'use strict'

const IPFS = require('ipfs')


function materialize_references_to_ipfs_content(node, element) {
    // Given an IPFS node and a DOM element with a relevant attribute referring to content on IPFS,
    // load that content and set it into the attribute as a blob.
    //
    // Return a promise for doing all of that.
    // TODO: Support <div style="background-image: url(./styles/img/main/alpha-sunrise.png);"> rewriting.
    for (let attribute_name of ['content', 'href', 'src']) {
        let attribute_value = element.getAttribute(attribute_name)
        if (attribute_value && attribute_value.startsWith('./')) {
            let base_hash = window.location.pathname.match(/(^\/ipfs\/\w+)/)[1]
            let uri = base_hash + attribute_value.slice(1)
            let anchor = document.createElement('a')
            anchor.href = uri
            console.log('loading IPFS sub-content for ' + anchor.pathname)

            return node.files.cat(anchor.pathname).then(function (contents_buffer) {
                element.setAttribute(attribute_name, URL.createObjectURL(new Blob([contents_buffer])))
            })
        }
    }
}


function App() {
    let node

    create()

    function create() {
        node = new IPFS({
            config: {
                Addresses: {
                    Swarm: [
//                        '/dns4/wrtc-star.discovery.libp2p.io/tcp/443/wss/p2p-websocket-star'
                    ]
                }
            }
        })

        node.on('ready', () => {
            console.log('IPFS node is ready')
            console.log('loading IPFS content for ' + window.location.pathname)

            // Load the page contents for the IPFS hash.
            node.files.cat(window.location.pathname)
            .then(function (contents_buffer) {
                let iframe = document.createElement('iframe')
                iframe.style = 'width: 100%; height: 100%; border: 0; overflow: hidden'

                // TODO: Should only do this if it's actually an HTML document. Need to gracefully skip this for other content types.
                let contents_document = new DOMParser().parseFromString(contents_buffer.toString(), 'text/html')
                let elements = contents_document.querySelectorAll('link,meta,script')
                let promises = []

                for (let element of elements) {
                    promises.push(materialize_references_to_ipfs_content(node, element))
                }

                Promise.all(promises).then(function () {
                    iframe.src = URL.createObjectURL(
                        new Blob([
                            new XMLSerializer().serializeToString(contents_document)
                        ])
                    )

                    document.body.appendChild(iframe)
                })
            })
        })
    }
}

module.exports = App

App()