<?php
/**
 * Class for downloading a file from a given URL.
 *
 * @package Merlin WP
 */

class Merlin_Downloader {
    /**
     * Holds full path to where the files will be saved.
     *
     * @var string
     */
    private $download_directory_path = '';

    /**
     * Constructor method.
     *
     * @param string $download_directory_path Full path to where the files will be saved.
     */
    public function __construct($download_directory_path = '') {
        $this->set_download_directory_path($download_directory_path);
    }


    /**
     * Download file from a given URL.
     *
     * @param string $url URL of file to download.
     * @param string $filename Filename of the file to save.
     * @return string|WP_Error Full path to the downloaded file or WP_Error object with error message.
     */
    public function download_file($url, $filename) {
        $content = $this->get_content_from_url($url);

        // Check if there was an error and break out.
        if (is_wp_error($content)) {
            Merlin_Logger::get_instance()->error($content->get_error_message(), array('url' => $url, 'filename' => $filename));

            return $content;
        }

        $saved_file = motiox_put_file_contents($this->download_directory_path . $filename, $content);

        if (!empty($saved_file)) {
            return $this->download_directory_path . $filename;
        }

        Merlin_Logger::get_instance()->error(esc_html__('The file was not able to save to disk, while trying to download it', 'motiox'), array('url' => $url, 'filename' => $filename));

        return false;
    }


    /**
     * Helper function: get content from an URL.
     *
     * @param string $url URL to the content file.
     * @return string|WP_Error, content from the URL or WP_Error object with error message.
     */
    private function get_content_from_url($url) {
        // Test if the URL to the file is defined.
        if (empty($url)) {
            return new \WP_Error(
                'missing_url',
                __('Missing URL for downloading a file!', 'motiox')
            );
        }

        // Get file content from the server.
        $response = wp_remote_get(
            $url,
            array('timeout' => apply_filters('merlin_timeout_for_downloading_import_file', 20))
        );

        // Test if the get request was not successful.
        if (is_wp_error($response) || 200 !== $response['response']['code']) {
            // Collect the right format of error data (array or WP_Error).
            $response_error = $this->get_error_from_response($response);

            return new \WP_Error(
                'download_error',
                sprintf(
                    __('An error occurred while fetching file from: %1$s%2$s%3$s!%4$sReason: %5$s - %6$s.', 'motiox'),
                    '<strong>',
                    $url,
                    '</strong>',
                    '<br>',
                    $response_error['error_code'],
                    $response_error['error_message']
                )
            );
        }

        // Return content retrieved from the URL.
        return wp_remote_retrieve_body($response);
    }


    /**
     * Helper function: get the right format of response errors.
     *
     * @param array|WP_Error $response Array or WP_Error or the response.
     * @return array Error code and error message.
     */
    private function get_error_from_response($response) {
        $response_error = array();

        if (is_array($response)) {
            $response_error['error_code']    = $response['response']['code'];
            $response_error['error_message'] = $response['response']['message'];
        } else {
            $response_error['error_code']    = $response->get_error_code();
            $response_error['error_message'] = $response->get_error_message();
        }

        return $response_error;
    }


    /**
     * Get download_directory_path attribute.
     */
    public function get_download_directory_path() {
        return $this->download_directory_path;
    }


    /**
     * Set download_directory_path attribute.
     * If no valid path is specified, the default WP upload directory will be used.
     *
     * @param string $download_directory_path Path, where the files will be saved.
     */
    public function set_download_directory_path($download_directory_path) {
        if (file_exists($download_directory_path)) {
            $this->download_directory_path = $download_directory_path;
        } else {
            $upload_dir                    = wp_upload_dir();
            $this->download_directory_path = apply_filters('merlin_upload_file_path', trailingslashit($upload_dir['path']));
        }
    }

    /**
     * Check, if the file already exists and return his full path.
     *
     * @param string $filename The name of the file.
     *
     * @return bool|string
     */
    public function fetch_existing_file($filename) {
        if (file_exists($this->download_directory_path . $filename)) {
            return $this->download_directory_path . $filename;
        }

        return false;
    }
}