#级联配置解析

let overrides: OverrideTree = {};

export function setConfigOverride(pathRaw: string, value: unknown): {
  ok: boolean;
  error?: string;
} {
  const parsed = parseConfigPath(pathRaw);
  if (!parsed.ok || !parsed.path) {
    return { ok: false, error: parsed.error ?? "Invalid path." };
  }
  setConfigValueAtPath(overrides, parsed.path, sanitizeOverrideValue(value));
  return { ok: true };
}

function mergeOverrides(base: unknown, override: unknown): unknown {
  if (!isPlainObject(base) || !isPlainObject(override)) {
    return override; // 非对象：完全替换
  }
  const next: OverrideTree = { ...base };
  for (const [key, value] of Object.entries(override)) {
    if (value === undefined || isBlockedObjectKey(key)) {
      continue; // 跳过 undefined 和原型污染键
    }
    next[key] = mergeOverrides((base as OverrideTree)[key], value);
  }
  return next;
}

const BLOCKED_KEYS = new Set([
  "__proto__",
  "constructor",
  "prototype",
]);

export function isBlockedObjectKey(key: string): boolean {
  return BLOCKED_KEYS.has(key);
}