//! Bytes kept beside the ledger, named by their BLAKE3 (spec §7.2): tool

//! call arguments and results in full, so the audit is never truncated;

//! retention drops old bodies and keeps the hashes (spec §22.1).

use anyhow::Result;

use std::path::Path;

/// Store `bytes` under `<data>/attachments/` and return their hash (hex).

pub fn put(data: &Path, bytes: &[u8]) -> Result<String> {

    let hash = blake3::hash(bytes).to_hex().to_string();

    let dir = data.join("attachments").join(&hash[..2]);

    let path = dir.join(&hash);

    if !path.exists() {

        std::fs::create_dir_all(&dir)?;

        crate::durable::write_atomic(&path, bytes)?;

    }

    Ok(hash)

}

/// The bytes stored under `hash`, if they are still kept.

pub fn get(data: &Path, hash: &str) -> Option<Vec<u8>> {

    if hash.len() < 3 || !hash.bytes().all(|b| b.is_ascii_hexdigit()) {

        return None;

    }

    std::fs::read(data.join("attachments").join(&hash[..2]).join(hash)).ok()

}