<?php
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * Per-key quota limiter (e.g. per user, per token) for FCM, Maps, and other API usage.
 * Uses database table quota_usage. Create with:
 * CREATE TABLE IF NOT EXISTS quota_usage (
 *   id INT AUTO_INCREMENT PRIMARY KEY,
 *   key_name VARCHAR(255) NOT NULL,
 *   period_type VARCHAR(16) NOT NULL,
 *   period_value VARCHAR(32) NOT NULL,
 *   count INT UNSIGNED NOT NULL DEFAULT 0,
 *   updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
 *   UNIQUE KEY uk_key_period (key_name, period_type, period_value)
 * );
 *
 * Callers pass limits; backend defaults often use FCM_LIMIT_PER_HOUR / FCM_LIMIT_PER_DAY from config.php.
 */

if (!function_exists('quota_limiter_allow')) {
    /**
     * Check and increment usage for the given key. Returns true if under limit, false if over.
     * @param string $key Unique key (e.g. "fcm:recipient:".hash($token) or "maps:user:123")
     * @param array $limits ['hour' => N, 'day' => N]. Use 0 to skip that period.
     * @return bool True if request is allowed, false if over limit
     */
    function quota_limiter_allow($key, $limits = array())
    {
        $CI = &get_instance();
        if (!isset($CI->db) || !$CI->db->conn_id) {
            return true;
        }
        $table = 'quota_usage';
        $hour_period = date('Y-m-d-H');
        $day_period = date('Y-m-d');
        $hour_limit = isset($limits['hour']) ? (int) $limits['hour'] : 100;
        $day_limit = isset($limits['day']) ? (int) $limits['day'] : 500;
        $key_safe = substr($key, 0, 255);

        foreach (array('hour' => array($hour_period, $hour_limit), 'day' => array($day_period, $day_limit)) as $period_type => $pair) {
            list($period_value, $limit) = $pair;
            if ($limit <= 0) {
                continue;
            }
            $CI->db->query("
                INSERT INTO {$table} (key_name, period_type, period_value, count, updated_at)
                VALUES (?, ?, ?, 1, NOW())
                ON DUPLICATE KEY UPDATE count = count + 1, updated_at = NOW()
            ", array($key_safe, $period_type, $period_value));
            $row = $CI->db->query("
                SELECT count FROM {$table}
                WHERE key_name = ? AND period_type = ? AND period_value = ?
            ", array($key_safe, $period_type, $period_value))->row();
            if ($row && (int) $row->count > $limit) {
                return false;
            }
        }
        return true;
    }
}

if (!function_exists('quota_limiter_fcm_key')) {
    function quota_limiter_fcm_key($recipient_identifier)
    {
        return 'fcm:' . substr(md5($recipient_identifier), 0, 32);
    }
}