src/topology.py

import networkx as nx
import pandas as pd

def build_graph(nodes_df: pd.DataFrame, edges_df: pd.DataFrame) -> nx.DiGraph:
    G = nx.DiGraph()
    
    for row in nodes_df.to_dict('records'):
        G.add_node(row["node_id"], **row)
        
    for row in edges_df.to_dict('records'):
        # Only add edge if it's not explicitly closed
        if pd.isna(row.get("closed")) or not row.get("closed"):
            G.add_edge(row["from_node"], row["to_node"], **row)
            
    return G

def get_base_travel_time(distance_m: float, speed_kph: float) -> float:
    # return minutes
    if speed_kph <= 0:
        return float('inf')
    return (distance_m / 1000.0) / speed_kph * 60.0