import pytest
from pathlib import Path
from datetime import date
from chitai.services.metadata_extractor import EpubExtractor, Extractor, PdfExtractor


@pytest.mark.asyncio()
class TestEpubExtractor:
    async def test_extraction_by_path(self):
        path = Path("tests/data_files/Moby Dick; Or, The Whale - Herman Melville.epub")

        metadata = await EpubExtractor.extract_metadata(path)

        assert metadata["title"] == "Moby Dick; Or, The Whale"
        assert metadata["authors"] == ["Herman Melville"]
        assert metadata["published_date"] == date(year=2001, month=7, day=1)



EPUB = Path("tests/data_files/Metamorphosis - Franz Kafka.epub")
PDF = Path("tests/data_files/Calculus Made Easy - Silvanus Thompson.pdf")


@pytest.mark.asyncio()
class TestIdentifierMerging:
    """A book's formats each contribute identifiers; none of them replaces the rest."""

    async def test_every_format_contributes(self, monkeypatch: pytest.MonkeyPatch) -> None:
        """
        Identifiers are a collection, not a single value.

        Merging the whole dict meant the last format to report won outright: an EPUB
        declaring an ASIN, a Google volume id and a Calibre id kept none of them once
        a PDF contributed one ISBN.
        """

        async def epub(_file):
            return {
                "title": "How Linux Works",
                "identifiers": {"isbn-13": "9781718500419", "asin": "1718500408"},
            }

        async def pdf(_file):
            return {"identifiers": {"isbn-13": "9781718500402", "isbn-10": "1593270356"}}

        monkeypatch.setattr(EpubExtractor, "extract_metadata", epub)
        monkeypatch.setattr(PdfExtractor, "extract_metadata", pdf)

        metadata = await Extractor.extract_metadata(
            [Path("How Linux Works.epub"), Path("How Linux Works.pdf")]
        )

        assert metadata["identifiers"] == {
            # Declared by the publisher's toolchain, so it outranks the PDF's, which
            # was scraped off a copyright page that also prints the print edition's.
            "isbn-13": "9781718500419",
            "asin": "1718500408",
            "isbn-10": "1593270356",
        }

    async def test_a_second_format_that_finds_nothing_erases_nothing(self) -> None:
        """The PDF fixture carries no ISBN, so it must leave the EPUB's alone."""
        metadata = await Extractor.extract_metadata([EPUB, PDF])

        assert metadata["identifiers"] == {"id": "http://www.gutenberg.org/5200"}

    async def test_one_format_on_its_own_is_unaffected(self) -> None:
        metadata = await Extractor.extract_metadata([EPUB])

        assert metadata["identifiers"] == {"id": "http://www.gutenberg.org/5200"}

    async def test_no_identifiers_anywhere_leaves_the_field_absent(self) -> None:
        """An empty dict would count as extracted metadata and overwrite nothing."""
        metadata = await Extractor.extract_metadata([PDF])

        assert "identifiers" not in metadata