swap.rs

use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program_error::ProgramError,
    pubkey::Pubkey,
    system_instruction,
};
use solana_program::program::{invoke};

entrypoint!(process_instruction);

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();
    let user = next_account_info(accounts_iter)?;
    let sol_source = next_account_info(accounts_iter)?;
    let usdc_destination = next_account_info(accounts_iter)?;
    let system_program = next_account_info(accounts_iter)?;

    if !user.is_signer {
        return Err(ProgramError::MissingRequiredSignature);
    }

    let sol_amount = 10_000_000_000; // 10 SOL in lamports
    msg!("Swapping {} SOL for USDC", sol_amount);

    invoke(
        &system_instruction::transfer(user.key, sol_source.key, sol_amount),
        &[user.clone(), sol_source.clone(), system_program.clone()],
    )?;

    // Logic to swap SOL for USDC from a liquidity pool would go here.
    // This would require integration with an AMM like Raydium.

    msg!("Swap successful, USDC credited to destination");
    
    Ok(())
}