icydb-schema 0.277.2

//! Canonical fixed-width subaccount atom.

use crate::{Principal, SchemaContractError, atom::deserialize_fixed_bytes};

use serde::{Deserialize, Deserializer, Serialize};
use std::fmt::{self, Display};

//
// Subaccount
//

type SubaccountBytes = [u8; 32];

#[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
/// A canonical 32-byte ICRC account subaccount.
pub struct Subaccount(SubaccountBytes);

impl Subaccount {
    /// The lexicographically smallest subaccount.
    pub const MIN: Self = Self::from_array([0x00; 32]);
    /// The lexicographically largest subaccount.
    pub const MAX: Self = Self::from_array([0xFF; 32]);

    /// Return the fixed-width byte array.
    #[must_use]
    pub const fn to_array(&self) -> [u8; 32] {
        self.0
    }

    /// Construct from the exact fixed-width byte array.
    #[must_use]
    pub const fn from_array(array: [u8; 32]) -> Self {
        Self(array)
    }

    /// Parse 64 ASCII hex digits, optionally prefixed by lowercase `0x`.
    ///
    /// # Errors
    /// Returns [`SchemaContractError::InvalidLiteral`] for invalid width,
    /// non-ASCII input or non-hex characters. No trimming is performed.
    pub fn from_hex(text: &str) -> Result<Self, SchemaContractError> {
        let text = text.strip_prefix("0x").unwrap_or(text);
        if text.len() != 64 || !text.is_ascii() {
            return Err(SchemaContractError::InvalidLiteral);
        }
        let mut bytes = [0; 32];
        for (index, pair) in text.as_bytes().as_chunks::<2>().0.iter().enumerate() {
            let pair =
                std::str::from_utf8(pair).map_err(|_| SchemaContractError::InvalidLiteral)?;
            bytes[index] =
                u8::from_str_radix(pair, 16).map_err(|_| SchemaContractError::InvalidLiteral)?;
        }
        Ok(Self::from_array(bytes))
    }

    /// Borrow the fixed-width bytes.
    #[must_use]
    pub const fn as_slice(&self) -> &[u8] {
        &self.0
    }

    /// Consume the value and return its fixed-width bytes.
    #[must_use]
    pub const fn to_bytes(self) -> [u8; 32] {
        self.0
    }
}

impl<'de> Deserialize<'de> for Subaccount {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        if deserializer.is_human_readable() {
            return SubaccountBytes::deserialize(deserializer).map(Self);
        }

        deserialize_fixed_bytes(deserializer).map(Self::from_array)
    }
}

impl Display for Subaccount {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for byte in &self.0 {
            write!(f, "{byte:02x}")?;
        }

        Ok(())
    }
}

// code taken from
// <https://docs.rs/ic-ledger-types/latest/src/ic_ledger_types/lib.rs.html#140-148>
#[expect(clippy::cast_possible_truncation)]
impl From<Principal> for Subaccount {
    fn from(principal: Principal) -> Self {
        let mut bytes = [0u8; 32];
        let p = principal.as_slice();

        // Defensive check: Principals are currently <= 29 bytes
        let len = p.len().min(31); // reserve 1 byte for the length prefix
        bytes[0] = len as u8;

        // Copy safely without panic risk
        bytes[1..=len].copy_from_slice(&p[..len]);

        Self(bytes)
    }
}

impl Serialize for Subaccount {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        if serializer.is_human_readable() {
            self.0.serialize(serializer)
        } else {
            serializer.serialize_bytes(&self.0)
        }
    }
}

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

    #[test]
    fn hex_text_preserves_every_byte_with_optional_prefix() {
        for byte in 0..=u8::MAX {
            let expected = Subaccount::from_array([byte; 32]);
            for text in [
                format!("{byte:02x}").repeat(32),
                format!("{byte:02X}").repeat(32),
            ] {
                assert_eq!(Subaccount::from_hex(&text), Ok(expected));
                assert_eq!(Subaccount::from_hex(&format!("0x{text}")), Ok(expected));
            }
        }
    }

    #[test]
    fn hex_text_rejects_width_unicode_and_nonhex_boundaries() {
        for text in [
            String::new(),
            "0x".into(),
            "0".repeat(63),
            "0".repeat(65),
            "g".repeat(64),
            format!("aé{}", "0".repeat(61)),
            format!(" {}", "0".repeat(64)),
            format!("0X{}", "0".repeat(64)),
        ] {
            assert_eq!(
                Subaccount::from_hex(&text),
                Err(SchemaContractError::InvalidLiteral)
            );
        }
    }

    #[test]
    fn binary_serde_and_wire_preserve_exact_subaccount_bytes() {
        for byte in [0, 23, 24, 128, 255] {
            let value = Subaccount::from_array([byte; 32]);
            let mut encoded = Vec::new();
            serde_cbor::to_writer(&mut encoded, &value).unwrap();
            assert_eq!(encoded.len(), 34);
            let wire: serde_cbor::Value = serde_cbor::from_slice(encoded.as_slice()).unwrap();
            assert_eq!(wire, serde_cbor::Value::Bytes(value.to_bytes().to_vec()));
            assert_eq!(
                serde_cbor::from_slice::<Subaccount>(encoded.as_slice()).unwrap(),
                value
            );

            let json = serde_json::to_string(&value).unwrap();
            assert_eq!(json, serde_json::to_string(&value.to_array()).unwrap());
            assert_eq!(serde_json::from_str::<Subaccount>(&json).unwrap(), value);

            let wire = crate::wire::encode_one(value).unwrap();
            assert_eq!(
                wire,
                crate::wire::encode_one(serde_bytes::Bytes::new(&value.to_array())).unwrap()
            );
            assert_eq!(wire.len(), 33);
            assert_eq!(crate::wire::decode_one::<Subaccount>(&wire).unwrap(), value);

            let batch = vec![value; 1_000];
            encoded.clear();
            serde_cbor::to_writer(&mut encoded, &batch).unwrap();
            assert_eq!(encoded.len(), 34_003);
            assert_eq!(
                serde_cbor::from_slice::<Vec<Subaccount>>(encoded.as_slice()).unwrap(),
                batch
            );
        }
    }

    #[test]
    fn binary_subaccount_ingress_enforces_width_and_byte_elements() {
        for len in [0, 31, 33, 1_024] {
            let wire = crate::wire::encode_one(vec![0_u8; len]).unwrap();
            assert!(crate::wire::decode_one::<Subaccount>(&wire).is_err());
            let mut encoded = Vec::new();
            serde_cbor::to_writer(&mut encoded, &serde_bytes::Bytes::new(&vec![0; len])).unwrap();
            assert!(serde_cbor::from_slice::<Subaccount>(encoded.as_slice()).is_err());
        }
        // Postcard carries values without source integer-type tags: use a value
        // outside the byte domain rather than zero, which also encodes as u8.
        let wire = crate::wire::encode_one(vec![256_u16; 32]).unwrap();
        assert!(crate::wire::decode_one::<Subaccount>(&wire).is_err());

        // Self-describing binary formats may present bytes as a byte string or
        // an array. Both retain the exact width and byte-element contract.
        let array = serde_cbor::to_vec(&vec![255_u8; 32]).unwrap();
        assert_eq!(
            serde_cbor::from_slice::<Subaccount>(&array).unwrap(),
            Subaccount::MAX
        );
        for array in [vec![0_u16; 31], vec![0; 33], vec![256; 32]] {
            let encoded = serde_cbor::to_vec(&array).unwrap();
            assert!(serde_cbor::from_slice::<Subaccount>(&encoded).is_err());
        }

        let mut encoded = Vec::new();
        serde_cbor::to_writer(&mut encoded, &Subaccount::MAX).unwrap();
        for end in 0..encoded.len() {
            assert!(serde_cbor::from_slice::<Subaccount>(&encoded[..end]).is_err());
        }
    }

    #[test]
    fn accounts_roundtrip_optional_subaccounts_in_all_transports() {
        for subaccount in [None, Some(Subaccount::MIN), Some(Subaccount::MAX)] {
            let account = Account::from_owner_and_subaccount(Principal::anonymous(), subaccount);
            let mut encoded = Vec::new();
            serde_cbor::to_writer(&mut encoded, &account).unwrap();
            assert_eq!(encoded.len(), if subaccount.is_some() { 54 } else { 21 });
            assert_eq!(
                serde_cbor::from_slice::<Account>(encoded.as_slice()).unwrap(),
                account
            );
            let json = serde_json::to_string(&account).unwrap();
            assert_eq!(serde_json::from_str::<Account>(&json).unwrap(), account);
            let wire = crate::wire::encode_one(account).unwrap();
            // Native account projection is the ordered owner/optional-bytes pair.
            assert_eq!(
                wire,
                crate::wire::encode_one((account.owner(), subaccount)).unwrap()
            );
            assert_eq!(crate::wire::decode_one::<Account>(&wire).unwrap(), account);
        }
    }
}