"""Tests for MIME sniffing (spec §6.1)."""

from __future__ import annotations

from pathlib import Path

import pytest

from ix.errors import IXErrorCode, IXException
from ix.ingestion import SUPPORTED_MIMES, detect_mime, require_supported

# Real-header fixtures. python-magic looks at bytes, not extensions, so
# these are the smallest valid-byte samples we can produce on the fly.

_PDF_BYTES = b"%PDF-1.4\n%\xe2\xe3\xcf\xd3\n1 0 obj\n<<>>\nendobj\nxref\n0 1\n0000000000 65535 f\ntrailer<<>>\nstartxref\n0\n%%EOF\n"

_PNG_BYTES = bytes.fromhex(
    # PNG magic + minimal IHDR + IDAT + IEND (1x1 all-black).
    "89504e470d0a1a0a"
    "0000000d49484452"
    "00000001000000010806000000"
    "1f15c4890000000d"
    "49444154789c6300010000000500010d0a2db400000000"
    "49454e44ae426082"
)

_JPEG_BYTES = (
    b"\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00"
    b"\xff\xdb\x00C\x00" + b"\x08" * 64
    + b"\xff\xc0\x00\x0b\x08\x00\x01\x00\x01\x01\x01\x11\x00"
    + b"\xff\xc4\x00\x1f\x00\x00\x01\x05\x01\x01\x01\x01\x01\x01\x00\x00"
    + b"\x00\x00\x00\x00\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b"
    + b"\xff\xda\x00\x08\x01\x01\x00\x00?\x00\xfb\xff\xd9"
)


def _make_tiff_bytes() -> bytes:
    # Tiny valid TIFF via PIL.
    from io import BytesIO

    from PIL import Image

    buf = BytesIO()
    Image.new("L", (2, 2), color=0).save(buf, format="TIFF")
    return buf.getvalue()


_TIFF_BYTES = _make_tiff_bytes()


@pytest.fixture
def fixtures_dir(tmp_path: Path) -> Path:
    d = tmp_path / "fixtures"
    d.mkdir()
    (d / "sample.pdf").write_bytes(_PDF_BYTES)
    (d / "sample.png").write_bytes(_PNG_BYTES)
    (d / "sample.jpg").write_bytes(_JPEG_BYTES)
    (d / "sample.tif").write_bytes(_TIFF_BYTES)
    (d / "sample.txt").write_bytes(b"this is plain text, no magic bytes\n")
    return d


class TestDetectMime:
    def test_pdf(self, fixtures_dir: Path) -> None:
        assert detect_mime(fixtures_dir / "sample.pdf") == "application/pdf"

    def test_png(self, fixtures_dir: Path) -> None:
        assert detect_mime(fixtures_dir / "sample.png") == "image/png"

    def test_jpeg(self, fixtures_dir: Path) -> None:
        assert detect_mime(fixtures_dir / "sample.jpg") == "image/jpeg"

    def test_tiff(self, fixtures_dir: Path) -> None:
        assert detect_mime(fixtures_dir / "sample.tif") == "image/tiff"


class TestSupportedSet:
    def test_supported_mimes_contents(self) -> None:
        assert {
            "application/pdf",
            "image/png",
            "image/jpeg",
            "image/tiff",
        } == set(SUPPORTED_MIMES)


class TestRequireSupported:
    def test_allows_supported(self) -> None:
        for m in SUPPORTED_MIMES:
            require_supported(m)  # no raise

    def test_rejects_unsupported(self) -> None:
        with pytest.raises(IXException) as ei:
            require_supported("text/plain")
        assert ei.value.code is IXErrorCode.IX_000_005
        assert "text/plain" in (ei.value.detail or "")