/*

   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>

const igraph_real_t eps = 1e-10;

bool vector_isininterval_eps(const igraph_vector_t *v, igraph_real_t lo, igraph_real_t hi) {

    const igraph_int_t n = igraph_vector_size(v);

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

        igraph_real_t x = VECTOR(*v)[i];

        if (igraph_cmp_epsilon(lo, x, eps) > 0 || igraph_cmp_epsilon(x, hi, eps) > 0) {

            return false;

        }

    }

    return true;

}

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

    igraph_t graph;

    igraph_vector_int_t edges;

    igraph_vector_t weights;

    igraph_set_warning_handler(igraph_warning_handler_ignore);

    if (Size % 3 == 0 || Size % 3 == 2 || Size > (3 * 256) + 1 || Size < 1) {

        return 0;

    }

    igraph_vector_int_init(&edges, ((Size-1) / 3) * 2);

    igraph_vector_init(&weights, (Size-1) / 3);

    for (size_t i=0; i < ((Size-1) / 3); ++i) {

        VECTOR(edges)[i * 2] = Data[i * 3 + 1];

        VECTOR(edges)[i * 2 + 1] = Data[i * 3 + 2];

        // We keep the weights strictly positive, as this is required by some algorithms.

        // Error at src/centrality/betweenness.c:437 : Weight vector must be positive. - Invalid value.

        VECTOR(weights)[i] = ((double) Data[i * 3 + 3] + 1.0) / 105.0;

    }

    // Turn on attribute handling. Weights will be stored as an edge attribute

    // in order to allow graph simplification while retainingweights.

    igraph_set_attribute_table(&igraph_cattribute_table);

    igraph_rng_seed(igraph_rng_default(), 42);

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

        const igraph_int_t vcount = igraph_vcount(&graph);

        igraph_vector_t v;

        igraph_vector_int_t iv;

        igraph_bool_t b;

        igraph_real_t r;

        /* Limit graph size for the sake of performance. */

        if (vcount <= 64) {

            igraph_vector_init(&v, 0);

            igraph_vector_int_init(&iv, 0);

            igraph_betweenness_cutoff(&graph, &weights, &v, igraph_vss_all(), IGRAPH_UNDIRECTED, false, 4);

            IGRAPH_ASSERT(vector_isininterval_eps(&v, 0, vcount == 0 ? 0 : (vcount-1)*(vcount-2)/2));

            igraph_betweenness_cutoff(&graph, &weights, &v, igraph_vss_all(), IGRAPH_DIRECTED, false, 5);

            IGRAPH_ASSERT(vector_isininterval_eps(&v, 0, vcount == 0 ? 0 : (vcount-1)*(vcount-2)));

            igraph_edge_betweenness_cutoff(&graph, &weights, &v, igraph_ess_all(IGRAPH_EDGEORDER_ID), IGRAPH_DIRECTED,

                                           false, 4);

            IGRAPH_ASSERT(vector_isininterval_eps(&v, 0, vcount*(vcount-1)/2));

            igraph_edge_betweenness_cutoff(&graph, &weights, &v, igraph_ess_all(IGRAPH_EDGEORDER_ID), IGRAPH_UNDIRECTED,

                                           false, 3);

            IGRAPH_ASSERT(vector_isininterval_eps(&v, 0, vcount*(vcount-1)));

            if (vcount >= 10) {

                igraph_betweenness_subset(&graph, &weights,

                                          &v,

                                          igraph_vss_range(0,5), igraph_vss_range(5,10),

                                          igraph_vss_all(), IGRAPH_DIRECTED, false);

                igraph_edge_betweenness_subset(&graph, &weights,

                                               &v,

                                               igraph_vss_range(0,10), igraph_vss_range(0, 10),

                                               igraph_ess_all(IGRAPH_EDGEORDER_ID), IGRAPH_DIRECTED,false);

            }

            igraph_closeness_cutoff(&graph, &v, &iv, &b, igraph_vss_all(), IGRAPH_ALL, &weights, true, 3);

            igraph_closeness_cutoff(&graph, &v, &iv, &b, igraph_vss_all(), IGRAPH_OUT, &weights, true, 4);

            igraph_harmonic_centrality_cutoff(&graph, &v, igraph_vss_all(), IGRAPH_ALL, &weights, true, 3);

            igraph_harmonic_centrality_cutoff(&graph, &v, igraph_vss_all(), IGRAPH_IN, &weights, true, 4);

            igraph_global_efficiency(&graph, &weights, &r, IGRAPH_DIRECTED);

            igraph_local_efficiency(&graph, &weights, &v, igraph_vss_all(), IGRAPH_DIRECTED, IGRAPH_OUT);

            igraph_pagerank(&graph, &weights, &v, &r, 0.6, IGRAPH_DIRECTED, igraph_vss_all(),

                            IGRAPH_PAGERANK_ALGO_PRPACK, NULL);

            IGRAPH_ASSERT(vcount == 0 || igraph_almost_equals(igraph_vector_sum(&v), 1.0, 1e-10));

            igraph_constraint(&graph, &v, igraph_vss_all(), &weights);

            {

                igraph_attribute_combination_t comb;

                SETEANV(&graph, "weight", &weights);

                igraph_attribute_combination(&comb,

                                             "weight", IGRAPH_ATTRIBUTE_COMBINE_SUM,

                                             IGRAPH_NO_MORE_ATTRIBUTES);

                // This operation would be simpler if we use IGRAPH_TO_UNDIRECTED_EACH,

                // as collapsing edges happens in the simplification step anyway.

                // We use IGRAPH_TO_UNDIRECTED_COLLAPSE to exercise more code.

                igraph_to_undirected(&graph, IGRAPH_TO_UNDIRECTED_COLLAPSE, &comb);

                igraph_simplify(&graph, true, true, &comb);

                igraph_attribute_combination_destroy(&comb);

                EANV(&graph, "weight", &weights);

                DELEA(&graph, "weight");

            }

            igraph_diversity(&graph, &weights, &v, igraph_vss_all());

            igraph_transitivity_barrat(&graph, &v, igraph_vss_all(), &weights, IGRAPH_TRANSITIVITY_NAN);

            igraph_vector_int_destroy(&iv);

            igraph_vector_destroy(&v);

        }

        igraph_destroy(&graph);

    }

    igraph_vector_int_destroy(&edges);

    igraph_vector_destroy(&weights);

    IGRAPH_ASSERT(IGRAPH_FINALLY_STACK_EMPTY);

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

}