/*

   igraph library.

   Copyright (C) 2024  The igraph development team

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

   02110-1301 USA

*/

#include <igraph.h>

#include <cstdlib>

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {

    igraph_t graph;

    igraph_vector_int_t edges;

    igraph_set_warning_handler(igraph_warning_handler_ignore);

    if (Size % 2 == 0 || Size > 512+1 || Size < 1) {

        return 0;

    }

    igraph_vector_int_init(&edges, Size-1);

    for (size_t i=0; i < Size-1; ++i) {

        VECTOR(edges)[i] = Data[i+1];

    }

    igraph_rng_seed(igraph_rng_default(), 137);

    /* Directed */

    if (igraph_create(&graph, &edges, Data[0], IGRAPH_DIRECTED) == IGRAPH_SUCCESS) {

        igraph_vector_int_list_t ivl1;

        igraph_vector_t v1, v2;

        igraph_vector_int_t iv1, iv2;

        igraph_real_t r1;

        igraph_bool_t b1;

        igraph_int_t i1, i2;

        igraph_t g;

        igraph_vector_int_list_init(&ivl1, 0);

        igraph_vector_init(&v1, 0);

        igraph_vector_init(&v2, 0);

        igraph_vector_int_init(&iv1, 0);

        igraph_vector_int_init(&iv2, 0);

        igraph_minimum_cycle_basis(&graph, NULL, &ivl1, -1, true, true);

        /* Count triangles in the minimum cycle basis. */

        i1 = igraph_vector_int_list_size(&ivl1);

        i2 = 0;

        for (igraph_int_t i=0; i < i1; i++) {

            if (igraph_vector_int_size(igraph_vector_int_list_get_ptr(&ivl1, i)) == 3) {

                i2++;

            }

        }

        igraph_fundamental_cycles(&graph, NULL, &ivl1, -1, -1);

        igraph_motifs_randesu(&graph, &v1, 3, NULL);

        igraph_list_triangles(&graph, &iv1);

        igraph_count_triangles(&graph, &r1);

        /* Cross-check direct triangle count to list of triangles. */

        IGRAPH_ASSERT(igraph_vector_int_size(&iv1) == 3*r1);

        /* Cross-check direct triangle count with 3-motifs that include a triangle. */

        IGRAPH_ASSERT(

            VECTOR(v1)[7] + VECTOR(v1)[8] +

            VECTOR(v1)[11] + VECTOR(v1)[12] +

            VECTOR(v1)[13] + VECTOR(v1)[14] + VECTOR(v1)[15] == r1);

        /* The number of triangles in the minimum cycle basis is no greater than the total.

         * Example when not all triangles are part of the basis: K_4 graph.

         */

        IGRAPH_ASSERT(i2 <= r1);

        igraph_is_triangle_free(&graph, &b1);

        IGRAPH_ASSERT((!b1) == (!!r1));

        igraph_ecc(&graph, &v1, igraph_ess_all(IGRAPH_EDGEORDER_ID), 3, false, true);

        igraph_count_reachable(&graph, &iv1, IGRAPH_OUT);

        igraph_transitive_closure(&graph, &g);

        igraph_destroy(&g);

        if (igraph_vcount(&graph) >= 2) {

            igraph_get_all_simple_paths(&graph, &ivl1, 0, igraph_vss_1(1), IGRAPH_ALL, -1, 5, IGRAPH_UNLIMITED);

        }

        if (igraph_vcount(&graph) >= 1) {

            igraph_t subg;

            igraph_random_walk(&graph, NULL, &iv1, &iv2, 0, IGRAPH_ALL, igraph_ecount(&graph), IGRAPH_RANDOM_WALK_STUCK_RETURN);

            igraph_induced_subgraph(&graph, &subg, igraph_vss_vector(&iv1), IGRAPH_SUBGRAPH_AUTO);

            igraph_destroy(&subg);

            igraph_subgraph_from_edges(&graph, &subg, igraph_ess_vector(&iv2), true);

            igraph_destroy(&subg);

            igraph_reverse_edges(&graph, igraph_ess_vector(&iv2));

        }

        i1 = igraph_vcount(&graph);

        i2 = igraph_ecount(&graph);

        igraph_to_undirected(&graph, IGRAPH_TO_UNDIRECTED_COLLAPSE, NULL);

        IGRAPH_ASSERT(igraph_vcount(&graph) == i1);

        IGRAPH_ASSERT(igraph_ecount(&graph) <= i2);

        IGRAPH_ASSERT(! igraph_is_directed(&graph));

        igraph_vector_resize(&v2, 4);

        igraph_vector_null(&v2);

        igraph_motifs_randesu(&graph, &v1, 4, &v2);

        if (igraph_vcount(&graph) >= 1) {

            igraph_random_walk(&graph, NULL, &iv1, &iv2, 0, IGRAPH_ALL, igraph_ecount(&graph), IGRAPH_RANDOM_WALK_STUCK_RETURN);

        }

        igraph_vector_int_destroy(&iv2);

        igraph_vector_int_destroy(&iv1);

        igraph_vector_destroy(&v2);

        igraph_vector_destroy(&v1);

        igraph_vector_int_list_destroy(&ivl1);

        igraph_destroy(&graph);

    }

    igraph_vector_int_destroy(&edges);

    IGRAPH_ASSERT(IGRAPH_FINALLY_STACK_EMPTY);

    return 0;  // Non-zero return values are reserved for future use.

}