<?php

	defined('ABSPATH') or die('Jog on!');

	/**
	 * Premium license?
	 *
	 * @return bool
	 */
	function sh_cd_license_is_premium() {
		return (bool) get_option( 'sh-cd-license-valid', false );
	}

	/**
	 * Return a link to the upgrade page
	 *
	 * @return string
	 */
	function sh_cd_license_upgrade_link() {

		$link = admin_url('admin.php?page=sh-cd-shortcode-variables-license');

		return esc_url( $link );
	}

	/**
	 *	Check an existing license's hash is still valid
	 **/
	function sh_cd_license_validate( $license ) {

		if ( true === empty( $license ) ) {
			return __( 'License missing', SH_CD_SLUG );
		}

		// Decode license
		$license = sh_cd_license_decode( $license );

		if ( true === empty( $license ) ) {
			return __( 'Could not decode / verify license', SH_CD_SLUG );
		}

		// Does site hash in license meet this site's actual hash?
		if ( true === empty( $license['site-hash'] ) ) {
			return __( 'Invalid license hash', SH_CD_SLUG );
		}

		// Match this site hash?
		if ( sh_cd_generate_site_hash() !== $license['site-hash']) {
			return __( 'This license doesn\'t appear to be for this site (no match on site hash).', SH_CD_SLUG );
		}

		// Valid date?
		$today_time = strtotime( date( 'Y-m-d' ) );
		$expire_time = strtotime( $license['expiry-date'] );

		if ( $expire_time < $today_time ) {
			return __( 'This license has expired.', SH_CD_SLUG );
		}

		return true;
	}

	/**
	 * Validate and decode a license
	 **/
	function sh_cd_license_decode( $license ) {

		if( true === empty( $license ) ) {
			return NULL;
		}

		// Base64 and JSON decode
		$license = base64_decode( $license );

		if( false === $license ) {
			return NULL;
		}

		$license = json_decode( $license, true );

		if( true === empty( $license ) ) {
			return NULL;
		}

		// Validate hash!
		$verify_hash = md5( 'yeken.uk' . $license['type'] . $license['expiry-days'] . $license['site-hash'] . $license['expiry-date'] );

		return ( $license['hash'] == $verify_hash && false === empty( $license ) ) ? $license : NULL;
	}


	/**
	 * Validate and apply a license
	 **/
	function sh_cd_license_apply( $license ) {

		// Validate license
		$license_result = sh_cd_license_validate($license);

		if( true === $license_result ) {

			update_option( 'sh-cd-license', $license );
			update_option( 'sh-cd-license-valid', true );

			return true;
		}

		return false;
	}

	/**
	 * Remove a license
	 **/
	function sh_cd_license_remove() {

		delete_option( 'sh-cd-license' );
		delete_option( 'sh-cd-license-valid' );
	}

	/**
	 *	Generate a site hash to identify this site.
	 **/
	function sh_cd_generate_site_hash() {

		$site_hash = get_option( 'sh-cd-hash' );

		// Generate a basic site key from URL and plugin slug
		if( false == $site_hash ) {

			$site_hash = md5( 'yeken-sh-cd-' . site_url() );
			$site_hash = substr( $site_hash, 0, 6 );

			update_option( 'sh-cd-hash', $site_hash );

		}
		return $site_hash;
	}

	/**
	 * Fetch license
	 *
	 * @return mixed
	 */
	function sh_cd_license() {
		return get_option( 'sh-cd-license', '' );
	}

    /**
     * Fetch license price
     *
     * @return float|null
     */
	function sh_cd_license_price() {

        $price = yeken_license_price( 'sv-premium' );

        return ( false === empty( $price ) ) ? $price : SH_CD_PREMIUM_PRICE;
    }

	if ( false === function_exists( 'yeken_license_api_fetch_licenses' ) ) {

        /**
         * Call out to YeKen API for license prices
         */
        function yeken_license_api_fetch_licenses() {

            if ( $cache = get_transient( 'yeken_api_prices' ) ) {
                return $cache;
            }

            $response = wp_remote_get( 'https://shop.yeken.uk/wp-json/yeken/v1/license-prices/' );

            // All ok?
            if ( 200 === wp_remote_retrieve_response_code( $response ) ) {

                $body = wp_remote_retrieve_body( $response );

                if ( false === empty( $body ) ) {

                    $body = json_decode( $body, true );
                    set_transient( 'yeken_api_prices', $body, 216000 ); // Cache for 6 hours

                    return $body;
                }
            }

            return NULL;
        }

        /**
         * Fetch a certain product price
         * @param $sku
         * @param string $type
         */
        function yeken_license_price( $sku, $type = 'yearly' ) {

            $licenses = yeken_license_api_fetch_licenses();

            return ( false === empty( $licenses[ $sku ][ $type ] ) ) ? $licenses[ $sku ][ $type ] : NULL;
        }

        /**
         * Render out license prices
         *
         * @param $args
         * @return mixed|string
         */
        function yeken_license_shortcode( $args ) {

            $args = wp_parse_args( $args, [ 'sku' => 'sv-premium', 'type' => 'yearly', 'prefix' => '&pound;' ] );

            $price = yeken_license_price( $args[ 'sku' ], $args[ 'type' ] );

            if ( false === empty( $price ) ) {
                return sprintf( '%s%d', esc_html(  $args[ 'prefix' ] ), $price );
            }

            return '';
        }
        add_shortcode( 'yeken-license-price', 'yeken_license_shortcode' );

    }