'use strict';

const Table = require('../models');
const {User, AuthToken} = Table.models;
const {ApiToken} = require('./api_token');

/**
 * Auth Model
 *
 * Handles authentication operations for the application.
 * Manages user login, token validation, and logout processes.
 *
 * Dependencies:
 * - User model: Validates user credentials
 * - AuthToken model: Creates and manages authentication tokens
 *
 * All methods throw standardized login errors on failure to avoid
 * leaking information about whether usernames exist or tokens are valid.
 */
class Auth{
	/**
	 * Standardized error responses for authentication failures.
	 * Returns generic "Invalid Credentials" message for security.
	 */
	static errors = {
		login: function(){
			let error = new Error('LoginFailed');
			error.name = 'LoginFailed';
			error.message = `Invalid Credentials, login failed.`;
			error.status = 401;

			return error;
		}
	}

	/**
	 * Authenticate user and create session token.
	 *
	 * @param {Object} data - Login credentials {username, password}
	 * @returns {Object} {user, token} - User object and auth token
	 * @throws {Error} Generic login error on any failure
	 *
	 * Flow:
	 * 1. Validate credentials via User.login()
	 * 2. Create new AuthToken for the user
	 * 3. Return both user data and token
	 */
	static async login(data){
		try{
			let user = await User.login(data);
			// Backends may attach group membership to the user (LDAP); default
			// to none for local/redis users.
			let groups = Array.isArray(user.groups) ? user.groups : [];
			let token = await AuthToken.create({username: user.username, groups});

			return {user, token}
		}catch(error){
			console.log('login error', error);
			throw this.errors.login();
		}
	}

	/**
	 * Establish a session for an OIDC-authenticated identity: JIT-provision the
	 * local user (redis-backed) and mint an AuthToken carrying the SSO groups.
	 *
	 * @param {Object} identity - {username, groups} from utils/oidc claims
	 * @returns {Object} {user, token}
	 */
	static async oidcSession(identity){
		let user = typeof User.upsertOidc === 'function'
			? await User.upsertOidc(identity)
			: await User.get(identity.username);
		let token = await AuthToken.create({
			username: user.username,
			groups: identity.groups || [],
		});

		return {user, token};
	}

	/**
	 * Validate an authentication token.
	 *
	 * @param {string} token - Token string to validate
	 * @returns {Object} Token object if valid
	 * @throws {Error} Generic login error if token invalid or expired
	 *
	 * Checks:
	 * 1. Token exists in database
	 * 2. Token has not expired (via token.check())
	 */
	static async checkToken(token){
		try{
			token = await AuthToken.get(token);
			if(token && token.check()) return token;

			throw this.errors.login();
		}catch(error){
			console.log('check error', error);
			throw this.errors.login();
		}
	}

	/**
	 * Validate an `Authorization: Bearer prx_<id>_<secret>` API token.
	 *
	 * Returns the authenticated ApiToken record (with created_by + the
	 * mint-time groups snapshot); middleware/auth.js wraps it into the
	 * req.token shape the authz layer expects. Every failure collapses to the
	 * same generic login 401 — no leak of existence / wrong secret / expired.
	 */
	static async checkApiToken(raw){
		try{
			return await ApiToken.authenticate(raw);
		}catch(error){
			console.log('api-token check error', error);
			throw this.errors.login();
		}
	}

	/**
	 * Destroy an authentication token (logout).
	 *
	 * @param {string} data - Token string to destroy
	 * @returns {void}
	 *
	 * Removes token from database, invalidating the session.
	 */
	static async logout(data){
		let token = await AuthToken.get(data);
		await token.destroy();
	}
}

module.exports = {Auth};