<?php
declare(strict_types=1);
/**
 * SFU join API — POST /api/join
 *
 * Client sends: { room_id, jsep: { type: "offer", sdp: "..." }, role: "publisher"|"subscriber" }
 * Server relays to Janus VideoRoom, returns: { jsep: { type: "answer", sdp: "..." }, handle_id, session_id }
 *
 * Client subsequently maintains a WebSocket to Janus directly (proxied via nginx /sfu/ws).
 */
require_once dirname(__DIR__, 2) . '/src/bootstrap.php';

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    sfuJsonErr('method not allowed', 405);
}

$user  = sfuRequireAuth();
$input = json_decode(file_get_contents('php://input'), true) ?? [];

$janusRoomId = (int) ($input['room_id'] ?? 0);
$jsep        = $input['jsep'] ?? null;
$role        = in_array($input['role'] ?? '', ['publisher', 'subscriber'], true)
             ? $input['role'] : 'publisher';

if (!$janusRoomId) { sfuJsonErr('room_id required'); }
if (!$jsep || empty($jsep['sdp'])) { sfuJsonErr('jsep.sdp required'); }

$repo  = new \AndroidCast\Sfu\SfuRoomRepository(sfuPdo());
$janus = janusClient();

$room = $repo->getByJanusId($janusRoomId);
if (!$room) { sfuJsonErr('room not found', 404); }

/* Create a fresh Janus session + handle for this participant */
$sid = $janus->createSession();
if (!$sid) { sfuJsonErr('Janus session failed'); }
$hid = $janus->attachVideoRoom($sid);
if (!$hid) { sfuJsonErr('Janus attach failed'); }

/* Send join + offer to Janus */
$joinBody = [
    'request'  => 'join',
    'room'     => $janusRoomId,
    'ptype'    => $role === 'publisher' ? 'publisher' : 'subscriber',
    'display'  => $user['email'] ?? 'anon',
];
$resp = $janus->sendJsep($sid, $hid, $joinBody, [
    'type' => $jsep['type'],
    'sdp'  => $jsep['sdp'],
]);

/* Record participant in DB */
$participantId = $repo->joinRoom(
    (int) $room['id'],
    (int) $user['id'],
    $hid,
    $role
);

/* Return negotiated JSEP answer + WS connection details */
$answer = $resp['jsep'] ?? null;
sfuJsonOk([
    'session_id'     => $sid,
    'handle_id'      => $hid,
    'participant_id' => $participantId,
    'jsep'           => $answer,
    'ws_url'         => '/app/androidcast_project/sfu/ws',
]);