<?php
/** @license MIT
 * Copyright 2017 J. King, Dustin Wilson et al.
 * See LICENSE and AUTHORS files for details */

declare(strict_types=1);
namespace JKingWeb\Arsse\REST\Fever;

use JKingWeb\Arsse\Arsse;
use JKingWeb\Arsse\Database;
use JKingWeb\Arsse\User;
use JKingWeb\Arsse\Service;
use JKingWeb\Arsse\Context\Context;
use JKingWeb\Arsse\Misc\ValueInfo;
use JKingWeb\Arsse\AbstractException;
use JKingWeb\Arsse\Db\ExceptionInput;
use JKingWeb\Arsse\Feed\Exception as FeedException;
use JKingWeb\Arsse\REST\Target;
use JKingWeb\Arsse\REST\Exception404;
use JKingWeb\Arsse\REST\Exception405;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use Zend\Diactoros\Response\JsonResponse;
use Zend\Diactoros\Response\EmptyResponse;

class API extends \JKingWeb\Arsse\REST\AbstractHandler {
    const LEVEL = 3;

    public function __construct() {
    }

    public function dispatch(ServerRequestInterface $req): ResponseInterface {
        $inR = $req->getQueryParams();
        $inW = $req->getParsedBody();
        if (!array_key_exists("api", $inR)) {
            // the original would have shown the Fever UI in the absence of the "api" parameter, but we'll return 404
            return new EmptyResponse(404);
        }
        $xml = $inR['api'] === "xml";
        switch ($req->getMethod()) {
            case "OPTIONS":
                // do stuff
                break;
            case "POST":
                if (strlen($req->getHeaderLine("Content-Type")) && $req->getHeaderLine("Content-Type") !== "application/x-www-form-urlencoded") {
                    return new EmptyResponse(415, ['Accept' => "application/x-www-form-urlencoded"]);
                }
                $out = [
                    'api_version' => self::LEVEL,
                    'auth' => 0,
                ];
                if ($req->getAttribute("authenticated", false)) {
                    // if HTTP authentication was successfully used, set the expected user ID
                    Arsse::$user->id = $req->getAttribute("authenticatedUser");
                    $out['auth'] = 1;
                } elseif (Arsse::$conf->userHTTPAuthRequired || Arsse::$conf->userPreAuth || $req->getAttribute("authenticationFailed", false)) {
                    // otherwise if HTTP authentication failed or is required, deny access at the HTTP level
                    return new EmptyResponse(401);
                }
                // check that the user specified credentials
                if ($this->logIn(strtolower($inW['api_key'] ?? ""))) {
                    $out['auth'] = 1;
                } else {
                    $out['auth'] = 0;
                    return $this->formatResponse($out, $xml);
                }
                // handle each possible parameter
                # do stuff
                // return the result
                return $this->formatResponse($out, $xml);
                break;
            default:
                return new EmptyResponse(405, ['Allow' => "OPTIONS,POST"]);
        }
    }

    protected function formatResponse(array $data, bool $xml): ResponseInterface {
        if ($xml) {
            throw \Exception("Not implemented yet");
        } else {
            return new JsonResponse($data, 200, [], \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE);
        }
    }

    protected function logIn(string $hash): bool {
        // if HTTP authentication was successful and sessions are not enforced, proceed unconditionally
        if (isset(Arsse::$user->id) && !Arsse::$conf->userSessionEnforced) {
            return true;
        }
        try {
            // verify the supplied hash is valid
            $s = Arsse::$db->TokenLookup("fever.login", $hash);
        } catch (\JKingWeb\Arsse\Db\ExceptionInput $e) {
            return false;
        }
        // set the user name
        Arsse::$user->id = $s['user'];
        return true;
    }

    public static function registerUser(string $user, string $password = null): string {
        $password = $password ?? Arsse::$user->generatePassword();
        $hash = md5("$user:$password");
        $tr = Arsse::$db->begin();
        Arsse::$db->tokenRevoke($user, "fever.login");
        Arsse::$db->tokenCreate($user, "fever.login", $hash);
        $tr->commit();
        return $password;
    }

    public static function unregisterUser(string $user): bool {
        return (bool) Arsse::$db->tokenRevoke($user, "fever.login");
    }
}