from app.ingest.chunker import chunk_text


def test_chunk_short_text_single_chunk():
    text = "Das ist ein kurzer Text mit wenigen Worten."
    chunks = chunk_text(text, size_words=500, overlap_words=50, page=1)
    assert len(chunks) == 1
    assert chunks[0].text == text
    assert chunks[0].page == 1


def test_chunk_size_and_overlap():
    words = [f"w{i}" for i in range(1200)]
    text = " ".join(words)
    chunks = chunk_text(text, size_words=500, overlap_words=50, page=1)

    # 1200 words, size 500, overlap 50 → step 450 → starts at 0, 450, 900 → 3 chunks
    assert len(chunks) == 3
    # First chunk has up to 500 words
    assert len(chunks[0].text.split()) <= 500
    # Overlap: last 50 words of chunk 0 are first 50 words of chunk 1
    last_50_of_first = chunks[0].text.split()[-50:]
    first_50_of_second = chunks[1].text.split()[:50]
    assert last_50_of_first == first_50_of_second


def test_chunk_respects_sentence_boundary_in_lookback_window():
    # 600 words, with a sentence ending around word 480 (within last 20% = words 400-500)
    words = [f"w{i}" for i in range(600)]
    words[479] = "ende."
    text = " ".join(words)
    chunks = chunk_text(text, size_words=500, overlap_words=50, page=1)

    # First chunk should end at the sentence boundary, not at word 500
    first_chunk_words = chunks[0].text.split()
    assert first_chunk_words[-1] == "ende."
    assert len(first_chunk_words) == 480


def test_chunk_no_sentence_boundary_in_window_falls_back_to_word_count():
    words = [f"w{i}" for i in range(600)]
    text = " ".join(words)
    chunks = chunk_text(text, size_words=500, overlap_words=50, page=1)
    # No sentence-end → exactly 500 words in first chunk
    assert len(chunks[0].text.split()) == 500


def test_chunk_empty_text_returns_empty_list():
    assert chunk_text("", size_words=500, overlap_words=50, page=1) == []


def test_chunk_carries_page_number():
    chunks = chunk_text("hallo welt", size_words=500, overlap_words=50, page=7)
    assert chunks[0].page == 7


def test_chunk_overlap_geq_size_does_not_loop_forever():
    words = [f"w{i}" for i in range(60)]
    text = " ".join(words)
    chunks = chunk_text(text, size_words=10, overlap_words=10, page=1)
    assert len(chunks) >= 5
    assert all(len(c.text.split()) <= 10 for c in chunks)


def test_chunk_ignores_sentence_boundary_outside_lookback_window():
    words = [f"w{i}" for i in range(600)]
    words[399] = "ende."
    text = " ".join(words)
    chunks = chunk_text(text, size_words=500, overlap_words=50, page=1)
    assert len(chunks[0].text.split()) == 500