<?php

/**
 * Based on https://github.com/radishconcepts/WordPress-GitHub-Plugin-Updater
 */

if ( ! defined( 'ABSPATH' ) || class_exists( 'WP_Updater' ) ) {
    return;
}

class WP_Updater {

    /** Updater version */
    const VERSION = 1.0;

    /** @var array config for the updater */
    public $config;

    /** @var array any config that is missing from the initialization of this instance */
    public $missing_config;

    /** @var array data from update */
    protected $update_server_data;

    /**
     * @param array $config the configuration required for the updater to work
     * @see has_minimum_config()
     */
    public function __construct( $config = [] ) {

        $defaults = [
            'slug'               => plugin_basename( __FILE__ ),
            'proper_folder_name' => dirname( plugin_basename( __FILE__ ) ),
            'sslverify'          => true,
        ];

        $this->config = wp_parse_args( $config, $defaults );

        if ( ! $this->has_minimum_config() ) {
            $message = 'The Updater was initialized without the minimum required configuration, please check the config in your plugin. The following params are missing: ';
            $message .= implode( ',', $this->missing_config );
            _doing_it_wrong( __CLASS__, $message , self::VERSION );
            return;
        }

        $this->set_defaults();

        add_filter( 'pre_set_site_transient_update_plugins', [ $this, 'api_check' ] );

        // Hook into the plugin details screen
        add_filter( 'plugins_api', [ $this, 'get_plugin_info' ], 10, 3 );
        add_filter( 'upgrader_post_install', [ $this, 'upgrader_post_install' ], 10, 3 );

        // set timeout
        add_filter( 'http_request_timeout', [ $this, 'http_request_timeout' ] );

        // set sslverify for zip download
        add_filter( 'http_request_args', [ $this, 'http_request_sslverify' ], 10, 2 );

    }

    public function has_minimum_config() {

        $this->missing_config = [];

        $required_config_params = [
            'updates_url',
            'zip_url',
            'requires',
            'tested',
            'release_info',
            'auth_username',
            'auth_password',
        ];

        foreach ( $required_config_params as $required_param ) {
            if ( empty( $this->config[$required_param] ) )
                $this->missing_config[] = $required_param;
        }

        return ( empty( $this->missing_config ) );

    }

    public function set_defaults() {

        if ( ! isset( $this->config['new_version'] ) ) {
            $this->config['new_version'] = $this->get_new_version();
        }

        if ( ! isset( $this->config['last_updated'] ) ) {
            $this->config['last_updated'] = $this->get_date();
        }

        if ( ! isset( $this->config['description'] ) ) {
            $this->config['description'] = $this->get_description();
        }

        $plugin_data = $this->get_plugin_data();

        if ( ! isset( $this->config['plugin_name'] ) ) {
            $this->config['plugin_name'] = $plugin_data['Name'];
        }

        if ( ! isset( $this->config['version'] ) ) {
            $this->config['version'] = $plugin_data['Version'];
        }

        if ( ! isset( $this->config['author'] ) ) {
            $this->config['author'] = $plugin_data['Author'];
        }

        if ( ! isset( $this->config['homepage'] ) ) {
            $this->config['homepage'] = $plugin_data['PluginURI'];
        }

        if ( ! isset( $this->config['release_info'] ) ) {
            $this->config['release_info'] = 'release_info.json';
        }

    }

    /**
     * Get Plugin data
     * @return array
     */
    public function get_plugin_data() {

        include_once ABSPATH . '/wp-admin/includes/plugin.php';
        $data = get_plugin_data( WP_PLUGIN_DIR . '/' . $this->config['slug'] );
        return $data;

    }

    /**
     * Get Data from the update server
     * @return array|false
     */
    public function get_update_server_data() {

        if ( null === $this->update_server_data ) {

            $transient = md5( $this->config['slug'] ) . '_update_server_data';

            if ( array_key_exists( 'remove_updater_transient', $_REQUEST ) ) {
                delete_site_transient( $transient );
            }
            $data = get_site_transient( $transient );

            if ( ! isset( $data ) || ! $data || '' == $data ) {
                $data = $this->remote_get( trailingslashit( $this->config['updates_url'] ) . $this->config['release_info'] );

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

                $data = json_decode( $data, true );
                set_site_transient( $transient, $data, 60 * 60 * 6 ); // refresh every 6 hours
            }

            $this->update_server_data = $data;
        }

        return $this->update_server_data;

    }

    /**
     * Get New Version from Update Server
     * @return string|false $version the version number
     */
    public function get_new_version() {

        if ( ( $data = $this->get_update_server_data() ) ) {
            return $data['current_version'];
        }
        return false;

    }

    /**
     * Get update date
     * @return string|false
     */
    public function get_date() {

        if ( ( $data = $this->get_update_server_data() ) ) {
            return $data['updated_at'];
        }
        return false;

    }

    /**
     * Get plugin description
     * @return string $description the description
     */
    public function get_description() {

        if ( ( $data = $this->get_update_server_data() ) ) {
            return $data['description'];
        }
        return false;

    }

    /**
     * Hook into the plugin update check and connect to GitHub
     * @param object  $transient the plugin data transient
     * @return object $transient updated plugin data transient
     */
    public function api_check( $transient ) {

        // Check if the transient contains the 'checked' information
        // If not, just return its value without hacking it
        if ( empty( $transient->checked ) ) {
            return $transient;
        }

        // check the version and decide if it's new
        $update = version_compare( $this->config['new_version'], $this->config['version'] );

        if ( 1 === $update ) {
            $response = new stdClass;
            $response->new_version = $this->config['new_version'];
            $response->slug = $this->config['proper_folder_name'];
            $response->url = add_query_arg( [], $this->config['updates_url'] );
            $response->package = $this->config['zip_url'];

            // If response is false, don't alter the transient
            if ( false !== $response )
                $transient->response[ $this->config['slug'] ] = $response;
        }

        return $transient;

    }

    /**
     * Get Plugin info
     * @param bool    $false  always false
     * @param string  $action the API function being performed
     * @param object  $args   plugin arguments
     * @return object|false $response the plugin info
     */
    public function get_plugin_info( $false, $action, $args ) {

        // Check if this call API is for the right plugin
        if ( ! isset( $args->slug ) || $args->slug != $this->config['proper_folder_name'] ) {
            return false;
        }

        $args->slug          = $this->config['slug'];
        $args->plugin_name   = $this->config['plugin_name'];
        $args->version       = $this->config['new_version'];
        $args->author        = $this->config['author'];
        $args->homepage      = $this->config['homepage'];
        $args->requires      = $this->config['requires'];
        $args->tested        = $this->config['tested'];
        $args->downloaded    = 0;
        $args->last_updated  = $this->config['last_updated'];
        $args->sections      = [ 'description' => $this->config['description'] ];
        $args->download_link = $this->config['zip_url'];

        return $args;

    }

    /**
     * Move & activate the plugin, echo the update message
     * @param boolean $true       always true
     * @param mixed   $hook_extra not used
     * @param array   $result     the result of the move
     * @return array $result the result of the move
     */
    public function upgrader_post_install( $true, $hook_extra, $result ) {

        /** @var WP_Filesystem_Base $wp_filesystem */
        global $wp_filesystem;

        // Move & Activate
        $proper_destination = WP_PLUGIN_DIR . '/' . $this->config['proper_folder_name'];
        $wp_filesystem->move( $result['destination'], $proper_destination );
        $result['destination'] = $proper_destination;
        $activate = activate_plugin( WP_PLUGIN_DIR . '/' . $this->config['slug'] );

        // Output the update message
        $fail  = __( 'The plugin has been updated, but could not be reactivated. Please reactivate it manually.' );
        $success = __( 'Plugin reactivated successfully.' );

        echo is_wp_error( $activate ) ? $fail : $success;

        return $result;

    }

    /**
     * Callback fn for the http_request_timeout filter
     * @return int timeout value
     */
    public function http_request_timeout() {

        return 2;

    }

    /**
     * Callback fn for the http_request_args filter
     * @param array $args
     * @param string $url
     * @return mixed
     */
    public function http_request_sslverify( $args, $url ) {

        if ( $this->config[ 'zip_url' ] == $url )
            $args[ 'sslverify' ] = $this->config[ 'sslverify' ];

        return $args;

    }

    /**
     * Interact with Update Server
     * @param string $url
     * @return mixed
     */
    public function remote_get( $url ) {

        $raw_response = wp_remote_get(
            $url,
            [
                'headers'  => [ 'Authorization' => 'Basic ' . base64_encode( $this->config['auth_username'] . ':' . $this->config['auth_password'] ) ],
                'sslverify' => $this->config['sslverify']
            ]
        );

        if ( 200 !== wp_remote_retrieve_response_code( $raw_response ) ) {
            return false;
        }

        return wp_remote_retrieve_body( $raw_response );

    }
}