// Read-only access abstraction for the memory store

use super::types::*;
use super::Store;

// ---------------------------------------------------------------------------
// StoreView: read-only access trait for search and graph code.
// ---------------------------------------------------------------------------

pub trait StoreView {
    /// Iterate all nodes. Callback receives (key, content, weight).
    fn for_each_node<F: FnMut(&str, &str, f32)>(&self, f: F);

    /// Iterate all nodes with metadata. Callback receives (key, node_type, timestamp).
    fn for_each_node_meta<F: FnMut(&str, NodeType, i64)>(&self, f: F);

    /// Iterate all relations. Callback receives (source_key, target_key, strength, rel_type).
    fn for_each_relation<F: FnMut(&str, &str, f32, RelationType)>(&self, f: F);

    /// Node weight by key, or the default weight if missing.
    fn node_weight(&self, key: &str) -> f64;

    /// Node content by key.
    fn node_content(&self, key: &str) -> Option<&str>;
}

impl StoreView for Store {
    fn for_each_node<F: FnMut(&str, &str, f32)>(&self, mut f: F) {
        for (key, node) in &self.nodes {
            f(key, &node.content, node.weight);
        }
    }

    fn for_each_node_meta<F: FnMut(&str, NodeType, i64)>(&self, mut f: F) {
        for (key, node) in &self.nodes {
            f(key, node.node_type, node.timestamp);
        }
    }

    fn for_each_relation<F: FnMut(&str, &str, f32, RelationType)>(&self, mut f: F) {
        for rel in &self.relations {
            if rel.deleted { continue; }
            f(&rel.source_key, &rel.target_key, rel.strength, rel.rel_type);
        }
    }

    fn node_weight(&self, key: &str) -> f64 {
        let cfg = crate::config::get();
        self.nodes.get(key).map(|n| n.weight as f64).unwrap_or(cfg.default_node_weight)
    }

    fn node_content(&self, key: &str) -> Option<&str> {
        self.nodes.get(key).map(|n| n.content.as_str())
    }
}