//! Opaque, serializable snapshot of application state used for
//! attach/daemon IPC transfer.

use serde::{Deserialize, Serialize};

/// A JSON-boxed snapshot of app state, opaque to the transport layer.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StateSnapshot {
    pub snapshot: serde_json::Value,
}

impl StateSnapshot {
    /// Create an empty snapshot (`{}`).
    pub fn new() -> Self {
        StateSnapshot {
            snapshot: serde_json::json!({}),
        }
    }
}

/// Serialize a snapshot to bytes for transport over the daemon socket.
///
/// Return: JSON-encoded bytes, or a serde error.
pub fn serialize_snapshot(snapshot: &StateSnapshot) -> anyhow::Result<Vec<u8>> {
    Ok(serde_json::to_vec(snapshot)?)
}

/// Parse a snapshot previously produced by `serialize_snapshot`.
///
/// Return: the decoded `StateSnapshot`, or a serde error.
pub fn deserialize_snapshot(data: &[u8]) -> anyhow::Result<StateSnapshot> {
    Ok(serde_json::from_slice(data)?)
}