rework: changed to basic implementation for dijkstra

include/graph.h

@@ -9,6 +9,8 @@ typedef struct Edge Edge;
 
 typedef enum {
     GRAPH_OK,
+    GRAPH_BAD_ALLOC,
+    GRAPH_NOT_FOUND,
 } GraphErr ;
 
 typedef enum {
@@ -16,5 +18,18 @@ typedef enum {
     GRAPH_UNDIRECTED,
 } GraphType;
 
+Graph *graph_create(GraphType type);
+GraphErr graph_destroy(Graph *graph);
+
+GraphErr graph_add_vertex(Graph *graph);
+
+GraphErr graph_connect_vertex(
+    Graph *graph,
+    size_t node1,
+    size_t node2,
+    size_t weight);
+
+GraphErr graph_vertex_count(size_t *out);
+GraphErr graph_get_vertex(Graph *graph, size_t index, Vertex *out);
 
 #endif