Update yield controller

docs/home.md

@@ -84,7 +84,7 @@ in climate projects while retaining the ability to unstake their SOL at any poin
 Carbon tokens serve a similar purpose as carbon credits by allowing
 individuals and institutions to offset their carbon emissions.
 
-Sunrise uses the [Toucan NCT Carbon Token](https://blog.toucan.earth/announcing-nct-nature-carbon-tonne/).
+Sunrise uses the [Toucan NCT Carbon Token](https://blog.toucan.earth/announcing-nct-nature-carbon-tonne/), with more carbon tokens coming online in Q3 2023.
 
 Each token represents 1 tonne of CO2 equivalent, Burning a token permanently retires the underlying carbon credit.
 

docs/other-questions.md

@@ -39,7 +39,7 @@ Once the pool is established, Sunrise will direct stake to this pool, resulting
 
 ## Is Sunrise Stake audited?
 
-Audit is planned for early 2023. Stay tuned!
+Audit is planned for 2023. Stay tuned!
 
 
 ## Where is the source code?

docs/spending.md

@@ -6,34 +6,81 @@ sidebar_label: Spending Yield
 
 # Spending Yield
 
-Thanks to the yield earned in the staking process, Sunrise can purchase carbon tokens and burn them to offset carbon emissions.
+The yield earned by the Sunrise Stake platform is spent on climate-positive projects. 
+The system that controls the spending of yield is called the [Yield Controller](https://github.com/sunrise-stake/yield-controller).
 
-![yield_controller_white_without_comments.png](/img/yield_controller_white_without_comments.png)
+The Yield Controller is responsible for:
+- Collecting yield from the stake program
+- Splitting it among the various spending destinations (called "targets")
+- Triggering the spending processes of these targets.
+
+![yield-controller-router.jpg](/img/yield-controller-router.jpg)
 
 ## 1. Yield transfer to the yield account
 
-The yield earned from staking SOL is transferred to the __yield account__.
+The yield earned from staking SOL is transferred to the [__yield account__](https://solscan.io/account/6HQrvpMJFqMj35JqMReyhnUrRXNucAAB6FywdDu7xPKA).
 
 It is a Program Derived Address ([PDA](https://docs.solana.com/developing/programming-model/calling-between-programs#program-derived-addresses))
-meaning that it is owned and controlled by a smart contract, not a private key.
+meaning that it is owned and controlled by a smart contract (the yield controller), not a private key.
+
+The yield account is specified in the [state](https://solana.fm/address/43m66crxGfXSJpmx5wXRoFuHubhHA1GCvtHgmHW6cM1P/anchor-account)
+of the Sunrise program (labelled 'treasury'). The permissionless `extract_yield` instruction transfers any accrued yield to this account.
+
+## 2. Splitting to targets
+
+The Yield Controller protocol includes a program called the `Yield Router`.
+
+This program is configured with a number of `targets` and `proportions`. 
+
+Executing the yield router's `allocate_yield` instruction sends funds from the `yield account`
+to a number of target `input accounts`. 
+
+Each input account is a PDA owned by a given target program.
 
-This smart contract is known as the __yield controller__.
-It can trigger a state change to buy or burn carbon tokens, thus retiring underlying carbon credits.
+## 3. Currently-supported Targets
 
-## 2. Purchasing carbon tokens
+### 3.1 Toucan Nature Carbon Tonne
 
-The carbon token used by Sunrise Stake is the Toucan Nature Carbon Tonne token.
+Sunrise Stake currently spends its yield by buying and retiring the Toucan Nature Carbon Tonne (NCT) token.
 
 NCT represents a tonne of CO2 or equivalent greenhouse gas removed from the atmosphere in various nature-based projects.
-It is issued on the Polygon and Celo blockchains and has been bridged to Solana via [Wormhole](https://wormhole.com/).
+It is issued on the Polygon and Celo blockchains.
 
 More on the NCT can be found on Toucan’s [blog](https://blog.toucan.earth/announcing-nct-nature-carbon-tonne/) or [GitHub](https://github.com/ToucanProtocol/contracts) repository.
 
-The Solana bridged token mint address is [7sbtAMfAuSfsUvZKPWiXUXaizYCnpLL2BBnKNTU3wjfT](https://solscan.io/token/7sbtAMfAuSfsUvZKPWiXUXaizYCnpLL2BBnKNTU3wjfT).
+#### 3.1.1 Buying and Retiring NCT
+
+Sunrise has built the [Offset Bridge](https://offset.sunrisestake.com/), a cross-chain protocol
+that to bridge funds from Solana to Polygon and Celo, and then uses them to buy and retire
+carbon credits using the Toucan protocol.
+
+##### Structure of the Offset Bridge
+
+The Offset Bridge is made up of:
+- The TokenSwap contract on Solana
+- The Holding contract on Polygon/Celo
+- The CarbonOffsetSettler contract on Polygon/Celo
+
+The steps are as follows:
+1. The Yield Controller transfers funds to the Offset Bridge target
+2. The Offset Bridge Solana program swaps SOL to USDCpo (Wormhole-wrapped Polygon USDC)
+3. The Offset Bridge Solana program bridges the USDCpo to Polygon and deposits it into a Holding Contract on Polygon
+4. The Holding Contract is a smart contract that is configured to retire carbon to a particular project on Toucan
+5. The Holding Contract calls the Toucan CarbonOffsetSettler contract and sends all USDC to it
+6. The CarbonOffsetSettler contract performs the following steps (atomically)
+   6a. Buys NCT with the USDC using SushiSwap
+   6b. Converts the NCT to tCO2 tokens using Toucan contracts
+   6c. Retires the tCO2 to the project specified in the Holding Contract
+   6d. Sends the resultant retirement certificate NFT to the Holding Contract
+7. The Holding Contract then bridges the NFT back through Wormhole, resulting in a retirmenet certificate NFT on Solana
+
+More details for the Offset Bridge can be found at https://github.com/sunrise-stake/offset-bridge.
+
+![offset-bridge.jpg](/img/offset-bridge.jpg)
 
-## 3. Burning the carbon tokens
+### 3.2 ecoToken
 
-The Sunrise yield controller purchases NCT from a DEX, and burns them.
+Starting in Q4 2023, Sunrise Stake will also be sending a portion of its funds to [ecoToken](https://eco-token.io/),
+a Solana-native project that issues a variety of eco-credits.
 
-_NOTE_:
-Until sufficient liquidity is present on Solana for NCT, Sunrise is maintaining a reserve of bridged NCT, and is automatically burning from this pot at a fixed price.
+ecoToken is linked with Regen Network, that certifies the credits.