lazarus-receipts 1.0.2

//! Hash utilities for Lazarus Receipts.

use sha2::{Sha256, Digest};

/// SHA-256 hash of input bytes.
pub fn hash256(data: &[u8]) -> [u8; 32] {
    let mut hasher = Sha256::new();
    hasher.update(data);
    hasher.finalize().into()
}

/// Convert hex string to 32-byte array.
pub fn hex_to_bytes(hex: &str) -> Result<[u8; 32], &'static str> {
    if hex.len() != 64 {
        return Err("Expected 64 hex characters for 32 bytes");
    }
    let mut result = [0u8; 32];
    for i in 0..32 {
        result[i] = u8::from_str_radix(&hex[i * 2..i * 2 + 2], 16)
            .map_err(|_| "Invalid hex character")?;
    }
    Ok(result)
}

/// Convert 32-byte array to hex string.
pub fn bytes_to_hex(bytes: &[u8; 32]) -> String {
    bytes.iter().map(|b| format!("{:02x}", b)).collect()
}

/// Hash receipt JSON bytes.
///
/// Placeholder until canonicalization is wired.
pub fn receipt_hash_from_json_bytes(bytes: &[u8]) -> [u8; 32] {
    hash256(bytes)
}

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

    #[test]
    fn test_hash256() {
        let result = hash256(b"test");
        assert_eq!(result.len(), 32);
    }

    #[test]
    fn test_hex_roundtrip() {
        let original = hash256(b"test");
        let hex = bytes_to_hex(&original);
        let recovered = hex_to_bytes(&hex).unwrap();
        assert_eq!(original, recovered);
    }
}