> For the complete documentation index, see [llms.txt](https://docs.tropicalwater.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tropicalwater.xyz/architecture/contract-architecture.md).

# Contract Architecture

`OpportunityOVault` is a single 768-line Solidity contract (`^0.8.24`) inheriting from four bases:

```mermaid
graph TD
    OV["OpportunityOVault<br/>src/OpportunityOVault.sol"]
    OFT["OFT<br/>LayerZero V2<br/>Omnichain share token"]
    ERC4626["IERC4626<br/>Standard vault interface<br/>(partial compliance — see notes)"]
    AC["AccessControl<br/>OpenZeppelin<br/>Role-based permissions"]
    RG["ReentrancyGuard<br/>OpenZeppelin<br/>Re-entrancy protection"]
    OApp["OApp<br/>LayerZero application base"]

    OV --> OFT
    OV --> ERC4626
    OV --> AC
    OV --> RG
    OFT --> OApp
```

### Chain Roles

The vault is deployed on multiple chains with different roles determined by the `IS_SOURCE_CHAIN` immutable set at construction.

| Role                               | `IS_SOURCE_CHAIN` | Accepts deposits | Manages yield                  | Auto-broadcasts state   | Accepts state sync |
| ---------------------------------- | :---------------: | ---------------- | ------------------------------ | ----------------------- | ------------------ |
| **Source chain** (e.g. Ethereum)   |       `true`      | ✅                | ✅ Admin sets rate/fee/cap      | ✅ On every admin setter | ❌ Reverts          |
| **Destination chain** (e.g. Monad) |      `false`      | Optional         | Read-only (synced from source) | ❌ Reverts               | ✅                  |

{% hint style="info" %}
**`IS_SOURCE_CHAIN` is an `immutable`** — it cannot be changed after deployment. A wrong value requires redeployment.
{% endhint %}

### Access Control

```mermaid
graph LR
    DA["DEFAULT_ADMIN_ROLE<br/>(_delegate address)<br/>Typically LZ delegate / deployer"]
    AR["ADMIN_ROLE<br/>(_admin address)"]
    U["No role<br/>(any address)"]

    DA -->|"grants / revokes"| AR
    AR -->|"setRate · setLockupPeriod<br/>setEarlyRedemptionFee · setCap<br/>addPeerEndpoint · removePeerEndpoint<br/>adminWithdraw"| OV["OpportunityOVault"]
    U -->|"deposit · requestRedemption<br/>cancelRedemption · completeRedemption<br/>redeemEarly · OFT bridge"| OV
```

| Role                 | Holder                                                            | Capabilities                                                                                |
| -------------------- | ----------------------------------------------------------------- | ------------------------------------------------------------------------------------------- |
| `DEFAULT_ADMIN_ROLE` | `_delegate` (LZ delegate, set at construction)                    | Grant / revoke any role via OpenZeppelin `AccessControl`. No direct vault operation access. |
| `ADMIN_ROLE`         | `_admin` (set at construction, grantable by DEFAULT\_ADMIN\_ROLE) | Full vault administration — see admin functions below.                                      |
| No role              | Any address                                                       | Deposit, redeem, bridge shares.                                                             |


---

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