//! Storage backend abstraction and implementations
//!
//! Provides multiple storage backends for KOGRAL:
//! - Filesystem: Git-friendly markdown files
//! - Memory: In-memory graph for dev/cache
//! - `SurrealDB`: Scalable database backend (optional)

use async_trait::async_trait;

use crate::error::Result;
use crate::models::{Graph, Node};

/// Storage backend trait
///
/// Provides abstraction over different storage implementations (filesystem,
/// `SurrealDB`, memory). All operations are async and return Result<T> for
/// error handling.
#[async_trait]
pub trait Storage: Send + Sync {
    /// Save a complete graph to storage
    ///
    /// Persists the entire graph including all nodes and edges.
    async fn save_graph(&mut self, graph: &Graph) -> Result<()>;

    /// Load a graph from storage
    ///
    /// Returns a fully reconstructed graph with all nodes and relationships.
    async fn load_graph(&self, name: &str) -> Result<Graph>;

    /// Save a single node to storage
    ///
    /// Persists a node, updating if it already exists.
    async fn save_node(&mut self, node: &Node) -> Result<()>;

    /// Load a node by ID from storage
    ///
    /// Searches across all node types (notes, decisions, guidelines, patterns,
    /// journal, execution).
    async fn load_node(&self, graph_name: &str, node_id: &str) -> Result<Node>;

    /// Delete a node from storage
    ///
    /// Removes the node and cleans up relationships.
    async fn delete_node(&mut self, graph_name: &str, node_id: &str) -> Result<()>;

    /// List all graphs in storage
    async fn list_graphs(&self) -> Result<Vec<String>>;

    /// List nodes in a graph, optionally filtered by type
    ///
    /// Returns all nodes of a specific type if `node_type` is provided,
    /// otherwise returns all nodes in the graph.
    async fn list_nodes(&self, graph_name: &str, node_type: Option<&str>) -> Result<Vec<Node>>;
}

pub mod filesystem;
pub mod memory;

#[cfg(feature = "surrealdb-backend")]
pub mod surrealdb;