<?php
require_once 'config.php';
try {
    $pdo = new PDO('sqlite:' . DB_FILE);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdo->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    die("Database connection failed: " . $e->getMessage());
}

function query($sql, $params = []) {
    global $pdo;
    $stmt = $pdo->prepare($sql);
    $stmt->execute($params);
    return $stmt;
}

function get_user($id) {
    global $pdo;
    $stmt = $pdo->prepare("SELECT * FROM users WHERE id = ?");
    $stmt->execute([$id]);
    return $stmt->fetch();
}

function get_user_groups($user_id) {
    global $pdo;
    $stmt = $pdo->prepare("SELECT g.* FROM groups g JOIN user_groups ug ON g.id = ug.group_id WHERE ug.user_id = ?");
    $stmt->execute([$user_id]);
    return $stmt->fetchAll();
}

function notify_user($user_id, $message) {
    global $pdo;
    $stmt = $pdo->prepare("INSERT INTO notifications (user_id, message) VALUES (?, ?)");
    $stmt->execute([$user_id, $message]);
    
    // Virtual hook for Email/Telegram/WhatsApp based on user features
    $user = get_user($user_id);
    if($user && isset($user['notify_channels'])) {
        $channels = explode(',', $user['notify_channels']);
        // Here we would actually send the message to the third party API.
        // For MVP we just assume it's sent.
    }
}

function notify_group($group_id, $message) {
    global $pdo;
    $stmt = $pdo->prepare("SELECT user_id FROM user_groups WHERE group_id = ?");
    $stmt->execute([$group_id]);
    $users = $stmt->fetchAll();
    foreach ($users as $u) {
        notify_user($u['user_id'], $message);
    }
}