/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*======
This file is part of TokuDB


Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.

    TokuDBis is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2,
    as published by the Free Software Foundation.

    TokuDB 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 TokuDB.  If not, see <http://www.gnu.org/licenses/>.

======= */

#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."

#if !defined(TOKUDB_ALTER_COMMON)
#define TOKUDB_ALTER_COMMON

TOKUDB_UNUSED(static bool tables_have_same_keys(
    TABLE* table,
    TABLE* altered_table,
    bool print_error,
    bool check_field_index));

static bool tables_have_same_keys(
    TABLE* table,
    TABLE* altered_table,
    bool print_error,
    bool check_field_index) {

    bool retval;
    if (table->s->keys != altered_table->s->keys) {
        if (print_error) {
            sql_print_error("tables have different number of keys");
        }
        retval = false;
        goto cleanup;
    }
    if (table->s->primary_key != altered_table->s->primary_key) {
        if (print_error) {
            sql_print_error(
                "Tables have different primary keys, %d %d",
                table->s->primary_key,
                altered_table->s->primary_key);
        }
        retval = false;
        goto cleanup;
    }
    for (uint32_t i=0; i < table->s->keys; i++) {
        KEY* curr_orig_key = &table->key_info[i];
        KEY* curr_altered_key = &altered_table->key_info[i];
        if (strcmp(curr_orig_key->name, curr_altered_key->name)) {
            if (print_error) {
                sql_print_error(
                    "key %d has different name, %s %s",
                    i,
                    curr_orig_key->name,
                    curr_altered_key->name);
            }
            retval = false;
            goto cleanup;
        }
        if (key_is_clustering(curr_orig_key) !=
            key_is_clustering(curr_altered_key)) {
            if (print_error) {
                sql_print_error(
                    "keys disagree on if they are clustering, %d, %d",
                    curr_orig_key->user_defined_key_parts,
                    curr_altered_key->user_defined_key_parts);
            }
            retval = false;
            goto cleanup;
        }
        if (((curr_orig_key->flags & HA_NOSAME) == 0) !=
            ((curr_altered_key->flags & HA_NOSAME) == 0)) {
            if (print_error) {
                sql_print_error(
                    "keys disagree on if they are unique, %d, %d",
                    curr_orig_key->user_defined_key_parts,
                    curr_altered_key->user_defined_key_parts);
            }
            retval = false;
            goto cleanup;
        }
        if (curr_orig_key->user_defined_key_parts !=
            curr_altered_key->user_defined_key_parts) {
            if (print_error) {
                sql_print_error(
                    "keys have different number of parts, %d, %d",
                    curr_orig_key->user_defined_key_parts,
                    curr_altered_key->user_defined_key_parts);
            }
            retval = false;
            goto cleanup;
        }
        //
        // now verify that each field in the key is the same
        //
        for (uint32_t j = 0; j < curr_orig_key->user_defined_key_parts; j++) {
            KEY_PART_INFO* curr_orig_part = &curr_orig_key->key_part[j];
            KEY_PART_INFO* curr_altered_part = &curr_altered_key->key_part[j];
            Field* curr_orig_field = curr_orig_part->field;
            Field* curr_altered_field = curr_altered_part->field;
            if (curr_orig_part->length != curr_altered_part->length) {
                if (print_error) {
                    sql_print_error(
                        "Key %s has different length at index %d",
                        curr_orig_key->name,
                        j);
                }
                retval = false;
                goto cleanup;
            }
            bool are_fields_same;
            are_fields_same = (check_field_index) ? 
                (curr_orig_part->fieldnr == curr_altered_part->fieldnr && 
                 fields_are_same_type(curr_orig_field, curr_altered_field)) :
                (are_two_fields_same(curr_orig_field,curr_altered_field));
                
            if (!are_fields_same) {
                if (print_error) {
                    sql_print_error(
                        "Key %s has different field at index %d",
                        curr_orig_key->name,
                        j);
                }
                retval = false;
                goto cleanup;
            }
        }
    }

    retval = true;
cleanup:
    return retval;
}

// MySQL sets the null_bit as a number that you can bit-wise AND a byte to
// to evaluate whether a field is NULL or not. This value is a power of 2, from
// 2^0 to 2^7. We return the position of the bit within the byte, which is
// lg null_bit
TOKUDB_UNUSED(static inline uint32_t get_null_bit_position(
    uint32_t null_bit));
static inline uint32_t get_null_bit_position(uint32_t null_bit) {
    uint32_t retval = 0;
    switch(null_bit) {
    case (1):
        retval = 0;
        break;
    case (2):
        retval = 1;
        break;
    case (4):
        retval = 2;
        break;
    case (8):
        retval = 3;
        break;
    case (16):
        retval = 4;
        break;
    case (32):
        retval = 5;
        break;
    case (64):
        retval = 6;
        break;
    case (128):
        retval = 7;
        break;
    default:
        assert_unreachable();
    }
    return retval;
}

// returns the index of the null bit of field. 
TOKUDB_UNUSED(static inline uint32_t get_overall_null_bit_position(
    TABLE* table,
    Field* field));
static inline uint32_t get_overall_null_bit_position(
    TABLE* table,
    Field* field) {

    uint32_t offset = get_null_offset(table, field);
    uint32_t null_bit = field->null_bit;
    return offset*8 + get_null_bit_position(null_bit);
}

// not static since 51 uses this and 56 does not
TOKUDB_UNUSED(static bool are_null_bits_in_order(TABLE* table));
static bool are_null_bits_in_order(TABLE* table) {
    uint32_t curr_null_pos = 0;
    bool first = true;
    bool retval = true;
    for (uint i = 0; i < table->s->fields; i++) {
        Field* curr_field = table->field[i];
        bool nullable = (curr_field->null_bit != 0);
        if (nullable) {
            uint32_t pos =
                get_overall_null_bit_position(table, curr_field);
            if (!first && pos != curr_null_pos+1){
                retval = false;
                break;
            }
            first = false;
            curr_null_pos = pos;
        }
    }
    return retval;
}

TOKUDB_UNUSED(static uint32_t get_first_null_bit_pos(TABLE* table));
static uint32_t get_first_null_bit_pos(TABLE* table) {
    uint32_t table_pos = 0;
    for (uint i = 0; i < table->s->fields; i++) {
        Field* curr_field = table->field[i];
        bool nullable = (curr_field->null_bit != 0);
        if (nullable) {
            table_pos =
                get_overall_null_bit_position(table, curr_field);
            break;
        }
    }
    return table_pos;
}

TOKUDB_UNUSED(static bool is_column_default_null(
    TABLE* src_table,
    uint32_t field_index));
static bool is_column_default_null(
    TABLE* src_table,
    uint32_t field_index) {

    Field* curr_field = src_table->field[field_index];
    bool is_null_default = false;
    bool nullable = curr_field->null_bit != 0;
    if (nullable) {
        uint32_t null_bit_position =
            get_overall_null_bit_position(src_table, curr_field);
        is_null_default =
            is_overall_null_position_set(
                src_table->s->default_values,
                null_bit_position);
    }
    return is_null_default;
}

static uint32_t fill_static_row_mutator(
    uchar* buf, 
    TABLE* orig_table,
    TABLE* altered_table,
    KEY_AND_COL_INFO* orig_kc_info,
    KEY_AND_COL_INFO* altered_kc_info,
    uint32_t keynr) {

    //
    // start packing extra
    //
    uchar* pos = buf;
    // says what the operation is
    pos[0] = UP_COL_ADD_OR_DROP;
    pos++;

    //
    // null byte information
    //
    memcpy(pos, &orig_table->s->null_bytes, sizeof(orig_table->s->null_bytes));
    pos += sizeof(orig_table->s->null_bytes);
    memcpy(
        pos,
        &altered_table->s->null_bytes,
        sizeof(orig_table->s->null_bytes));
    pos += sizeof(altered_table->s->null_bytes);

    //
    // num_offset_bytes
    //
    assert_always(orig_kc_info->num_offset_bytes <= 2);
    pos[0] = orig_kc_info->num_offset_bytes;
    pos++;
    assert_always(altered_kc_info->num_offset_bytes <= 2);
    pos[0] = altered_kc_info->num_offset_bytes;
    pos++;

    //
    // size of fixed fields
    //
    uint32_t fixed_field_size = orig_kc_info->mcp_info[keynr].fixed_field_size;
    memcpy(pos, &fixed_field_size, sizeof(fixed_field_size));
    pos += sizeof(fixed_field_size);
    fixed_field_size = altered_kc_info->mcp_info[keynr].fixed_field_size;
    memcpy(pos, &fixed_field_size, sizeof(fixed_field_size));
    pos += sizeof(fixed_field_size);

    //
    // length of offsets
    //
    uint32_t len_of_offsets = orig_kc_info->mcp_info[keynr].len_of_offsets;
    memcpy(pos, &len_of_offsets, sizeof(len_of_offsets));
    pos += sizeof(len_of_offsets);
    len_of_offsets = altered_kc_info->mcp_info[keynr].len_of_offsets;
    memcpy(pos, &len_of_offsets, sizeof(len_of_offsets));
    pos += sizeof(len_of_offsets);

    uint32_t orig_start_null_pos = get_first_null_bit_pos(orig_table);
    memcpy(pos, &orig_start_null_pos, sizeof(orig_start_null_pos));
    pos += sizeof(orig_start_null_pos);
    uint32_t altered_start_null_pos = get_first_null_bit_pos(altered_table);
    memcpy(pos, &altered_start_null_pos, sizeof(altered_start_null_pos));
    pos += sizeof(altered_start_null_pos);

    assert_always((pos-buf) == STATIC_ROW_MUTATOR_SIZE);
    return pos - buf;
}

static uint32_t fill_dynamic_row_mutator(
    uchar* buf,
    uint32_t* columns, 
    uint32_t num_columns,
    TABLE* src_table,
    KEY_AND_COL_INFO* src_kc_info,
    uint32_t keynr,
    bool is_add,
    bool* out_has_blobs) {

    uchar* pos = buf;
    bool has_blobs = false;
    uint32_t cols = num_columns;
    memcpy(pos, &cols, sizeof(cols));
    pos += sizeof(cols);
    for (uint32_t i = 0; i < num_columns; i++) {
        uint32_t curr_index = columns[i];
        Field* curr_field = src_table->field[curr_index];

        pos[0] = is_add ? COL_ADD : COL_DROP;
        pos++;
        //
        // NULL bit information
        //
        bool is_null_default = false;
        bool nullable = curr_field->null_bit != 0;
        if (!nullable) {
            pos[0] = 0;
            pos++;
        } else {
            pos[0] = 1;
            pos++;
            // write position of null byte that is to be removed
            uint32_t null_bit_position =
                get_overall_null_bit_position(src_table, curr_field);
            memcpy(pos, &null_bit_position, sizeof(null_bit_position));
            pos += sizeof(null_bit_position);
            //
            // if adding a column, write the value of the default null_bit
            //
            if (is_add) {
                is_null_default =
                    is_overall_null_position_set(
                        src_table->s->default_values,
                        null_bit_position);
                pos[0] = is_null_default ? 1 : 0;
                pos++;
            }
        }
        if (is_fixed_field(src_kc_info, curr_index)) {
            // we have a fixed field being dropped
            // store the offset and the number of bytes
            pos[0] = COL_FIXED;
            pos++;
            //store the offset
            uint32_t fixed_field_offset =
                src_kc_info->cp_info[keynr][curr_index].col_pack_val;
            memcpy(pos, &fixed_field_offset, sizeof(fixed_field_offset));
            pos += sizeof(fixed_field_offset);
            //store the number of bytes
            uint32_t num_bytes = src_kc_info->field_lengths[curr_index];
            memcpy(pos, &num_bytes, sizeof(num_bytes));
            pos += sizeof(num_bytes);
            if (is_add && !is_null_default) {
                uint curr_field_offset = field_offset(curr_field, src_table);
                memcpy(
                    pos,
                    src_table->s->default_values + curr_field_offset,
                    num_bytes);
                pos += num_bytes;
            }
        } else if (is_variable_field(src_kc_info, curr_index)) {
            pos[0] = COL_VAR;
            pos++;
            //store the index of the variable column
            uint32_t var_field_index =
                src_kc_info->cp_info[keynr][curr_index].col_pack_val;
            memcpy(pos, &var_field_index, sizeof(var_field_index));
            pos += sizeof(var_field_index);
            if (is_add && !is_null_default) {
                uint curr_field_offset = field_offset(curr_field, src_table);
                uint32_t len_bytes = src_kc_info->length_bytes[curr_index];
                uint32_t data_length =
                    get_var_data_length(
                        src_table->s->default_values + curr_field_offset,
                        len_bytes);
                memcpy(pos, &data_length, sizeof(data_length));
                pos += sizeof(data_length);
                memcpy(
                    pos, 
                    src_table->s->default_values + curr_field_offset + len_bytes,
                    data_length);
                pos += data_length;
            }
        } else {
            pos[0] = COL_BLOB;
            pos++;
            has_blobs = true;
        }
    }
    *out_has_blobs = has_blobs;
    return pos-buf;
}

static uint32_t fill_static_blob_row_mutator(
    uchar* buf,
    TABLE* src_table,
    KEY_AND_COL_INFO* src_kc_info) {

    uchar* pos = buf;
    // copy number of blobs
    memcpy(pos, &src_kc_info->num_blobs, sizeof(src_kc_info->num_blobs));
    pos += sizeof(src_kc_info->num_blobs);
    // copy length bytes for each blob
    for (uint32_t i = 0; i < src_kc_info->num_blobs; i++) {
        uint32_t curr_field_index = src_kc_info->blob_fields[i]; 
        Field* field = src_table->field[curr_field_index];
        uint32_t len_bytes = field->row_pack_length();
        assert_always(len_bytes <= 4);
        pos[0] = len_bytes;
        pos++;
    }

    return pos-buf;
}

static uint32_t fill_dynamic_blob_row_mutator(
    uchar* buf,
    uint32_t* columns, 
    uint32_t num_columns,
    TABLE* src_table,
    KEY_AND_COL_INFO* src_kc_info,
    bool is_add) {

    uchar* pos = buf;
    for (uint32_t i = 0; i < num_columns; i++) {
        uint32_t curr_field_index = columns[i];
        Field* curr_field = src_table->field[curr_field_index];
        if (is_blob_field(src_kc_info, curr_field_index)) { 
            // find out which blob it is
            uint32_t blob_index = src_kc_info->num_blobs;
            for (uint32_t j = 0; j < src_kc_info->num_blobs; j++) {
                if (curr_field_index  == src_kc_info->blob_fields[j]) {
                    blob_index = j;
                    break;
                }
            }
            // assert we found blob in list
            assert_always(blob_index < src_kc_info->num_blobs);
            pos[0] = is_add ? COL_ADD : COL_DROP;
            pos++;
            memcpy(pos, &blob_index, sizeof(blob_index));
            pos += sizeof(blob_index);
            if (is_add) {
                uint32_t len_bytes = curr_field->row_pack_length();
                assert_always(len_bytes <= 4);
                pos[0] = len_bytes;
                pos++;

                // create a zero length blob field that can be directly copied
                // in for now, in MySQL, we can only have blob fields
                // that have no default value
                memset(pos, 0, len_bytes);
                pos += len_bytes;
            }
        }
    }
    return pos-buf;
}

// TODO: carefully review to make sure that the right information is used
// TODO: namely, when do we get stuff from share->kc_info and when we get
// TODO: it from altered_kc_info, and when is keynr associated with the right thing
uint32_t ha_tokudb::fill_row_mutator(
    uchar* buf,
    uint32_t* columns,
    uint32_t num_columns,
    TABLE* altered_table,
    KEY_AND_COL_INFO* altered_kc_info,
    uint32_t keynr,
    bool is_add) {

    if (TOKUDB_UNLIKELY(TOKUDB_DEBUG_FLAGS(TOKUDB_DEBUG_ALTER_TABLE))) {
        TOKUDB_HANDLER_TRACE("*****some info:*************");
        TOKUDB_HANDLER_TRACE(
            "old things: num_null_bytes %d, num_offset_bytes %d, "
            "fixed_field_size %d, fixed_field_size %d",
            table->s->null_bytes,
            share->kc_info.num_offset_bytes,
            share->kc_info.mcp_info[keynr].fixed_field_size,
            share->kc_info.mcp_info[keynr].len_of_offsets);
        TOKUDB_HANDLER_TRACE(
            "new things: num_null_bytes %d, num_offset_bytes %d, "
            "fixed_field_size %d, fixed_field_size %d",
            altered_table->s->null_bytes,
            altered_kc_info->num_offset_bytes,
            altered_kc_info->mcp_info[keynr].fixed_field_size,
            altered_kc_info->mcp_info[keynr].len_of_offsets);
        TOKUDB_HANDLER_TRACE("****************************");
    }
    uchar* pos = buf;
    bool has_blobs = false;
    pos +=
        fill_static_row_mutator(
            pos,
            table,
            altered_table,
            &share->kc_info,
            altered_kc_info,
            keynr);

    if (is_add) {
        pos +=
            fill_dynamic_row_mutator(
                pos,
                columns,
                num_columns,
                altered_table,
                altered_kc_info,
                keynr,
                is_add,
                &has_blobs);
    } else {
        pos +=
            fill_dynamic_row_mutator(
                pos,
                columns,
                num_columns,
                table,
                &share->kc_info,
                keynr,
                is_add,
                &has_blobs);
    }
    if (has_blobs) {
        pos += fill_static_blob_row_mutator(pos, table, &share->kc_info);
        if (is_add) {
            pos +=
                fill_dynamic_blob_row_mutator(
                    pos,
                    columns,
                    num_columns,
                    altered_table,
                    altered_kc_info,
                    is_add);
        } else {
            pos +=
                fill_dynamic_blob_row_mutator(
                    pos,
                    columns,
                    num_columns,
                    table,
                    &share->kc_info,
                    is_add);
        }
    }
    return pos-buf;
}

static bool all_fields_are_same_type(TABLE *table_a, TABLE *table_b) {
    if (table_a->s->fields != table_b->s->fields)
        return false;
    for (uint i = 0; i < table_a->s->fields; i++) {
        Field* field_a = table_a->field[i];
        Field* field_b = table_b->field[i];
        if (!fields_are_same_type(field_a, field_b))
            return false;
    }
    return true;
}

TOKUDB_UNUSED(static bool column_rename_supported(
    TABLE* orig_table,
    TABLE* new_table,
    bool alter_column_order));
static bool column_rename_supported(
    TABLE* orig_table,
    TABLE* new_table,
    bool alter_column_order) {

    bool retval = false;
    bool keys_same_for_cr;
    uint num_fields_with_different_names = 0;
    uint field_with_different_name = orig_table->s->fields;
    if (orig_table->s->fields != new_table->s->fields) {
        retval = false;
        goto cleanup;
    }
    if (alter_column_order) {
        retval = false;
        goto cleanup;
    }
    if (!all_fields_are_same_type(orig_table, new_table)) {
        retval = false;
        goto cleanup;
    }
    for (uint i = 0; i < orig_table->s->fields; i++) {
        Field* orig_field = orig_table->field[i];
        Field* new_field = new_table->field[i];
        if (!fields_have_same_name(orig_field, new_field)) {
            num_fields_with_different_names++;
            field_with_different_name = i;
        }
    }
    // only allow one renamed field
    if (num_fields_with_different_names != 1) {
        retval = false;
        goto cleanup;
    }
    assert_always(field_with_different_name < orig_table->s->fields);
    //
    // at this point, we have verified that the two tables have
    // the same field types and with ONLY one field with a different name.
    // We have also identified the field with the different name
    //
    // Now we need to check the indexes
    //
    keys_same_for_cr =
        tables_have_same_keys(
            orig_table,
            new_table,
            false,
            true);
    if (!keys_same_for_cr) {
        retval = false;
        goto cleanup;
    }
    retval = true;
cleanup:
    return retval;
}

TOKUDB_UNUSED(static int find_changed_columns(
    uint32_t* changed_columns,
    uint32_t* num_changed_columns,
    TABLE* smaller_table,
    TABLE* bigger_table));
static int find_changed_columns(
    uint32_t* changed_columns,
    uint32_t* num_changed_columns,
    TABLE* smaller_table,
    TABLE* bigger_table) {

    int retval;
    uint curr_new_col_index = 0;
    uint32_t curr_num_changed_columns=0;
    assert_always(bigger_table->s->fields > smaller_table->s->fields);
    for (uint i = 0; i < smaller_table->s->fields; i++, curr_new_col_index++) {
        if (curr_new_col_index >= bigger_table->s->fields) {
            sql_print_error("error in determining changed columns");
            retval = 1;
            goto cleanup;
        }
        Field* curr_field_in_new = bigger_table->field[curr_new_col_index];
        Field* curr_field_in_orig = smaller_table->field[i];
        while (!fields_have_same_name(curr_field_in_orig, curr_field_in_new)) {
            changed_columns[curr_num_changed_columns] = curr_new_col_index;
            curr_num_changed_columns++;
            curr_new_col_index++;
            curr_field_in_new = bigger_table->field[curr_new_col_index];
            if (curr_new_col_index >= bigger_table->s->fields) {
                sql_print_error("error in determining changed columns");
                retval = 1;
                goto cleanup;
            }
        }
        // at this point, curr_field_in_orig and curr_field_in_new should be
        // the same, let's verify make sure the two fields that have the same
        // name are ok
        if (!are_two_fields_same(curr_field_in_orig, curr_field_in_new)) {
            sql_print_error(
                "Two fields that were supposedly the same are not: %s in "
                "original, %s in new",
                curr_field_in_orig->field_name,
                curr_field_in_new->field_name);
            retval = 1;
            goto cleanup;
        }
    }
    for (uint i = curr_new_col_index; i < bigger_table->s->fields; i++) {
        changed_columns[curr_num_changed_columns] = i;
        curr_num_changed_columns++;
    }
    *num_changed_columns = curr_num_changed_columns;
    retval = 0;
cleanup:
    return retval;
}

TOKUDB_UNUSED(static bool tables_have_same_keys_and_columns(
    TABLE* first_table,
    TABLE* second_table,
    bool print_error));
static bool tables_have_same_keys_and_columns(
    TABLE* first_table,
    TABLE* second_table,
    bool print_error) {

    bool retval;
    if (first_table->s->null_bytes != second_table->s->null_bytes) {
        retval = false;
        if (print_error) {
            sql_print_error(
                "tables have different number of null bytes, %d, %d",
                first_table->s->null_bytes,
                second_table->s->null_bytes);
        }
        goto exit;
    }
    if (first_table->s->fields != second_table->s->fields) {
        retval = false;
        if (print_error) {
            sql_print_error(
                "tables have different number of fields, %d, %d",
                first_table->s->fields,
                second_table->s->fields);
        }
        goto exit;
    }
    for (uint i = 0; i < first_table->s->fields; i++) {
        Field* a = first_table->field[i];
        Field* b = second_table->field[i];
        if (!are_two_fields_same(a,b)) {
            retval = false;
            sql_print_error(
                "tables have different fields at position %d",
                i);
            goto exit;
        }
    }
    if (!tables_have_same_keys(first_table, second_table, print_error, true)) {
        retval = false;
        goto exit;
    }

    retval = true;
exit:
    return retval;
}

#if TOKU_INCLUDE_WRITE_FRM_DATA
// write the new frm data to the status dictionary using the alter table
// transaction
int ha_tokudb::write_frm_data(const uchar* frm_data, size_t frm_len) {
    TOKUDB_DBUG_ENTER("write_frm_data");

    int error = 0;
    if (TOKU_PARTITION_WRITE_FRM_DATA || table->part_info == NULL) {
        // write frmdata to status
        THD* thd = ha_thd();
        tokudb_trx_data* trx =
            (tokudb_trx_data*)thd_get_ha_data(thd, tokudb_hton);
        assert_always(trx);
        DB_TXN* txn = trx->stmt; // use alter table transaction
        assert_always(txn);
        error =
            write_to_status(
                share->status_block,
                hatoku_frm_data,
                (void*)frm_data,
                (uint)frm_len,
                txn);
    }

    TOKUDB_DBUG_RETURN(error);
}
#endif

#endif
