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use regex::Regex;
use std::fmt::{self, Display, Formatter};
use std::iter::FromIterator;
use std::str::FromStr;
use bitcoin::util::bip32::{ChildNumber, DerivationPath, ExtendedPubKey};
use miniscript::MiniscriptKey;
use slip132::FromSlip132;
use strict_encoding::{self, StrictDecode, StrictEncode};
use super::{DerivationRangeVec, HardenedNormalSplit, UnhardenedIndex};
#[derive(
Clone,
PartialEq,
Eq,
PartialOrd,
Ord,
Hash,
Debug,
StrictEncode,
StrictDecode,
)]
pub struct DerivationComponents {
pub master_xpub: ExtendedPubKey,
pub branch_path: DerivationPath,
pub branch_xpub: ExtendedPubKey,
pub terminal_path: Vec<u32>,
pub index_ranges: Option<DerivationRangeVec>,
}
impl DerivationComponents {
pub fn count(&self) -> u32 {
match self.index_ranges {
None => ::std::u32::MAX,
Some(ref ranges) => ranges.count(),
}
}
pub fn derivation_path(&self) -> DerivationPath {
self.branch_path.extend(self.terminal_path())
}
pub fn terminal_path(&self) -> DerivationPath {
DerivationPath::from_iter(
self.terminal_path
.iter()
.map(|i| ChildNumber::Normal { index: *i }),
)
}
pub fn index_ranges_string(&self) -> String {
self.index_ranges
.as_ref()
.map(DerivationRangeVec::to_string)
.unwrap_or_default()
}
pub fn child(&self, child: u32) -> ExtendedPubKey {
let derivation = self
.terminal_path()
.into_child(ChildNumber::Normal { index: child });
self.branch_xpub
.derive_pub(&crate::SECP256K1, &derivation)
.expect("Non-hardened derivation does not fail")
}
pub fn derive_public_key(
&self,
child_index: UnhardenedIndex,
) -> bitcoin::PublicKey {
self.child(child_index.into()).public_key
}
}
impl Display for DerivationComponents {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
if f.alternate() {
write!(f, "[{}]", self.master_xpub.fingerprint())?;
} else {
write!(f, "[{}]", self.master_xpub)?;
}
f.write_str(self.branch_path.to_string().trim_start_matches("m"))?;
if f.alternate() {
f.write_str("/")?;
} else if self.branch_xpub != self.master_xpub {
write!(f, "=[{}]", self.branch_xpub)?;
}
f.write_str(self.terminal_path().to_string().trim_start_matches("m"))?;
f.write_str("/")?;
if let Some(_) = self.index_ranges {
f.write_str(&self.index_ranges_string())
} else {
f.write_str("*")
}
}
}
#[derive(
Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug, Display, Error,
)]
#[display(inner)]
pub struct ComponentsParseError(pub String);
impl FromStr for DerivationComponents {
type Err = ComponentsParseError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
lazy_static! {
static ref RE_DERIVATION: Regex = Regex::new(
r"(?x)^
\[(?P<xpub>[xyztuvXYZTUV]pub[1-9A-HJ-NP-Za-km-z]{107,108})\]
/(?P<deriv>([0-9]{1,10}[h']?)+)
(/(?P<range>\*|([0-9]{1,10}([,-][0-9]{1,10})*)))?
$",
)
.expect("Regexp expression for `DerivationComponents` is broken");
}
let mut split = s.split('=');
let (branch, terminal) = match (split.next(), split.next(), split.next()) {
(Some(branch), Some(terminal), None) => (Some(branch), terminal),
(Some(terminal), None, None) => (None, terminal),
(None, None, None) => unreachable!(),
_ => Err(ComponentsParseError(s!("Derivation components string must contain at most two parts separated by `=`")))?
};
let caps = if let Some(caps) = RE_DERIVATION.captures(terminal) {
caps
} else {
Err(ComponentsParseError(s!(
"Wrong composition of derivation components data"
)))?
};
let branch_xpub = ExtendedPubKey::from_slip132_str(
caps.name("xpub").expect("regexp engine is broken").as_str(),
)
.map_err(|err| ComponentsParseError(err.to_string()))?;
let terminal_path = caps
.name("deriv")
.expect("regexp engine is broken")
.as_str();
let terminal_path =
DerivationPath::from_str(&format!("m/{}", terminal_path))
.map_err(|err| ComponentsParseError(err.to_string()))?;
let (prefix, terminal_path) = terminal_path.hardened_normal_split();
if !prefix.as_ref().is_empty() {
Err(ComponentsParseError(s!(
"Terminal derivation path must not contain hardened keys"
)))?;
}
let index_ranges = caps
.name("range")
.as_ref()
.map(regex::Match::as_str)
.map(DerivationRangeVec::from_str)
.transpose()
.map_err(|err| ComponentsParseError(err.to_string()))?;
let (master_xpub, branch_path) = if let Some(caps) =
branch.and_then(|branch| RE_DERIVATION.captures(branch))
{
let master_xpub = ExtendedPubKey::from_slip132_str(
caps.name("xpub").expect("regexp engine is broken").as_str(),
)
.map_err(|err| ComponentsParseError(err.to_string()))?;
let branch_path = caps
.name("deriv")
.expect("regexp engine is broken")
.as_str();
let branch_path =
DerivationPath::from_str(&format!("m/{}", branch_path))
.map_err(|err| ComponentsParseError(err.to_string()))?;
(master_xpub, branch_path)
} else {
(
branch_xpub.clone(),
DerivationPath::from(Vec::<ChildNumber>::new()),
)
};
Ok(DerivationComponents {
master_xpub,
branch_path,
branch_xpub,
terminal_path,
index_ranges,
})
}
}
impl MiniscriptKey for DerivationComponents {
type Hash = Self;
fn to_pubkeyhash(&self) -> Self::Hash {
self.clone()
}
}