of 9 words each = 90 words total
        sentences = [f"S{i} " + " ".join(["word"] * 8) + "." for i in range(10)]
        chunks = split_into_chunks(" ".join(sentences), max_words=25)
        self.assertGreater(len(chunks), 1)
        self.assertTrue(all(len(c.split()) <= 25 for c in chunks))
        self.assertEqual(sum(len(c.split()) for c in chunks), 90)

    def test_long_sentence_split_keeps_punctuation(self):
        # 10 clauses of 5 words each, joined by comma+space
        sentence = ", ".join([" ".join(["w"] * 5) for _ in range(10)]) + "."
        chunks = split_into_chunks(sentence, max_words=12)
        self.assertGreater(len(chunks), 1)
        self.assertTrue(all(len(c.split()) <= 12 for c in chunks))
        self.assertIn(",", chunks[0])  # commas retained for TTS prosody

    def test_clause_split_never_breaks_numbers(self):
        # Regression: the clause split used to fire at every comma even
        # without whitespace, mutating "1,000,000" into "1, 000, 000".
        sentence = ("There were exactly 1,000,000 soldiers marching at 12:30, "
                    + "and they kept marching onward " * 30) + "endlessly."
        chunks = split_into_chunks(sentence, max_words=25)
        self.assertGreater(len(chunks), 1)
        joined = " ".join(chunks)
        self.assertIn("1,000,000", joined)
        self.assertIn("12:30", joined)
        self.assertNotIn("1, 000", joined)
        self.assertNotIn("000, 000", joined)
        self.assertNotIn("12: 30", joined)

    def test_clause_split_requires_whitespace_after_punctuation(self):
        # Run-on clauses without spaces after commas have no split point and
        # must stay byte-identical rather than being re-joined with spaces.
        sentence = ",".join([" ".join(["w"] * 5) for _ in range(10)]) + "."
        chunks = split_into_chunks(sentence, max_words=12)
        self.assertEqual(chunks, [sentence])

    def test_single_oversized_sentence_stays_intact(self):
        sentence = " ".join(["word"] * 30) + "."
        chunks = split_into_chunks(sentence, max_words=10)
        self.assertEqual(chunks, [sentence])


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