type ContextStore = Record<string, any>;

const contextStack: ContextStore[] = [];
const defaultContext: ContextStore = {};

export function setDefaultContext(context: ContextStore) {
  Object.assign(defaultContext, context);
}

export function withContext<T>(context: ContextStore, fn: () => T): T {
  contextStack.push(context);
  try {
    return fn();
  } finally {
    contextStack.pop();
  }
}

export const ctx = new Proxy(
  {},
  {
    get(_, prop: string) {
      for (let i = contextStack.length - 1; i >= 0; i--) {
        if (prop in contextStack[i]) return contextStack[i][prop];
      }
      if (prop in defaultContext) return defaultContext[prop]; // ✅ Fallback to default
      throw new Error(`Context variable '${prop}' is not defined.`);
    },
  },
) as Record<string, any>;

export function getContext() {
  return ctx;
}