#ifndef INCLUDED_C_NONRECURSIVETOPOLOGICAL_H
#define INCLUDED_C_NONRECURSIVETOPOLOGICAL_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_VertexIdList_t   order;       /* Stores the topological order sequence if found */
    c_bool_t           has_order;   /* Is the graph a DAG (has a valid topological order)? */
    c_Allocator_t      allocator;   /* Deep copy of the user-provided allocator */
} c_NonrecursiveTopological_t;

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

/**
 * @brief Non-recursively computes a topological order for the specified digraph using Kahn's algorithm.
 * @param allocator Explicit allocator context used to allocate internal routing objects
 */
c_err_t c_NonrecursiveTopological_Init(c_NonrecursiveTopological_t* self, c_Digraph_t* graph, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers
 */
void c_NonrecursiveTopological_Destroy(c_NonrecursiveTopological_t* self);

/**
 * @brief Does the digraph have a topological order (is it a DAG)?
 */
C_STATIC_FORCE_INLINE
c_bool_t c_NonrecursiveTopological_HasOrder(c_NonrecursiveTopological_t* self) {
    return self ? self->has_order : C_FALSE;
}

/**
 * @brief Gets the topological order sequence of vertices.
 * @param out_order An initialized c_VertexIdList_t container to collect the sequence.
 * @return C_SUCCESS on success, C_ERR_FAIL if no order exists (not a DAG), or parameter error.
 */
c_err_t c_NonrecursiveTopological_GetOrder(c_NonrecursiveTopological_t* self, c_VertexIdList_t* out_order);


#endif /*INCLUDED_C_NONRECURSIVETOPOLOGICAL_H*/