"""Bundled assets referenced by CSS must actually exist and be servable.

A missing font file does not raise anything -- the browser quietly renders the
fallback stack, which looks like a design choice rather than a broken build.
"""

import re
from pathlib import Path

import pytest

from core import config
from core.serve import serve

COMPOSER_CSS = config.APP_DIR / "ui" / "composer" / "composer.css"
URL_PREFIX = config.UI_PREFIX + "/app/"

FONTS_CSS = config.APP_DIR / "ui" / "composer" / "tokens" / "fonts.css"


def font_urls():
    """Every font the frontend declares."""
    return re.findall(r"url\('([^']+)'\)", FONTS_CSS.read_text())


def test_fonts_css_is_imported_first():
    # Faces have to be declared before any rule uses the family, and tokens.css
    # names them immediately.
    imports = re.findall(r'@import\s+"([^"]+)"', COMPOSER_CSS.read_text())
    assert imports and imports[0] == "./tokens/fonts.css", imports


def test_there_are_faces_at_all():
    assert len(font_urls()) >= 1


@pytest.mark.parametrize("url", font_urls())
def test_every_declared_face_resolves_to_a_servable_file(url):
    assert url.startswith(URL_PREFIX), f"{url} is not under {URL_PREFIX}"
    tail = url[len(URL_PREFIX):]
    served = serve(config.APP_DIR, tail, config.APP_EXTS)
    assert served.status == 200, f"{url} -> {served.status}"
    assert served.content_type == "font/woff2"
    assert served.body[:4] == b"wOF2", "not a woff2 file"


def test_fonts_are_cacheable_but_code_is_not():
    # A font filename encodes family, weight range and subset, so its bytes
    # never change -- but everything else must not be cached, because the editor
    # is edited while it is running.
    font = serve(config.APP_DIR, font_urls()[0][len(URL_PREFIX):], config.APP_EXTS)
    assert "immutable" in font.headers["Cache-Control"]

    code = serve(config.APP_DIR, "ui/boot.js", config.APP_EXTS)
    assert code.headers["Cache-Control"] == "no-cache" and code.headers["ETag"]      # kept, but asked about every time


def test_cache_headers_are_not_shared_between_responses():
    # Served.headers is a mutable dict handed to callers; two responses must not
    # end up pointing at the same one.
    a = serve(config.APP_DIR, "ui/boot.js", config.APP_EXTS)
    b = serve(config.APP_DIR, "ui/boot.js", config.APP_EXTS)
    a.headers["X-Test"] = "1"
    assert "X-Test" not in b.headers


def test_every_bundled_font_is_actually_referenced():
    # The reverse direction: a font file nothing declares is dead weight in the
    # repo, and usually means a face was renamed and its file left behind.
    declared = {Path(u).name for u in font_urls()}
    on_disk = {p.name for p in (config.APP_DIR / "assets" / "fonts").glob("*.woff2")}
    assert on_disk - declared == set(), f"unreferenced: {sorted(on_disk - declared)}"


def declared_families():
    return set(re.findall(r"font-family:\s*'([^']+)'", FONTS_CSS.read_text()))


def test_each_family_ships_its_licence():
    # SIL OFL: the licence has to travel with the fonts we redistribute, so a
    # newly bundled family without its OFL.txt is a licence violation, not a
    # tidiness problem.
    fonts_dir = config.APP_DIR / "assets" / "fonts"
    for family in declared_families():
        licence = fonts_dir / f"OFL-{family.replace(' ', '')}.txt"
        assert licence.is_file(), f"{family} is bundled without {licence.name}"
        assert "SIL OPEN FONT LICENSE" in licence.read_text().upper()