Cuentas CPMM

import { PublicKey } from "@solana/web3.js";
import BN from "bn.js";

const CPMM_PROGRAM_ID = new PublicKey(
  "CPMMoo8L3F4NbTegBCKVNunggL7H1ZpdTHKxQB5qKP1C"
); // mainnet — see reference/program-addresses

function u16ToBytes(n: number): Buffer {
  const b = Buffer.alloc(2);
  b.writeUInt16BE(n);
  return b;
}

// token0 < token1 by byte order. Getting this wrong yields a valid PDA
// that points at a nonexistent pool.
function sortMints(a: PublicKey, b: PublicKey): [PublicKey, PublicKey] {
  return Buffer.compare(a.toBuffer(), b.toBuffer()) < 0 ? [a, b] : [b, a];
}

export function deriveCpmmAccounts(
  mintA: PublicKey,
  mintB: PublicKey,
  ammConfigIndex = 0,
) {
  const [token0Mint, token1Mint] = sortMints(mintA, mintB);

  const [ammConfig] = PublicKey.findProgramAddressSync(
    [Buffer.from("amm_config"), u16ToBytes(ammConfigIndex)],
    CPMM_PROGRAM_ID,
  );
  const [authority] = PublicKey.findProgramAddressSync(
    [Buffer.from("vault_and_lp_mint_auth_seed")],
    CPMM_PROGRAM_ID,
  );
  const [poolState] = PublicKey.findProgramAddressSync(
    [
      Buffer.from("pool"),
      ammConfig.toBuffer(),
      token0Mint.toBuffer(),
      token1Mint.toBuffer(),
    ],
    CPMM_PROGRAM_ID,
  );
  const [lpMint] = PublicKey.findProgramAddressSync(
    [Buffer.from("pool_lp_mint"), poolState.toBuffer()],
    CPMM_PROGRAM_ID,
  );
  const [vault0] = PublicKey.findProgramAddressSync(
    [Buffer.from("pool_vault"), poolState.toBuffer(), token0Mint.toBuffer()],
    CPMM_PROGRAM_ID,
  );
  const [vault1] = PublicKey.findProgramAddressSync(
    [Buffer.from("pool_vault"), poolState.toBuffer(), token1Mint.toBuffer()],
    CPMM_PROGRAM_ID,
  );
  const [observation] = PublicKey.findProgramAddressSync(
    [Buffer.from("observation"), poolState.toBuffer()],
    CPMM_PROGRAM_ID,
  );

  return {
    ammConfig,
    authority,
    poolState,
    lpMint,
    token0Mint,
    token1Mint,
    vault0,
    vault1,
    observation,
  };
}

// programs/cp-swap/src/states/pool.rs
pub struct PoolState {
    pub amm_config: Pubkey,               // binds this pool to an AmmConfig
    pub pool_creator: Pubkey,             // who ran initialize
    pub token_0_vault: Pubkey,            // == vault0 PDA
    pub token_1_vault: Pubkey,            // == vault1 PDA

    pub lp_mint: Pubkey,
    pub token_0_mint: Pubkey,
    pub token_1_mint: Pubkey,

    pub token_0_program: Pubkey,          // SPL Token or Token-2022 program
    pub token_1_program: Pubkey,

    pub observation_key: Pubkey,          // == observation PDA
    pub auth_bump: u8,
    pub status: u8,                       // bitmask: deposit | withdraw | swap
    pub lp_mint_decimals: u8,
    pub mint_0_decimals: u8,
    pub mint_1_decimals: u8,

    pub lp_supply: u64,                   // mirrors lp_mint supply
    pub protocol_fees_token_0: u64,
    pub protocol_fees_token_1: u64,
    pub fund_fees_token_0: u64,
    pub fund_fees_token_1: u64,

    pub open_time: u64,                   // unix; swaps rejected before this
    pub recent_epoch: u64,

    // Creator-fee state (added after the original layout):
    pub creator_fee_on: u8,               // 0=BothToken, 1=OnlyToken0, 2=OnlyToken1
    pub enable_creator_fee: bool,
    pub padding1: [u8; 6],
    pub creator_fees_token_0: u64,
    pub creator_fees_token_1: u64,

    pub padding: [u64; 28],
}

pub struct AmmConfig {
    pub bump: u8,
    pub disable_create_pool: bool,
    pub index: u16,                       // matches the seed
    pub trade_fee_rate: u64,              // e.g., 2500 = 0.25%
    pub protocol_fee_rate: u64,           // fraction of trade fee to protocol
    pub fund_fee_rate: u64,               // fraction of trade fee to fund
    pub create_pool_fee: u64,             // paid once at init (in SOL or token)
    pub protocol_owner: Pubkey,           // can call CollectProtocolFee
    pub fund_owner: Pubkey,               // can call CollectFundFee
    pub creator_fee_rate: u64,            // optional pool-creator fee rate (1/1_000_000 of volume)
    pub padding: [u64; 15],
}

pub struct Permission {
    pub authority: Pubkey,    // who is allowed to call InitializeWithPermission
    pub padding: [u64; 8],
}

// OBSERVATION_NUM is hardcoded in the program to 100.
pub const OBSERVATION_NUM: usize = 100;

pub struct Observation {
    pub block_timestamp:              u64,
    pub cumulative_token_0_price_x32: u128,   // Q32.32, top 64 bits left for overflow
    pub cumulative_token_1_price_x32: u128,
}

pub struct ObservationState {
    pub initialized:           bool,
    pub observation_index:     u16,                            // circular index
    pub pool_id:               Pubkey,
    pub observations:          [Observation; OBSERVATION_NUM], // 100 entries
    pub last_update_timestamp: u64,                            // timestamp of the most recent append
    pub padding:               [u64; 3],
}