// Forked from https://github.com/ipfs/ipfs-service-worker which does not work with recent versions
// of js-ipfs.

/* global self, Response */

'use strict'

const IPFS = require('ipfs')
let node

// https://redfin.engineering/how-to-fix-the-refresh-button-when-using-service-workers-a8e27af6df68
self.skipWaiting()

self.addEventListener('install', (event) => {
    console.log('install step')

    event.waitUntil(self.skipWaiting())
})

self.addEventListener('activate', (event) => {
    console.log('activate step')

    event.waitUntil(self.clients.claim())
})

function initialize_ipfs() {
    return new Promise((resolve, reject) => {
        node = new IPFS()

        node.on('ready', () => {
            console.log('js-ipfs node is ready')
            resolve()
        })
        node.on('error', (err) => {
            console.log('js-ipfs node errored', err)
            reject(err)
        })
    })
}

let ipfs_initialized

self.addEventListener('fetch', (event) => {
    if (!event.request.url.startsWith(self.location.origin + '/ipfs')) {
        return console.log('Fetch not in scope:', event.request.url)
    }

    console.log('Handling fetch event:', event.request.url)

    const headers = {
        status: 200,
        statusText: 'OK',
        headers: {}
    }

    if (!ipfs_initialized) {
        ipfs_initialized = initialize_ipfs()
    }

    event.respondWith(
        ipfs_initialized.then(function() {
            const url = new URL(event.request.url)
            const multihash = url.pathname
            return node.files.cat(multihash)
        }).then(function (contents_buffer) {
            return new Promise((resolve, reject) => {
                const response = new Response(contents_buffer, headers)

                resolve(response)
            })
        })
    )
})