"""Small shared helpers: timestamps, hashing, semver, input validation."""
from __future__ import annotations

import hashlib
import re
from datetime import datetime, timezone
from pathlib import Path

PLUGIN_ID_RE = re.compile(r"^[a-z0-9][a-z0-9._-]{0,63}$")
VERSION_RE = re.compile(r"^[0-9A-Za-z][0-9A-Za-z.+-]{0,31}$")
SETTING_KEY_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9_.:-]{0,127}$")
USERNAME_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._-]{0,63}$")


def now_iso() -> str:
    return datetime.now(timezone.utc).isoformat(timespec="seconds")


def sha256_bytes(data: bytes) -> str:
    return hashlib.sha256(data).hexdigest()


def sha256_text(text: str) -> str:
    return hashlib.sha256(text.encode("utf-8")).hexdigest()


def sha256_file(path: Path) -> str:
    h = hashlib.sha256()
    with open(path, "rb") as f:
        for chunk in iter(lambda: f.read(1 << 20), b""):
            h.update(chunk)
    return h.hexdigest()


def semver_tuple(version: str) -> tuple[int, int, int]:
    """Best-effort numeric compare key: '1.10.0-beta' -> (1, 10, 0)."""
    parts: list[int] = []
    for p in version.split("."):
        digits = ""
        for ch in p:
            if ch.isdigit():
                digits += ch
            else:
                break
        parts.append(int(digits) if digits else 0)
    while len(parts) < 3:
        parts.append(0)
    return tuple(parts[:3])