> For the complete documentation index, see [llms.txt](https://docs.yuzu.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.yuzu.finance/move.fun/technical/smart-contracts-1.md).

# Smart Contracts

### Module: `move_fun::bonding_curve`

#### Module Info

* **Description**: Core logic for managing bonding curves used in fungible asset pricing.

***

#### Resources

**`BondingCurves`**

```move
struct BondingCurves has key {
    table: table::Table<String, BondingCurve>
}
```

**`BondingCurve`**

```move
struct BondingCurve has key, drop, store, copy {
    initial_price_numerator: u128,
    initial_price_denominator: u128,
    growth_constant: u128
}
```

***

#### Public Functions

| Function                     | Arguments                                    | Type               | Description                                           |
| ---------------------------- | -------------------------------------------- | ------------------ | ----------------------------------------------------- |
| `initialize<CoinType>`       | –                                            | –                  | Initialize bonding curve for a token.                 |
| `initialize_fa`              | –                                            | –                  | Initialize bonding curve for a fungible asset object. |
| `calculate_k`                | `initial_price_n`, `initial_price_d`, `goal` | `u128, u128, u128` | Calculate the growth constant `k`.                    |
| `calculate_buy_amount_out`   | `amount_in`, `supply`, `k`                   | `u128, u128, u128` | Get amount out when buying with given input.          |
| `calculate_buy_amount_in`    | `amount_out`, `supply`, `k`                  | `u128, u128, u128` | Get amount needed to buy specific output.             |
| `calculate_sell_amount_out`  | `amount_in`, `supply`, `k`                   | `u128, u128, u128` | Get amount received when selling tokens.              |
| `calculate_sell_amount_in`   | `amount_out`, `supply`, `k`                  | `u128, u128, u128` | Calculate tokens needed to get a specific return.     |
| `calculate_price`            | `supply`, `k`                                | `u128, u128`       | Calculate token price based on supply.                |
| `calculate_price_by_amounts` | `amount`, `supply`, `k`                      | `u128, u128, u128` | Quick price calculation helper.                       |
| `set_market_cap_goal`        | `curve_id`, `new_goal`                       | `String, u128`     | Adjust bonding curve’s growth constant `k`.           |
| `bonding_curve<CoinType>`    | –                                            | –                  | Access bonding curve for a token.                     |
| `fa_bonding_curve`           | `fa_addr`                                    | `address`          | Access bonding curve for a fungible asset.            |
| `initial_price`              | `curve_id`                                   | `String`           | Return initial price numerator and denominator.       |
| `growth_constant`            | `curve_id`                                   | `String`           | Return the growth constant `k`.                       |

***

#### Errors

| Code | Description                       |
| ---- | --------------------------------- |
| `1`  | Same growth constant as existing. |
| `2`  | Amount out exceeds limits.        |

***

### Module: `move_fun::fungible_asset`

#### Module Info

* **Description**: Defines a fungible asset backed by a bonding curve with mechanisms for buying, selling, and tracking supply.

***

#### Resources

| Resource     | Description                                          |
| ------------ | ---------------------------------------------------- |
| `Registry`   | Manages fungible asset info per address.             |
| `Info`       | Stores bonding curve data and metadata.              |
| `Store`      | Manages virtual balances for wallets.                |
| `FaMetadata` | Holds icon, banner, description, and external links. |

***

#### Events

| Event          | Description                             |
| -------------- | --------------------------------------- |
| `FaDeployed`   | Emitted after deploying a FA.           |
| `FaBought`     | Emitted after a successful FA buy.      |
| `FaSold`       | Emitted after a successful FA sale.     |
| `BundleBuy`    | Emitted after bundled buy distribution. |
| `FeeExtracted` | Emitted after fee extraction.           |

***

#### Entry Functions

| Function                         | Arguments                          | Type                                    | Description                                       |
| -------------------------------- | ---------------------------------- | --------------------------------------- | ------------------------------------------------- |
| `initialize_registry`            | –                                  | –                                       | Setup the registry resource.                      |
| `initialize<DEX>`                | `signer`, metadata, config         | `&signer, struct, struct`               | Initialize a new fungible asset with DEX target.  |
| `buy_exact_out`                  | `&signer`, `amount`                | `&signer, u64`                          | Buy exact amount of FA, paying MOVE.              |
| `buy_exact_in`                   | `&signer`, `amount_in`             | `&signer, u64`                          | Buy as much FA as possible with fixed MOVE input. |
| `sell_exact_in`                  | `&signer`, `amount_in`             | `&signer, u64`                          | Sell fixed amount of FA for MOVE.                 |
| `sell_exact_out`                 | `&signer`, `amount_out`            | `&signer, u64`                          | Sell tokens to receive exact MOVE amount.         |
| `quote_buy_exact_in`             | `amount_in`                        | `u64`                                   | Return FA amount receivable for given MOVE input. |
| `quote_buy_exact_out`            | `amount_out`                       | `u64`                                   | Return MOVE needed to get exact FA amount.        |
| `quote_sell_exact_in`            | `amount_in`                        | `u64`                                   | Return MOVE receivable from selling FA.           |
| `quote_sell_exact_out`           | `amount_out`                       | `u64`                                   | Return FA needed to receive target MOVE.          |
| `retrieve_accumulated_supply`    | `&signer`                          | `&signer`                               | Withdraw raised MOVE from bonding curve.          |
| `claim`                          | `&signer`                          | `&signer`                               | Claim tokens after bonding phase ends.            |
| `retrieve_liquidity_supply`      | `&signer`                          | `&signer`                               | Withdraw liquidity-bound FA.                      |
| `distribute_virtual_balances`    | –                                  | –                                       | Distribute virtual tokens to holders.             |
| `target_price`                   | –                                  | –                                       | Get the current FA target price.                  |
| `transfer_from_virtual_balance`  | `&signer`, `recipient`, `amount`   | `&signer, address, u64`                 | Transfer virtual balance tokens.                  |
| `batch_transfer`                 | `&signer`, `recipients`, `amounts` | `&signer, vector<address>, vector<u64>` | Transfer to many recipients.                      |
| `set_bonding_curve_goal_reached` | `&signer`                          | `&signer`                               | Finalize bonding curve.                           |