zesdex/crates/zesdex-cms/src/infrastructure/persistence/conversation_repo.rs

//! JSON file–backed `ConversationRepository`.
//!
//! Path: `<session_dir>/conversation.json`
//!
//! Uses write-then-rename with fsync for crash safety.

use std::path::Path;

use anyhow::{Context, Result};
use zesdex_utils::write_json_atomic;

use crate::domain::conversation::Conversation;
use crate::domain::repository::ConversationRepository;

/// Persists `Conversation` as pretty-printed JSON at `<session_dir>/conversation.json`.
#[derive(Debug, Clone, Default)]
pub struct JsonConversationRepository;

impl JsonConversationRepository {
    /// Create a new repository instance.
    pub fn new() -> Self {
        Self
    }
}

impl ConversationRepository for JsonConversationRepository {
    fn load(&self, session_dir: &Path) -> Result<Conversation> {
        let path = session_dir.join("conversation.json");
        let data = std::fs::read_to_string(&path)
            .with_context(|| format!("failed to read conversation at '{}'", path.display()))?;
        let conv: Conversation = serde_json::from_str(&data)
            .with_context(|| format!("failed to parse conversation at '{}'", path.display()))?;
        Ok(conv)
    }

    fn save(&self, session_dir: &Path, conversation: &Conversation) -> Result<()> {
        std::fs::create_dir_all(session_dir)
            .with_context(|| format!("failed to create session dir '{}'", session_dir.display()))?;
        let path = session_dir.join("conversation.json");
        write_json_atomic(&path, conversation, None)
            .with_context(|| "failed to save conversation")?;
        tracing::debug!("conversation saved to '{}'", path.display());
        Ok(())
    }
}