<?php

namespace WP_CLI;

use WP_CLI;

/**
 * Manage caching with whitelisting
 *
 * @package WP_CLI
 */
class WpHttpCacheManager {

    /**
     * @var array<string, array{key:string, ttl:int}> map whitelisted urls to keys and ttls
     */
    protected $whitelist = [];

    /**
     * @var FileCache
     */
    protected $cache;

    /**
     * @param FileCache $cache
     */
    public function __construct( FileCache $cache ) {
        $this->cache = $cache;

        // hook into wp http api
        add_filter( 'pre_http_request', [ $this, 'filter_pre_http_request' ], 10, 3 );
        add_filter( 'http_response', [ $this, 'filter_http_response' ], 10, 3 );
    }

    /**
     * short circuit wp http api with cached file
     */
    public function filter_pre_http_request( $response, $args, $url ) {
        // check if whitelisted
        if ( ! isset( $this->whitelist[ $url ] ) ) {
            return $response;
        }
        // check if downloading
        if ( 'GET' !== $args['method'] || empty( $args['filename'] ) ) {
            return $response;
        }
        // check cache and export to designated location
        $filename = $this->cache->has( $this->whitelist[ $url ]['key'], $this->whitelist[ $url ]['ttl'] );
        if ( $filename ) {
            WP_CLI::log( sprintf( 'Using cached file \'%s\'...', $filename ) );
            if ( copy( $filename, $args['filename'] ) ) {
                // simulate successful download response
                return [
                    'response' => [
                        'code'    => 200,
                        'message' => 'OK',
                    ],
                    'filename' => $args['filename'],
                ];
            }

            WP_CLI::error( sprintf( 'Error copying cached file %s to %s', $filename, $url ) );
        }
        return $response;
    }


    /**
     * cache wp http api downloads
     *
     * @param array $response
     * @param array $args
     * @param string $url
     * @return array
     */
    public function filter_http_response( $response, $args, $url ) {
        // check if whitelisted
        if ( ! isset( $this->whitelist[ $url ] ) ) {
            return $response;
        }
        // check if downloading
        if ( 'GET' !== $args['method'] || empty( $args['filename'] ) ) {
            return $response;
        }
        // check if download was successful
        if ( is_wp_error( $response ) || 200 !== wp_remote_retrieve_response_code( $response ) ) {
            return $response;
        }
        // cache downloaded file
        $this->cache->import( $this->whitelist[ $url ]['key'], $response['filename'] );
        return $response;
    }

    /**
     * whitelist a package url
     *
     * @param string $url
     * @param string $group   package group (themes, plugins, ...)
     * @param string $slug    package slug
     * @param string $version package version
     * @param int    $ttl
     */
    public function whitelist_package( $url, $group, $slug, $version, $ttl = null ) {
        $ext = pathinfo( Utils\parse_url( $url, PHP_URL_PATH ), PATHINFO_EXTENSION );
        $key = "$group/$slug-$version.$ext";
        $this->whitelist_url( $url, $key, $ttl );
        wp_update_plugins();
    }

    /**
     * whitelist a url
     *
     * @param string $url
     * @param string $key
     * @param int    $ttl
     */
    public function whitelist_url( $url, $key = null, $ttl = null ) {
        $key                     = $key ? : $url;
        $this->whitelist[ $url ] = [
            'key' => $key,
            'ttl' => $ttl,
        ];
    }

    /**
     * check if url is whitelisted
     *
     * @param string $url
     * @return bool
     */
    public function is_whitelisted( $url ) {
        return isset( $this->whitelist[ $url ] );
    }
}