Manually creating a PDA in the instruction function - rust

Question

I am trying to dynamically allocate a PDA with system_program's create_account instruction, but I feel like I am missing some key piece of information. I keep getting an error saying:
Error: failed to send transaction: Transaction simulation failed: Error processing Instruction 0: Cross-program invocation with unauthorized signer or writable account
I managed to deduce that the create_account call itself is what fails; I am not sure if I passed in the wrong seeds, or if my signers on the frontend/context are configured wrong (previously I was going with a Signer<'info> directly, but then following the Anchor Book article on PDAs, I turned that into an unchecked account, for better or worse.
pub fn init_collection(
_ctx: Context<InitCollection>,
) -> Result<()> {
msg!("checking if account is initialized");
if !_ctx.accounts.col.data_is_empty() {
msg!("account is already initialized");
return Ok(());
}
let acc = _ctx.accounts.borrow_mut();
init_pda(
&_ctx.accounts.col.to_account_info(),
&_ctx.accounts.rent,
14,
&crate::id(),
&_ctx.accounts.payer.to_account_info(),
&_ctx.accounts.system_program,
&[
b"col".as_ref(),
&[255],
])?;
Ok(())
}
#[derive(Accounts)]
pub struct InitCollection<'info> {
/// CHECK: Is checked in the program.
#[account(mut, seeds = [b"col".as_ref()], bump)]
col: UncheckedAccount<'info>,
/// CHECK: Is checked in the CPI.
payer: UncheckedAccount<'info>,
system_program: Program<'info, System>,
rent: Sysvar<'info, Rent>,
}
For creating the account itself, I basically lifted the functionality from the anchor project:
pub fn init_pda<'a>(
new_account: &AccountInfo<'a>,
rent_key: &Sysvar<'a, Rent>,
space: usize,
owner: &Pubkey,
payer: &AccountInfo<'a>,
system_program: &AccountInfo<'a>,
seeds_with_nonce: &[&[u8]],
) -> Result<()>
{
let rent = &Rent::from_account_info(&rent_key.to_account_info())?;
// If the account being initialized already has lamports, then
// return them all back to the payer so that the account has
// zero lamports when the system program's create instruction
// is eventually called.
let __current_lamports = new_account.lamports();
if __current_lamports == 0 {
// Create the token account with right amount of lamports and space, and the correct owner.
let lamports = rent.minimum_balance(space);
let cpi_accounts = anchor_lang::system_program::CreateAccount {
from: payer.to_account_info(),
to: new_account.to_account_info()
};
let cpi_context = anchor_lang::context::CpiContext::new(system_program.to_owned(), cpi_accounts);
anchor_lang::system_program::create_account(cpi_context.with_signer(&[seeds_with_nonce]), lamports, space as u64, owner)?; // <== This seems to be where it's failing
} else {
// Fund the account for rent exemption.
let required_lamports = rent
.minimum_balance(space)
.max(1)
.saturating_sub(__current_lamports);
if required_lamports > 0 {
let cpi_accounts = anchor_lang::system_program::Transfer {
from: payer.to_owned(),
to: new_account.to_owned(),
};
let cpi_context = anchor_lang::context::CpiContext::new(system_program.to_owned(), cpi_accounts);
anchor_lang::system_program::transfer(cpi_context, required_lamports)?;
}
// Allocate space.
let cpi_accounts = anchor_lang::system_program::Allocate {
account_to_allocate: new_account.to_owned(),
};
let cpi_context = anchor_lang::context::CpiContext::new(system_program.to_account_info(), cpi_accounts);
anchor_lang::system_program::allocate(cpi_context.with_signer(&[seeds_with_nonce]), space as u64)?;
// Assign to the spl token program.
let cpi_accounts = anchor_lang::system_program::Assign {
account_to_assign: new_account.to_owned()
};
let cpi_context = anchor_lang::context::CpiContext::new(system_program.to_account_info(), cpi_accounts);
anchor_lang::system_program::assign(cpi_context.with_signer(&[seeds_with_nonce]), owner)?;
}
Ok(())
}
Can anyone point me to the right direction? I can't seem to be able to figure out where exactly what I am missing.
Thank you!