/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*
COPYING CONDITIONS NOTICE:

  This program is free software; you can redistribute it and/or modify
  it under the terms of version 2 of the GNU General Public License as
  published by the Free Software Foundation, and provided that the
  following conditions are met:

      * Redistributions of source code must retain this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
        DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below).

      * Redistributions in binary form must reproduce this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
        DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below) in the documentation and/or other materials
        provided with the distribution.

  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.

COPYRIGHT NOTICE:

  TokuDB, Tokutek Fractal Tree Indexing Library.
  Copyright (C) 2007-2013 Tokutek, Inc.

DISCLAIMER:

  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.

UNIVERSITY PATENT NOTICE:

  The technology is licensed by the Massachusetts Institute of
  Technology, Rutgers State University of New Jersey, and the Research
  Foundation of State University of New York at Stony Brook under
  United States of America Serial No. 11/760379 and to the patents
  and/or patent applications resulting from it.

PATENT MARKING NOTICE:

  This software is covered by US Patent No. 8,185,551.
  This software is covered by US Patent No. 8,489,638.

PATENT RIGHTS GRANT:

  "THIS IMPLEMENTATION" means the copyrightable works distributed by
  Tokutek as part of the Fractal Tree project.

  "PATENT CLAIMS" means the claims of patents that are owned or
  licensable by Tokutek, both currently or in the future; and that in
  the absence of this license would be infringed by THIS
  IMPLEMENTATION or by using or running THIS IMPLEMENTATION.

  "PATENT CHALLENGE" shall mean a challenge to the validity,
  patentability, enforceability and/or non-infringement of any of the
  PATENT CLAIMS or otherwise opposing any of the PATENT CLAIMS.

  Tokutek hereby grants to you, for the term and geographical scope of
  the PATENT CLAIMS, a non-exclusive, no-charge, royalty-free,
  irrevocable (except as stated in this section) patent license to
  make, have made, use, offer to sell, sell, import, transfer, and
  otherwise run, modify, and propagate the contents of THIS
  IMPLEMENTATION, where such license applies only to the PATENT
  CLAIMS.  This grant does not include claims that would be infringed
  only as a consequence of further modifications of THIS
  IMPLEMENTATION.  If you or your agent or licensee institute or order
  or agree to the institution of patent litigation against any entity
  (including a cross-claim or counterclaim in a lawsuit) alleging that
  THIS IMPLEMENTATION constitutes direct or contributory patent
  infringement, or inducement of patent infringement, then any rights
  granted to you under this License shall terminate as of the date
  such litigation is filed.  If you or your agent or exclusive
  licensee institute or order or agree to the institution of a PATENT
  CHALLENGE, then Tokutek may terminate any rights granted to you
  under this License.
*/

#ident "Copyright (c) 2007-2013 Tokutek Inc.  All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."
namespace tokudb {

    // Set the key_info cardinality counters for the table.
    void set_card_in_key_info(TABLE *table, uint rec_per_keys, uint64_t rec_per_key[]) {
        uint next_key_part = 0;
        for (uint i = 0; i < table->s->keys; i++) {
            bool is_unique_key = (i == table->s->primary_key) || (table->key_info[i].flags & HA_NOSAME);
            uint num_key_parts = get_key_parts(&table->key_info[i]);
            for (uint j = 0; j < num_key_parts; j++) {
                assert(next_key_part < rec_per_keys);
                ulong val = rec_per_key[next_key_part++];
                if (is_unique_key && j == num_key_parts-1)
                    val = 1;
                table->key_info[i].rec_per_key[j] = val;
            }
        }
    }
    
    // Put the cardinality counters into the status dictionary.
    void set_card_in_status(DB *status_db, DB_TXN *txn, uint rec_per_keys, uint64_t rec_per_key[]) {
        // encode cardinality into the buffer
        tokudb::buffer b;
        size_t s;
        s = b.append_ui<uint32_t>(rec_per_keys);
        assert(s > 0);
        for (uint i = 0; i < rec_per_keys; i++) {
            s = b.append_ui<uint64_t>(rec_per_key[i]);
            assert(s > 0);
        }
        // write cardinality to status
        int error = write_to_status(status_db, hatoku_cardinality, b.data(), b.size(), txn);
        assert(error == 0);
    }

    // Get the cardinality counters from the status dictionary.
    int get_card_from_status(DB *status_db, DB_TXN *txn, uint rec_per_keys, uint64_t rec_per_key[]) {
        // read cardinality from status
        void *buf = 0; size_t buf_size = 0;
        int error = get_status_realloc(status_db, txn, hatoku_cardinality, &buf, &buf_size);
        if (error == 0) {
            // decode cardinality from the buffer
            tokudb::buffer b(buf, 0, buf_size);
            size_t s;
            uint32_t num_parts;
            s = b.consume_ui<uint32_t>(&num_parts);
            if (s == 0 || num_parts != rec_per_keys) 
                error = EINVAL;
            if (error == 0) {
                for (uint i = 0; i < rec_per_keys; i++) {
                    s = b.consume_ui<uint64_t>(&rec_per_key[i]);
                    if (s == 0) {
                        error = EINVAL;
                        break;
                    }
                }
            }
        }
        // cleanup
        free(buf);
        return error;
    }

    // Delete the cardinality counters from the status dictionary.
    void delete_card_from_status(DB *status_db, DB_TXN *txn) {
        int error = remove_from_status(status_db, hatoku_cardinality, txn);
        assert(error == 0);
    }

    bool find_index_of_key(const char *key_name, TABLE_SHARE *table_share, uint *index_offset_ptr) {
        for (uint i = 0; i < table_share->keys; i++) {
            if (strcmp(key_name, table_share->key_info[i].name) == 0) {
                *index_offset_ptr = i;
                return true;
            }
        }
        return false;
    }

    // Altered table cardinality = select cardinality data from current table cardinality for keys that exist 
    // in the altered table and the current table.
    void set_card_from_status(DB *status_db, DB_TXN *txn, TABLE_SHARE *table_share, TABLE_SHARE *altered_table_share) {
        int error;
        // read existing cardinality data from status
        uint64_t rec_per_key[table_share->key_parts];
        error = get_card_from_status(status_db, txn, table_share->key_parts, rec_per_key);
        // set altered records per key to unknown
        uint64_t altered_rec_per_key[altered_table_share->key_parts];
        for (uint i = 0; i < altered_table_share->key_parts; i++)
            altered_rec_per_key[i] = 0;
        // compute the beginning of the key offsets in the original table
        uint orig_key_offset[table_share->keys];
        uint orig_key_parts = 0;
        for (uint i = 0; i < table_share->keys; i++) {
            orig_key_offset[i] = orig_key_parts;
            orig_key_parts += get_key_parts(&table_share->key_info[i]);
        }
        // if orig card data exists, then use it to compute new card data
        if (error == 0) {
            uint next_key_parts = 0;
            for (uint i = 0; error == 0 && i < altered_table_share->keys; i++) {
                uint ith_key_parts = get_key_parts(&altered_table_share->key_info[i]);
                uint orig_key_index;
                if (find_index_of_key(altered_table_share->key_info[i].name, table_share, &orig_key_index)) {
                    memcpy(&altered_rec_per_key[next_key_parts], &rec_per_key[orig_key_offset[orig_key_index]], ith_key_parts);
                }
                next_key_parts += ith_key_parts;
            }
        }
        if (error == 0)
            set_card_in_status(status_db, txn, altered_table_share->key_parts, altered_rec_per_key);
        else
            delete_card_from_status(status_db, txn);
    }

    // Compute records per key for all key parts of the ith key of the table.
    // For each key part, put records per key part in *rec_per_key_part[key_part_index].
    // Returns 0 if success, otherwise an error number.
    // TODO statistical dives into the FT
    int analyze_card(DB *db, DB_TXN *txn, bool is_unique __attribute__((unused)), uint64_t num_key_parts, uint64_t *rec_per_key_part,
                     int (*key_compare)(DB *, const DBT *, const DBT *, uint),
                     int (*analyze_progress)(void *extra, uint64_t rows), void *progress_extra) {
        int error = 0;
        uint64_t rows = 0;
        uint64_t unique_rows[num_key_parts];
        if (is_unique && num_key_parts == 1) {
            // dont compute for unique keys with a single part.  we already know the answer.
            rows = unique_rows[0] = 1;
        } else {
            DBC *cursor = NULL;
            error = db->cursor(db, txn, &cursor, 0);
            if (error == 0) {
                for (uint64_t i = 0; i < num_key_parts; i++)
                    unique_rows[i] = 1;
                // stop looking when the entire dictionary was analyzed, or a cap on execution time was reached, or the analyze was killed.
                DBT key = {}; key.flags = DB_DBT_REALLOC;
                DBT prev_key = {}; prev_key.flags = DB_DBT_REALLOC;
                while (1) {
                    error = cursor->c_get(cursor, &key, 0, DB_NEXT);
                    if (error != 0) {
                        if (error == DB_NOTFOUND)
                        error = 0; // eof is not an error
                        break;
                    }
                    rows++;
                    // first row is a unique row, otherwise compare with the previous key
                    bool copy_key = false;
                    if (rows == 1) {
                        copy_key = true;
                    } else {
                        // compare this key with the previous key.  ignore appended PK for SK's.
                        // TODO if a prefix is different, then all larger keys that include the prefix are also different.
                        // TODO if we are comparing the entire primary key or the entire unique secondary key, then the cardinality must be 1,
                        // so we can avoid computing it.
                        for (uint64_t i = 0; i < num_key_parts; i++) {
                            int cmp = key_compare(db, &prev_key, &key, i+1);
                            if (cmp != 0) {
                                unique_rows[i]++;
                                copy_key = true;
                            }
                        }
                    }
                    // prev_key = key
                    if (copy_key) {
                        prev_key.data = realloc(prev_key.data, key.size);
                        assert(prev_key.data);
                        prev_key.size = key.size;
                        memcpy(prev_key.data, key.data, prev_key.size);
                    }
                    // check for limit
                    if (analyze_progress && (rows % 1000) == 0) {
                        error = analyze_progress(progress_extra, rows);
                        if (error)
                            break;
                    }
                }
                // cleanup
                free(key.data);
                free(prev_key.data);
                int close_error = cursor->c_close(cursor);
                assert(close_error == 0);
            }
        }
        // return cardinality
        if (error == 0 || error == ETIME) {
            for (uint64_t i = 0; i < num_key_parts; i++)
                rec_per_key_part[i]  = rows / unique_rows[i];
        }
        return error;
    }
}