#ifndef INCLUDED_C_DEPTHFIRSTDIRECTEDPATHS_H
#define INCLUDED_C_DEPTHFIRSTDIRECTEDPATHS_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 from s to w */
    c_size_t       s;           /* Source vertex */
    c_Allocator_t  allocator;   /* Copied allocator from the graph for isolation */
} c_DepthFirstDirectedPaths_t;

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

/**
 * @brief Computes a directed path tree from a single source vertex 's' using DFS
 */
c_err_t c_DepthFirstDirectedPaths_Init(c_DepthFirstDirectedPaths_t* self, const c_Digraph_t* graph, c_size_t s, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers
 */
void c_DepthFirstDirectedPaths_Destroy(c_DepthFirstDirectedPaths_t* self);

/**
 * @brief Is there a directed path from the source 's' to vertex 'v'?
 */
C_STATIC_FORCE_INLINE c_bool_t c_DepthFirstDirectedPaths_HasPathTo(c_DepthFirstDirectedPaths_t* self, c_size_t v, c_size_t total_V) {
    if (!self || !self->marked || v >= total_V) return C_FALSE;
    return self->marked[v];
}

/**
 * @brief Reconstructs the exact path from source 's' to vertex 'v' and appends it to out_path
 * @param out_path An initialized c_VertexIdList_t container to collect the sequence
 */
c_err_t c_DepthFirstDirectedPaths_PathTo(c_DepthFirstDirectedPaths_t* self, c_size_t v, c_size_t total_V, c_VertexIdList_t* out_path);


#endif /*INCLUDED_C_DEPTHFIRSTDIRECTEDPATHS_H*/