Im trying to split up a utxo in a Script into a value of 1 ada what do I do

Question

Here is my code currently it ends up sending all of the value on the script to the caller but I only want it to send 1 ADA. How do I fix this? Is there anyway to create a smaller output to send

purchase :: AsContractError e => MintParams -> Contract w s e ()
purchase mp =  do
    utxos <- fundsAtAddressGeq valAddress (Ada.lovelaceValueOf 1)

    let redeemer = ()
        pkh = ownPubKey
        tx       = collectFromScript utxos redeemer

    void (submitTxConstraintsSpending lootBox utxos tx)

Answer 1

Because this is a utxo system all utxo's must be consumed and the outputs must balance. In the above case, if I understand your code correctly, the redeemer is the unit () which always passes. As such, any input/output consuming the contract would be accepted. You could send 1 ada to someone and send the rest back to the contract's script address (with fees subtracted) to do what you want.