from pathlib import Path

import pytest

from techdocs_graphrag.ingestion import (
    ParagraphSplitter,
    SourceDocument,
    chunk_documents,
    load_documents,
)


def test_splitter_respects_chunk_size_and_covers_every_paragraph() -> None:
    paragraphs = [f"P{index:02d} " + "mot " * 40 for index in range(10)]
    chunks = ParagraphSplitter(chunk_size=120, chunk_overlap=20).split("\n\n".join(paragraphs))
    joined = " ".join(chunks)

    assert all(len(chunk) <= 120 for chunk in chunks)
    assert all(f"P{index:02d}" in joined for index in range(10))


def test_splitter_keeps_short_paragraphs_together() -> None:
    chunks = ParagraphSplitter(chunk_size=100, chunk_overlap=10).split("Un.\n\nDeux.\n\nTrois.")
    assert chunks == ["Un.\n\nDeux.\n\nTrois."]


def test_splitter_rejects_overlap_larger_than_chunk() -> None:
    with pytest.raises(ValueError):
        ParagraphSplitter(chunk_size=10, chunk_overlap=10)


def test_load_documents_reads_supported_files_recursively(tmp_path: Path) -> None:
    (tmp_path / "guides").mkdir()
    (tmp_path / "intro.md").write_text("Intro", encoding="utf-8")
    (tmp_path / "guides" / "setup.md").write_text("Setup", encoding="utf-8")
    (tmp_path / "image.png").write_bytes(b"\x89PNG")

    documents = load_documents(tmp_path)

    assert [document.name for document in documents] == ["guides/setup.md", "intro.md"]


def test_chunk_ids_are_deterministic_and_unique() -> None:
    documents = [SourceDocument("a.md", "Alpha.\n\nBeta."), SourceDocument("b.md", "Alpha.")]
    splitter = ParagraphSplitter(chunk_size=8, chunk_overlap=0)

    first_run = chunk_documents(documents, splitter)
    second_run = chunk_documents(documents, splitter)

    assert [chunk.id for chunk in first_run] == [chunk.id for chunk in second_run]
    assert len({chunk.id for chunk in first_run}) == len(first_run)