Amazing and fully native swap

[katleta3000]

Hi there, welcome to my swap feature implementation 🚀

That was an exciting challenge, but due to my limited time and priorities, I decided to focus only on the swap feature.

Here, you can take a look at the overall result:
https://github.com/tonkeeper/ios/assets/1257625/32ab2e1b-78e8-4afd-baac-21804d1de181

All three kinds of swap work without using any webview.
As STON.fi defines its individual list of provided tokens, I did the same with USDT, NOT, ANON, PUNK, jUSDT.

Also, in SwapAvailableTokenController, you can find the commented code for receiving tokens from the TON blockchain. Unfortunately, there is no API to search through more than 35k tokens and no way to receive only tokens that are whitelisted. I thought about making recursive requests in the background to get the whole database, but I dropped the realisation from the final codebase. That's why I also didn't finish the ChooseTokenViewController, as it can't be fully implemented to work as expected in Figma. Cheers to those who succeded 🫡

Here are some known issues and polishing things I didn't have time to implement:

• The settings feature for choosing the price variability is not complete. But you can find the line private var priceChangeLimit: Double = 0.01 // 1% in SwapViewModel.swift. And this is a working settings, but with no UI implemented.
• New strings use only the en locale.
• No dynamic update of the token rates on the swap screen – the rate is fixed after the last input.
• No tips in the provider details (also removed the liquidity provider fee)
• There are several duplicated functions between SendV3Controller and the new SwapController; I suggest adding shared controllers or common extensions or moving the re-used codes to other architecture layers.

Some other suggestions for the codebase:

• How about writing unit-tests? As the wallet is an open-source solution, as a potential user, I want to be sure that the code was well tested. I have found two crashes and fixed them as well. unit tests could definitely find them.
• There are duplicated formatters. Please see the attachment below

• Also, there is a lot about the architecture. It's pretty nice and easy to read. However, some layers are not used as they could be, and the SPM modules don't have any intuitive principles of their separation. If you're interested, I can provide my thoughts afterward.