<?php

class OpenAIService
{
    private static $apiKey;
    private static $model;

    public static function init()
    {
        self::$apiKey = getenv('OPENAI_API_KEY');
        self::$model = getenv('OPENAI_MODEL') ?: 'gpt-4o-mini';
    }

    public static function getCompletion($message)
    {
        if (empty(self::$apiKey)) {
            return ['error' => 'OpenAI API key is not configured.'];
        }

        $url = 'https://api.openai.com/v1/chat/completions';

        $data = [
            'model' => self::$model,
            'messages' => [
                ['role' => 'system', 'content' => 'You are a helpful assistant.'],
                ['role' => 'user', 'content' => $message]
            ],
            'max_tokens' => 150
        ];

        $headers = [
            'Content-Type: application/json',
            'Authorization: Bearer ' . self::$apiKey
        ];

        $options = [
            'http' => [
                'header'  => implode("\r\n", $headers),
                'method'  => 'POST',
                'content' => json_encode($data),
                'ignore_errors' => true,
                'timeout' => 30,
            ],
        ];

        $context  = stream_context_create($options);
        $response = @file_get_contents($url, false, $context);

        // Get HTTP status code from the response headers
        $httpcode = 0;
        if (isset($http_response_header[0])) {
            preg_match('{HTTP/1\.\d (\d{3})}', $http_response_header[0], $matches);
            if (isset($matches[1])) {
                $httpcode = (int)$matches[1];
            }
        }

        if ($response === false) {
            $error = error_get_last();
            return ['error' => 'API call failed: ' . ($error['message'] ?? 'Unknown error')];
        }

        if ($httpcode !== 200) {
            return ['error' => 'API returned status ' . $httpcode . ': ' . $response];
        }

        $decodedResponse = json_decode($response, true);

        if (isset($decodedResponse['choices'][0]['message']['content'])) {
            return ['reply' => $decodedResponse['choices'][0]['message']['content']];
        } elseif (isset($decodedResponse['error'])) {
            return ['error' => $decodedResponse['error']['message']];
        }

        return ['error' => 'Unexpected API response format.'];
    }
}

OpenAIService::init();