"""Load backend/.env into os.environ without overwriting a real process environment."""
from __future__ import annotations

import os
from pathlib import Path

ENV_PATH = Path(__file__).resolve().parent / ".env"


def load_env_file(path: Path | None = None) -> None:
    target = path or ENV_PATH
    if not target.is_file():
        return
    for raw in target.read_text(encoding="utf-8").splitlines():
        line = raw.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, value = line.split("=", 1)
        key = key.strip()
        if not key or key in os.environ:
            continue
        value = value.strip()
        if len(value) >= 2 and value[0] == value[-1] and value[0] in {"'", '"'}:
            value = value[1:-1]
        os.environ[key] = value


def runtime_env() -> str:
    """development/test may use remote plaintext detect. production must not."""
    raw = (os.environ.get("KANSHO_ENV") or "").strip().lower()
    if raw in {"production", "prod"}:
        return "production"
    if raw in {"test", "testing"}:
        return "test"
    if raw in {"development", "dev"}:
        return "development"
    return "development"


def allows_remote_plaintext_detect() -> bool:
    return runtime_env() != "production"


def upsert_env_value(name: str, value: str, path: Path | None = None) -> None:
    """Write one key into backend/.env and the current process. Never log the value."""
    target = path or ENV_PATH
    name = name.strip()
    if not name:
        raise ValueError("empty env name")
    lines: list[str] = []
    if target.is_file():
        lines = target.read_text(encoding="utf-8").splitlines()
    found = False
    updated: list[str] = []
    prefix = f"{name}="
    for line in lines:
        stripped = line.strip()
        if stripped.startswith(prefix) or stripped.startswith(f"{name} ="):
            updated.append(f"{name}={value}")
            found = True
        else:
            updated.append(line)
    if not found:
        if updated and updated[-1] != "":
            updated.append("")
        updated.append(f"{name}={value}")
    target.write_text("\n".join(updated) + "\n", encoding="utf-8")
    os.environ[name] = value