// graph.c

#include <string.h>
#include <limits.h>
#include <stdlib.h>

#include "graph.h"

// initialize a graph of a given number of cities
void init_graph(struct graph* graph, int size) {
    graph->size = size;

    // allocate space for the matrix and labels
    graph->matrix = malloc(sizeof(int*) * size);
    graph->labels = malloc(sizeof(char*) * size);
    for (int i = 0; i < size; i++) {
        graph->matrix[i] = malloc(sizeof(unsigned int) * size);
        graph->labels[i] = malloc(sizeof(char) * 64);
    }

    // set the distances all to "infiniti"
    for (int i = 0; i < graph->size; i++) {
        for (int j = 0; j < graph->size; j++) {
            graph->matrix[i][j] = INT_MAX;
        }
    }
}

// add a label to the graph
void set_label(struct graph* graph, int node, char* label) {
    strcpy(graph->labels[node], label);
}

// get the value of a node
const char* get_label(struct graph* graph, int index) {
    return graph->labels[index];
}

// lookup a node number by the label
int lookup(struct graph* graph, const char* label) {
    for (int i = 0; i < graph->size; i++) {
        if (strcmp(graph->labels[i], label) == 0) {
            return i;
        }
    }
    return -1;
}

// insert an edge between two nodes in the graph
void insert_edge(struct graph* graph, int from, int to, int cost) {
    // insert the edge
    graph->matrix[from][to] = cost;
}

// return the cost of an edge in the graph
unsigned int get_cost(struct graph* graph, int from, int to) {
    return graph->matrix[from][to];
}