<?php
// Multiplayer noughts & crosses.
require_once __DIR__ . '/mplib.php';
$me = require_login();
$uid = (int)$me['id'];
$SELF = '/games/ttt.php';

function ttt_win(array $b): ?string {
    $lines = [[0,1,2],[3,4,5],[6,7,8],[0,3,6],[1,4,7],[2,5,8],[0,4,8],[2,4,6]];
    foreach ($lines as $l) {
        if ($b[$l[0]] !== '' && $b[$l[0]] === $b[$l[1]] && $b[$l[1]] === $b[$l[2]]) return $b[$l[0]];
    }
    return null;
}

$msg = '';
$mid = (int)($_GET['g'] ?? 0);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    require_csrf();
    $act = $_POST['act'] ?? '';
    if ($act === 'create') {
        $mid = mp_create('ttt', $uid, json_encode(['b' => array_fill(0, 9, '')]));
        redirect($SELF, ['g' => $mid]);
    }
    if ($act === 'move') {
        $mid = (int)($_POST['mid'] ?? 0);
        $m = mp_get('ttt', $mid);
        $seat = $m ? mp_seat($m, $uid) : 0;
        if (!$m || $m['status'] !== 'playing') $msg = 'Game is not in play.';
        elseif ($seat === 0) $msg = 'You are not in this game.';
        elseif ($seat !== (int)$m['turn']) $msg = 'Not your turn.';
        else {
            $st = json_decode($m['state'], true);
            $cell = (int)($_POST['cell'] ?? 0) - 1;   // players type 1-9
            if ($cell < 0 || $cell > 8 || $st['b'][$cell] !== '') {
                $msg = 'That square is not free (pick 1-9).';
            } else {
                $mark = $seat === 1 ? 'X' : 'O';
                $st['b'][$cell] = $mark;
                $w = ttt_win($st['b']);
                $full = !in_array('', $st['b'], true);
                if ($w !== null) {
                    mp_save($mid, json_encode($st), $seat, 'done', $uid);
                    db()->prepare("INSERT INTO scores (game,user_id,score,detail,created_at)
                                   VALUES ('ttt',?,?,?,?)")->execute([$uid, 50, 'win', time()]);
                    $msg = 'You win!';
                } elseif ($full) {
                    mp_save($mid, json_encode($st), $seat, 'done', null);
                    $msg = 'Draw!';
                } else {
                    mp_save($mid, json_encode($st), $seat === 1 ? 2 : 1);
                    $msg = 'Move played. Waiting for your opponent.';
                }
            }
        }
    }
}

if ($mid && !empty($_GET['join'])) {
    if (mp_join('ttt', $mid, $uid)) $msg = 'You joined the game. Player 2 is O.';
    else $msg = 'Could not join that game.';
}

page_start('Noughts & Crosses', ['back' => '/games.php']);
if ($msg) p_para($msg);

if (!$mid) {
    mp_lobby('ttt', $SELF, $uid, json_encode(['b' => array_fill(0, 9, '')]));
    p_links([['/games.php', 'Games']]);
    page_end();
    exit;
}

$m = mp_get('ttt', $mid);
if (!$m) bail('Game', 'No such game.', $SELF);
$st = json_decode($m['state'], true);
$b = $st['b'];
$seat = mp_seat($m, $uid);

p_para('#' . $m['id'] . ': X=' . ($m['n1'] ?? '?') . ' vs O=' . ($m['n2'] ?? 'waiting'));

// board: 3 rows, free cells show their number so WAP users know what to type
for ($r = 0; $r < 3; $r++) {
    $cells = [];
    for ($c = 0; $c < 3; $c++) {
        $i = $r * 3 + $c;
        $cells[] = $b[$i] === '' ? (string)($i + 1) : $b[$i];
    }
    p_para(implode(' | ', $cells));
}
p_rule();

if ($m['status'] === 'open') {
    p_para('Waiting for an opponent to join. Tell a friend to open Games > Noughts & Crosses.');
} elseif ($m['status'] === 'done') {
    if ($m['winner'] === null) p_para('Result: draw.');
    else {
        $wn = ((int)$m['winner'] === (int)$m['p1']) ? $m['n1'] : $m['n2'];
        p_para('Winner: ' . $wn);
    }
} elseif ($seat === 0) {
    p_para('You are watching. Turn: player ' . $m['turn']);
} elseif ($seat === (int)$m['turn']) {
    p_para('Your turn (' . ($seat === 1 ? 'X' : 'O') . '). Enter a free square number.');
    p_form($SELF . '?g=' . $mid, [
        ['name' => 'act',  'type' => 'hidden', 'value' => 'move'],
        ['name' => 'mid',  'type' => 'hidden', 'value' => (string)$mid],
        ['name' => 'cell', 'label' => 'Square (1-9)', 'maxlength' => 1, 'format' => 'N'],
    ], 'Play');
} else {
    p_para('Opponent to move. Check back shortly.');
}

p_links([[$SELF, 'Refresh', ['g' => $mid]], [$SELF, 'Lobby'], ['/games.php', 'Games']]);
page_end();