<?php

declare(strict_types=1);

namespace authkit2\Http\Controllers;

use Illuminate\Http\Request;
use authkit2\Models\Token;

/**
 * Methods for handling user authentication operations.
 */
class AuthenticationController extends Controller
{
	/**
	 * OIDC flow to mediate the actual login process and exchanges.
	 * @var \authkit2\Oidc\Flows\UserFlow
	 */
	protected $user_flow;

	public function __construct(\authkit2\Oidc\Flows\UserFlow $user_flow)
	{
		$this->user_flow = $user_flow;
	}

	/**
	 * Start the login flow for a user.
	 *
	 * Redirects the user to the SSO service
	 *
	 * @return mixed
	 */
	public function login()
	{
		// TODO: Pass in 'previous' URL from session so we can redirect back
		// if we were redirected to login from a guard?
		return redirect($this->user_flow->getRedirectUrl(config('authkit.authn.openid.redirect_uri'), config('authkit.authn.scopes')));
	}

	/**
	 * Handle the response from the SSO service.
	 *
	 * Exchange the code for a token and fetches basic user information.
	 * Attempts to log the user into this app, and creates them if they
	 * don't exist. Then redirects the user to the configured post_login url.
	 *
	 * @param  Request $request
	 * @return mixed
	 */
	public function callback(Request $request)
	{
		$user_class = (string)config('auth.providers.users.model');

		// Verify the passed in state value
		$this->user_flow->validateState($request->state);

		// TODO: Check for error response

		// Exchange the code for a token
		$oidc_token = $this->user_flow->exchangeCodeForToken($request->code, config('authkit.authn.openid.redirect_uri'));
		$user_info = $oidc_token->getUserInfo();

		// Try and find a token for that user id
		$token = Token::where('id', $oidc_token->getUserId())->first();

		// If that failed
		if (!isset($token))
		{
			// No token for that user, either create them or migrate
			$register_event_result = event(new \authkit2\Events\UserRegistration(null, $user_info));

			if (sizeof($register_event_result) == 0)
			{
				// If there were no register event handlers then just assume we're using laravel default
				// stuff and create a user for them.
				$user = new $user_class();
				$user->name = $user_info['name'];
				$user->email = $user_info['email'];
				$user->save();
			}
			else
			{
				// Otherwise, expect one returned by the event handlers.
				$user = null;
				foreach ($register_event_result as $result)
				{
					if (is_object($result))
					{
						$user = $result;
					}
				}
			}

			// TODO: Log a useful error message in these cases
			if (!isset($user))
			{
				abort(500);
				// We die() after each abort to help the static analyzer (phan)
				// along, otherwise it doesn't realize that abort ends execution
				// and is worried that we've hit the below code in an invalid state.
				die();
			}
			elseif (!method_exists($user, 'save'))
			{
				abort(500);
				die();
			}
			elseif (!method_exists($user, 'getAuthIdentifierName'))
			{
				abort(500);
				die();
			}

			$token = new Token();
			$token->id = $oidc_token->getUserId();
			$token->access_token = $oidc_token->getAccessToken();
			$refresh_token = $oidc_token->getRefreshToken();
			if (!isset($refresh_token))
			{
				abort(500);
				die();
			}
			$token->refresh_token = $refresh_token;
			$token->user_id = $user->{$user->getAuthIdentifierName()};
			$token->save();
		}
		else
		{
			$user = new $user_class();
			$user = $user_class::where($user->getAuthIdentifierName(), $token->user_id)->first();
		}

		\Auth::login($user);
		$login_event_result = event(new \authkit2\Events\UserLogin($user, $user_info));
		if (!sizeof($login_event_result))
		{
			if (!isset($user) || !method_exists($user, 'save'))
			{
				// TODO: Log a useful error message
				abort(500);
				die();
			}
			// If nothing handled the login event, assume we're using laravel default
			// everything and just go ahead and update the name/email
			$user->name = $user_info['name'];
			$user->email = $user_info['email'];
			$user->save();
		}

		return redirect(url(config('authkit.authn.urls.post_login')));
	}

	/**
	 * Explicitly log out of this application and the SSO service.
	 *
	 * @return mixed
	 */
	public function logout()
	{
		event(new \authkit2\Events\UserLogout(\Auth::user()));
		// Log out locally
		\Auth::logout();
		// Redirect to log out remotely as well
		return redirect($this->user_flow->getLogoutUrl(url(config('authkit.authn.urls.post_logout'))));
	}
}