/*
 * graph.c - "Graph" abstract data type.
 */

#include <stdio.h>
#include <stdlib.h>
#include "graph.h"
#include "emalloc.h"

struct graph {
    int maxnodes;  /* original maxnodes value passed to new_graph() */
    int nnodes;  /* how many stored so far */
    char **node_name;
    int *colour;
};


/* Create a new empty graph. */
GRAPH new_graph(int maxnodes)
{
    struct graph *g = (struct graph *)emalloc(sizeof(struct graph));
    g->maxnodes = maxnodes;
    g->nnodes = 0;
    g->node_name = (char **)emalloc(maxnodes * sizeof(char *));
    g->colour = (int *)emalloc(maxnodes * sizeof(int));
    return g;
}


/* Delete a graph. */
void free_graph(GRAPH g)
{
    free(g->node_name);
    free(g->colour);
    free(g);
}


/* Add a vertex. */
int add_vertex(GRAPH g, char *name)
{
    g->node_name[g->nnodes] = name;
    g->colour[g->nnodes] = -1;
    return g->nnodes++;
}


/* Add a directed edge. */
void add_edge(GRAPH g, int from, int to)
{
FILL THIS IN
}


int get_graph_nodes(GRAPH g)
{
    return g->nnodes;
}

int is_adjacent(GRAPH g, int from, int to)
{
FILL THIS IN
}

char *get_vertex_name(GRAPH g, int i)
{
    return g->node_name[i];
}

int get_vertex_colour(GRAPH g, int i)
{
    return g->colour[i];
}


/* Colour the graph. */
void colour_graph(GRAPH g)
{
/* FILL THIS IN */
}


/* dump data for testing */
void print_graph(GRAPH g)
{
    int row, col;

    printf("name col |  ");
    for (col = 0; col < g->nnodes; col++)
        printf("%-3.3s", g->node_name[col]);
    printf("\n");
    printf("---------+--");
    for (col = 0; col < g->nnodes; col++)
        printf("---");
    printf("\n");
    for (row = 0; row < g->nnodes; row++) {
        printf("%-4s %3d | ", g->node_name[row], g->colour[row]);
        for (col = 0; col < g->nnodes; col++)
            printf("%-3d", is_adjacent(g, row, col));
        printf("\n");
    }
}