Gottwik/Enduro

// * ———————————————————————————————————————————————————————— * //
// *     offline_handler
// *    set of tools that enables running enduro website offline
// *    TODO: developed under time constrain, should be refactored and tested
// * ———————————————————————————————————————————————————————— * //
const offline_handler = function () {}

// * vendor dependencies
const Promise = require('bluebird')
const http = require('http')
const fs = require('fs')
const path = require('path')

// * enduro dependencies
const logger = require(enduro.enduro_path + '/libs/logger')
const pagelist_generator = require(enduro.enduro_path + '/libs/build_tools/pagelist_generator')
const flat = require(enduro.enduro_path + '/libs/flat_db/flat')
const flat_helpers = require(enduro.enduro_path + '/libs/flat_db/flat_helpers')

offline_handler.prototype.convert_cms_file_to_offline = function (cms_file) {

    let list_of_external_resources_to_download = []

    return flat.load(cms_file)
        .then((context) => {

            // console.log(cms_file)
            // this fills list_of_external_resources_to_download
            traverse_offline(context, list_of_external_resources_to_download)

            // returns after all external resources are loaded
            return Promise.all(list_of_external_resources_to_download)
        })
}

offline_handler.prototype.convert_all_to_offline = function () {
    const self = this

    pagelist_generator.generate_cms_list()
        .then((cmslist) => {
            return Promise.all(cmslist.flat.map((page) => { return self.convert_cms_file_to_offline(page.fullpath) }))
        })
}

// * ———————————————————————————————————————————————————————— * //
// *     parse_for_external_links
// *
// *    @param link {string} - text where links should be found
// *    return array - list of link found in the provided text
// * ———————————————————————————————————————————————————————— * //
function parse_for_external_links (link) {
    if (link.substring(0, 4) == 'http') {
        return [link]
    }

    let matches = link.match(/(https.*?)"/g)

    if (matches != null) {
        matches = matches.map((match) => {
            return match.match(/(https.*?)"/)[1]
        })
        return matches
    }

    return []
}

function download_external_resource (external_link) {
    return new Promise(function (resolve, reject) {
        logger.twolog('Downloading ', external_link)

        // handle https
        external_link = external_link.replace(/^https/, 'http')

        const new_filename = path.join('assets', 'img', 'offline', external_link.match(/\/([^\/]*)$/)[1])
        flat_helpers.ensure_directory_existence(path.join(enduro.project_path, new_filename))
            .then(() => {
                const file = fs.createWriteStream(new_filename)
                http.get(external_link, function (response) {
                    response.pipe(file)
                    resolve(new_filename)
                })
            })
    })
}

// traverses context, finds external links and pushes it to the provided list
function traverse_offline (context, list_of_external_resources_to_download) {
    for (c in context) {

        if (typeof context[c] === 'string') {
            links = parse_for_external_links(context[c])

            for (l in links) {
                list_of_external_resources_to_download.push(download_external_resource(links[l]).then((local_url) => {
                    // context['$' + c + '_offline'] = context[c]
                    // context[c] = local_url
                }))
            }
        }

        if (typeof context[c] === 'object') {
            traverse_offline(context[c], list_of_external_resources_to_download)
        }
    }
}

module.exports = new offline_handler()