Tx structure improvements

[saiy2k]

Following updates are needed with Tx structure:

1. tx.inputs is now of type TxOut. It should be TxIn that has outpoint and scriptSig for each inputs. Right now TxOut has outpoint.
2. tx.outputs should have asset specific data right? for liquid and for usdt (in our case)?

[i5hi]

1. I had this thought initially too but check out this struct from lwk: https://docs.rs/lwk_wollet/latest/lwk_wollet/struct.WalletTx.html - inputs and outputs are both WalletTxOut. The field tx: Transaction, has input and output as TxIn and TxOut but this is a native bitcoin struct and does not have the Liquid specific data

2. https://docs.rs/lwk_wollet/latest/lwk_wollet/struct.WalletTxOut.html -> https://docs.rs/elements/0.24.1/elements/struct.TxOutSecrets.html asset can be found here. In lwk-dart its under TxOut->TxOutSecrets :

#[derive(Clone, Debug, PartialEq)]
pub struct TxOut {
    pub script_pubkey: String,
    pub outpoint: OutPoint,
    pub height: Option<u32>,
    pub unblinded: TxOutSecrets,
}

#[derive(Clone, Debug, PartialEq)]
pub struct TxOutSecrets{
    pub value: u64,
    pub value_bf: String,
    pub asset: String,
    pub asset_bf: String,
}

[i5hi]

1. I don't think we have any use for TxIn, do we? Other users of the library may, but not sure what to do because we are just following lwk's structure.

[saiy2k]

So if a single tx spends both liquid and usdt (if that is even possible), it will have 2 txouts, one for liquid and another for usdt. right?