CPMM 费用

// 改写自 raydium-cp-swap/programs/cp-swap/src/curve/{calculator,fees}.rs。
// 实际代码根据 `is_creator_fee_on_input` 分支；两个分支都保持
// creator_fee 是其自己的费率，永远不是 trade_fee 的一部分的不变量。

const FEE_RATE_DENOMINATOR_VALUE: u64 = 1_000_000;

pub struct FeeBreakdown {
    pub amount_in_after_fees: u64,    // 输入减去输入侧收取的所有费用
    pub amount_out_after_fees: u64,   // 输出减去输出侧收取的任何创建者费
    pub trade_fee:    u64,            // → 分割为下面的 LP / 协议 / 基金桶
    pub protocol_fee: u64,            // trade_fee 的份额
    pub fund_fee:     u64,            // trade_fee 的份额
    pub creator_fee:  u64,            // 独立桶（输入或输出侧）
}

fn take_fees_on_input(
    amount_in: u64,
    trade_rate: u64,
    creator_rate: u64,
    protocol_rate: u64,
    fund_rate: u64,
) -> (u64 /* trade_fee */, u64 /* creator_fee */, u64 /* amount_in_after_fees */) {
    // 两个费率相加，所以我们对组合费用四舍五入一次，然后按比例分割
    // — 这纯粹是一个四舍五入/效率技巧。分割遵守费率：
    // creator_fee/trade_fee == creator_rate/trade_rate。
    let total_fee = ((amount_in as u128) * ((trade_rate + creator_rate) as u128))
        .div_ceil(FEE_RATE_DENOMINATOR_VALUE as u128) as u64;

    let creator_fee = ((total_fee as u128) * (creator_rate as u128)
                       / ((trade_rate + creator_rate) as u128)) as u64;
    let trade_fee   = total_fee - creator_fee;

    (trade_fee, creator_fee, amount_in - total_fee)
}

fn take_creator_fee_on_output(amount_out_swapped: u64, creator_rate: u64) -> (u64, u64) {
    // 当 creator_fee_on 将创建者费路由到输出侧时，
    // trade_fee 作为单个费率在输入上收取，creator_fee
    // 根据曲线输出计算。
    let creator_fee = ((amount_out_swapped as u128) * (creator_rate as u128))
        .div_ceil(FEE_RATE_DENOMINATOR_VALUE as u128) as u64;
    (amount_out_swapped - creator_fee, creator_fee)
}

fn split_trade_fee(
    trade_fee: u64,
    protocol_rate: u64,
    fund_rate: u64,
) -> (u64 /* protocol_fee */, u64 /* fund_fee */) {
    let protocol_fee = (trade_fee as u128 * protocol_rate as u128
                        / FEE_RATE_DENOMINATOR_VALUE as u128) as u64;
    let fund_fee     = (trade_fee as u128 * fund_rate as u128
                        / FEE_RATE_DENOMINATOR_VALUE as u128) as u64;
    (protocol_fee, fund_fee)
}

raw_vault_0_balance = getTokenAccountBalance(vault_0).amount
                    = lp_entitled + protocol_fees_token0
                      + fund_fees_token0 + creator_fees_token0

curve_x = raw_vault_0_balance − (protocol_fees_token0
                                  + fund_fees_token0
                                  + creator_fees_token0)

// 链下：每个桶中当前累积的费用
const pool = await connection.getAccountInfo(poolStatePda);
const decoded = PoolState.decode(pool.data);
console.log(
  "Protocol accrued:",
  decoded.protocolFeesToken0.toString(),
  decoded.protocolFeesToken1.toString(),
);
console.log(
  "Fund accrued:",
  decoded.fundFeesToken0.toString(),
  decoded.fundFeesToken1.toString(),
);
console.log(
  "Creator accrued:",
  decoded.creatorFeesToken0.toString(),
  decoded.creatorFeesToken1.toString(),
);

// 链下：今天的有效费率。
// trade_fee_rate、creator_fee_rate 是交换量的分数（分母 1e6）。
// protocol_fee_rate、fund_fee_rate 是*交易费*的分数（相同分母）。
const config = await fetch("https://api-v3.raydium.io/main/cpmm-config")
  .then((r) => r.json());
const tier = config.data.find((t) => t.index === decoded.ammConfigIndex);

const tradeFeeOfVolume   = tier.tradeFeeRate / 1_000_000;
const protocolOfTradeFee = tier.protocolFeeRate / 1_000_000;
const fundOfTradeFee     = tier.fundFeeRate / 1_000_000;
const lpOfTradeFee       = 1 - protocolOfTradeFee - fundOfTradeFee;

console.log("LP fee effective:",       (tradeFeeOfVolume * lpOfTradeFee * 100).toFixed(4), "%");
console.log("Protocol fee effective:", (tradeFeeOfVolume * protocolOfTradeFee * 100).toFixed(4), "%");
console.log("Fund fee effective:",     (tradeFeeOfVolume * fundOfTradeFee * 100).toFixed(4), "%");
console.log(
  "Creator fee effective:",
  decoded.enableCreatorFee
    ? ((tier.creatorFeeRate / 1_000_000) * 100).toFixed(4) + " %"
    : "0 % (disabled on this pool)",
);