import java.util.*;

import xml.Node;
import xml.NodeId;
import xml.Path;

// TODO documentation

// TODO possibly auxiliary classes

public class Graph {

    // TODO fields
    // TODO methods

    HashMap<Node, HashMap<Path, Integer>> nodeMap;

    /** Create an empty graph. */
    public Graph() {
        nodeMap = new HashMap<Node, HashMap<Path, Integer>>();
    }

    public Node nodeFetch(String id){
        for(Node n : nodeMap.keySet()){
            if(n.id == id) return n;
        }
        return null;
    }


    /** Create a graph from an XML-parsed graph. */
    public Graph (xml.Graph graph) {
        this();
        addGraph(graph);
    }

    /** Add all nodes and paths from an xml.Graph. */
    public void addGraph(xml.Graph graph) {
        for (Node node : graph.nodes) addNode(node);
        for (Path path : graph.paths) addPath(path);
    }

    /** Add a node. If already present, do nothing. */
    public void addNode(Node node) {
        // TODO
        boolean isPresent = false;
        for(Node k : nodeMap.keySet()){
            if(k.id == node.id) isPresent = true;
        }
        if(isPresent) nodeMap.put(node, null);
    }

    /** Add an undirected edge (called path). The nodes must be present already. */
    public void addPath(Path path) {
        // TODO
        boolean isSourcePresent = false;
        boolean isTargetPresent = false;

        for(Node k : nodeMap.keySet()){
            if(k.id == path.source.id) isSourcePresent = true;
            if(k.id == path.target.id) isTargetPresent = true;
        }

        if(isSourcePresent && isTargetPresent){
            HashMap<Path, Integer> pathMap = nodeMap.get(nodeFetch(path.source.id));
            pathMap.put(path, path.weight);

            nodeMap.put(nodeFetch(path.source.id), pathMap);
        }
    }



}