Investigate 1inch integration

[LukSteib]

Goal

Get understanding wether it is feasible to create a 1inch based callee contract

Context

An exchange callee contract that is based on 1inch is a thought after feature. This is due to the fact that 1inch functions as a DEX aggregator and allows to determine the most lucrative paths for token swaps across protocols. The existing callees rely on hardcoded paths. Upside of a 1inch based callee would be a dynamic routing resulting in better market prices to execute swaps.

To check feasibility we want to investigate wether 1inch can be used in a way to get the raw call data that could be used to assemble such a callee contract

Assets

• 1inch aggregation protocol docs: https://docs.1inch.io/docs/aggregation-protocol/introduction#

Tasks

• Outline investigation results

[valiafetisov]

Everything seems to be working via the REST API, according to the quick start page, even the transactions are signed off-chain and sent to their REST API in a raw format.

• There is REST endpoint to get quotes https://docs.1inch.io/docs/aggregation-protocol/api/quote-params
• The contract that will withdraw funds during the exchange will need to set allowance (not sure what it means in case of a flash loan, does VAT contract needs to set the allowance?)
• Only works with IERC20 tokens
• Callee contract will need to utilise clipperSwapToWithPermit
  • It doesn't accept route details, so the data, route, profit, etc returned from the /api/quote can be different from the actual transaction
• There is no official SDK for their API, but unofficial

Actions that can be taken already:

• We need to check if we can directly use their API from the frontend (technically, but also legally)
• We can integrate 1inch quoter into frontend to display 1inch exchange price alongside uniswap price (at least on the dashboard) to see the difference even if we don't yet allow exchange
• We need to Conceptualise support of several callees per collateral #374 in terms of UI