Exploring bdk-tx for Wallet type

[thunderbiscuit]

This is just me hacking away at leveraging the bdk-tx crate to build transactions.

[thunderbiscuit]

The API for building transactions using bdk-tx doesn't have to be any different than what we currently have with the TxBuilder, but it could also be. Here are some rough sketches.

Builder pattern

let mut tx_builder = wallet.create_transaction_builder();
tx_builder
    .add_output(address.script_pubkey(), SEND_AMOUNT)
    .fee_rate(FeeRate::from_sat_per_vb(4).unwrap());
let mut psbt = tx_builder.finish()?;

Single method

// pseudocode

let mut psbt = wallet.create_transaction(
    outputs,
    target_feerate,
    must_spend,
    // ...
    // 12 other arguments that basically mimic the current TxBuilder methods
);

Note that this method could also take a single argument TransactionParams which would just be a data structure of the requirements for the tx, again similar to what we have in the private fields of the TxBuilder.

let transaction_params = TransactionParams {
    outputs: vec![(address.script_pubkey(), SEND_AMOUNT)],
    target_feerate: FeeRate::from_sat_per_vb(4).unwrap(),
    must_spend: Vec::new(),
};
let mut psbt = wallet.create_transaction(transaction_params);

2 methods (one for simple common cases)

The first one for simple cases often used and one that takes the full TransactionParams argument.

// For simple transactions
let mut psbt = wallet.create_simple_transaction(
    outputs,        // (Script, Amount)
    target_feerate, // FeeRate
);

// For transactions that require more customization
let mut psbt = wallet.create_complex_transaction(transaction_params);

[coveralls]

Pull Request Test Coverage Report for Build 14316252517

Details

• 0 of 102 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-1.0%) to 85.487%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
wallet/src/wallet/mod.rs	0	102	0.0%

Totals
Change from base Build 14270666930:	-1.0%
Covered Lines:	7269
Relevant Lines:	8503

---

💛 - Coveralls

[thunderbiscuit]

The API for this is being built for production in #297. Note that the method chosen in that PR is the "single method" mentioned above with a Params struct passed to the method rather than the builder.