ultragraph 0.8.4

/*
 * SPDX-License-Identifier: MIT
 * Copyright (c) "2025" . The DeepCausality Authors and Contributors. All Rights Reserved.
 */
use std::fmt::{Display, Formatter};
use ultragraph::*;

#[derive(Default, Debug, Copy, Clone, Hash, Eq, PartialEq)]
pub struct Data {
    x: u8,
}

impl Display for Data {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.x)
    }
}

pub fn main() -> Result<(), Box<dyn std::error::Error>> {
    run_get_node_example()?;
    println!("--------------------");
    run_outgoing_edges_example()?;
    println!("--------------------");
    run_shortest_path_example()?;
    println!("--------------------");
    run_update_and_remove_example()?;

    Ok(())
}

fn run_get_node_example() -> Result<(), Box<dyn std::error::Error>> {
    println!("Running: Get Node Example");
    let mut g = UltraGraph::with_capacity(10, None);
    assert!(g.is_empty());

    // Add nodes to the graph
    let root_index = g.add_root_node(Data { x: 3 })?;
    let node_a_index = g.add_node(Data { x: 7 })?;
    let node_b_index = g.add_node(Data { x: 9 })?;
    let node_c_index = g.add_node(Data { x: 11 })?;

    // Link nodes together
    g.add_edge(root_index, node_a_index, ()).unwrap();
    g.add_edge(node_a_index, node_b_index, ()).unwrap();
    g.add_edge(root_index, node_c_index, ()).unwrap();

    // Get node a
    let node = g.get_node(node_a_index);
    assert!(node.is_some());

    let data = node.unwrap();
    assert_eq!(data.x, 7);
    println!("Retrieved Node A with data: {data:?}");

    println!("Freeze the graph to enable high-performance traversal");
    g.freeze(); // This is the crucial step!

    // neighbors is just a vector of indices
    // so you can iterate over them to get the actual nodes
    println!("Neighbors of root node: ");
    println!("Iterating over neighbors of Node A with a for loop:");
    for neighbor_index in g.outbound_edges(root_index)? {
        // You can use the index to get the node's data
        let neighbor_data = g.get_node(neighbor_index).unwrap();
        println!("- Found neighbor: {neighbor_data} at index {neighbor_index}");
    }

    Ok(())
}

fn run_shortest_path_example() -> Result<(), Box<dyn std::error::Error>> {
    println!("Running: Shortest Path Example");

    let mut g = UltraGraph::with_capacity(10, None);
    assert!(g.is_empty());

    // Add nodes to the graph
    let root_index = g.add_root_node(Data { x: 1 })?;
    let node_a_index = g.add_node(Data { x: 6 })?;
    let node_b_index = g.add_node(Data { x: 9 })?;
    let node_c_index = g.add_node(Data { x: 11 })?;
    let node_d_index = g.add_node(Data { x: 13 })?;
    let node_e_index = g.add_node(Data { x: 17 })?;
    let node_f_index = g.add_node(Data { x: 23 })?;

    // Link nodes together
    g.add_edge(root_index, node_a_index, ()).unwrap();
    g.add_edge(node_a_index, node_b_index, ()).unwrap();
    g.add_edge(node_b_index, node_c_index, ()).unwrap();
    g.add_edge(node_c_index, node_e_index, ()).unwrap();
    g.add_edge(node_a_index, node_d_index, ()).unwrap();
    g.add_edge(node_d_index, node_e_index, ()).unwrap();
    g.add_edge(node_e_index, node_f_index, ()).unwrap();

    println!("Freeze the graph to enable high-performance traversal");
    g.freeze(); // This is the crucial step!

    let path = g
        .shortest_path(node_a_index, node_f_index)
        .expect("Failed to get Shortest path")
        .unwrap();

    assert_eq!(path.len(), 4);
    assert_eq!(
        path,
        vec![node_a_index, node_d_index, node_e_index, node_f_index]
    );

    println!("Shortest path from Node A to Node F: {path:?}");

    Ok(())
}

fn run_outgoing_edges_example() -> Result<(), Box<dyn std::error::Error>> {
    println!("Running: Outgoing Edges Example");

    let mut g = UltraGraph::with_capacity(10, None);
    assert!(g.is_empty());

    // Add some nodes to the graph
    let root_index = g.add_root_node(Data { x: 1 })?;
    let node_a_index = g.add_node(Data { x: 6 })?;
    let node_b_index = g.add_node(Data { x: 9 })?;

    // Link root node to node a
    g.add_edge(root_index, node_a_index, ()).unwrap();
    // Link root node to node b
    g.add_edge(root_index, node_b_index, ()).unwrap();

    println!("Freeze the graph to enable high-performance traversal");
    g.freeze(); // This is the crucial step!

    // get all outgoing_edges of root node
    let neighbors: Vec<usize> = g.outbound_edges(root_index).unwrap().collect();
    println!("Neighbors of root node: {neighbors:?}");
    assert_eq!(neighbors.len(), 2);

    Ok(())
}

fn run_update_and_remove_example() -> Result<(), Box<dyn std::error::Error>> {
    println!("Running: Update and Remove Example");
    let mut g = UltraGraph::with_capacity(10, None);
    assert!(g.is_empty());

    let node_a = g.add_node(Data { x: 10 })?;
    let node_b = g.add_node(Data { x: 20 })?;
    g.add_edge(node_a, node_b, ()).unwrap();
    println!("Initial graph with edge from {node_a} -> {node_b}");

    // Update node A's data
    println!("Updating Node A's data from 10 to 99...");
    g.update_node(node_a, Data { x: 99 }).unwrap();
    let updated_node_a = g.get_node(node_a).unwrap();
    println!("Retrieved updated Node A: {updated_node_a:?}");
    assert_eq!(updated_node_a.x, 99);

    // The edge is preserved after the update
    let edge_exists = g.contains_edge(node_a, node_b);
    println!("Edge from A to B still exists after update: {edge_exists}");
    assert!(edge_exists);

    // Remove the edge
    println!("Removing edge from A to B...");
    g.remove_edge(node_a, node_b).unwrap();
    let edge_exists_after_remove = g.contains_edge(node_a, node_b);
    println!("Edge from A to B exists after removal: {edge_exists_after_remove}");
    assert!(!edge_exists_after_remove);

    // The nodes are preserved after edge removal
    let node_a_exists = g.contains_node(node_a);
    println!("Node A still exists after edge removal: {node_a_exists}");
    assert!(node_a_exists);

    // Remove a node
    println!("Removing Node B...");
    g.remove_node(node_b).unwrap();
    let node_b_exists = g.contains_node(node_b);
    println!("Node B exists after removal: {node_b_exists}");
    assert!(!node_b_exists);

    Ok(())
}