<?php

/**
 * This file manages interactions with the AltTextLab API service
 *
 */
class AltTextLab_API
{

    /**
     * API key used to authenticate connections with the service.
     *
     */
    private $api_key;

    /**
     * Base URL for the API service endpoints.
     *
     */
    private $base_url;

    /**
     * Initializes the class instance with necessary configuration parameters.
     *
     */
    public function __construct($api_key)
    {
        $this->api_key = sanitize_text_field($api_key);
        $this->base_url = 'https://app.alttextlab.com/api/';
    }

    /**
     * Fetches user account information from the API service.
     *
     */
    public function get_account()
    {
        $api_version = 'v1';
        $response = $this->request('GET', $api_version, '/subscriptions/info');

        if (!is_array($response) || is_wp_error($response)) {
            return false;
        }

        /**
         * Verify if the response status indicates failure (any non-2xx HTTP code)
         */
        if (substr(wp_remote_retrieve_response_code($response), 0, 1) != '2') {
            return false;
        }

        $response = json_decode(wp_remote_retrieve_body($response), true);
        $account = array(
            'plan'            => sanitize_text_field($response['planName']),
            'isActive'        => $response['isActive'],
            'credits'         => intval($response['credits']),
            'nextReceiving'   => sanitize_text_field($response['nextReceiving']),
            'nextReceivingAt' => sanitize_text_field($response['nextReceivingAt'])
        );

        return $account;
    }

    /**
     * Produces alternative text descriptions for the given image.
     *
     */
    public function generate_alt_text($attachment_id, $attachment_url, $api_options, &$response_code)
    {
        $api_version = 'v1';

        $body = $this->build_body($attachment_id, $attachment_url, $api_options);
        $response = $this->request('POST', $api_version, '/alt-text/generate', $body, intval(get_option('alttextlab_timeout', 20)));

        $response_code = wp_remote_retrieve_response_code($response);

        $attachment_edit_url = empty($attachment_id) ? $attachment_url : get_edit_post_link($attachment_id);

        if (!is_array($response) || is_wp_error($response)) {
            error_log(print_r($response, true));
            $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, 'Unknown error.', 'alttextlab_try_later_notice', MINUTE_IN_SECONDS);
            return false;
        }

        $response_body = json_decode(wp_remote_retrieve_body($response), true);

        if ($response_code == '401') {
            error_log(print_r($response, true));
            $error_message = 'API_KEY_IS_INVALID';

            $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, $error_message, 'alttextlab_api_key_invalid_notice', MINUTE_IN_SECONDS);
            return 'API_KEY_IS_INVALID';
        } else if ($response_code == '403') {
            $error_message = $response_body['key'] ? : 'Something went wrong!';
            error_log(print_r($response, true));

            if ($error_message === 'NOT_ENOUGH_FUNDS') {
                $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, $error_message, 'alttextlab_insufficient_credits', MONTH_IN_SECONDS);
                return 'NOT_ENOUGH_FUNDS';
            }

            $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, $error_message, 'alttextlab_try_later_notice', MINUTE_IN_SECONDS);
            return false;
        } else if($response_code == '429'){
            $error_message = $response_body['key'];
            error_log(print_r($response, true));

            if ($error_message === 'MONTHLY_LIMIT_EXCEEDED') {
                $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, $error_message, 'alttextlab_monthly_limit_exceeded', MONTH_IN_SECONDS);
                return 'MONTHLY_LIMIT_EXCEEDED';
            }

            $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, $error_message, 'alttextlab_try_later_notice', MINUTE_IN_SECONDS);
            return false;
        } elseif (substr($response_code, 0, 1) != '2') {
            error_log(print_r($response, true));

            $this->log_api_error($attachment_id, $attachment_edit_url, $response_code, 'API error.', 'alttextlab_try_later_notice', MINUTE_IN_SECONDS);
            return false;
        }

        return $response_body;
    }

    /**
     * Builds the request payload for the alt text generation API.
     *
     */
    private function build_body($attachment_id, $attachment_url, $api_options)
    {
        $body = [];

        if (empty($attachment_id) || get_option('alttextlab_public') === 'yes') {
            // When dealing with public websites, create ALT text by sending the image URL to the API
            $body = array(
                'imageUrl' => $attachment_url
            );
        } else {
            // In the case of private websites, generate ALT text by base64 encoding and transmitting the image file directly to the API
            $body = array(
                'imageRaw' => base64_encode(file_get_contents(get_attached_file($attachment_id)))
            );
        }

        $body['source'] = 'wordpress';
        return array_merge($body, $api_options);
    }

    /**
     * Sends an HTTP request to the AltTextLab API.
     *
     */
    private function request($method, $version, $endpoint, $body = null, $timeout = 20)
    {
        $args = [
            'headers' => [
                'Content-Type' => 'application/json',
                'X-Api-Key' => $this->api_key,
            ],
            'timeout' => $timeout,
        ];

        if ($body) {
            $args['body'] = wp_json_encode($body);
        }

        $url = $this->base_url . $version . $endpoint;

        return $method === 'GET' ? wp_remote_get($url, $args) : wp_remote_post($url, $args);
    }

    private function log_api_error($id, $url, $code, $message, $transient_key, $transient_duration)
    {
        AltTextLab_Logger::log_error(
            sprintf('[%d] <a href="%s" target="_blank">Image #%d</a>: %s', (int)$code, esc_url($url), (int)$id, esc_html($message))
        );
        set_transient($transient_key, true, $transient_duration);
    }

}