"""Static checks: translation keys and preference defaults stay in sync."""

from __future__ import annotations

import json
import re
from pathlib import Path

APP_ROOT = Path(__file__).resolve().parents[1]
SRC_DIR = APP_ROOT / "src"
LOCALES_DIR = APP_ROOT / "config" / "locales"
DEFAULTS_JSON = APP_ROOT / "config" / "preferences.default.json"

REPO_ROOT = APP_ROOT.parents[1]
STORE_PY = REPO_ROOT / "shared" / "src" / "orisys_app_shared" / "prefs" / "store.py"

_T_CALL = re.compile(r"""\bt\(\s*["']([A-Za-z0-9_.]+)["']""")
_DEFAULT_BLOCK = re.compile(r"_DEFAULTS[^=]*=\s*\{(?P<body>.*?)\n\}", re.DOTALL)
_KEY = re.compile(r"""["']([A-Za-z0-9_]+)["']\s*:""")


def _load_locale(name: str) -> dict:
    return json.loads((LOCALES_DIR / f"{name}.json").read_text(encoding="utf-8"))


def _flatten(data: dict, prefix: str = "") -> set[str]:
    keys: set[str] = set()
    for key, value in data.items():
        dotted = f"{prefix}{key}"
        if isinstance(value, dict):
            keys |= _flatten(value, f"{dotted}.")
        else:
            keys.add(dotted)
    return keys


def _referenced_keys() -> set[str]:
    found: set[str] = set()
    for path in sorted(SRC_DIR.rglob("*.py")):
        found |= set(_T_CALL.findall(path.read_text(encoding="utf-8")))
    return found


def test_locales_parity_and_used_keys():
    zh = _flatten(_load_locale("zh_CN"))
    en = _flatten(_load_locale("en_US"))

    assert zh == en, {
        "zh_only": sorted(zh - en),
        "en_only": sorted(en - zh),
    }

    referenced = _referenced_keys()
    assert referenced, "no t() calls found — the source scan is broken"
    missing = sorted(key for key in referenced if key not in zh)
    assert not missing, f"t() keys missing from locale files: {missing}"


def test_preference_defaults_match_store_defaults():
    json_keys = set(json.loads(DEFAULTS_JSON.read_text(encoding="utf-8")))
    source = STORE_PY.read_text(encoding="utf-8")
    match = _DEFAULT_BLOCK.search(source)
    assert match, "could not locate _DEFAULTS in prefs/store.py"
    store_keys = set(_KEY.findall(match.group("body")))

    assert json_keys == store_keys, {
        "json_only": sorted(json_keys - store_keys),
        "store_only": sorted(store_keys - json_keys),
    }


def test_locale_files_are_valid_utf8_json():
    for name in ("zh_CN", "en_US"):
        data = _load_locale(name)
        assert isinstance(data, dict)
        assert data.get("app", {}).get("title")


#: Sequences that only ever appear when UTF-8 text was decoded as a single-byte
#: codepage and then re-encoded. A ``Get-Content -Raw | Set-Content`` round trip
#: in Windows PowerShell does exactly that and silently mangles every non-ASCII
#: string, which is how the Chinese UI once ended up unreadable.
#:
#: Written as escapes, with no literal examples in the comments, so that this
#: guard cannot itself be corrupted by the same mistake.
_MOJIBAKE = (
    "\u00c3",
    "\u00c2",
    "\u00e2\u20ac",
    "\u00e3\u20ac",
    "\u00ef\u00bf\u00bd",
)


def test_locale_files_are_utf8_without_bom_and_not_mojibake():
    for name in ("zh_CN", "en_US"):
        path = LOCALES_DIR / f"{name}.json"
        raw = path.read_bytes()
        assert not raw.startswith(b"\xef\xbb\xbf"), f"{name}.json starts with a BOM"
        text = raw.decode("utf-8")  # raises if it is not valid UTF-8

        for sequence in _MOJIBAKE:
            assert sequence not in text, (
                f"{name}.json contains {sequence!r}: the file was decoded with the "
                "wrong encoding. Rewrite it with an explicit UTF-8 writer instead "
                "of a PowerShell Get-Content/Set-Content round trip."
            )


def test_chinese_locale_actually_contains_chinese():
    """A corrupted zh_CN.json still parses as JSON, so check the content."""
    data = _load_locale("zh_CN")
    for key in ("menu/theme_dark", "app/about_title", "chart/mode_follow"):
        node = data
        for part in key.split("/"):
            node = node[part]
        assert any("\u4e00" <= char <= "\u9fff" for char in node), (
            f"zh_CN.{key} has no Chinese characters: {node!r}"
        )