#include <c_DijkstraAllPairsSP.h>

c_err_t c_DijkstraAllPairsSP_Init(c_DijkstraAllPairsSP_t* self, c_EdgeWeightedDigraph_t* graph, c_Allocator_t* allocator) {
    if (!self || !graph) return C_ERR_PARAM;

    self->allocator = allocator ? *allocator : c_DefaultAllocator;
    self->V = graph->V;
    self->sp_matrix = NULL;

    if (self->V == 0) return C_SUCCESS;

    /* 1. Allocate an array of DijkstraSP structures */
    self->sp_matrix = (c_DijkstraSP_t*)c_Allocator_Calloc(
        &self->allocator,
        self->V,
        sizeof(c_DijkstraSP_t)
    );
    if (!self->sp_matrix) return C_ERR_NOMEM;

    /* 2. Run a full single-source Dijkstra search engine out from each vertex */
    for (c_size_t v = 0; v < self->V; ++v) {
        c_err_t err = c_DijkstraSP_Init(&self->sp_matrix[v], graph, v, allocator);

        if (err != C_SUCCESS) {
            /* Atomic Rollback: Destroy previously allocated instances to prevent OOM memory leaks */
            for (c_size_t i = 0; i < v; ++i) {
                c_DijkstraSP_Destroy(&self->sp_matrix[i]);
            }
            c_Allocator_Free(&self->allocator, self->sp_matrix);
            self->sp_matrix = NULL;
            self->V = 0;
            return err;
        }
    }

    return C_SUCCESS;
}

void c_DijkstraAllPairsSP_Destroy(c_DijkstraAllPairsSP_t* self) {
    if (!self) return;

    if (self->sp_matrix) {
        /* Safely deallocate every single active search instance */
        for (c_size_t i = 0; i < self->V; ++i) {
            c_DijkstraSP_Destroy(&self->sp_matrix[i]);
        }
        c_Allocator_Free(&self->allocator, self->sp_matrix);
        self->sp_matrix = NULL;
    }
    self->V = 0;
}

c_err_t c_DijkstraAllPairsSP_Path(c_DijkstraAllPairsSP_t* self, c_size_t u, c_size_t v, c_VertexIdList_t* out_path) {
    if (!self || !self->sp_matrix || u >= self->V || v >= self->V || !out_path) return C_ERR_PARAM;

    /* Safely delegate extraction to the underlying single-source engine */
    return c_DijkstraSP_PathTo(&self->sp_matrix[u], v, out_path);
}