PintPass

// Burn points and stamp an immutable on-chain receipt PDA
pub fn handle_redeem(ctx: Context<Redeem>) -> Result<()> {
    let loyalty_program = &mut ctx.accounts.loyalty_program;
    let reward_cost = loyalty_program.reward_cost;

    token::burn(
        CpiContext::new(
            ctx.accounts.token_program.to_account_info(),
            Burn {
                mint: ctx.accounts.points_mint.to_account_info(),
                from: ctx.accounts.customer_token_account.to_account_info(),
                authority: ctx.accounts.customer.to_account_info(),
            },
        ),
        reward_cost,
    )?;

    let receipt = &mut ctx.accounts.receipt;
    receipt.customer = ctx.accounts.customer.key();
    receipt.loyalty_program = loyalty_program.key();
    receipt.receipt_number = loyalty_program.redemption_count;
    receipt.points_burned = reward_cost;
    receipt.timestamp = Clock::get()?.unix_timestamp;
    receipt.bump = ctx.bumps.receipt;

    loyalty_program.total_redeemed = loyalty_program.total_redeemed.checked_add(reward_cost).ok_or(PointPassError::MathOverflow)?;
    loyalty_program.redemption_count = loyalty_program.redemption_count.checked_add(1).ok_or(PointPassError::MathOverflow)?;

    Ok(())
}