CDPManager

The CDPManager is the core engine of Moonight Protocol. It handles the full CDP lifecycle: opening positions, managing collateral and debt, interest accrual, and liquidations.

Address (Sepolia): 0x300a5714cc1bafe5e13297654739cc395703beb15701be71ffb9bf6cdc1a982

Data Structures

PositionData

struct PositionData {
    collateral_type: felt252,    // e.g. 'WBTC'
    collateral_amount: u256,     // 18 decimals
    debt: u256,                  // moonUSD owed (18 decimals)
    interest_rate: u256,         // annual rate (18 decimals, e.g. 0.05e18 = 5%)
    last_update: u64,            // timestamp of last interest accrual
    created_at: u64,             // position creation timestamp
}

Write Functions

open_position

Opens a new CDP. Transfers collateral from caller, mints a PositionNFT, and mints moonUSD to the caller.

fn open_position(
    ref self: TContractState,
    collateral_type: felt252,    // 'WBTC'
    collateral_amount: u256,     // amount to deposit
    debt_amount: u256,           // moonUSD to mint
    interest_rate: u256,         // chosen annual rate
) -> u256                        // returns position_id

Requirements:

• debt_amount >= min_debt (default 100 moonUSD)
• LTV ratio must not exceed max_ltv for the collateral type
• interest_rate must be within [min_rate, max_rate]
• Oracle price must be fresh (not stale)

Side effects:

• Deducts borrow fee (7 days of interest): 75% to Stability Pool, 25% to treasury
• Inserts position into RedemptionManager sorted queue

close_position

Repays all debt and returns collateral to the position owner.

fn close_position(ref self: TContractState, position_id: u256)

deposit_collateral

Adds collateral to an existing position, improving its health factor.

fn deposit_collateral(ref self: TContractState, position_id: u256, amount: u256)

withdraw_collateral

Removes collateral from a position. Fails if the resulting health factor would drop below min_hf_after_withdrawal (default 1.1).

fn withdraw_collateral(ref self: TContractState, position_id: u256, amount: u256)

mint_more

Mints additional moonUSD against an existing position. Charges a borrow fee on the new debt.

fn mint_more(ref self: TContractState, position_id: u256, amount: u256)

repay

Repays debt on an existing position. Burns the caller’s moonUSD.

fn repay(ref self: TContractState, position_id: u256, amount: u256)

set_rate

Changes the interest rate on a position. Rate decreases have a cooldown period (default 12 hours) to prevent gaming.

fn set_rate(ref self: TContractState, position_id: u256, new_rate: u256)

liquidate

Liquidates a position with health factor ≤ 1.0.

fn liquidate(ref self: TContractState, position_id: u256)

Liquidation paths (in priority order):

1. Stability Pool absorption — SP burns moonUSD, receives collateral + 10% bonus
2. Redistribution — debt and collateral spread across remaining positions

add_collateral_type

Registers a new collateral token. Owner-only.

fn add_collateral_type(
    ref self: TContractState,
    collateral_type: felt252,
    token_address: ContractAddress,
    max_ltv: u256,               // e.g. 0.8e18 = 80%
    liquidation_bonus: u256,     // e.g. 0.1e18 = 10%
)

Read Functions

get_position

fn get_position(self: @TContractState, position_id: u256) -> PositionData

get_health_factor

Returns the current health factor: HF = (collateral * price * max_ltv) / debt

fn get_health_factor(self: @TContractState, position_id: u256) -> u256

get_current_debt

Returns debt with accrued interest up to the current timestamp.

fn get_current_debt(self: @TContractState, position_id: u256) -> u256

get_market_average_rate

Weighted average interest rate across all active positions.

fn get_market_average_rate(self: @TContractState) -> u256

get_borrow_fee

Calculates the upfront borrow fee for a given debt amount and rate.

fn get_borrow_fee(self: @TContractState, debt_amount: u256, rate: u256) -> u256

get_total_debt / get_active_positions

fn get_total_debt(self: @TContractState) -> u256
fn get_active_positions(self: @TContractState) -> u256

Events