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

class Hubtel_api
{
    private $client_id;
    private $client_secret;
    private $CI;
    private $api_endpoint = 'https://smsc.hubtel.com/v1/messages/send';

    public function __construct()
    {
        $this->CI = &get_instance();
        
        // Load Hubtel credentials from options
        $this->client_id = get_option('hubtel_sms_client_id');
        $this->client_secret = get_option('hubtel_sms_client_secret');
    }

    /**
     * Send SMS using Hubtel API
     * 
     * @param string $to Recipient phone number (E164 format)
     * @param string $message Message content (max 160 characters)
     * @param string $from Sender ID (max 11 alpha-numeric characters)
     * @return array Response with success status and message
     */
    public function send_sms($to, $message, $from)
    {
        // Validate credentials
        if (empty($this->client_id) || empty($this->client_secret)) {
            return [
                'success' => false,
                'message' => 'API credentials not configured'
            ];
        }

        // Validate sender ID (must be 11 alpha-numeric characters or less)
        if (strlen($from) > 11 || !preg_match('/^[a-zA-Z0-9]+$/', $from)) {
            return [
                'success' => false,
                'message' => 'Invalid Sender ID. Must be 11 alpha-numeric characters or less.'
            ];
        }

        // Check message length
        if (strlen($message) > 160) {
            return [
                'success' => false,
                'message' => 'Message content exceeds 160 characters'
            ];
        }

        // Prepare the request URL with parameters
        $params = [
            'clientid' => $this->client_id,
            'clientsecret' => $this->client_secret,
            'from' => $from,
            'to' => $to,
            'content' => $message
        ];

        $url = $this->api_endpoint . '?' . http_build_query($params);

        // Set up cURL request
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_HTTPGET, true); // Using GET method as per API spec

        // Execute the request
        $response = curl_exec($ch);
        $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $curl_error = curl_error($ch);
        
        curl_close($ch);

        // Handle cURL errors
        if ($curl_error) {
            return [
                'success' => false,
                'message' => 'cURL Error: ' . $curl_error
            ];
        }

        // Parse response
        $result = json_decode($response, true);

        // Handle API response
        if ($http_code === 200) {
            return [
                'success' => true,
                'message' => $result['message'] ?? 'Message sent',
                'responseCode' => $result['responseCode'] ?? '',
                'data' => [
                    'rate' => $result['data']['rate'] ?? 0,
                    'messageId' => $result['data']['messageId'] ?? '',
                    'status' => $result['data']['status'] ?? 0,
                    'networkId' => $result['data']['networkId'] ?? ''
                ]
            ];
        }

        return [
            'success' => false,
            'message' => $result['message'] ?? 'Failed to send SMS',
            'responseCode' => $result['responseCode'] ?? '',
            'data' => $result['data'] ?? null
        ];
    }

    /**
     * Get account balance
     * 
     * @return array Response with account balance
     */
    public function get_balance()
    {
        if (empty($this->client_id) || empty($this->client_secret)) {
            return [
                'success' => false,
                'message' => 'API credentials not configured'
            ];
        }

        $params = [
            'clientid' => $this->client_id,
            'clientsecret' => $this->client_secret
        ];

        $url = 'https://smsc.hubtel.com/v1/accounts/balance?' . http_build_query($params);

        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_HTTPGET, true);

        $response = curl_exec($ch);
        $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $curl_error = curl_error($ch);
        
        curl_close($ch);

        if ($curl_error) {
            return [
                'success' => false,
                'message' => 'cURL Error: ' . $curl_error
            ];
        }

        $result = json_decode($response, true);

        if ($http_code === 200) {
            return [
                'success' => true,
                'balance' => $result['data']['balance'] ?? 0,
                'currency' => $result['data']['currency'] ?? 'GHS',
                'responseCode' => $result['responseCode'] ?? '',
                'response' => $result
            ];
        }

        return [
            'success' => false,
            'message' => $result['message'] ?? 'Failed to get balance',
            'responseCode' => $result['responseCode'] ?? '',
            'response' => $result
        ];
    }
}