#ifndef INCLUDED_C_CYCLE_H
#define INCLUDED_C_CYCLE_H

#ifndef INCLUDED_C_GRAPH_H
#include <c_Graph.h>
#endif /*INCLUDED_C_GRAPH_H*/


#ifndef INCLUDED_C_VERTEXIDLIST_H
#include <c_VertexIdList.h>
#endif /*INCLUDED_C_VERTEXIDLIST_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct {
    c_bool_t*     marked;       // marked[v] = has vertex v been visited?
    c_size_t*     edge_to;      // edge_to[v] = previous vertex on DFS path to v
    c_VertexIdList_t cycle;       // Stores the path sequence of the detected cycle
    c_bool_t      has_cycle;    // Global structural cycle status flag
    c_size_t      V;      // Cached local vertex dimension boundary
    c_Allocator_t allocator;    // Memory allocator copy
} c_Cycle_t;

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

/**
 * @brief Computes whether the undirected graph contains a cycle.
 * @param self Pointer to the uninitialized cycle tracking structure.
 * @param G Pointer to the constant target graph object to verify.
 * @param allocator Memory allocator instance pointer to deploy.
 * @return C_SUCCESS on success, or an error status code on allocation failure.
 */
c_err_t  c_Cycle_Init(c_Cycle_t* self, const c_Graph_t* G, c_Allocator_t* allocator);

/**
 * @brief Drops all internal allocation states within the cycle instance safely.
 */
void     c_Cycle_Destroy(c_Cycle_t* self);

/**
 * @brief Does the graph contain at least one cycle?
 */
c_bool_t c_Cycle_HasCycle(const c_Cycle_t* self);

/**
 * @brief Returns the vertex sequence forming the cycle path, or empty if acyclic.
 */
const c_VertexIdList_t* c_Cycle_Path(const c_Cycle_t* self);

#endif /*INCLUDED_C_CYCLE_H*/