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

static vertex_t *create_vertex(char ref)
{
    // Get some space TODO check for null
    vertex_t *v = malloc(sizeof(vertex_t));

    // Set values
    v->ref = ref;
    v->dist = -1;
    v->p = NULL;
    v->adj = NULL;
    return v;
}

static edge_t *create_edge(vertex_t *from, vertex_t *to, int weight)
{
    edge_t *old = from->adj;

    // Create new list node
    edge_t *e = malloc(sizeof(edge_t));
    e->weight = weight;
    e->from = from;
    e->to = to;

    // Do new link
    e->next = old;
    if (old) {
        e->prev = old->prev;
        old->prev = e;
    } else {
        e->prev = NULL;
    }

    if (e->prev) {
        e->prev->next = e;
    }

    from->adj = e;

    return e;
}

// For iterating edges
edge_t *edge_next(graph_t *g, edge_t *e)
{
    if (e == NULL || e->next == NULL) {
        // Find next index

        // Chose starting index 0 if NULL e
        unsigned char i = e ? e->from->ref + 1 : 0;
        for (; i < 128; i++) {
            if (g->vertexes[i] && g->vertexes[i]->adj) {
                return g->vertexes[i]->adj;
            }
        }
        // No next vertex
        return NULL;
    }

    // Not finished with this adj list
    return e->next;
}

vertex_t *vertex_next(graph_t *g, vertex_t *v)
{
    unsigned char ref = v ? v->ref + 1 : 0;
    for (; ref < 128; ref++) {
        if (g->vertexes[ref]) {
            return g->vertexes[ref];
        }
    }

    return NULL;
}

void graph_edge(graph_t *g, char from, char to, int weight)
{
    // Does a exists
    if (g->vertexes[from] == NULL) {
        g->vertexes[from] = create_vertex(from);
    }
    // What about b
    if (g->vertexes[to] == NULL) {
        g->vertexes[to] = create_vertex(to);
    }

    // Add edge
    create_edge(g->vertexes[from], g->vertexes[to], weight);
}

int graph_print_adj(graph_t *g, char ref)
{
    if (g->vertexes[ref] == NULL) {
        return 1;
    }

    edge_t *e = g->vertexes[ref]->adj;
    printf("[ ");
    while (e && e->from->ref == ref) {
        printf("%c[%d] ", e->to->ref, e->weight);
        e = e->next;
    }
    printf("]\n");

    return 0;
}

int graph_to_dot(FILE *f, graph_t *g)
{
    // print pre stuff
    fprintf(f, "digraph coolgraph {\n");

    // Label all nodes
    vertex_t *v = vertex_next(g, NULL);
    while (v) {
        fprintf(f, "%c [label=\"%c(%d)\"];\n", v->ref, v->ref, v->dist);
        v = vertex_next(g, v);
    }
    // Print all the edges
    edge_t *e = edge_next(g, NULL);
    while (e) {
        fprintf(f, "%c -> %c [label = %d%s];\n", e->from->ref, e->to->ref,
                e->weight, e->to->p == e->from ? " color=blue" : "");
        e = edge_next(g, e);
    }

    // done
    fprintf(f, "}\n");
}