<?php
declare(strict_types=1);

require_once __DIR__ . '/../config.php';

/**
 * Returns a shared PDO connection for the current request.
 */
function db(): PDO
{
    static $pdo = null;
    if ($pdo !== null) {
        return $pdo;
    }

    $pdo = new PDO(
        sprintf('mysql:host=%s;dbname=%s;charset=utf8mb4', DB_HOST, DB_NAME),
        DB_USER,
        DB_PASS,
        [
            PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES   => false,
        ]
    );

    // Idempotent migrations — safe to run on every boot
    $pdo->exec('ALTER TABLE delivery_log ADD COLUMN IF NOT EXISTS is_sandbox TINYINT(1) NOT NULL DEFAULT 0');
    $pdo->exec("INSERT IGNORE INTO `system` (setting_name, setting_value) VALUES ('sandbox_mode', '0')");

    return $pdo;
}

/**
 * Sends a JSON response and exits.
 */
function json_out(mixed $data, int $status = 200): never
{
    http_response_code($status);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode($data, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);
    exit;
}

/**
 * Decodes the request body as JSON and returns an array.
 */
function json_body(): array
{
    $raw = file_get_contents('php://input');
    if ($raw === false || $raw === '') {
        return [];
    }
    return json_decode($raw, true) ?? [];
}

/**
 * Sends a JSON error response and exits.
 */
function error_out(string $message, int $status = 400): never
{
    json_out(['error' => $message], $status);
}

/**
 * Aborts with 400 if no Clickatell API key has been configured.
 */
function require_api_key(): void
{
    $stmt = db()->prepare("SELECT setting_value FROM `system` WHERE setting_name = 'clickatell_api_key'");
    $stmt->execute();
    $key = $stmt->fetchColumn();
    if ($key === false || trim((string) $key) === '') {
        error_out('No Clickatell API key is configured. Set one in Admin → Clickatell Settings before sending or scheduling messages.', 400);
    }
}