<?php
/**
 * 简航 SimpleNav —— 搜索联想代理
 * 浏览器直接调用各搜索引擎的联想接口会有跨域/JSONP 限制，这里由服务端代理并统一输出 JSON。
 * 用法：suggest.php?slug=bing&q=关键词
 */
declare(strict_types=1);
require_once __DIR__ . '/functions.php';

header('Content-Type: application/json; charset=utf-8');
header('Cache-Control: no-store');

$slug = isset($_GET['slug']) ? preg_replace('/[^a-z0-9\-_]/i', '', (string)$_GET['slug']) : '';
$q = isset($_GET['q']) ? trim((string)$_GET['q']) : '';

if ($q === '') {
    echo json_encode(['q' => '', 'items' => []]);
    exit;
}

$items = [];
try {
    $st = db()->prepare('SELECT * FROM engines WHERE slug=? AND is_active=1 LIMIT 1');
    $st->execute([$slug]);
    $engine = $st->fetch();
    if ($engine && $engine['suggest_url'] !== '') {
        $u = str_replace('{q}', rawurlencode($q), $engine['suggest_url']);
        $resp = http_get($u, 100000, 5);
        if ($resp !== null) {
            $items = parse_suggest($engine['suggest_type'], ensure_utf8($resp['body']), $q);
        }
    }
} catch (Throwable $e) {
    $items = [];
}

// 去重、限长、裁剪
$items = array_values(array_unique(array_filter(array_map('trim', $items))));
$items = array_slice($items, 0, 10);

echo json_encode(['q' => $q, 'items' => $items], JSON_UNESCAPED_UNICODE);
exit;

/** 按引擎类型解析联想结果 */
function parse_suggest(string $type, string $body, string $q): array
{
    $body = trim($body);
    $out = [];

    switch ($type) {
        case 'bing_osjson':
        case 'google_firefox':
            // ["query", ["s1","s2",...]]
            $j = json_decode($body, true);
            if (is_array($j) && isset($j[1]) && is_array($j[1])) {
                $out = $j[1];
            }
            break;

        case 'baidu_sugrec':
            // {"q":"x","g":[{"type":"..","q":".."}], ...}
            $j = json_decode($body, true);
            if (is_array($j)) {
                if (!empty($j['g']) && is_array($j['g'])) {
                    foreach ($j['g'] as $it) { if (isset($it['q'])) $out[] = $it['q']; }
                } elseif (!empty($j['s']) && is_array($j['s'])) {
                    $out = $j['s'];
                }
            }
            break;

        case 'so360':
            // {"s":[".."]} 或 {"result":[{"word":".."}]}
            $j = json_decode($body, true);
            if (is_array($j)) {
                if (!empty($j['s']) && is_array($j['s'])) { $out = $j['s']; }
                elseif (!empty($j['result']) && is_array($j['result'])) {
                    foreach ($j['result'] as $it) { if (isset($it['word'])) $out[] = $it['word']; }
                }
            }
            break;

        case 'sogou_ajaj':
            // {"query":"x","items":["a","b"]}（可能是 GBK，已在上面转码）
            $j = json_decode($body, true);
            if (is_array($j) && !empty($j['items']) && is_array($j['items'])) {
                $out = $j['items'];
            } else {
                // 兜底：正则抓引号字符串
                if (preg_match_all('#"([^"]{1,40})"#u', $body, $m)) {
                    $out = array_slice($m[1], 1); // 跳过 query 自身
                }
            }
            break;

        case 'ddg':
            // [{"phrase":".."},...]
            $j = json_decode($body, true);
            if (is_array($j)) {
                foreach ($j as $it) {
                    if (is_array($it) && isset($it['phrase'])) { $out[] = $it['phrase']; }
                    elseif (is_string($it)) { $out[] = $it; }
                }
            }
            break;

        default:
            // 通用兜底：尝试 JSON，再退化正则
            $j = json_decode($body, true);
            if (is_array($j)) {
                if (isset($j[1]) && is_array($j[1])) { $out = $j[1]; }
                elseif (!empty($j['s']) && is_array($j['s'])) { $out = $j['s']; }
            }
    }
    return $out;
}