/*

   igraph library.

   Copyright (C) 2005-2020  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_foreign.h"

#include "igraph_attributes.h"

#include "igraph_interface.h"

#include "io/dl-header.h"

#include "io/parsers/dl-parser.h"

int igraph_dl_yylex_init_extra (igraph_i_dl_parsedata_t *user_defined,

                                void *scanner);

int igraph_dl_yylex_destroy(void *scanner);

int igraph_dl_yyparse(igraph_i_dl_parsedata_t *context);

void igraph_dl_yyset_in(FILE *in_str, void *yyscanner);

/* for IGRAPH_FINALLY, which assumes that destructor functions return void */

void igraph_dl_yylex_destroy_wrapper (void *scanner ) {

    (void) igraph_dl_yylex_destroy(scanner);

}

/**

 * \function igraph_read_graph_dl

 * \brief Reads a file in the DL format of UCINET.

 *

 * This is a simple textual file format used by UCINET. See

 * http://www.analytictech.com/networks/dataentry.htm for

 * examples. All the forms described here are supported by

 * igraph. Vertex names and edge weights are also supported and they

 * are added as attributes. (If an attribute handler is attached.)

 *

 * </para><para> Note the specification does not mention whether the

 * format is case-sensitive or not. For igraph DL files are case

 * sensitive, i.e. \c Larry and \c larry are not the same.

 *

 * \param graph Pointer to an uninitialized graph object.

 * \param instream The stream to read the DL file from.

 * \param directed Boolean, whether to create a directed graph.

 * \return Error code.

 *

 * Time complexity: linear in terms of the number of edges and

 * vertices, except for the matrix format, which is quadratic in the

 * number of vertices.

 *

 * \example examples/simple/igraph_read_graph_dl.c

 */

igraph_error_t igraph_read_graph_dl(igraph_t *graph, FILE *instream,

                         igraph_bool_t directed) {

    igraph_int_t n, n2;

    const igraph_strvector_t *namevec = 0;

    igraph_attribute_record_list_t name, weight;

    igraph_attribute_record_list_t *pname = NULL;

    igraph_attribute_record_list_t *pweight = NULL;

    igraph_attribute_record_t *namerec, *weightrec;

    const char *namestr = "name", *weightstr = "weight";

    igraph_i_dl_parsedata_t context;

    context.eof = 0;

    context.mode = 0;

    context.n = -1;

    context.from = 0;

    context.to = 0;

    context.errmsg[0] = '\0';

    context.igraph_errno = IGRAPH_SUCCESS;

    IGRAPH_VECTOR_INT_INIT_FINALLY(&context.edges, 0);

    IGRAPH_VECTOR_INIT_FINALLY(&context.weights, 0);

    IGRAPH_CHECK(igraph_strvector_init(&context.labels, 0));

    IGRAPH_FINALLY(igraph_strvector_destroy, &context.labels);

    IGRAPH_TRIE_INIT_FINALLY(&context.trie, /*names=*/ 1);

    igraph_dl_yylex_init_extra(&context, &context.scanner);

    IGRAPH_FINALLY(igraph_dl_yylex_destroy_wrapper, context.scanner);

    igraph_dl_yyset_in(instream, context.scanner);

    /* Use ENTER/EXIT to avoid destroying context.scanner before this function returns */

    IGRAPH_FINALLY_ENTER();

    int err = igraph_dl_yyparse(&context);

    IGRAPH_FINALLY_EXIT();

    switch (err) {

    case 0: /* success */

        break;

    case 1: /* parse error */

        if (context.errmsg[0] != 0) {

            IGRAPH_ERROR(context.errmsg, IGRAPH_PARSEERROR);

        } else if (context.igraph_errno != IGRAPH_SUCCESS) {

            IGRAPH_ERROR("", context.igraph_errno);

        } else {

            IGRAPH_ERROR("Cannot read DL file.", IGRAPH_PARSEERROR);

        }

        break;

    case 2: /* out of memory */

        IGRAPH_ERROR("Cannot read DL file.", IGRAPH_ENOMEM); /* LCOV_EXCL_LINE */

        break;

    default: /* must never reach here */

        /* Hint: This will usually be triggered if an IGRAPH_CHECK() is used in a Bison

         * action instead of an IGRAPH_YY_CHECK(), resulting in an igraph errno being

         * returned in place of a Bison error code.

         * TODO: What if future Bison versions introduce error codes other than 0, 1 and 2?

         */

        IGRAPH_FATALF("Parser returned unexpected error code (%d) when reading DL file.", err);

    }

    /* Extend the weight vector, if needed */

    n = igraph_vector_size(&context.weights);

    n2 = igraph_vector_int_size(&context.edges) / 2;

    if (n != 0) {

        IGRAPH_CHECK(igraph_vector_resize(&context.weights, n2));

        for (; n < n2; n++) {

            VECTOR(context.weights)[n] = IGRAPH_NAN;

        }

    }

    /* Check number of vertices */

    if (n2 > 0) {

        n = igraph_vector_int_max(&context.edges);

    } else {

        n = 0;

    }

    if (n >= context.n) {

        IGRAPH_WARNING("More vertices than specified in `DL' file");

        context.n = n;

    }

    /* Prepare attributes */

    /* Labels */

    if (igraph_strvector_size(&context.labels) != 0) {

        namevec = (const igraph_strvector_t*) &context.labels;

    } else if (igraph_trie_size(&context.trie) != 0) {

        namevec = igraph_i_trie_borrow_keys(&context.trie);

    }

    if (namevec) {

        IGRAPH_CHECK(igraph_attribute_record_list_init(&name, 1));

        IGRAPH_FINALLY(igraph_attribute_record_list_destroy, &name);

        namerec = igraph_attribute_record_list_get_ptr(&name, 0);

        IGRAPH_CHECK(igraph_attribute_record_set_name(namerec, namestr));

        IGRAPH_CHECK(igraph_attribute_record_set_type(namerec, IGRAPH_ATTRIBUTE_STRING));

        IGRAPH_CHECK(igraph_strvector_update(namerec->value.as_strvector, namevec));

        pname = &name;

    }

    /* Weights */

    if (igraph_vector_size(&context.weights) != 0) {

        IGRAPH_CHECK(igraph_attribute_record_list_init(&weight, 1));

        IGRAPH_FINALLY(igraph_attribute_record_list_destroy, &weight);

        weightrec = igraph_attribute_record_list_get_ptr(&weight, 0);

        IGRAPH_CHECK(igraph_attribute_record_set_name(weightrec, weightstr));

        IGRAPH_CHECK(igraph_attribute_record_set_type(weightrec, IGRAPH_ATTRIBUTE_NUMERIC));

        igraph_vector_swap(weightrec->value.as_vector, &context.weights);

        pweight = &weight;

    }

    /* Create graph */

    IGRAPH_CHECK(igraph_empty(graph, 0, directed));

    IGRAPH_FINALLY(igraph_destroy, graph);

    IGRAPH_CHECK(igraph_add_vertices(graph, context.n, pname));

    IGRAPH_CHECK(igraph_add_edges(graph, &context.edges, pweight));

    if (pweight) {

        igraph_attribute_record_list_destroy(pweight);

        IGRAPH_FINALLY_CLEAN(1);

    }

    if (pname) {

        igraph_attribute_record_list_destroy(pname);

        IGRAPH_FINALLY_CLEAN(1);

    }

    /* don't destroy the graph itself but pop it from the finally stack */

    IGRAPH_FINALLY_CLEAN(1);

    igraph_trie_destroy(&context.trie);

    igraph_strvector_destroy(&context.labels);

    igraph_vector_int_destroy(&context.edges);

    igraph_vector_destroy(&context.weights);

    igraph_dl_yylex_destroy(context.scanner);

    IGRAPH_FINALLY_CLEAN(5);

    return IGRAPH_SUCCESS;

}