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//! Crate defining an interface for performing a hook on transfer, where the
//! token program calls into a separate program with additional accounts after
//! all other logic, to be sure that a transfer has accomplished all required
//! preconditions.

#![allow(clippy::arithmetic_side_effects)]
#![deny(missing_docs)]
#![cfg_attr(not(test), forbid(unsafe_code))]

pub mod error;
pub mod instruction;
pub mod offchain;
pub mod onchain;

// Export current sdk types for downstream users building with a different sdk
// version
pub use solana_program;
use solana_program::pubkey::Pubkey;

/// Namespace for all programs implementing transfer-hook
pub const NAMESPACE: &str = "spl-transfer-hook-interface";

/// Seed for the state
const EXTRA_ACCOUNT_METAS_SEED: &[u8] = b"extra-account-metas";

/// Get the state address PDA
pub fn get_extra_account_metas_address(mint: &Pubkey, program_id: &Pubkey) -> Pubkey {
    get_extra_account_metas_address_and_bump_seed(mint, program_id).0
}

/// Function used by programs implementing the interface, when creating the PDA,
/// to also get the bump seed
pub fn get_extra_account_metas_address_and_bump_seed(
    mint: &Pubkey,
    program_id: &Pubkey,
) -> (Pubkey, u8) {
    Pubkey::find_program_address(&collect_extra_account_metas_seeds(mint), program_id)
}

/// Function used by programs implementing the interface, when creating the PDA,
/// to get all of the PDA seeds
pub fn collect_extra_account_metas_seeds(mint: &Pubkey) -> [&[u8]; 2] {
    [EXTRA_ACCOUNT_METAS_SEED, mint.as_ref()]
}

/// Function used by programs implementing the interface, when creating the PDA,
/// to sign for the PDA
pub fn collect_extra_account_metas_signer_seeds<'a>(
    mint: &'a Pubkey,
    bump_seed: &'a [u8],
) -> [&'a [u8]; 3] {
    [EXTRA_ACCOUNT_METAS_SEED, mint.as_ref(), bump_seed]
}