/* This file is part of the Zebra server.
   Copyright (C) Index Data

Zebra 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, or (at your option) any later
version.

Zebra 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 St, Fifth Floor, Boston, MA  02110-1301  USA

*/


#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <assert.h>
#ifdef WIN32
#include <io.h>
#else
#include <unistd.h>
#endif

#include "index.h"
#include "rank.h"
#include <yaz/diagbib1.h>
#include <rset.h>

#define ZSET_SORT_MAX_LEVEL 10

struct zebra_set_term_entry {
    int reg_type;
    char *db;
    char *index_name;
    char *term;
};

struct zebra_set {
    char *name;
    RSET rset;
    NMEM nmem;
    NMEM rset_nmem; /* for creating the rsets in */
    zint hits;
    int num_bases;
    const char **basenames;
    Z_RPNQuery *rpn;
    Z_SortKeySpecList *sortSpec;
    struct zset_sort_info *sort_info;
    struct zebra_set_term_entry *term_entries;
    int term_entries_max;
    struct zebra_set *next;
    int locked;
    int estimated_hit_count;

    zint cache_position;  /* last position */
    RSFD cache_rfd;       /* rfd (NULL if not existing) */
    zint cache_psysno;    /* sysno for last position */
    zint approx_limit;    /* limit before we do approx */
};

struct zset_sort_entry {
    zint sysno;
    int score;
};

struct zset_sort_info {
    int max_entries;
    int num_entries;
    struct zset_sort_entry *all_entries;
    struct zset_sort_entry **entries;
};

static int log_level_set=0;
static int log_level_sort=0;
static int log_level_searchhits=0;
static int log_level_searchterms=0;
static int log_level_resultsets=0;

static void loglevels(void)
{
    if (log_level_set)
        return;
    log_level_sort = yaz_log_module_level("sorting");
    log_level_searchhits = yaz_log_module_level("searchhits");
    log_level_searchterms = yaz_log_module_level("searchterms");
    log_level_resultsets = yaz_log_module_level("resultsets");
    log_level_set = 1;
}


static ZEBRA_RES resultSetSearch(ZebraHandle zh, NMEM nmem, NMEM rset_nmem,
                                 Z_RPNQuery *rpn, ZebraSet sset)
{
    RSET rset = 0;
    Z_SortKeySpecList *sort_sequence;
    int sort_status, i;
    ZEBRA_RES res = ZEBRA_OK;

    sort_sequence = (Z_SortKeySpecList *)
        nmem_malloc(nmem, sizeof(*sort_sequence));
    sort_sequence->num_specs = 10; /* FIXME - Hard-coded number */
    sort_sequence->specs = (Z_SortKeySpec **)
        nmem_malloc(nmem, sort_sequence->num_specs *
                    sizeof(*sort_sequence->specs));
    for (i = 0; i<sort_sequence->num_specs; i++)
        sort_sequence->specs[i] = 0;

    rpn_get_top_approx_limit(zh, rpn->RPNStructure, &sset->approx_limit);

    res = rpn_search_top(zh, rpn->RPNStructure, rpn->attributeSetId,
                         sset->approx_limit,
                         nmem, rset_nmem,
                         sort_sequence,
                         sset->num_bases, sset->basenames,
                         &rset);
    if (res != ZEBRA_OK)
    {
        sset->rset = 0;
        return res;
    }
    for (i = 0; sort_sequence->specs[i]; i++)
        ;
    sort_sequence->num_specs = i;
    rset_set_hits_limit(rset, sset->approx_limit);

    if (!i)
    {
        res = resultSetRank(zh, sset, rset, rset_nmem);
    }
    else
    {
        res = resultSetSortSingle(zh, nmem, sset, rset,
                                  sort_sequence, &sort_status);
    }
    sset->rset = rset;
    return res;
}


ZEBRA_RES resultSetAddRPN(ZebraHandle zh, NMEM m, Z_RPNQuery *rpn,
                          int num_bases, char **basenames,
                          const char *setname,
                          zint *hits, int *estimated_hit_count)
{
    ZebraSet zebraSet;
    int i;
    ZEBRA_RES res;

    *hits = 0;
    *estimated_hit_count = 0;

    zebraSet = resultSetAdd(zh, setname, 1);
    if (!zebraSet)
        return ZEBRA_FAIL;
    zebraSet->locked = 1;
    zebraSet->rpn = 0;
    zebraSet->nmem = m;
    zebraSet->rset_nmem = nmem_create();

    zebraSet->num_bases = num_bases;
    zebraSet->basenames =
        nmem_malloc(zebraSet->nmem, num_bases * sizeof(*zebraSet->basenames));
    for (i = 0; i<num_bases; i++)
        zebraSet->basenames[i] = nmem_strdup(zebraSet->nmem, basenames[i]);

    res = resultSetSearch(zh, zebraSet->nmem, zebraSet->rset_nmem,
                          rpn, zebraSet);
    *hits = zebraSet->hits;
    if (zebraSet->estimated_hit_count)
        *estimated_hit_count = 1;

    if (zebraSet->rset)
        zebraSet->rpn = rpn;
    zebraSet->locked = 0;
    if (!zebraSet->rset)
        return ZEBRA_FAIL;
    return res;
}

void resultSetAddTerm(ZebraHandle zh, ZebraSet s, int reg_type,
                      const char *db, const char *index_name,
                      const char *term)
{
    assert(zh); /* compiler shut up */
    if (!s->nmem)
        s->nmem = nmem_create();
    if (!s->term_entries)
    {
        int i;
        s->term_entries_max = 1000;
        s->term_entries =
            nmem_malloc(s->nmem, s->term_entries_max *
                        sizeof(*s->term_entries));
        for (i = 0; i < s->term_entries_max; i++)
            s->term_entries[i].term = 0;
    }
    if (s->hits < s->term_entries_max)
    {
        s->term_entries[s->hits].reg_type = reg_type;
        s->term_entries[s->hits].db = nmem_strdup(s->nmem, db);
        s->term_entries[s->hits].index_name = nmem_strdup(s->nmem, index_name);
        s->term_entries[s->hits].term = nmem_strdup(s->nmem, term);
    }
    (s->hits)++;
}

ZebraSet resultSetAdd(ZebraHandle zh, const char *name, int ov)
{
    ZebraSet s;
    int i;

    for (s = zh->sets; s; s = s->next)
        if (!strcmp(s->name, name))
            break;

    if (!log_level_set)
        loglevels();
    if (s)
    {
        yaz_log(log_level_resultsets, "updating result set %s", name);
        if (!ov || s->locked)
            return NULL;
        if (s->rset)
        {
            if (s->cache_rfd)
                rset_close(s->cache_rfd);
            rset_delete(s->rset);
        }
        if (s->rset_nmem)
            nmem_destroy(s->rset_nmem);
        if (s->nmem)
            nmem_destroy(s->nmem);
    }
    else
    {
        const char *sort_max_str = zebra_get_resource(zh, "sortmax", "1000");

        yaz_log(log_level_resultsets, "adding result set %s", name);
        s = (ZebraSet) xmalloc(sizeof(*s));
        s->next = zh->sets;
        zh->sets = s;
        s->name = xstrdup(name);

        s->sort_info = (struct zset_sort_info *)
            xmalloc(sizeof(*s->sort_info));
        s->sort_info->max_entries = atoi(sort_max_str);
        if (s->sort_info->max_entries < 2)
            s->sort_info->max_entries = 2;

        s->sort_info->entries = (struct zset_sort_entry **)
            xmalloc(sizeof(*s->sort_info->entries) *
                    s->sort_info->max_entries);
        s->sort_info->all_entries = (struct zset_sort_entry *)
            xmalloc(sizeof(*s->sort_info->all_entries) *
                    s->sort_info->max_entries);
        for (i = 0; i < s->sort_info->max_entries; i++)
            s->sort_info->entries[i] = s->sort_info->all_entries + i;
    }
    s->locked = 0;
    s->term_entries = 0;
    s->hits = 0;
    s->rset = 0;
    s->rset_nmem = 0;
    s->nmem = 0;
    s->rpn = 0;
    s->sortSpec = 0;
    s->cache_position = 0;
    s->cache_rfd = 0;
    s->approx_limit = zh->approx_limit;
    s->estimated_hit_count = 0;
    return s;
}

ZebraSet resultSetGet(ZebraHandle zh, const char *name)
{
    ZebraSet s;

    for (s = zh->sets; s; s = s->next)
        if (!strcmp(s->name, name))
        {
            if (!s->term_entries && !s->rset && s->rpn)
            {
                NMEM nmem = nmem_create();
                yaz_log(log_level_resultsets, "research %s", name);
                if (!s->rset_nmem)
                    s->rset_nmem = nmem_create();
                resultSetSearch(zh, nmem, s->rset_nmem, s->rpn, s);
                if (s->rset && s->sortSpec)
                {
                    int sort_status;
                    yaz_log(log_level_resultsets, "resort %s", name);
                    resultSetSortSingle(zh, nmem, s, s->rset, s->sortSpec,
                                        &sort_status);
                }
                nmem_destroy(nmem);
            }
            return s;
        }
    return NULL;
}

ZEBRA_RES resultSetGetBaseNames(ZebraHandle zh, const char *setname,
                                const char ***basenames, int *num_bases)
{
    ZebraSet sset = resultSetGet(zh, setname);
    if (!sset)
        return ZEBRA_FAIL;
    *basenames = sset->basenames;
    *num_bases = sset->num_bases;
    return ZEBRA_OK;

}

void resultSetInvalidate(ZebraHandle zh)
{
    ZebraSet s = zh->sets;

    yaz_log(log_level_resultsets, "invalidating result sets");
    for (; s; s = s->next)
    {
        if (s->rset)
        {
            if (s->cache_rfd)
                rset_close(s->cache_rfd);
            rset_delete(s->rset);
        }
        s->rset = 0;
        s->cache_rfd = 0;
        s->cache_position = 0;
        if (s->rset_nmem)
            nmem_destroy(s->rset_nmem);
        s->rset_nmem=0;
    }
}

void resultSetDestroy(ZebraHandle zh, int num, char **names,int *statuses)
{
    ZebraSet * ss = &zh->sets;
    int i;

    if (statuses)
        for (i = 0; i<num; i++)
            statuses[i] = Z_DeleteStatus_resultSetDidNotExist;
    while (*ss)
    {
        int i = -1;
        ZebraSet s = *ss;
        if (num >= 0)
        {
            for (i = 0; i<num; i++)
                if (!strcmp(s->name, names[i]))
                {
                    if (statuses)
                        statuses[i] = Z_DeleteStatus_success;
                    i = -1;
                    break;
                }
        }
        if (i < 0)
        {
            *ss = s->next;

            xfree(s->sort_info->all_entries);
            xfree(s->sort_info->entries);
            xfree(s->sort_info);

            if (s->nmem)
                nmem_destroy(s->nmem);
            if (s->rset)
            {
                if (s->cache_rfd)
                    rset_close(s->cache_rfd);
                rset_delete(s->rset);
            }
            if (s->rset_nmem)
                nmem_destroy(s->rset_nmem);
            xfree(s->name);
            xfree(s);
        }
        else
            ss = &s->next;
    }
}

ZebraMetaRecord *zebra_meta_records_create_range(ZebraHandle zh,
                                                 const char *name,
                                                 zint start, int num)
{
    zint pos_small[10];
    zint *pos = pos_small;
    ZebraMetaRecord *mr;
    int i;

    if (num > 10000 || num <= 0)
        return 0;

    if (num > 10)
        pos = xmalloc(sizeof(*pos) * num);

    for (i = 0; i<num; i++)
        pos[i] = start+i;

    mr = zebra_meta_records_create(zh, name, num, pos);

    if (num > 10)
        xfree(pos);
    return mr;
}

ZebraMetaRecord *zebra_meta_records_create(ZebraHandle zh, const char *name,
                                           int num, zint *positions)
{
    ZebraSet sset;
    ZebraMetaRecord *sr = 0;
    RSET rset;
    int i;
    struct zset_sort_info *sort_info;
    size_t sysno_mem_index = 0;

    if (zh->m_staticrank)
        sysno_mem_index = 1;

    if (!log_level_set)
        loglevels();
    if (!(sset = resultSetGet(zh, name)))
        return NULL;
    if (!(rset = sset->rset))
    {
        if (!sset->term_entries)
            return 0;
        sr = (ZebraMetaRecord *) xmalloc(sizeof(*sr) * num);
        for (i = 0; i<num; i++)
        {
            sr[i].sysno = 0;
            sr[i].score = -1;
            sr[i].term = 0;
            sr[i].db = 0;

            if (positions[i] <= sset->term_entries_max)
            {
                sr[i].term = sset->term_entries[positions[i]-1].term;
                sr[i].db = sset->term_entries[positions[i]-1].db;
            }
        }
    }
    else
    {
        sr = (ZebraMetaRecord *) xmalloc(sizeof(*sr) * num);
        for (i = 0; i<num; i++)
        {
            sr[i].sysno = 0;
            sr[i].score = -1;
            sr[i].term = 0;
            sr[i].db = 0;
        }
        sort_info = sset->sort_info;
        if (sort_info)
        {
            zint position;

            for (i = 0; i<num; i++)
            {
                position = positions[i];
                if (position > 0 && position <= sort_info->num_entries)
                {
                    yaz_log(log_level_sort, "got pos=" ZINT_FORMAT
                            " (sorted)", position);
                    sr[i].sysno = sort_info->entries[position-1]->sysno;
                    sr[i].score = sort_info->entries[position-1]->score;
                }
            }
        }
        /* did we really get all entries using sort ? */
        for (i = 0; i<num; i++)
        {
            if (!sr[i].sysno)
                break;
        }
        if (i < num) /* nope, get the rest, unsorted - sorry */
        {
            zint position = 0;
            int num_i = 0;
            zint psysno = 0;
            RSFD rfd;
            struct it_key key;

            if (sort_info)
                position = sort_info->num_entries;
            while (num_i < num && positions[num_i] <= position)
                num_i++;

            if (sset->cache_rfd &&
                num_i < num && positions[num_i] > sset->cache_position)
            {
                position = sset->cache_position;
                rfd = sset->cache_rfd;
                psysno = sset->cache_psysno;
            }
            else
            {
                if (sset->cache_rfd)
                    rset_close(sset->cache_rfd);
                rfd = rset_open(rset, RSETF_READ);
            }
            while (num_i < num && rset_read(rfd, &key, 0))
            {
                zint this_sys = key.mem[sysno_mem_index];
                if (this_sys != psysno)
                {
                    psysno = this_sys;
                    if (sort_info)
                    {
                        /* determine we alreay have this in our set */
                        for (i = sort_info->num_entries; --i >= 0; )
                            if (psysno == sort_info->entries[i]->sysno)
                                break;
                        if (i >= 0)
                            continue;
                    }
                    position++;
                    assert(num_i < num);
                    if (position == positions[num_i])
                    {
                        sr[num_i].sysno = psysno;
                        yaz_log(log_level_sort, "got pos=" ZINT_FORMAT " (unsorted)", position);
                        sr[num_i].score = -1;
                        num_i++;
                    }
                }
            }
            sset->cache_position = position;
            sset->cache_psysno = psysno;
            sset->cache_rfd = rfd;
        }
    }
    return sr;
}

void zebra_meta_records_destroy(ZebraHandle zh, ZebraMetaRecord *records,
                                int num)
{
    assert(zh); /* compiler shut up about unused arg */
    xfree(records);
}

struct sortKeyInfo {
    int relation;
    int *ord; /* array of ord for each database searched */
    int *numerical; /* array of ord for each database searched */
    const char *index_type;
};

void resultSetInsertSort(ZebraHandle zh, ZebraSet sset,
                         int database_no,
                         struct sortKeyInfo *criteria, int num_criteria,
                         zint sysno,
                         char *cmp_buf[], char *tmp_cmp_buf[])
{
    struct zset_sort_entry *new_entry = NULL;
    struct zset_sort_info *sort_info = sset->sort_info;
    int i, j;
    WRBUF w = wrbuf_alloc();

    zebra_sort_sysno(zh->reg->sort_index, sysno);
    for (i = 0; i<num_criteria; i++)
    {
        char *this_entry_buf = tmp_cmp_buf[i];
        memset(this_entry_buf, '\0', SORT_IDX_ENTRYSIZE);

        if (criteria[i].ord[database_no] != -1)
        {
            yaz_log(log_level_sort, "pre zebra_sort_type ord is %d",
                    criteria[i].ord[database_no]);
            zebra_sort_type(zh->reg->sort_index, criteria[i].ord[database_no]);
            wrbuf_rewind(w);
            if (zebra_sort_read(zh->reg->sort_index, 0, w))
            {
                /* consider each sort entry and take lowest/highest one
                   of the one as sorting key depending on whether sort is
                   ascending/descending */
                int off = 0;
                while (off != wrbuf_len(w))
                {
                    size_t l = strlen(wrbuf_buf(w)+off);
                    assert(off < wrbuf_len(w));

                    if (l >= SORT_IDX_ENTRYSIZE)
                        l = SORT_IDX_ENTRYSIZE-1;
                    if ( (off == 0)
                         || (criteria[i].relation == 'A'
                             && strcmp(wrbuf_buf(w)+off, this_entry_buf) < 0)
                         || (criteria[i].relation == 'D'
                             && strcmp(wrbuf_buf(w)+off, this_entry_buf) > 0)
                        )
                    {
                        memcpy(this_entry_buf, wrbuf_buf(w)+off, l);
                        this_entry_buf[l] = '\0';
                    }
                    off += 1 + strlen(wrbuf_buf(w)+off);
                }
            }
        }
        else
        {
            yaz_log(log_level_sort, "criteria[i].ord is -1 so not reading from sort index");
        }
    }
    wrbuf_destroy(w);
    i = sort_info->num_entries;
    while (--i >= 0)
    {
        int rel = 0;
        for (j = 0; j<num_criteria; j++)
        {
            char *this_entry_buf = tmp_cmp_buf[j];
            char *other_entry_buf =
                cmp_buf[j] + i * SORT_IDX_ENTRYSIZE;
            if (criteria[j].numerical[database_no])
            {
                char this_entry_org[1024];
                char other_entry_org[1024];
                double diff;
                const char *index_type = criteria[j].index_type;
                zebra_term_untrans(zh, index_type, this_entry_org,
                                   this_entry_buf);
                zebra_term_untrans(zh, index_type, other_entry_org,
                                   other_entry_buf);
                diff = atof(this_entry_org) - atof(other_entry_org);

                if (diff > 0.0)
                    rel = 1;
                else if (diff < 0.0)
                    rel = -1;
                else
                    rel = 0;
            }
            else
            {
                rel = memcmp(this_entry_buf, other_entry_buf,
                             SORT_IDX_ENTRYSIZE);
            }
            /* when the compare is equal, continue to next criteria,
               else break out */
            if (rel)
                break;
        }
        if (!rel)
            break;
        if (criteria[j].relation == 'A')
        {
            if (rel > 0)
                break;
        }
        else if (criteria[j].relation == 'D')
        {
            if (rel < 0)
                break;
        }
    }
    ++i;
    yaz_log(log_level_sort, "ok, we want to insert record at position %d",i);
    j = sort_info->max_entries;
    if (i == j){
        yaz_log(log_level_sort, "sort_info->max_entries reached (%d) abort sort",j);
        return;
    }

    if (sort_info->num_entries == j)
        --j;
    else
        j = (sort_info->num_entries)++;
    new_entry = sort_info->entries[j];
    /* move up all higher entries (to make room) */
    while (j != i)
    {
        int k;
        for (k = 0; k<num_criteria; k++)
        {
            char *j_buf = cmp_buf[k] + j * SORT_IDX_ENTRYSIZE;
            char *j_1_buf = cmp_buf[k] + (j-1) * SORT_IDX_ENTRYSIZE;
            memcpy(j_buf, j_1_buf, SORT_IDX_ENTRYSIZE);
        }
        sort_info->entries[j] = sort_info->entries[j-1];
        --j;
    }
    /* and insert the new entry at the correct place */
    sort_info->entries[i] = new_entry;
    assert(new_entry);
    /* and add this to the compare buffer */
    for (i = 0; i<num_criteria; i++)
    {
        char *new_entry_buf = cmp_buf[i] + j * SORT_IDX_ENTRYSIZE;
        char *this_entry_buf = tmp_cmp_buf[i];
        memcpy(new_entry_buf, this_entry_buf, SORT_IDX_ENTRYSIZE);
    }
    new_entry->sysno = sysno;
    new_entry->score = -1;
}

void resultSetInsertRank(ZebraHandle zh, struct zset_sort_info *sort_info,
                         zint sysno, int score, int relation)
{
    struct zset_sort_entry *new_entry = NULL;
    int i, j;
    assert(zh); /* compiler shut up about unused arg */

    i = sort_info->num_entries;
    while (--i >= 0)
    {
        int rel = 0;

        rel = score - sort_info->entries[i]->score;

        if (relation == 'D')
        {
            if (rel >= 0)
                break;
        }
        else if (relation == 'A')
        {
            if (rel <= 0)
                break;
        }
    }
    ++i;
    j = sort_info->max_entries;
    if (i == j)
        return;

    if (sort_info->num_entries == j)
        --j;
    else
        j = (sort_info->num_entries)++;

    new_entry = sort_info->entries[j];
    while (j != i)
    {
        sort_info->entries[j] = sort_info->entries[j-1];
        --j;
    }
    sort_info->entries[i] = new_entry;
    assert(new_entry);
    new_entry->sysno = sysno;
    new_entry->score = score;
}

static Z_RPNQuery *copy_RPNQuery(Z_RPNQuery *src, NMEM nmem)
{
    Z_RPNQuery *dst = 0;
    ODR encode = odr_createmem(ODR_ENCODE);
    ODR decode = odr_createmem(ODR_DECODE);

    if (z_RPNQuery(encode, &src, 0, 0))
    {
        int len;
        char *buf = odr_getbuf(encode, &len, 0);

        if (buf)
        {
            odr_setbuf(decode, buf, len, 0);
            z_RPNQuery(decode, &dst, 0, 0);
        }
    }
    nmem_transfer(nmem, decode->mem);
    odr_destroy(encode);
    odr_destroy(decode);
    return dst;
}

static Z_SortKeySpecList *copy_SortKeySpecList(Z_SortKeySpecList *src, NMEM nmem)
{
    Z_SortKeySpecList *dst = 0;
    ODR encode = odr_createmem(ODR_ENCODE);
    ODR decode = odr_createmem(ODR_DECODE);

    if (z_SortKeySpecList(encode, &src, 0, 0))
    {
        int len;
        char *buf = odr_getbuf(encode, &len, 0);

        if (buf)
        {
            odr_setbuf(decode, buf, len, 0);
            z_SortKeySpecList(decode, &dst, 0, 0);
        }
    }
    nmem_transfer(nmem, decode->mem);
    odr_destroy(encode);
    odr_destroy(decode);
    return dst;
}

ZebraSet resultSetClone(ZebraHandle zh, const char *setname,
                        ZebraSet rset)
{
    ZebraSet nset;
    int i;

    nset = resultSetAdd(zh, setname, 1);
    if (!nset)
        return 0;

    nset->nmem = nmem_create();

    nset->num_bases = rset->num_bases;
    nset->basenames =
        nmem_malloc(nset->nmem, nset->num_bases * sizeof(*rset->basenames));
    for (i = 0; i<rset->num_bases; i++)
        nset->basenames[i] = nmem_strdup(nset->nmem, rset->basenames[i]);

    if (rset->rset)
        nset->rset = rset_dup(rset->rset);
    if (rset->rpn)
        nset->rpn = copy_RPNQuery(rset->rpn, nset->nmem);
    return nset;
}

ZEBRA_RES resultSetSort(ZebraHandle zh, NMEM nmem,
                        int num_input_setnames, const char **input_setnames,
                        const char *output_setname,
                        Z_SortKeySpecList *sort_sequence, int *sort_status)
{
    ZebraSet sset;
    RSET rset;

    if (num_input_setnames == 0)
    {
        zebra_setError(zh, YAZ_BIB1_NO_RESULT_SET_NAME_SUPPLIED_ON_SORT, 0);
        return ZEBRA_FAIL;
    }
    if (num_input_setnames > 1)
    {
        zebra_setError(zh, YAZ_BIB1_SORT_TOO_MANY_INPUT_RESULTS, 0);
        return ZEBRA_FAIL;
    }
    if (!log_level_set)
        loglevels();
    yaz_log(log_level_sort, "result set sort input=%s output=%s",
            *input_setnames, output_setname);
    sset = resultSetGet(zh, input_setnames[0]);
    if (!sset)
    {
        zebra_setError(zh, YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
                       input_setnames[0]);
        return ZEBRA_FAIL;
    }
    if (!(rset = sset->rset))
    {
        zebra_setError(zh, YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
                       input_setnames[0]);
        return ZEBRA_FAIL;
    }
    if (strcmp(output_setname, input_setnames[0]))
        sset = resultSetClone(zh, output_setname, sset);
    sset->sortSpec = copy_SortKeySpecList(sort_sequence, sset->nmem);
    return resultSetSortSingle(zh, nmem, sset, rset, sort_sequence,
                               sort_status);
}

ZEBRA_RES resultSetSortSingle(ZebraHandle zh, NMEM nmem,
                              ZebraSet sset, RSET rset,
                              Z_SortKeySpecList *sort_sequence,
                              int *sort_status)
{
    int i;
    int ib;
    int n = 0;
    zint kno = 0;
    zint psysno = 0;
    struct it_key key;
    struct sortKeyInfo sort_criteria[ZSET_SORT_MAX_LEVEL];
    char *cmp_buf[ZSET_SORT_MAX_LEVEL];
    char *tmp_cmp_buf[ZSET_SORT_MAX_LEVEL];
    int num_criteria;
    RSFD rfd;
    TERMID termid;
    TERMID *terms;
    int numTerms = 0;
    size_t sysno_mem_index = 0;

    int numbases = zh->num_basenames;
    yaz_log(log_level_sort, "searching %d databases",numbases);

    if (zh->m_staticrank)
        sysno_mem_index = 1;

    assert(nmem); /* compiler shut up about unused param */
    sset->sort_info->num_entries = 0;

    rset_getterms(rset, 0, 0, &n);
    terms = (TERMID *) nmem_malloc(nmem, sizeof(*terms)*n);
    rset_getterms(rset, terms, n, &numTerms);

    sset->hits = 0;
    num_criteria = sort_sequence->num_specs;
    if (num_criteria > ZSET_SORT_MAX_LEVEL)
        num_criteria = ZSET_SORT_MAX_LEVEL;
    /* set up the search criteria */
    for (i = 0; i < num_criteria; i++)
    {
        Z_SortKeySpec *sks = sort_sequence->specs[i];
        Z_SortKey *sk;

        sort_criteria[i].ord = (int *)
            nmem_malloc(nmem, sizeof(int)*numbases);
        sort_criteria[i].numerical = (int *)
            nmem_malloc(nmem, sizeof(int)*numbases);

        /* initialize ord and numerical for each database */
        for (ib = 0; ib < numbases; ib++)
        {
            sort_criteria[i].ord[ib] = -1;
            sort_criteria[i].numerical[ib] = 0;
        }

        if (sks->which == Z_SortKeySpec_missingValueData)
        {
            zebra_setError(zh, YAZ_BIB1_UNSUPP_MISSING_DATA_ACTION, 0);
            return ZEBRA_FAIL;
        }
        if (*sks->sortRelation == Z_SortKeySpec_ascending)
            sort_criteria[i].relation = 'A';
        else if (*sks->sortRelation == Z_SortKeySpec_descending)
            sort_criteria[i].relation = 'D';
        else
        {
            zebra_setError(zh, YAZ_BIB1_ILLEGAL_SORT_RELATION, 0);
            return ZEBRA_FAIL;
        }
        if (sks->sortElement->which == Z_SortElement_databaseSpecific)
        {
            zebra_setError(zh, YAZ_BIB1_DATABASE_SPECIFIC_SORT_UNSUPP, 0);
            return ZEBRA_FAIL;
        }
        else if (sks->sortElement->which != Z_SortElement_generic)
        {
            zebra_setError(zh, YAZ_BIB1_SORT_ILLEGAL_SORT, 0);
            return ZEBRA_FAIL;
        }
        sk = sks->sortElement->u.generic;
        switch (sk->which)
        {
        case Z_SortKey_sortField:
            yaz_log(log_level_sort, "key %d is of type sortField", i+1);
            for (ib = 0; ib < numbases; ib++)
            {
                zebraExplain_curDatabase(zh->reg->zei, zh->basenames[ib]);
                sort_criteria[i].numerical[ib] = 0;
                sort_criteria[i].ord[ib] =
                    zebraExplain_lookup_attr_str(zh->reg->zei,
                                                 zinfo_index_category_sort,
                                                 0, sk->u.sortField);
                if (sks->which != Z_SortKeySpec_null
                    && sort_criteria[i].ord[ib] == -1)
                {
                    zebra_setError(zh,
                                   YAZ_BIB1_CANNOT_SORT_ACCORDING_TO_SEQUENCE, 0);
                    return ZEBRA_FAIL;
                }
            }
            break;
        case Z_SortKey_elementSpec:
            yaz_log(log_level_sort, "key %d is of type elementSpec", i+1);
            zebra_setError(zh, YAZ_BIB1_CANNOT_SORT_ACCORDING_TO_SEQUENCE, 0);
            return ZEBRA_FAIL;
        case Z_SortKey_sortAttributes:
            yaz_log(log_level_sort, "key %d is of type sortAttributes", i+1);
            /* for every database we searched, get the sort index file
               id (ord) and its numerical indication and store them in
               the sort_criteria */
            for (ib = 0; ib < numbases; ib++)
            {
                zebraExplain_curDatabase(zh->reg->zei, zh->basenames[ib]);
                if (zebra_sort_get_ord(zh, sk->u.sortAttributes,
                                       &sort_criteria[i].ord[ib],
                                       &sort_criteria[i].numerical[ib]) !=
                    ZEBRA_OK && sks->which != Z_SortKeySpec_null)
                    return ZEBRA_FAIL;
            }
            break;
        }
        /* right now we look up the index type based on the first database
           if the index_type's can differ between the indexes of different
           databases (which i guess they can?) then we have to store the
           index types for each database, just like the ord and numerical */
        if (zebraExplain_lookup_ord(zh->reg->zei, sort_criteria[i].ord[0],
                                    &sort_criteria[i].index_type,
                                    0, 0))
        {
            zebra_setError(zh, YAZ_BIB1_CANNOT_SORT_ACCORDING_TO_SEQUENCE, 0);
            return ZEBRA_FAIL;
        }
    }
    /* allocate space for each cmpare buf + one extra for tmp comparison */
    /* cmp_buf is an array of array, the first dimension is the criteria and the second dimension are
       all other result entries to compare against. This is slowly filled when records are processed.
       tmp_cmp_buf is an array with a value of the current record for each criteria
    */
    for (i = 0; i<num_criteria; i++)
    {
        cmp_buf[i] = xmalloc(sset->sort_info->max_entries
                             * SORT_IDX_ENTRYSIZE);
        tmp_cmp_buf[i] = xmalloc(SORT_IDX_ENTRYSIZE);
    }
    rfd = rset_open(rset, RSETF_READ);
    while (rset_read(rfd, &key, &termid))
    {
        zint this_sys = key.mem[sysno_mem_index];
        if (log_level_searchhits)
            key_logdump_txt(log_level_searchhits, &key, termid->name);
        kno++;
        if (this_sys != psysno)
        {
            int database_no = 0;
            if ((sset->hits & 255) == 0 && zh->break_handler_func)
            {
                if (zh->break_handler_func(zh->break_handler_data))
                {
                    rset_set_hits_limit(rset, 0);
                    break;
                }
            }
            (sset->hits)++;
            psysno = this_sys;

            /* determine database from the term, but only bother if more than
               one database is in use*/
            if (numbases > 1 && termid->ol)
            {
                const char *this_db = 0;
                if (zebraExplain_lookup_ord(zh->reg->zei, termid->ol->ord,  0, &this_db, 0)
                    == 0 && this_db)
                {
                    for (ib = 0; ib < numbases; ib++)
                        if (!strcmp(this_db, zh->basenames[ib]))
                            database_no = ib;
                }
            }
#if 0
            yaz_log(YLOG_LOG, "sysno=" ZINT_FORMAT " database_no=%d", this_sys,
                database_no);
            ord_list_print(termid->ol);
#endif
            resultSetInsertSort(zh, sset, database_no,
                                sort_criteria, num_criteria, psysno, cmp_buf,
                                tmp_cmp_buf);
        }
    }
    rset_close(rfd);

    /* free the compare buffers */
    for (i = 0; i<num_criteria; i++)
    {
        xfree(cmp_buf[i]);
        xfree(tmp_cmp_buf[i]);
    }

    yaz_log(log_level_sort, ZINT_FORMAT " keys, " ZINT_FORMAT " sysnos, sort",
            kno, sset->hits);
    for (i = 0; i < numTerms; i++)
        yaz_log(log_level_sort, "term=\"%s\" type=%s count=" ZINT_FORMAT,
                terms[i]->name, terms[i]->flags, terms[i]->rset->hits_count);
    *sort_status = Z_SortResponse_success;
    return ZEBRA_OK;
}

RSET resultSetRef(ZebraHandle zh, const char *resultSetId)
{
    ZebraSet s;

    if ((s = resultSetGet(zh, resultSetId)))
        return s->rset;
    return NULL;
}

ZEBRA_RES resultSetRank(ZebraHandle zh, ZebraSet zebraSet,
                        RSET rset, NMEM nmem)
{
    struct it_key key;
    TERMID termid;
    TERMID *terms;
    zint kno = 0;
    int numTerms = 0;
    int n = 0;
    int i;
    ZebraRankClass rank_class;
    struct zset_sort_info *sort_info;
    const char *rank_handler_name = res_get_def(zh->res, "rank", "rank-1");
    size_t sysno_mem_index = 0;

    if (zh->m_staticrank)
        sysno_mem_index = 1;

    if (!log_level_set)
        loglevels();
    sort_info = zebraSet->sort_info;
    sort_info->num_entries = 0;
    zebraSet->hits = 0;
    zebraSet->estimated_hit_count = 0;
    rset_getterms(rset, 0, 0, &n);
    terms = (TERMID *) nmem_malloc(nmem, sizeof(*terms)*n);
    rset_getterms(rset, terms, n, &numTerms);

    rank_class = zebraRankLookup(zh, rank_handler_name);
    if (!rank_class)
    {
        yaz_log(YLOG_WARN, "No such rank handler: %s", rank_handler_name);
        zebra_setError(zh, YAZ_BIB1_UNSUPP_SEARCH, "Cannot find rank handler");
        return ZEBRA_FAIL;
    }
    else
    {
        RSFD rfd = rset_open(rset, RSETF_READ);
        struct rank_control *rc = rank_class->control;
        int score;
        zint count = 0;
        void *handle = (*rc->begin) (zh->reg, rank_class->class_handle, rset,
                                     nmem, terms, numTerms);
        zint psysno = 0;  /* previous doc id / sys no */
        zint pstaticrank = 0; /* previous static rank */
        int stop_flag = 0;
        while (rset_read(rfd, &key, &termid))
        {
            zint this_sys = key.mem[sysno_mem_index];

            zint seqno = key.mem[key.len-1];
            kno++;
            if (log_level_searchhits)
                key_logdump_txt(log_level_searchhits, &key, termid->name);
            if (this_sys != psysno)
            {   /* new record .. */
                if (!(rfd->counted_items & 255) && zh->break_handler_func)
                {
                    if (zh->break_handler_func(zh->break_handler_data))
                    {
                        yaz_log(YLOG_LOG, "Aborted search");
                        stop_flag = 1;
                    }
                }
                if (rfd->counted_items > rset->hits_limit)
                    stop_flag = 1;
                if (stop_flag)
                {
                    zebraSet->estimated_hit_count = 1;
                    break;
                }
                if (psysno)
                {   /* only if we did have a previous record */
                    score = (*rc->calc)(handle, psysno, pstaticrank,
                                        &stop_flag);
                    /* insert the hit. A=Ascending */
                    resultSetInsertRank(zh, sort_info, psysno, score, 'A');
                    count++;
                }
                psysno = this_sys;
                if (zh->m_staticrank)
                    pstaticrank = key.mem[0];
            }
            (*rc->add)(handle, CAST_ZINT_TO_INT(seqno), termid);
        }
        /* no more items */
        if (psysno)
        {   /* we had - at least - one record */
            score = (*rc->calc)(handle, psysno, pstaticrank, &stop_flag);
            /* insert the hit. A=Ascending */
            resultSetInsertRank(zh, sort_info, psysno, score, 'A');
            count++;
        }
        (*rc->end)(zh->reg, handle);
        rset_close(rfd);
    }
    zebraSet->hits = rset->hits_count;

    yaz_log(log_level_searchterms, ZINT_FORMAT " keys, "
            ZINT_FORMAT " sysnos, rank",  kno, zebraSet->hits);
    for (i = 0; i < numTerms; i++)
    {
        yaz_log(log_level_searchterms, "term=\"%s\" type=%s count="
                ZINT_FORMAT,
                terms[i]->name, terms[i]->flags, terms[i]->rset->hits_count);
    }
    return ZEBRA_OK;
}

ZebraRankClass zebraRankLookup(ZebraHandle zh, const char *name)
{
    ZebraRankClass p = zh->reg->rank_classes;
    while (p && strcmp(p->control->name, name))
        p = p->next;
    if (p && !p->init_flag)
    {
        if (p->control->create)
            p->class_handle = (*p->control->create)(zh);
        p->init_flag = 1;
    }
    return p;
}

void zebraRankInstall(struct zebra_register *reg, struct rank_control *ctrl)
{
    ZebraRankClass p = (ZebraRankClass) xmalloc(sizeof(*p));
    p->control = (struct rank_control *) xmalloc(sizeof(*p->control));
    memcpy(p->control, ctrl, sizeof(*p->control));
    p->control->name = xstrdup(ctrl->name);
    p->init_flag = 0;
    p->next = reg->rank_classes;
    reg->rank_classes = p;
}

void zebraRankDestroy(struct zebra_register *reg)
{
    ZebraRankClass p = reg->rank_classes;
    while (p)
    {
        ZebraRankClass p_next = p->next;
        if (p->init_flag && p->control->destroy)
            (*p->control->destroy)(reg, p->class_handle);
        xfree(p->control->name);
        xfree(p->control);
        xfree(p);
        p = p_next;
    }
    reg->rank_classes = NULL;
}

static int trav_rset_for_termids(RSET rset, TERMID *termid_array,
                                 zint *hits_array, int *approx_array)
{
    int no = 0;
    int i;
    for (i = 0; i<rset->no_children; i++)
        no += trav_rset_for_termids(rset->children[i],
                                    (termid_array ? termid_array + no : 0),
                                    (hits_array ? hits_array + no : 0),
                                    (approx_array ? approx_array + no : 0));
    if (rset->term && rset->term->name[0])
    {
        if (termid_array)
            termid_array[no] = rset->term;
        if (hits_array)
            hits_array[no] = rset->hits_count;
        if (approx_array)
            approx_array[no] = rset->hits_approx;
#if 0
        yaz_log(YLOG_LOG, "rset=%p term=%s limit=" ZINT_FORMAT
                " count=" ZINT_FORMAT,
                rset, rset->term->name, rset->hits_limit, rset->hits_count);
#endif
        no++;
    }
    return no;
}

ZEBRA_RES zebra_result_set_term_no(ZebraHandle zh, const char *setname,
                                   int *num_terms)
{
    ZebraSet sset = resultSetGet(zh, setname);
    *num_terms = 0;
    if (sset)
    {
        *num_terms = trav_rset_for_termids(sset->rset, 0, 0, 0);
        return ZEBRA_OK;
    }
    return ZEBRA_FAIL;
}

ZEBRA_RES zebra_result_set_term_info(ZebraHandle zh, const char *setname,
                                     int no, zint *count, int *approx,
                                     char *termbuf, size_t *termlen,
                                     const char **term_ref_id)
{
    ZebraSet sset = resultSetGet(zh, setname);
    if (sset)
    {
        int num_terms = trav_rset_for_termids(sset->rset, 0, 0, 0);
        if (no >= 0 && no < num_terms)
        {
            TERMID *term_array = xmalloc(num_terms * sizeof(*term_array));
            zint *hits_array = xmalloc(num_terms * sizeof(*hits_array));
            int *approx_array = xmalloc(num_terms * sizeof(*approx_array));

            trav_rset_for_termids(sset->rset, term_array,
                                  hits_array, approx_array);

            if (count)
                *count = hits_array[no];
            if (approx)
                *approx = approx_array[no];
            if (termbuf)
            {
                char *inbuf = term_array[no]->name;
                size_t inleft = strlen(inbuf);
                size_t outleft = *termlen - 1;

                if (zh->iconv_from_utf8 != 0)
                {
                    char *outbuf = termbuf;
                    size_t ret;

                    ret = yaz_iconv(zh->iconv_from_utf8, &inbuf, &inleft,
                                    &outbuf, &outleft);
                    if (ret == (size_t)(-1))
                        *termlen = 0;
                    else
                    {
                        yaz_iconv(zh->iconv_from_utf8, 0, 0,
                                  &outbuf, &outleft);
                        *termlen = outbuf - termbuf;
                    }
                }
                else
                {
                    if (inleft > outleft)
                        inleft = outleft;
                    *termlen = inleft;
                    memcpy(termbuf, inbuf, *termlen);
                }
                termbuf[*termlen] = '\0';
            }
            if (term_ref_id)
                *term_ref_id = term_array[no]->ref_id;

            xfree(term_array);
            xfree(hits_array);
            xfree(approx_array);
            return ZEBRA_OK;
        }
    }
    return ZEBRA_FAIL;
}

ZEBRA_RES zebra_snippets_hit_vector(ZebraHandle zh, const char *setname,
                                    zint sysno, zebra_snippets *snippets)
{
    ZebraSet sset = resultSetGet(zh, setname);
    yaz_log(YLOG_DEBUG, "zebra_get_hit_vector setname=%s zysno=" ZINT_FORMAT,
            setname, sysno);
    if (!sset)
        return ZEBRA_FAIL;
    else
    {
        struct rset_key_control *kc = zebra_key_control_create(zh);
        NMEM nmem = nmem_create();
        struct it_key key;
        RSET rsets[2], rset_comb;
        RSET rset_temp = rset_create_temp(nmem, kc, kc->scope,
                                          res_get(zh->res, "setTmpDir"),0 );

        TERMID termid;
        RSFD rsfd = rset_open(rset_temp, RSETF_WRITE);

        key.mem[0] = sysno;
        key.mem[1] = 0;
        key.mem[2] = 0;
        key.mem[3] = 0;
        key.len = 2;
        rset_write(rsfd, &key);
        rset_close(rsfd);

        rsets[0] = rset_temp;
        rsets[1] = rset_dup(sset->rset);

        rset_comb = rset_create_and(nmem, kc, kc->scope, 2, rsets);

        rsfd = rset_open(rset_comb, RSETF_READ);

        while (rset_read(rsfd, &key, &termid))
        {
            if (termid)
            {
                struct ord_list *ol;
                for (ol = termid->ol; ol; ol = ol->next)
                {
                    zebra_snippets_append(snippets, key.mem[key.len-1], 0,
                                          ol->ord, termid->name);
                }
            }
        }
        rset_close(rsfd);

        rset_delete(rset_comb);
        nmem_destroy(nmem);
        kc->dec(kc);
    }
    return ZEBRA_OK;
}

static ZEBRA_RES zebra_recid_to_sysno(ZebraHandle zh,
                                      const char **basenames, int num_bases,
                                      zint recid,
                                      zint *sysnos, int *no_sysnos)
{
    ZEBRA_RES res = ZEBRA_OK;
    int sysnos_offset = 0;
    int i;

    if (!zh->reg->isamb || !zh->m_segment_indexing)
    {
        if (sysnos_offset < *no_sysnos)
            *sysnos = recid;
        sysnos_offset++;
    }
    else
    {
        for (i = 0; res == ZEBRA_OK && i < num_bases; i++)
        {
            const char *database = basenames[i];
            if (zebraExplain_curDatabase(zh->reg->zei, database) == 0)
            {
                const char *index_type = "w";
                const char *use_string = "_ALLRECORDS";
                int ord;
                zinfo_index_category_t cat = zinfo_index_category_alwaysmatches;
                ord = zebraExplain_lookup_attr_str(zh->reg->zei, cat,
                                                   index_type, use_string);
                if (ord != -1)
                {
                    char ord_buf[32];
                    int ord_len = key_SU_encode(ord, ord_buf);
                    char *info;

                    ord_buf[ord_len] = '\0';

                    info = dict_lookup(zh->reg->dict, ord_buf);
                    if (info)
                    {
                        if (*info != sizeof(ISAM_P))
                        {
                            res = ZEBRA_FAIL;
                        }
                        else
                        {
                            ISAM_P isam_p;
                            ISAMB_PP pt;
                            struct it_key key_until, key_found;
                            int i = 0;
                            int r;

                            memcpy(&isam_p, info+1, sizeof(ISAM_P));

                            pt = isamb_pp_open(zh->reg->isamb, isam_p, 2);
                            if (!pt)
                                res = ZEBRA_FAIL;
                            else
                            {
                                key_until.mem[i++] = recid;
                                key_until.mem[i++] = 0;  /* section_id */
                                if (zh->m_segment_indexing)
                                    key_until.mem[i++] = 0; /* segment */
                                key_until.mem[i++] = 0;
                                key_until.len = i;

                                r = isamb_pp_forward(pt, &key_found, &key_until);
                                while (r && key_found.mem[0] == recid)
                                {
                                    if (sysnos_offset < *no_sysnos)
                                        sysnos[sysnos_offset++] =
                                            key_found.mem[key_found.len-1];
                                    r = isamb_pp_read(pt, &key_found);
                                }
                                isamb_pp_close(pt);
                            }
                        }
                    }
                }
            }
        }
    }
    *no_sysnos = sysnos_offset;
    return res;
}

ZEBRA_RES zebra_result_recid_to_sysno(ZebraHandle zh,
                                      const char *setname,
                                      zint recid,
                                      zint *sysnos, int *no_sysnos)
{
    const char **basenames;
    int num_bases;
    ZEBRA_RES res;

    res = resultSetGetBaseNames(zh, setname, &basenames, &num_bases);
    if (res != ZEBRA_OK)
        return ZEBRA_FAIL;

    return zebra_recid_to_sysno(zh, basenames, num_bases,
                                recid, sysnos, no_sysnos);
}

void zebra_count_set(ZebraHandle zh, RSET rset, zint *count,
                     zint approx_limit)
{
    zint psysno = 0;
    struct it_key key;
    RSFD rfd;

    yaz_log(YLOG_DEBUG, "count_set");

    rset->hits_limit = approx_limit;

    *count = 0;
    rfd = rset_open(rset, RSETF_READ);
    while (rset_read(rfd, &key,0 /* never mind terms */))
    {
        if (key.mem[0] != psysno)
        {
            psysno = key.mem[0];
            if (rfd->counted_items >= rset->hits_limit)
                break;
        }
    }
    rset_close(rfd);
    *count = rset->hits_count;
}


/*
 * Local variables:
 * c-basic-offset: 4
 * c-file-style: "Stroustrup"
 * indent-tabs-mode: nil
 * End:
 * vim: shiftwidth=4 tabstop=8 expandtab
 */