#ifndef INCLUDED_C_FLOYDWARSHALL_H
#define INCLUDED_C_FLOYDWARSHALL_H

#ifndef INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H
#include <c_EdgeWeightedDigraph.h>
#endif /*INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H*/

#ifndef INCLUDED_C_EDGEIDLIST_H
#include <c_EdgeIdList.h>
#endif /*INCLUDED_C_EDGEIDLIST_H*/



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

typedef struct {
    double**           dist_to;       /* dist_to[u][v] = distance of shortest path from u to v */
    c_size_t**         next_vertex;   /* next_vertex[u][v] = immediate next vertex on path from u to v */
    c_size_t**         edge_to;       /* edge_to[u][v] = global directed edge_id for choice transition u -> next */
    c_size_t           V;             /* Total number of vertices in the digraph */
    c_bool_t           has_neg_cycle; /* Flag indicating if a negative cycle was intercepted */
    c_Allocator_t      allocator;     /* Deep copy of the user-provided allocator */
} c_FloydWarshall_t;

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

/**
 * @brief Computes all-pairs shortest paths in a general edge-weighted digraph.
 * @param allocator Explicit allocator context used to configure internal tracking state memory
 */
c_err_t c_FloydWarshall_Init(c_FloydWarshall_t* self, c_EdgeWeightedDigraph_t* graph, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers safely.
 */
void c_FloydWarshall_Destroy(c_FloydWarshall_t* self);

/**
 * @brief Is there a directed path from vertex 'u' to vertex 'v'?
 */
C_STATIC_FORCE_INLINE c_bool_t c_FloydWarshall_HasPath(c_FloydWarshall_t* self, c_size_t u, c_size_t v) {
    if (!self || self->has_neg_cycle || u >= self->V || v >= self->V || !self->dist_to) return C_FALSE;
    return self->dist_to[u][v] < DBL_MAX;
}

/**
 * @brief Returns the distance of the shortest path from vertex 'u' to vertex 'v'.
 * @return Distance value, or DBL_MAX if unreachable / parameter error
 */
C_STATIC_FORCE_INLINE double c_FloydWarshall_Dist(c_FloydWarshall_t* self, c_size_t u, c_size_t v) {
    if (!self || u >= self->V || v >= self->V || !self->dist_to) return DBL_MAX;
    if (self->has_neg_cycle) return -DBL_MAX;
    return self->dist_to[u][v];
}

/**
 * @brief Does the edge-weighted digraph contain any negative cycles?
 */
C_STATIC_FORCE_INLINE
c_bool_t c_FloydWarshall_HasNegativeCycle(c_FloydWarshall_t* self) {
    return self ? self->has_neg_cycle : C_FALSE;
}

/**
 * @brief Reconstructs the exact shortest path from vertex 'u' to vertex 'v' and appends it to out_path.
 * @param out_path An initialized c_EdgeIdList_t container to collect the sequence of global directed edge_ids.
 */
c_err_t c_FloydWarshall_Path(c_FloydWarshall_t* self, c_size_t u, c_size_t v, c_EdgeIdList_t* out_path);


#endif /*INCLUDED_C_FLOYDWARSHALL_H*/