[V2] Yamato.redeemAll() for flashbots

[0xMotoko]

Problem

• As we discussed Gasgolf/huge redemption2 #73, a huge redemption requires relative amount of txcost against the redemption amount.

Harm

• Given there's a redemption efficiency graph, it is constant.
• Both a small redemption and a huge redemption pay a few percent of txcost.

Cause

• Traversing pledges and expensing each one.
• Larger redemption, more traversing and processing.

Solution

• redeemAll() and expense all pledges at once. txcost will be cheaper.
• Given there's a redemption efficiency graph, it will be linear.
• A huge redemption is more efficient.
• Flashbots are much more profitable.

[0xMotoko]

As sidenotes

A good example of flashbots trick.

Flashbots pattern - CJPY is cheaper(weaker) in Uniswap!

• Assumptions and prerequisites
  • 520000CJPY/ETH in Uniswap
  • 500000JPY/ETH in Oracle
  • $50M concentrated liquidity in Uniswap

1. Alice borrows 10000ETH at Aave
2. Alice sells ETH for 5.2B CJPY in the Uniswap
3. Alice redeems 5.2B CJPY in Yamato and get 10400ETH (with a constant amount of txcost 💯 )
4. Alice repays 10000ETH to Aave and secured 400ETH

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And not a flashbots pattern but whale pattern of a trick ;)

Whale pattern - CJPY is more expensive(stronger) in Uniswap!

• Assumptions and prerequisites
  • 300000CJPY/ETH in Uniswap
  • 520000JPY/ETH in Oracle
  • $50M concentrated liquidity in Uniswap

1. Bob has 10000ETH
2. Bob deposits 10000ETH to Yamato protocol
3. In another tx, Bob borrows 3.84B CJPY. (MCR1.3, 4% fee)
4. Bob sells 3.84B CJPY in Uniswap and get 12800ETH
5. Bob deposits some ETH to Yamato and wait until Uniswap-Oracle depeg will be fixed.
6. Now Uniswap and Oracle are synced, Bob buy back CJPY in the market and repay all, then withdraw all deposited ETH.
7. Bob has approximately 15000ETH.

[0xMotoko]

A note about the contract size

• Yamato.sol is 22.914KB
• YamatoHelper.sol is 24.286KB
• reduceAll() will hits both of them.
• So separating YamatoHelper.sol into YamatoRouter.sol, YamatoDepositer.sol, YamatoBorrower.sol, YamatoRepayer.sol, YamatoWithdrawer.sol, YamatoRedeemer.sol, and YamatoSweeper.sol would be better.
• All those YamatoXxxer.sol should inherit YamatoHelperBase.sol
• reduceAll() should be in YamatoRedeemer.sol