"""Shared .env read/write helpers (UTF-8 LF, quoted values)."""

from __future__ import annotations

import re
from pathlib import Path

from server.utils.text_io import read_utf8_text, write_utf8_lf

_ENV_KEY_RE = re.compile(r"^([A-Z0-9_]+)=(.*)$")


def escape_env_value(value: str) -> str:
    escaped = value.replace("\\", "\\\\").replace('"', '\\"').replace("\n", "\\n")
    return f'"{escaped}"'


def read_env_var(path: Path, key: str) -> str | None:
    """Return unquoted value for key, or None if missing/empty."""
    if not path.is_file():
        return None
    for line in read_utf8_text(path).splitlines():
        m = _ENV_KEY_RE.match(line.strip())
        if not m or m.group(1) != key:
            continue
        raw = m.group(2).strip()
        if not raw:
            return None
        if len(raw) >= 2 and raw[0] == raw[-1] == '"':
            inner = raw[1:-1]
            return inner.replace("\\n", "\n").replace('\\"', '"').replace("\\\\", "\\")
        return raw
    return None


def upsert_env_vars(path: Path, updates: dict[str, str]) -> bool:
    """Upsert keys in a .env file. Creates file if missing. Returns True if written."""
    if not updates:
        return False

    lines: list[str] = []
    if path.is_file():
        lines = read_utf8_text(path).splitlines()

    seen: set[str] = set()
    out: list[str] = []
    for line in lines:
        m = _ENV_KEY_RE.match(line.strip())
        if m and m.group(1) in updates:
            key = m.group(1)
            out.append(f"{key}={escape_env_value(updates[key])}")
            seen.add(key)
        else:
            out.append(line)

    for key, value in updates.items():
        if key not in seen:
            out.append(f"{key}={escape_env_value(value)}")

    path.parent.mkdir(parents=True, exist_ok=True)
    body = "\n".join(out)
    if body and not body.endswith("\n"):
        body += "\n"
    write_utf8_lf(path, body)
    return True