Adding descriptor generator

src/commands.rs

@@ -13,7 +13,6 @@
 //! All subcommands are defined in the below enums.
 
 #![allow(clippy::large_enum_variant)]
-
 use bdk_wallet::bitcoin::{
     bip32::{DerivationPath, Xpriv},
     Address, Network, OutPoint, ScriptBuf,
@@ -104,6 +103,42 @@ pub enum CliSubCommand {
         #[command(flatten)]
         wallet_opts: WalletOpts,
     },
+    /// Generate a Bitcoin descriptor either from a provided XPRV or by generating a new random mnemonic.
+    ///
+    /// This function supports two modes:
+    ///
+    /// 1. **Using a provided XPRV**:
+    ///    - Generates BIP32-based descriptors from the provided extended private key.
+    ///    - Derives both external (`/0/*`) and internal (`/1/*`) paths.
+    ///    - Automatically detects the script type from the `--type` flag (e.g., BIP44, BIP49, BIP84, BIP86).
+    ///
+    /// 2. **Generating a new mnemonic**:
+    ///    - Creates a new 12-word BIP39 mnemonic phrase.
+    ///    - Derives a BIP32 root XPRV using the standard derivation path based on the selected script type.
+    ///    - Constructs external and internal descriptors using that XPRV.
+    ///
+    /// The output is a prettified JSON object containing:
+    /// - `mnemonic` (if generated): the 12-word seed phrase.
+    /// - `external`: public and private descriptors for receive addresses (`/0/*`)
+    /// - `internal`: public and private descriptors for change addresses (`/1/*`)
+    /// - `fingerprint`: master key fingerprint used in the descriptors
+    /// - `network`: either `mainnet`, `testnet`, `signet`, or `regtest`
+    /// - `type`: one of `bip44`, `bip49`, `bip84`, or `bip86`
+    ///
+    /// > ⚠️ **Security Warning**: This feature is intended for testing and development purposes.
+    /// > Do **not** use generated descriptors or mnemonics to secure real Bitcoin funds on mainnet.
+    ///
+    Descriptor(GenerateDescriptorArgs),
+}
+#[derive(Debug, Clone, PartialEq, Args)]
+pub struct GenerateDescriptorArgs {
+    #[clap(long, value_parser = clap::value_parser!(u8).range(44..=86))]
+    pub r#type: u8, // 44, 49, 84, 86
+
+    #[clap(long)]
+    pub multipath: bool,
+
+    pub key: Option<String>, // Positional argument (tprv/tpub/xprv/xpub)
 }
 
 /// Wallet operation subcommands.

src/error.rs

@@ -89,4 +89,31 @@ pub enum BDKCliError {
     #[cfg(feature = "cbf")]
     #[error("BDK-Kyoto error: {0}")]
     BuilderError(#[from] bdk_kyoto::builder::BuilderError),
+
+    #[error("Mnemonic generation failed: {0}")]
+    MnemonicGenerationError(String),
+
+    #[error("Xpriv creation failed: {0}")]
+    XprivCreationError(String),
+
+    #[error("Descriptor parsing failed: {0}")]
+    DescriptorParsingError(String),
+
+    #[error("Invalid extended public key (xpub): {0}")]
+    InvalidXpub(String),
+
+    #[error("Invalid extended private key (xprv): {0}")]
+    InvalidXprv(String),
+
+    #[error("Invalid derivation path: {0}")]
+    InvalidDerivationPath(String),
+
+    #[error("Unsupported script type: {0}")]
+    UnsupportedScriptType(u8),
+
+    #[error("Descriptor key conversion failed: {0}")]
+    DescriptorKeyError(String),
+
+    #[error("Invalid arguments: {0}")]
+    InvalidArguments(String),
 }

src/handlers.rs

@@ -20,11 +20,25 @@ use bdk_wallet::bip39::{Language, Mnemonic};
 use bdk_wallet::bitcoin::bip32::{DerivationPath, KeySource};
 use bdk_wallet::bitcoin::consensus::encode::serialize_hex;
 use bdk_wallet::bitcoin::script::PushBytesBuf;
+use bdk_wallet::bitcoin::secp256k1::Secp256k1;
 use bdk_wallet::bitcoin::Network;
-use bdk_wallet::bitcoin::{secp256k1::Secp256k1, Txid};
-use bdk_wallet::bitcoin::{Amount, FeeRate, Psbt, Sequence};
 use bdk_wallet::descriptor::Segwitv0;
 use bdk_wallet::keys::bip39::WordCount;
+use bdk_wallet::keys::{GeneratableKey, GeneratedKey};
+use bdk_wallet::serde::ser::Error as SerdeErrorTrait;
+use serde_json::json;
+use serde_json::Error as SerdeError;
+use serde_json::Value;
+
+#[cfg(any(
+    feature = "electrum",
+    feature = "esplora",
+    feature = "cbf",
+    feature = "rpc"
+))]
+use bdk_wallet::bitcoin::Transaction;
+use bdk_wallet::bitcoin::Txid;
+use bdk_wallet::bitcoin::{Amount, FeeRate, Psbt, Sequence};
 #[cfg(feature = "sqlite")]
 use bdk_wallet::rusqlite::Connection;
 #[cfg(feature = "compiler")]
@@ -33,18 +47,18 @@ use bdk_wallet::{
     miniscript::policy::Concrete,
 };
 use bdk_wallet::{KeychainKind, SignOptions, Wallet};
+use std::fmt;
+use std::str::FromStr;
 
 use bdk_wallet::keys::DescriptorKey::Secret;
-use bdk_wallet::keys::{DerivableKey, DescriptorKey, ExtendedKey, GeneratableKey, GeneratedKey};
+use bdk_wallet::keys::{DerivableKey, DescriptorKey, ExtendedKey};
 use bdk_wallet::miniscript::miniscript;
-use serde_json::json;
 use std::collections::BTreeMap;
 #[cfg(any(feature = "electrum", feature = "esplora"))]
 use std::collections::HashSet;
 use std::convert::TryFrom;
 #[cfg(feature = "repl")]
 use std::io::Write;
-use std::str::FromStr;
 
 #[cfg(feature = "electrum")]
 use crate::utils::BlockchainClient::Electrum;
@@ -57,7 +71,7 @@ use bdk_wallet::bitcoin::base64::prelude::*;
 ))]
 use {
     crate::commands::OnlineWalletSubCommand::*,
-    bdk_wallet::bitcoin::{consensus::Decodable, hex::FromHex, Transaction},
+    bdk_wallet::bitcoin::{consensus::Decodable, hex::FromHex},
 };
 #[cfg(feature = "esplora")]
 use {crate::utils::BlockchainClient::Esplora, bdk_esplora::EsploraAsyncExt};
@@ -820,10 +834,24 @@ pub(crate) async fn handle_command(cli_opts: CliOpts) -> Result<String, Error> {
             }
             Ok("".to_string())
         }
+        CliSubCommand::Descriptor(args) => {
+            let network = cli_opts.network; // Or just use cli_opts directly
+            let json = handle_generate_descriptor(args.clone(), network)?;
+            Ok(json)
+        }
     };
     result.map_err(|e| e.into())
 }
 
+pub fn handle_generate_descriptor(
+    args: GenerateDescriptorArgs,
+    network: Network,
+) -> Result<String, SerdeError> {
+    let descriptor = generate_descriptor_from_args(args, network)
+        .map_err(|e| SerdeErrorTrait::custom(e.to_string()))?;
+    serde_json::to_string_pretty(&descriptor)
+}
+
 #[cfg(feature = "repl")]
 async fn respond(
     network: Network,
@@ -915,3 +943,52 @@ mod test {
         assert!(is_final(&full_signed_psbt).is_ok());
     }
 }
+
+pub fn generate_descriptor_from_args(
+    args: GenerateDescriptorArgs,
+    network: Network,
+) -> Result<serde_json::Value, Error> {
+    match (args.multipath, args.key.as_ref()) {
+        (true, Some(key)) => generate_multipath_descriptor(&network, args.r#type, key),
+        (false, Some(key)) => generate_standard_descriptor(&network, args.r#type, key),
+        (false, None) => {
+            // New default: generate descriptor from fresh mnemonic (for script_type 84 only maybe)
+            if args.r#type == 84 {
+                generate_new_bip84_descriptor_with_mnemonic(network)
+            } else {
+                Err(Error::Generic(
+                    "Only script type 84 is supported for mnemonic-based generation".to_string(),
+                ))
+            }
+        }
+        _ => Err(Error::InvalidArguments(
+            "Invalid arguments: please provide a key or a weak string".to_string(),
+        )),
+    }
+}
+
+pub fn generate_standard_descriptor(
+    network: &Network,
+    script_type: u8,
+    key: &str,
+) -> Result<Value, Error> {
+    match script_type {
+        84 => generate_bip84_descriptor_from_key(network, key),
+        86 => generate_bip86_descriptor_from_key(network, key),
+        49 => generate_bip49_descriptor_from_key(network, key),
+        44 => generate_bip44_descriptor_from_key(network, key),
+        _ => Err(Error::UnsupportedScriptType(script_type)),
+    }
+}
+
+impl fmt::Display for DescriptorType {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = match self {
+            DescriptorType::Bip44 => "bip44",
+            DescriptorType::Bip49 => "bip49",
+            DescriptorType::Bip84 => "bip84",
+            DescriptorType::Bip86 => "bip86",
+        };
+        write!(f, "{}", s)
+    }
+}