# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""What an upload is decided to be, from its bytes and never its name."""

from __future__ import annotations

import pytest

from signal_bot.media_sniff import (
    AVIF,
    GIF,
    HEIC,
    HEIF,
    JPEG,
    KINDS,
    M4V,
    MOV,
    MP4,
    PNG,
    SVG,
    WEBM,
    WEBP,
    MediaKind,
    sniff,
)
from signal_bot.pack import MEDIA_TYPES


def _iso(brand: bytes) -> bytes:
    return b"\x00\x00\x00\x20ftyp" + brand + b"\x00\x00\x02\x00rest"


@pytest.mark.parametrize(
    ("payload", "expected"),
    [
        (b"\xff\xd8\xff\xe0JFIF", JPEG),
        (b"\x89PNG\r\n\x1a\n....", PNG),
        (b"GIF87a....", GIF),
        (b"GIF89a....", GIF),
        (b"RIFF\x00\x00\x00\x00WEBPVP8 ", WEBP),
        (b"\x1a\x45\xdf\xa3....", WEBM),
        (_iso(b"isom"), MP4),
        (_iso(b"mp42"), MP4),
        (_iso(b"qt  "), MOV),
        (_iso(b"M4V "), M4V),
        (_iso(b"heic"), HEIC),
        (_iso(b"HEIX"), HEIC),
        (_iso(b"mif1"), HEIF),
        (_iso(b"avif"), AVIF),
        (b'<?xml version="1.0"?><svg/>', SVG),
        (b"<svg xmlns='x'/>", SVG),
        (b"\xef\xbb\xbf  <svg/>", SVG),
    ],
)
def test_every_allowlisted_format_is_recognised(payload: bytes, expected: MediaKind) -> None:
    assert sniff(payload) is expected


@pytest.mark.parametrize(
    "payload",
    [
        b"",
        b"just some text",
        b"RIFF\x00\x00\x00\x00WAVEfmt ",  # RIFF, but not a picture
        b"RIFF",  # truncated before the form type
        b"%PDF-1.7",
        b"\x00\x00\x00\x20ftyq" + b"isom",  # "ftyq", not "ftyp"
        b"MZ\x90\x00",
    ],
)
def test_anything_off_the_allowlist_is_refused(payload: bytes) -> None:
    assert sniff(payload) is None


def test_a_jpeg_named_as_a_png_is_still_a_jpeg() -> None:
    """The filename is attacker-chosen and is never consulted."""
    assert sniff(b"\xff\xd8\xff\xe0evil.png") is JPEG


def test_every_kind_has_a_media_type_the_pack_knows() -> None:
    """The gap that takes startup down: ingested here, refused by pack_load.

    A file stored with a suffix MEDIA_TYPES does not carry uploads fine and
    then fails the *next* load, so this is the check that has to exist.
    """
    for kind in KINDS:
        assert kind.suffix in MEDIA_TYPES, kind.suffix
        assert MEDIA_TYPES[kind.suffix] == kind.media_type


def test_only_webm_and_svg_are_stored_unstripped() -> None:
    """kuhy's decision of 2026-08-31, pinned so it cannot spread silently."""
    unstrippable = {kind.suffix for kind in KINDS if not kind.strippable}
    assert unstrippable == {".webm", ".svg"}