"""Поиск системных шрифтов (в т.ч. с кириллицей)."""
from __future__ import annotations

import subprocess
from functools import lru_cache
from pathlib import Path

SEARCH_DIRS = [
    Path(__file__).resolve().parent / "assets" / "fonts",  # шрифты, вложенные в проект
    Path("/usr/share/fonts"),
    Path("/usr/local/share/fonts"),
    Path.home() / ".local/share/fonts",
    Path("/Library/Fonts"),
    Path("/System/Library/Fonts"),
    Path("C:/Windows/Fonts"),
]

ALIASES = {
    "serif": "DejaVuSerif",
    "serif-bold": "DejaVuSerif-Bold",
    "serif-italic": "DejaVuSerif-Italic",
    "serif-bolditalic": "DejaVuSerif-BoldItalic",
    "sans": "DejaVuSans",
    "sans-bold": "DejaVuSans-Bold",
    "sans-italic": "DejaVuSans-Oblique",
    "sans-bolditalic": "DejaVuSans-BoldOblique",
    "mono": "DejaVuSansMono",
}


@lru_cache(maxsize=1)
def _index() -> dict[str, str]:
    idx: dict[str, str] = {}
    for d in SEARCH_DIRS:
        if not d.exists():
            continue
        for f in d.rglob("*"):
            if f.suffix.lower() in (".ttf", ".otf", ".ttc"):
                idx.setdefault(f.stem.lower(), str(f))
                idx.setdefault(f.name.lower(), str(f))
    return idx


def _fallback() -> str:
    idx = _index()
    for key in ("dejavusans", "dejavuserif", "liberationsans", "notosans",
                "arial", "arialunicode"):
        if key in idx:
            return idx[key]
    return next(iter(idx.values()), "")


@lru_cache(maxsize=256)
def find_font(name: str | None) -> str:
    """Вернуть путь к файлу шрифта по имени или алиасу."""
    name = (name or "sans").strip()
    p = Path(name)
    if p.is_absolute() and p.exists():
        return str(p)

    key = ALIASES.get(name.lower(), name).lower()
    idx = _index()

    if key in idx:
        return idx[key]
    if key + ".ttf" in idx:
        return idx[key + ".ttf"]

    # частичное совпадение
    matches = [v for k, v in idx.items() if key in k]
    if matches:
        return matches[0]

    # спросим fontconfig
    try:
        out = subprocess.run(
            ["fc-match", "-f", "%{file}", name],
            capture_output=True, text=True, timeout=10,
        )
        path = out.stdout.strip()
        if path and Path(path).exists():
            return path
    except Exception:
        pass

    return _fallback()