#ifndef INCLUDED_C_DIRECTEDCYCLE_H
#define INCLUDED_C_DIRECTEDCYCLE_H

#ifndef INCLUDED_C_DIGRAPH_H
#include <c_Digraph.h>
#endif /*INCLUDED_C_DIGRAPH_H*/

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




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

typedef struct {
    c_bool_t*      marked;      /* Visited tracking array (size of graph->V) */
    c_size_t*      edge_to;     /* edge_to[w] = last edge on path to w */
    c_bool_t*      on_stack;    /* Keeps track of vertices currently on the recursive DFS stack */
    c_VertexIdList_t    cycle;       /* Stores the cycle sequence if found */
    c_Allocator_t  allocator;   /* Deep copy of the user-provided allocator */
} c_DirectedCycle_t;

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

/**
 * @brief Determines if the digraph has a directed cycle, and if so, finds one.
 * @param allocator Explicit allocator context used to allocate internal routing arrays
 */
c_err_t c_DirectedCycle_Init(c_DirectedCycle_t* self, const c_Digraph_t* graph, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers
 */
void c_DirectedCycle_Destroy(c_DirectedCycle_t* self);

/**
 * @brief Does the digraph have a directed cycle?
 */
C_STATIC_FORCE_INLINE c_bool_t c_DirectedCycle_HasCycle(c_DirectedCycle_t* self) {
    if (!self) return C_FALSE;
    return !c_VertexIdList_IsEmpty(&self->cycle);
}

/**
 * @brief Gets the vertices on a directed cycle.
 * @param out_cycle An initialized c_VertexIdList_t container to collect the sequence.
 */
c_err_t c_DirectedCycle_GetCycle(c_DirectedCycle_t* self, c_VertexIdList_t* out_cycle);


#endif /*INCLUDED_C_DIRECTEDCYCLE_H*/