# ActionAddRemoveLiq

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**Source:** `src/fira_bonding/router/ActionAddRemoveLiqV3.sol`
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## Add liquidity variants

| Function                        | Input      | Strategy                                    |
| ------------------------------- | ---------- | ------------------------------------------- |
| `addLiquidityDualTokenAndBt`    | Token + BT | Mint FW from token, add with BT             |
| `addLiquidityDualFwAndBt`       | FW + BT    | Direct dual-sided add                       |
| `addLiquiditySingleToken`       | Token only | Mint FW, swap portion to BT, add both       |
| `addLiquiditySingleBt`          | BT only    | Swap portion to FW, add both                |
| `addLiquiditySingleFw`          | FW only    | Swap portion to BT, add both                |
| `addLiquiditySingleTokenKeepCt` | Token only | Mint FW, mint BT+CT, use BT for LP, keep CT |
| `addLiquiditySingleFwKeepCt`    | FW only    | Same keep-CT strategy                       |

### Keep-CT strategy

Instead of swapping FW to BT, the router mints BT+CT from FW. BT goes to the market for liquidity, CT goes to the user. This way the user gets LP exposure plus floating yield from CT simultaneously.

## Remove liquidity variants

| Function                        | Output                                                     |
| ------------------------------- | ---------------------------------------------------------- |
| `removeLiquidityDualFwAndBt`    | FW + BT separately                                         |
| `removeLiquidityDualTokenAndBt` | Token (from FW redeem) + BT                                |
| `removeLiquiditySingleBt`       | BT only (FW swapped to BT)                                 |
| `removeLiquiditySingleFw`       | FW only (BT swapped to FW, or redeemed via CT post-expiry) |
| `removeLiquiditySingleToken`    | Token (everything converted)                               |

### Post-expiry removal

Since the market doesn't allow swaps post-expiry, single-FW removal sends BT to the CT contract and redeems via `CT.redeemBC()`.

## Core mechanics

All add operations ultimately call `FiraMarket.mint(receiver, netFwUsed, netBtUsed)`. Single-sided adds use approximation libraries to calculate how much to swap before depositing both sides. All remove operations call `FiraMarket.burn`.