"""Tests for the public-landing locale loader and language detection."""
from __future__ import annotations

import pytest

from app.services.locales import (
    ACTIVE_PUBLIC_LANGS,
    DEFAULT_LANG,
    detect_public_lang,
    get_locale,
    load_locales,
)


# ---------------------------------------------------------------------------
# YAML loading
# ---------------------------------------------------------------------------


def test_locales_load_all_active_languages():
    """Every code in ACTIVE_PUBLIC_LANGS must have a YAML file and
    return a usable dict — keeps deploys honest when a new language
    is added to the list but the YAML is missing."""
    load_locales()
    for lang in ACTIVE_PUBLIC_LANGS:
        t = get_locale(lang)
        assert t, f"no copy loaded for {lang}"


def test_locale_dotted_access():
    """Templates use {{ t.hero.subhead }} syntax — the wrapper must
    expose nested dotted access through the whole tree."""
    t = get_locale("en")
    assert isinstance(t.hero.tagline, str)
    assert isinstance(t.features.news.title, str)
    assert isinstance(t.not_strip.items, list)
    assert t.not_strip.items[0]  # non-empty


def test_unknown_locale_falls_back_to_default():
    t = get_locale("zz")
    # Same shape as the default — the lookup should hand back the
    # default locale, not raise.
    assert hasattr(t, "hero") or t == {}


def test_en_and_it_have_matching_top_level_keys():
    """Translation parity check — both languages must define the
    same top-level sections. Lets a missing IT section show up in
    CI rather than as a 500 on the live page."""
    en_keys = set(iter(get_locale("en")))
    it_keys = set(iter(get_locale("it")))
    assert en_keys == it_keys


# ---------------------------------------------------------------------------
# detect_public_lang precedence chain
# ---------------------------------------------------------------------------


def test_detect_user_lang_wins_over_everything():
    """A logged-in user's stored preference is the highest-priority
    signal — never overridden by detection on a public surface."""
    lang = detect_public_lang(
        cookie_lang="it",
        accept_language="fr,fr-FR;q=0.9",
        cf_country="DE",
        user_lang="en",
    )
    assert lang == "en"


def test_detect_cookie_wins_over_header_and_geo():
    lang = detect_public_lang(
        cookie_lang="it",
        accept_language="en-US",
        cf_country="DE",
        user_lang=None,
    )
    assert lang == "it"


def test_detect_accept_language_first_subtag():
    """Accept-Language is parsed to its base subtag — 'en-GB' resolves
    to 'en'. Falls through cookie (None) to header."""
    lang = detect_public_lang(
        cookie_lang=None,
        accept_language="en-GB,en;q=0.9,it;q=0.5",
        cf_country=None,
        user_lang=None,
    )
    assert lang == "en"


def test_detect_geolocation_when_no_other_signal():
    lang = detect_public_lang(
        cookie_lang=None,
        accept_language=None,
        cf_country="IT",
        user_lang=None,
    )
    assert lang == "it"


def test_detect_default_when_nothing_matches():
    """Falls through to DEFAULT_LANG when no signal returns a code
    in ACTIVE_PUBLIC_LANGS. e.g. a French browser hitting from a
    German IP — neither lang is in our active set, default wins."""
    lang = detect_public_lang(
        cookie_lang=None,
        accept_language="fr-FR,fr;q=0.9",
        cf_country="DE",
        user_lang=None,
    )
    assert lang == DEFAULT_LANG


def test_detect_invalid_cookie_ignored():
    """A cookie pointing at a language we don't support shouldn't
    derail detection — fall through to the next signal."""
    lang = detect_public_lang(
        cookie_lang="zz",
        accept_language="it",
        cf_country=None,
        user_lang=None,
    )
    assert lang == "it"


def test_detect_empty_inputs_default():
    lang = detect_public_lang(
        cookie_lang=None,
        accept_language=None,
        cf_country=None,
        user_lang=None,
    )
    assert lang == DEFAULT_LANG