dig-rpc-types 0.1.0

//! Shared domain types used across multiple RPC methods.
//!
//! This module collects the wire types that more than one method consumes
//! or produces: hex-string hashes / pubkeys / signatures, XCH amounts,
//! block summaries, validator records.
//!
//! All hex-encoded types follow a single convention:
//!
//! - On **serialize**: emit `0x` + lowercase hex.
//! - On **deserialize**: accept upper / lower / mixed case, optional `0x`
//!   prefix.
//!
//! This matches the Chia wire format (where hashes are `0x`-prefixed) and
//! the Ethereum RPC convention, giving us maximum cross-ecosystem
//! compatibility.

use std::fmt;
use std::str::FromStr;

use serde::{Deserialize, Serialize};

// ===========================================================================
// Hex-encoded fixed-length byte arrays
// ===========================================================================

/// A 32-byte hex-encoded value (block hash, coin id, state root, etc).
///
/// Wire form is `"0x"` followed by 64 lowercase hex chars. Deserialization
/// accepts mixed case and optional `0x` prefix.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct HashHex(
    /// Raw 32-byte value.
    pub [u8; 32],
);

impl HashHex {
    /// Construct from a raw 32-byte array.
    pub const fn new(bytes: [u8; 32]) -> Self {
        Self(bytes)
    }

    /// Borrow the underlying 32 bytes.
    pub fn as_bytes(&self) -> &[u8; 32] {
        &self.0
    }
}

impl fmt::Display for HashHex {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "0x{}", hex::encode(self.0))
    }
}

impl FromStr for HashHex {
    type Err = HexParseError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let bytes = parse_hex_fixed::<32>(s)?;
        Ok(Self(bytes))
    }
}

impl Serialize for HashHex {
    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
        s.collect_str(self)
    }
}

impl<'de> Deserialize<'de> for HashHex {
    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
        String::deserialize(d)?
            .parse()
            .map_err(serde::de::Error::custom)
    }
}

/// A 48-byte BLS12-381 G1 compressed public key.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct PubkeyHex(
    /// Raw 48-byte compressed G1 element.
    pub [u8; 48],
);

impl PubkeyHex {
    /// Construct from a raw 48-byte array.
    pub const fn new(bytes: [u8; 48]) -> Self {
        Self(bytes)
    }

    /// Borrow the underlying 48 bytes.
    pub fn as_bytes(&self) -> &[u8; 48] {
        &self.0
    }
}

impl fmt::Display for PubkeyHex {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "0x{}", hex::encode(self.0))
    }
}

impl FromStr for PubkeyHex {
    type Err = HexParseError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let bytes = parse_hex_fixed::<48>(s)?;
        Ok(Self(bytes))
    }
}

impl Serialize for PubkeyHex {
    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
        s.collect_str(self)
    }
}

impl<'de> Deserialize<'de> for PubkeyHex {
    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
        String::deserialize(d)?
            .parse()
            .map_err(serde::de::Error::custom)
    }
}

/// A 96-byte BLS12-381 G2 compressed signature.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct SignatureHex(
    /// Raw 96-byte compressed G2 element.
    pub [u8; 96],
);

impl SignatureHex {
    /// Construct from a raw 96-byte array.
    pub const fn new(bytes: [u8; 96]) -> Self {
        Self(bytes)
    }

    /// Borrow the underlying 96 bytes.
    pub fn as_bytes(&self) -> &[u8; 96] {
        &self.0
    }
}

impl fmt::Display for SignatureHex {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "0x{}", hex::encode(self.0))
    }
}

impl FromStr for SignatureHex {
    type Err = HexParseError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let bytes = parse_hex_fixed::<96>(s)?;
        Ok(Self(bytes))
    }
}

impl Serialize for SignatureHex {
    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
        s.collect_str(self)
    }
}

impl<'de> Deserialize<'de> for SignatureHex {
    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
        String::deserialize(d)?
            .parse()
            .map_err(serde::de::Error::custom)
    }
}

// ===========================================================================
// Scalars
// ===========================================================================

/// A Chia amount in mojos (1 XCH = 10^12 mojos).
///
/// Encoded as a JSON number — safe for amounts up to 2^53 − 1 mojos
/// (~9000 XCH) before float round-trip issues. Larger amounts would need
/// string encoding; not a current concern.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
#[serde(transparent)]
pub struct Amount(
    /// Raw mojo count.
    pub u64,
);

impl Amount {
    /// Zero mojos.
    pub const ZERO: Self = Self(0);
}

// ===========================================================================
// Block / validator summaries
// ===========================================================================

/// Compact metadata for a single L2 block. Returned by `get_block_records`
/// and embedded in larger envelopes like `get_blockchain_state`.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BlockSummary {
    /// Block height on the L2 chain.
    pub height: u64,
    /// Canonical block hash.
    pub hash: HashHex,
    /// Parent block hash.
    pub parent_hash: HashHex,
    /// Unix timestamp (seconds) from the proposer's signed header.
    pub timestamp: u64,
    /// Block proposer's BLS public key.
    pub proposer: PubkeyHex,
    /// Number of transactions included.
    pub tx_count: u32,
    /// Cumulative attestation weight.
    pub weight: u64,
}

/// Validator lifecycle state.
///
/// Values match the state machine in
/// [`docs/superpowers/specs/2026-04-20-validator-lifecycle-checkpoint-gated-design.md`](https://github.com/DIG-Network/dig-network/tree/main/docs)
/// and pair with the [`ValidatorSummary`] struct below.
#[non_exhaustive]
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "snake_case")]
pub enum ValidatorStatus {
    /// Validator has an L1 registration coin but is not yet in the VMR.
    PendingRegister,
    /// Validator is in the current checkpoint's VMR and may sign.
    Active,
    /// Validator submitted a voluntary-exit signal; waiting for next checkpoint.
    ExitingVoluntary,
    /// Validator force-exited by L2 (inactivity / slashing / governance).
    ExitingForced,
    /// Validator's exit was committed to an exit-ledger leaf.
    Exited,
    /// Registration coin was spent to a withdraw-delay coin; waiting for delay.
    WithdrawalPending,
    /// Withdraw-delay coin was released; collateral paid out.
    Withdrawn,
}

/// Summary record for a single validator, returned by `get_validator` /
/// `get_active_validators`.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ValidatorSummary {
    /// BLS12-381 G1 public key — the canonical validator identifier.
    pub pubkey: PubkeyHex,
    /// Current lifecycle state.
    pub status: ValidatorStatus,
    /// Leaf index in the validator-merkle-root, if active. `None` until activation.
    pub validator_index: Option<u32>,
    /// Effective balance (Ethereum-parity hysteresis). In mojos.
    pub effective_balance: Amount,
    /// Cumulative slashed amount. In mojos.
    pub slashed_amount: Amount,
    /// Epoch in which activation committed. `None` if not yet active.
    pub activation_epoch: Option<u64>,
    /// Epoch in which exit committed. `None` if not yet exiting.
    pub exit_epoch: Option<u64>,
}

// ===========================================================================
// Hex parsing helper
// ===========================================================================

/// Errors from parsing a hex string into a fixed-size byte array.
#[derive(Debug, thiserror::Error)]
pub enum HexParseError {
    /// The hex string (after stripping `0x`) had the wrong length.
    #[error(
        "wrong hex length: expected {expected} bytes ({expected_hex_chars} hex chars), got {got}"
    )]
    WrongLength {
        /// Required byte length.
        expected: usize,
        /// Required hex-char length (`expected * 2`).
        expected_hex_chars: usize,
        /// Actual hex-char length observed.
        got: usize,
    },
    /// The hex string contained a non-hex character.
    #[error("invalid hex: {0}")]
    InvalidHex(#[from] hex::FromHexError),
}

fn parse_hex_fixed<const N: usize>(s: &str) -> Result<[u8; N], HexParseError> {
    let stripped = s
        .strip_prefix("0x")
        .or_else(|| s.strip_prefix("0X"))
        .unwrap_or(s);
    if stripped.len() != N * 2 {
        return Err(HexParseError::WrongLength {
            expected: N,
            expected_hex_chars: N * 2,
            got: stripped.len(),
        });
    }
    let mut out = [0u8; N];
    hex::decode_to_slice(stripped, &mut out)?;
    Ok(out)
}

#[cfg(test)]
mod tests {
    use super::*;

    /// **Proves:** a 32-byte `HashHex` serializes as `"0x"` + 64 lowercase
    /// hex chars.
    ///
    /// **Why it matters:** External tooling (explorers, dashboards,
    /// light-clients) identifies coins and blocks by this exact string
    /// form. Any case change or prefix drop would break equality checks
    /// across the ecosystem.
    ///
    /// **Catches:** a regression where `Display` uses uppercase (`{:X}`),
    /// or drops the `0x` prefix.
    #[test]
    fn hash_hex_display() {
        let h = HashHex::new([0xAB; 32]);
        let s = h.to_string();
        assert_eq!(s.len(), 2 + 64);
        assert!(s.starts_with("0x"));
        assert_eq!(s, format!("0x{}", "ab".repeat(32)));
    }

    /// **Proves:** `HashHex::from_str` accepts `0x`-prefixed lowercase,
    /// `0x`-prefixed uppercase, bare lowercase, and mixed case.
    ///
    /// **Why it matters:** JSON ecosystems are inconsistent about hex case
    /// — Rust tends to emit lowercase, JavaScript and Java often emit
    /// mixed. Accepting all forms at deserialize time makes the RPC
    /// resilient to client-library quirks.
    ///
    /// **Catches:** a regression that tightens parsing to one canonical
    /// form, silently breaking some clients.
    #[test]
    fn hash_hex_parse_accepts_case_and_prefix_variations() {
        let want = HashHex::new([0xAB; 32]);

        let inputs = [
            format!("0x{}", "ab".repeat(32)),
            format!("0X{}", "AB".repeat(32)),
            "ab".repeat(32),
            "AB".repeat(32),
        ];

        for s in inputs {
            let parsed: HashHex = s.parse().expect(&s);
            assert_eq!(parsed, want, "parse of {s:?} mismatched");
        }
    }

    /// **Proves:** parsing a hex string of the wrong length (62 chars
    /// instead of 64) returns [`HexParseError::WrongLength`].
    ///
    /// **Why it matters:** Hex-length checks catch truncated values early.
    /// Without this, a shortened hash silently rounded up to 32 bytes
    /// would produce wrong-but-valid-looking coin IDs.
    ///
    /// **Catches:** removing the length check; using `decode` (which ignores
    /// truncation) instead of `decode_to_slice`.
    #[test]
    fn hash_hex_parse_rejects_wrong_length() {
        let short = format!("0x{}", "a".repeat(62));
        let err = short.parse::<HashHex>().unwrap_err();
        assert!(matches!(err, HexParseError::WrongLength { .. }));
    }

    /// **Proves:** `HashHex` and its siblings round-trip through serde JSON
    /// unchanged.
    ///
    /// **Why it matters:** This is the actual wire exercise — serialize to
    /// JSON and deserialize back, checking bit-exact equality.
    ///
    /// **Catches:** a regression where `Serialize`/`Deserialize` impls drift
    /// out of sync (e.g., serializer uses lowercase but deserializer
    /// requires `0x` prefix that the serializer emits).
    #[test]
    fn fixed_hex_types_roundtrip_via_serde() {
        let h = HashHex::new([1u8; 32]);
        let j = serde_json::to_string(&h).unwrap();
        let back: HashHex = serde_json::from_str(&j).unwrap();
        assert_eq!(h, back);

        let p = PubkeyHex::new([2u8; 48]);
        let j = serde_json::to_string(&p).unwrap();
        let back: PubkeyHex = serde_json::from_str(&j).unwrap();
        assert_eq!(p, back);

        let s = SignatureHex::new([3u8; 96]);
        let j = serde_json::to_string(&s).unwrap();
        let back: SignatureHex = serde_json::from_str(&j).unwrap();
        assert_eq!(s, back);
    }

    /// **Proves:** `Amount` serializes as a bare number (transparent
    /// `u64`), not as an object.
    ///
    /// **Why it matters:** An `Amount` of 42 should serialize as `42`, not
    /// `{"0": 42}`. The `#[serde(transparent)]` attribute pins this.
    ///
    /// **Catches:** dropping `#[serde(transparent)]` — which would produce
    /// object form and break every client that expects a bare number.
    #[test]
    fn amount_transparent_serde() {
        let a = Amount(42);
        let s = serde_json::to_string(&a).unwrap();
        assert_eq!(s, "42");
    }

    /// **Proves:** `ValidatorStatus` serializes in snake_case — e.g.,
    /// `"pending_register"`, not `"PendingRegister"`.
    ///
    /// **Why it matters:** JSON conventions favour snake_case for enum
    /// variants; the rest of the crate's types already follow this. Clients
    /// will pattern-match on the exact string.
    ///
    /// **Catches:** a regression that drops `#[serde(rename_all = "snake_case")]`.
    #[test]
    fn validator_status_serialises_snake_case() {
        let s = serde_json::to_string(&ValidatorStatus::PendingRegister).unwrap();
        assert_eq!(s, "\"pending_register\"");

        let s = serde_json::to_string(&ValidatorStatus::WithdrawalPending).unwrap();
        assert_eq!(s, "\"withdrawal_pending\"");
    }

    /// **Proves:** `BlockSummary` + `ValidatorSummary` round-trip through
    /// JSON unchanged when populated with realistic values.
    ///
    /// **Why it matters:** These are the two most-referenced domain types.
    /// If they drift (a field renamed, dropped, or re-typed) every method
    /// that returns them breaks in lockstep.
    ///
    /// **Catches:** accidentally making a field `serde(skip)` that clients
    /// depend on; reordering tuple-like struct fields (which would break
    /// wire form even though compilation succeeds).
    #[test]
    fn summaries_roundtrip() {
        let b = BlockSummary {
            height: 123,
            hash: HashHex::new([1u8; 32]),
            parent_hash: HashHex::new([0u8; 32]),
            timestamp: 1_700_000_000,
            proposer: PubkeyHex::new([9u8; 48]),
            tx_count: 7,
            weight: 10_000,
        };
        let j = serde_json::to_string(&b).unwrap();
        let back: BlockSummary = serde_json::from_str(&j).unwrap();
        assert_eq!(b.height, back.height);
        assert_eq!(b.hash, back.hash);

        let v = ValidatorSummary {
            pubkey: PubkeyHex::new([5u8; 48]),
            status: ValidatorStatus::Active,
            validator_index: Some(42),
            effective_balance: Amount(32_000_000_000_000),
            slashed_amount: Amount::ZERO,
            activation_epoch: Some(7),
            exit_epoch: None,
        };
        let j = serde_json::to_string(&v).unwrap();
        let back: ValidatorSummary = serde_json::from_str(&j).unwrap();
        assert_eq!(back.pubkey, v.pubkey);
        assert_eq!(back.status, v.status);
    }
}