# Technical Overview

The PRFI NFT Staking System uses a fully upgradeable, omnichain architecture built on the Diamond Standard (EIP-2535) and LayerZero. Users stake PRFI, level up NFTs, and earn rewards across chains.

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## Architecture

All staking logic and NFT management are modularized into facets within a single proxy contract on the main chain:

| Facet         | Description                                           |
| ------------- | ----------------------------------------------------- |
| `ERC721Facet` | Core NFT logic: minting, burning, bridging, metadata  |
| `StakerFacet` | Staking engine: stake, merge, lock, rewards, claiming |
| `AdminFacet`  | Configuration, pausing, access control                |
| `GetterFacet` | Read-only data for frontend and integrations          |

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## Omnichain NFT Support (ONFT)

NFTs are **omnichain** - they can be bridged between Base and other supported chains using LayerZero.

* All economic logic lives on the mainnet (single source of truth).
* Users interact from low-gas chains (e.g., Base).
* NFTs preserve full metadata and reward history when bridged.

A sidechain contract manages local NFT ownership and forwards user actions (stake, claim, withdraw, redeem) to the mainchain. The mainchain executes the logic and replies with confirmations.

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## Staking Mechanics

* **Stake PRFI into your NFT** to begin earning rewards.
* **NFT Level** increases as stake crosses defined thresholds (up to level 20).
* **Rarity Multiplier** and **Level** combine into a **weight** that determines rewards.

### Reward Calculation

Rewards are distributed monthly and split into two equal buckets:

* **50%** based on the NFT's `multiplier` (rarity + level)
* **50%** based on `stake x weight` (multiplier x staked PRFI)

This ensures fair rewards for both quality (rarity) and quantity (stake commitment).

### Claiming

* Rewards are claimable on any chain.
* Calling `claim()` syncs missed distributions and updates the last claimed amount.
* High-precision math (`ABDKMathQuad`) ensures exact distribution.

### Merging

* Two NFTs of the same rarity can be merged into one with a higher rarity.
* The resulting NFT inherits the combined stake and an upgraded multiplier.
* Merged NFTs are burned; a new NFT is minted from a reserved ID range.

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## Withdrawing & Redeeming

* **Partial withdrawal:** Remove a portion of staked PRFI (20% fee, redistributed to other holders).
* **Burn to redeem:** Destroy the NFT to withdraw all staked PRFI.
* Withdrawals are blocked during lock periods.

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## Security

| Measure               | Detail                                                     |
| --------------------- | ---------------------------------------------------------- |
| **Diamond Standard**  | Facets can be added or upgraded without contract migration |
| **Reentrancy Guard**  | Prevents reentrancy attacks                                |
| **Pausable**          | Authorized roles can pause functions during incidents      |
| **Trusted Endpoints** | LayerZero messages restricted to trusted chains/contracts  |
| **On-chain**          | All data is auditable and fully deterministic              |

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## Technical Parameters

| Parameter      | Value                                                         |
| -------------- | ------------------------------------------------------------- |
| Withdrawal fee | 20% (configurable)                                            |
| Max level      | 20                                                            |
| Rewards pool   | Funded via protocol earnings, royalties, and monthly airdrops |
| Storage        | NFT state replicated between chains via bridging              |