<?php

class IkhokhaClient {
    private string $appId;
    private string $appSecret;
    private string $apiUrl;

    public function __construct() {
        // Try getenv first, then fallback to $_ENV if available
        $this->appId     = getenv('IKHOKHA_APP_ID') ?: ($_ENV['IKHOKHA_APP_ID'] ?? '');
        $this->appSecret = getenv('IKHOKHA_APP_SECRET') ?: ($_ENV['IKHOKHA_APP_SECRET'] ?? '');
        $this->apiUrl    = getenv('IKHOKHA_API_URL') ?: ($_ENV['IKHOKHA_API_URL'] ?? '');
    }

    /**
     * Make a request to the iKhokha API. Signs the payload per API docs.
     * $endpoint should be the path portion starting with '/public-api/...'
     */
    private function request(string $endpoint, array $data, string $method = 'POST') {
        // Validate apiUrl
        if (empty($this->apiUrl)) {
            return ['error' => true, 'errno' => 3, 'message' => 'IKHOKHA_API_URL is not configured in environment'];
        }

        // If the configured API URL already contains the endpoint path, use it as-is.
        if ((function_exists('str_ends_with') && str_ends_with($this->apiUrl, $endpoint)) ||
            (substr_compare($this->apiUrl, $endpoint, -strlen($endpoint)) === 0)) {
            $url = $this->apiUrl;
        } else {
            $url = rtrim($this->apiUrl, '/') . $endpoint;
        }
        $body = json_encode($data);

        // Build payload to sign: path + body and apply escape rules per iKhokha docs
        $parsed = parse_url($url);
        $path = $parsed['path'] ?? $endpoint;
        $payloadToSign = $path . $body;

        // Escape function from iKhokha example
        $escapeString = function ($str) {
            $escaped = preg_replace(['/[\\\"\'\"]/u', '/\x00/'], ['\\\\$0', '\\0'], (string)$str);
            $cleaned = str_replace('\/', '/', $escaped);
            return $cleaned;
        };

        $escapedPayload = $escapeString($payloadToSign);
        $signature = hash_hmac('sha256', $escapedPayload, $this->appSecret);

        $ch = curl_init($url);

        $headers = [
            'Content-Type: application/json',
            "IK-APPID: {$this->appId}",
            "IK-SIGN: {$signature}"
        ];

        // Optional debug logging to logs/ikhokha.log when IKHOKHA_DEBUG_LOG is true
        $debugLog = getenv('IKHOKHA_DEBUG_LOG') ?: ($_ENV['IKHOKHA_DEBUG_LOG'] ?? null);
        if ($debugLog) {
            $logPath = dirname(__DIR__) . '/logs/ikhokha.log';
            $logEntry = [
                'time' => date('c'),
                'url' => $url,
                'headers' => $headers,
                'body' => $data,
                'signature' => $signature
            ];
            @file_put_contents($logPath, json_encode(['request' => $logEntry]) . PHP_EOL, FILE_APPEND | LOCK_EX);
        }

        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

        if (strtoupper($method) === 'POST') {
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
        } else {
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);
        }

        $response = curl_exec($ch);
        $errno = curl_errno($ch);
        $error = curl_error($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        // Log response if debug enabled
        if (!empty($debugLog)) {
            $logPath = dirname(__DIR__) . '/logs/ikhokha.log';
            $respEntry = [
                'time' => date('c'),
                'http_code' => $httpCode,
                'errno' => $errno,
                'error' => $error,
                'response' => $response
            ];
            @file_put_contents($logPath, json_encode(['response' => $respEntry]) . PHP_EOL, FILE_APPEND | LOCK_EX);
        }

        if ($response === false) {
            return ['error' => true, 'message' => $error, 'errno' => $errno];
        }

        return json_decode($response, true);
    }

    /**
     * Create a payment link using the iKhokha create payment endpoint.
     * $body must match iKhokha request schema (amount in smallest unit, urls, externalTransactionID, etc.)
     */
    public function createPaymentLink(array $body) {
        return $this->request('/public-api/v1/api/payment', $body, 'POST');
    }

    public function getPaymentStatus($paymentId) {
        // Use the GET status endpoint
        $endpoint = '/public-api/v1/api/getStatus/' . urlencode($paymentId);
        return $this->request($endpoint, [], 'GET');
    }
}