import { jwtVerify } from "jose";

// Secret key for JWT verification (must match the one used for signing)
const JWT_SECRET = new TextEncoder().encode(process.env.JWT_SECRET);

export interface JWTPayload {
  email: string;
  role: string;
  iat: number;
  exp: number;
}

/**
 * Validates a JWT token and returns the payload if valid
 */
export async function validateToken(token: string): Promise<JWTPayload | null> {
  try {
    const { payload } = await jwtVerify(token, JWT_SECRET);
    return payload as unknown as JWTPayload;
  } catch (error) {
    console.error("Token validation error:", error);
    return null;
  }
}

/**
 * Checks if a token is expired
 */
export function isTokenExpired(payload: JWTPayload): boolean {
  const currentTime = Math.floor(Date.now() / 1000);
  return payload.exp < currentTime;
}

/**
 * Gets token expiration time in a human-readable format
 */
export function getTokenExpirationTime(payload: JWTPayload): Date {
  return new Date(payload.exp * 1000);
}

/**
 * Gets time until token expires in seconds
 */
export function getTimeUntilExpiration(payload: JWTPayload): number {
  const currentTime = Math.floor(Date.now() / 1000);
  return Math.max(0, payload.exp - currentTime);
}