<?php
/**
 * WEVIA KB Gateway — S88
 * Bridges to S89 PostgreSQL for knowledge_base operations
 * Runs on S88, connects to S89 PG remotely
 * 
 * Endpoints:
 *   POST /wevia-kb-gateway.php?action=search&q=keyword
 *   POST /wevia-kb-gateway.php?action=stats
 *   POST /wevia-kb-gateway.php?action=ingest (with file upload)
 */

header('Content-Type: application/json');

// S89 PostgreSQL connection (remote)
define('PG_HOST', '127.0.0.1');
define('PG_PORT', '5432');
define('PG_DB', 'adx_system');
define('PG_USER', 'admin');
define('PG_PASS', 'admin123');

function getDb() {
    static $pdo = null;
    if (!$pdo) {
        $dsn = "pgsql:host=" . PG_HOST . ";port=" . PG_PORT . ";dbname=" . PG_DB;
        $pdo = new PDO($dsn, PG_USER, PG_PASS, [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_TIMEOUT => 5
        ]);
    }
    return $pdo;
}

function respond($data, $code = 200) {
    http_response_code($code);
    echo json_encode($data, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
    exit;
}

$action = $_GET['action'] ?? $_POST['action'] ?? 'stats';

try {
    $db = getDb();
    
    switch ($action) {
        case 'stats':
            $r = $db->query("SELECT count(*) as total, 
                max(updated_at) as last_update,
                count(DISTINCT section) as sections,
                count(DISTINCT category) as categories
                FROM knowledge_base");
            $stats = $r->fetch(PDO::FETCH_ASSOC);
            
            $bc = $db->query("SELECT count(*) as total FROM brain_config WHERE is_active=true");
            $brainConfigs = $bc->fetch(PDO::FETCH_ASSOC);
            
            respond([
                'status' => 'ok',
                'knowledge_base' => $stats,
                'brain_configs' => $brainConfigs,
                'server' => 'S88 gateway → S89 PG'
            ]);
            break;
            
        case 'search':
            $q = $_GET['q'] ?? $_POST['q'] ?? '';
            if (!$q) respond(['error' => 'Missing q parameter'], 400);
            
            $limit = intval($_GET['limit'] ?? 10);
            $stmt = $db->prepare("SELECT id, section, title, content, category, 
                similarity(title || ' ' || content, :q) as relevance
                FROM knowledge_base 
                WHERE title || ' ' || content ILIKE :pattern
                ORDER BY relevance DESC 
                LIMIT :lim");
            $stmt->execute(['q' => $q, 'pattern' => "%$q%", 'lim' => $limit]);
            $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
            
            respond(['status' => 'ok', 'query' => $q, 'count' => count($results), 'results' => $results]);
            break;
            
        case 'sections':
            $r = $db->query("SELECT section, count(*) as entries FROM knowledge_base GROUP BY section ORDER BY entries DESC");
            respond(['status' => 'ok', 'sections' => $r->fetchAll(PDO::FETCH_ASSOC)]);
            break;

        case 'ingest':
            $title = $_POST['title'] ?? '';
            $content = $_POST['content'] ?? '';
            $section = $_POST['section'] ?? 'general';
            $category = $_POST['category'] ?? 'manual';
            
            if (!$title || !$content) respond(['error' => 'Missing title or content'], 400);
            
            $stmt = $db->prepare("INSERT INTO knowledge_base (section, title, content, category, created_at, updated_at) 
                VALUES (:section, :title, :content, :category, NOW(), NOW()) RETURNING id");
            $stmt->execute(['section' => $section, 'title' => $title, 'content' => $content, 'category' => $category]);
            $id = $stmt->fetchColumn();
            
            respond(['status' => 'ok', 'id' => $id, 'message' => "Entry ingested: $title"]);
            break;
            
        default:
            respond(['error' => 'Unknown action', 'available' => ['stats','search','sections','ingest']], 400);
    }
} catch (Exception $e) {
    error_log("WEVIA_KB_GW: " . $e->getMessage());
    respond(['error' => 'DB connection failed', 'detail' => $e->getMessage()], 500);
}