Boltz Improvement Proposal: Make swap work on iPhones and iPads

[peartobear]

Problem statement: At this moment, it is not recommended to do a Boltz swap on Apple's iPhone or iPad devices simply because iOS and iPadOS don't allow for triggering the automated or manual download of files, ergo, the user is left stranded with refund.json file opened in the browser while doing a reverse swap with no way to either download the refund.json file or go back and continue the swap without it. This problem is detrimental to the adoption for Boltz because most wallets are mobile-first and use a built-in Safari browser extension to access different lapps.

Solution: Convert the refund.json file to a QR code in .png format We already generate QR code client-side for the lightning invoices. Parse the refund.json file and refactor the saving and loading logic to use the QR code. Apple devices allow for a swift download of .png file so the QR-fied version of the refund.json could help us work around this Apple bottleneck. Likewise, refactor the refund logic to accommodate reading from the QR code instead of json files. A QR code is easily portable across devices and it will improve the overall experience around Boltz. The QR code is alphanumeric and has the maximum char limit of 4,296, which is well within the range for the contents of refund.json file.

This is a WIP and all the discussion/improvements are welcome.

• Explore the QR code design to include Boltz refund logo and the trade ID explicitly written on the QR code. Look at QR codes for WeChat mini-programs
• Decide on whether to make this consistent across all devices or this would be Apple-only feature craved out of necessity. My vote: We should strive to have a uniform UX across all the devices.
• What is the best way to go about it from architectural POV, A next.js export module or an inbulit python script which runs client-side, parses the file, and creates the code.