<?php
require_once __DIR__ . '/../includes/bootstrap.php';
header('Content-Type: application/json; charset=utf-8');

function dame_out($d) { echo json_encode($d, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES); exit; }
function dame_fail($msg, $code = 400) { http_response_code($code); dame_out(['ok' => false, 'message' => $msg]); }

function dame_initial_board(): array {
    $b = array_fill(0, 8, array_fill(0, 8, null));
    for ($r = 0; $r < 8; $r++) for ($c = 0; $c < 8; $c++) {
        if (($r + $c) % 2 !== 1) continue;
        if ($r <= 2) $b[$r][$c] = ['c' => 2, 'k' => 0];
        elseif ($r >= 5) $b[$r][$c] = ['c' => 1, 'k' => 0];
    }
    return $b;
}

function dame_state_row(array $m, ?string $seat = null): array {
    $yourSeat = 0;
    if ($seat && hash_equals($m['seat1_token'], $seat)) $yourSeat = 1;
    elseif ($seat && $m['seat2_token'] && hash_equals($m['seat2_token'], $seat)) $yourSeat = 2;
    return [
        'ok'        => true,
        'token'     => $m['token'],
        'board'     => json_decode($m['board'], true),
        'turn'      => (int)$m['turn'],
        'status'    => $m['status'],
        'winner'    => (int)$m['winner'],
        'move_count'=> (int)$m['move_count'],
        'names'     => [1 => $m['seat1_name'], 2 => $m['seat2_name']],
        'your_seat' => $yourSeat,
        'joined'    => $m['seat2_token'] ? true : false,
        'last_move' => isset($m['last_move']) && $m['last_move'] !== null ? json_decode($m['last_move'], true) : null,
    ];
}

$payload = json_decode(file_get_contents('php://input'), true) ?: [];
$action  = (string)($_GET['action'] ?? $payload['action'] ?? '');
$pdo = db();

$loadMatch = function (string $token) use ($pdo) {
    $token = preg_replace('/[^a-f0-9]/', '', $token);
    if ($token === '') return null;
    $stmt = $pdo->prepare('SELECT * FROM dame_matches WHERE token = ? LIMIT 1');
    $stmt->execute([$token]);
    return $stmt->fetch() ?: null;
};

try {
    if ($action === 'create') {
        $user = current_user();
        $name = trim((string)($payload['name'] ?? '')) ?: ($user['username'] ?? 'Spieler 1');
        $name = mb_substr($name, 0, 40);
        $token = bin2hex(random_bytes(8));
        $seat1 = bin2hex(random_bytes(12));
        $board = json_encode(dame_initial_board(), JSON_UNESCAPED_SLASHES);
        $pdo->prepare('INSERT INTO dame_matches (token, board, turn, seat1_token, seat1_name, host_user_id, status, created_at, updated_at) VALUES (?,?,1,?,?,?,"waiting",NOW(),NOW())')
            ->execute([$token, $board, $seat1, $name, $user['id'] ?? null]);
        dame_out(['ok' => true, 'token' => $token, 'seat' => $seat1, 'your_seat' => 1]);
    }

    if ($action === 'join') {
        $m = $loadMatch((string)($payload['token'] ?? ''));
        if (!$m) dame_fail('Partie nicht gefunden.', 404);
        $seat = (string)($payload['seat'] ?? '');
        // Rejoin mit bekanntem Sitz-Token
        if ($seat && (hash_equals($m['seat1_token'], $seat) || ($m['seat2_token'] && hash_equals($m['seat2_token'], $seat)))) {
            dame_out(array_merge(dame_state_row($m, $seat), ['seat' => $seat]));
        }
        if ($m['seat2_token']) dame_fail('Diese Partie ist bereits voll.', 409);
        $user = current_user();
        $name = trim((string)($payload['name'] ?? '')) ?: ($user['username'] ?? 'Spieler 2');
        $name = mb_substr($name, 0, 40);
        $seat2 = bin2hex(random_bytes(12));
        $pdo->prepare('UPDATE dame_matches SET seat2_token=?, seat2_name=?, status="playing", updated_at=NOW() WHERE token=? AND seat2_token IS NULL')
            ->execute([$seat2, $name, $m['token']]);
        $m = $loadMatch($m['token']);
        dame_out(array_merge(dame_state_row($m, $seat2), ['seat' => $seat2]));
    }

    if ($action === 'state') {
        $m = $loadMatch((string)($_GET['token'] ?? $payload['token'] ?? ''));
        if (!$m) dame_fail('Partie nicht gefunden.', 404);
        dame_out(dame_state_row($m, (string)($_GET['seat'] ?? $payload['seat'] ?? '')));
    }

    if ($action === 'move') {
        $m = $loadMatch((string)($payload['token'] ?? ''));
        if (!$m) dame_fail('Partie nicht gefunden.', 404);
        if ($m['status'] === 'finished') dame_fail('Partie ist beendet.');
        $seat = (string)($payload['seat'] ?? '');
        $turn = (int)$m['turn'];
        $expected = $turn === 1 ? $m['seat1_token'] : $m['seat2_token'];
        if (!$expected || !hash_equals($expected, $seat)) dame_fail('Du bist nicht am Zug.', 403);

        $board = $payload['board'] ?? null;
        if (!is_array($board) || count($board) !== 8) dame_fail('Ungültiges Brett.');
        $nextTurn = (int)($payload['turn'] ?? ($turn === 1 ? 2 : 1));
        $winner = (int)($payload['winner'] ?? 0);
        $status = $winner ? 'finished' : 'playing';
        $lastMove = isset($payload['move']) ? json_encode($payload['move'], JSON_UNESCAPED_SLASHES) : null;
        $pdo->prepare('UPDATE dame_matches SET board=?, turn=?, winner=?, status=?, last_move=?, move_count=move_count+1, updated_at=NOW() WHERE token=?')
            ->execute([json_encode($board, JSON_UNESCAPED_SLASHES), $nextTurn, $winner, $status, $lastMove, $m['token']]);
        $m = $loadMatch($m['token']);
        dame_out(dame_state_row($m, $seat));
    }

    dame_fail('Unbekannte Aktion.');
} catch (Throwable $e) {
    dame_fail('Serverfehler: ' . $e->getMessage(), 500);
}