"""Read and write a plain-text pngx.env credential file alongside the database."""
from pathlib import Path


def _path() -> Path:
    from .config import get_config
    return Path(get_config().db_path).parent / "pngx.env"


def read() -> dict[str, str]:
    """Return all key=value pairs from pngx.env, ignoring comments/blanks."""
    p = _path()
    if not p.exists():
        return {}
    result: dict[str, str] = {}
    for line in p.read_text().splitlines():
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        if "=" in line:
            key, _, value = line.partition("=")
            result[key.strip()] = value.strip()
    return result


def write(updates: dict[str, str]) -> None:
    """Merge updates into pngx.env, preserving unrelated existing lines."""
    p = _path()
    lines: list[str] = []
    key_to_line: dict[str, int] = {}

    if p.exists():
        for i, line in enumerate(p.read_text().splitlines()):
            stripped = line.strip()
            if stripped and not stripped.startswith("#") and "=" in stripped:
                k, _, _ = stripped.partition("=")
                key_to_line[k.strip()] = i
            lines.append(line)

    for key, value in updates.items():
        if key in key_to_line:
            lines[key_to_line[key]] = f"{key}={value}"
        else:
            lines.append(f"{key}={value}")

    p.write_text("\n".join(lines) + "\n")


def replica_keys(name: str) -> tuple[str, str]:
    """Return the env var names for a replica (URL key, token key)."""
    safe = name.upper().replace(" ", "_").replace("-", "_")
    return f"REPLICA_{safe}_URL", f"REPLICA_{safe}_TOKEN"