buy

Swaps quote → base in a constant-product (x·y=k) pool. Supports exact-in and exact-out with slippage protection. Applies protocol (and optional creator) fees in quote tokens and emits a structured trade log (log_trade_internal) for indexers.

---

Arguments

pub struct BuyArgs {
    /// Quote tokens to spend (exact-in) or max-in (exact-out) — in quote mint’s base units
    pub quote_amount: u64,
    /// Minimum base tokens to receive (exact-in) or exact base out (exact-out)
    pub base_out: u64,
    /// true => exact-in, false => exact-out
    pub is_exact_in: bool,
}

Semantics

• Exact-in (is_exact_in = true): spend up to quote_amount; must receive ≥ base_out base tokens.

• Exact-out (is_exact_in = false): receive exactly base_out base tokens; must spend ≤ quote_amount quote tokens.

---

Required Accounts

Constants available on-chain:

• TRADERSDEX_CURVE_PROGRAM, SOL_MINT, MASTER_ADMIN

• FEE_ACCOUNTS: fixed allowlist of protocol fee recipients

#	Name	Writable	Seeds / Constraints
0	config		["global_config"] (PDA)
1	pool	✅	["pool", base_mint, quote_mint] (PDA); pool.state == 1 (LIVE); pool.base_mint == base_mint; pool.quote_mint == quote_mint
2	base_mint		Owner == SPL Token program
3	quote_mint		Owner == SPL Token program
4	base_vault	✅	["vault", pool, base_mint] (PDA); key == pool.base_vault; owner == pool; mint == base_mint
5	quote_vault	✅	["vault", pool, quote_mint] (PDA); key == pool.quote_vault; owner == pool; mint == quote_mint
6	user	✅
7	user_base_account	✅	mint == base_mint, owner == user
8	user_quote_account	✅	mint == quote_mint, owner == user
9	protocol_fee_recipient	✅	Must equal one of FEE_ACCOUNTS
10	protocol_fee_recipient_token_account	✅	ATA(quote_mint, protocol_fee_recipient)
11	token_program		Must equal SPL Token program ID
12	associated_token_program
13	system_program
14	tradersdex_swap		Must equal this Swap program ID (crate::ID)
15	event_authority		["event_authority"] (PDA)
16	token_creator		Present if pool has creator fees OPTIONAL
17	token_creator_fee_ata	✅	ATA(quote_mint, token_creator); OPTIONAL

---

Behavior (high level)

• Pricing: constant-product x·y=k. Larger trades move price more (slippage).

• Fees (quote side): protocol (and optional creator) fees are taken in quote.

  • protocol_fee_recipient_token_account receives protocol fees.

  • If creator fees apply and token_creator is provided, token_creator_fee_ata receives creator fees (if it is not init then no creator fee).