/* 
 * Copyright (c) 2007, 2014, Oracle and/or its affiliates. All rights reserved.
 *
 * 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; version 2 of the
 * License.
 * 
 * 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 St, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

#include "var_grid_model_be.h"
#include "base/string_utilities.h"
#include "sqlide_generics_private.h"
#include <sqlite/execute.hpp>
#include <sqlite/query.hpp>
#include <boost/foreach.hpp>
#include "glib/gstdio.h"


using namespace bec;
using namespace grt;
using namespace base;

//--------------------------------------------------------------------------------------------------

// sqlite supports up to 2000 columns (w/o need to recompile sources), see SQLITE_MAX_COLUMN on http://www.sqlite.org/limits.html
// but in fact we are restriced by more severe SQLITE_MAX_VARIABLE_NUMBER constant, which is 999 and which is used at max value when caching data
const int VarGridModel::DATA_SWAP_DB_TABLE_MAX_COL_COUNT= 999;

//--------------------------------------------------------------------------------------------------

class VarGridModel::IconForVal : public boost::static_visitor<IconId>
{
public:
  IconForVal(bool treat_blobnull_as_blob) : _treat_blobnull_as_blob(treat_blobnull_as_blob)
  {
    IconManager *icon_man= IconManager::get_instance();
    _null_icon= icon_man->get_icon_id("field_overlay_null.png");
    _blob_icon= icon_man->get_icon_id("field_overlay_blob.png");
  }
private:
  IconId _null_icon;
  IconId _blob_icon;
  bool _treat_blobnull_as_blob;

public:
  template<typename T> result_type operator()(const T &t, const sqlite::null_t &v) const { return _null_icon; }
  result_type operator()(const sqlite::null_t &v) const { return _null_icon; }
  result_type operator()(const sqlite::blob_ref_t &t, const sqlite::null_t &v) const { return _treat_blobnull_as_blob ? _blob_icon : _null_icon; }
  template<typename V> result_type operator()(const sqlite::blob_ref_t &t, const V &v) const { return _blob_icon; }

  template<typename T, typename V>
  result_type operator()(const T &t, const V &v) const { return 0; }
};

//--------------------------------------------------------------------------------------------------

VarGridModel::VarGridModel(GRTManager *grtm)
:
_grtm(grtm),
_readonly(true),
_is_field_value_truncation_enabled(false),
_edited_field_row(-1),
_edited_field_col(-1)
{

  {
    grt::DictRef options= DictRef::cast_from(_grtm->get_grt()->get("/wb/options/options"));
    _optimized_blob_fetching= (options.get_int("Recordset:OptimizeBlobFetching", 0) != 0);
  }
}

//--------------------------------------------------------------------------------------------------

VarGridModel::~VarGridModel()
{
  _refresh_connection.disconnect();

  _data_swap_db.reset();
  // clean temporary file to prevent crowding of files
  if (!_data_swap_db_path.empty())
    g_remove(_data_swap_db_path.c_str());
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::reset()
{
  _data_swap_db.reset();
  if (_data_swap_db_path.empty())
  {
    _data_swap_db_path= _grtm->get_unique_tmp_subdir();
    _data_swap_db_path.resize(_data_swap_db_path.size()-1); // remove trailing path separator
    _data_swap_db_path+= ".db";

    boost::shared_ptr<sqlite::connection> data_swap_db= this->data_swap_db();

    sqlite::execute(*data_swap_db, "create table `data` (`id` integer)", true);
    sqlite::execute(*data_swap_db, "create table `data_index` (`id` integer)", true);
    sqlite::execute(*data_swap_db, "create table `deleted_rows` (`id` integer)", true);
    sqlite::execute(*data_swap_db, "create table `changes` (`id` integer primary key autoincrement, `record` integer, `action` integer, `column` integer)", true);
  }

  {
    base::RecMutexLock data_mutex UNUSED (_data_mutex);
    reinit(_data);
  }
  reinit(_column_names);
  reinit(_column_types);
  reinit(_real_column_types);
  reinit(_column_flags);

  _column_count= 0;
  _row_count= 0;
  _data_frame_begin= 0;
  _data_frame_end= 0;

  _icon_for_val.reset(new IconForVal(_optimized_blob_fetching));
}

//--------------------------------------------------------------------------------------------------

int VarGridModel::floating_point_visible_scale()
{
  grt::DictRef options= grt::DictRef::cast_from(_grtm->get_grt()->get("/wb/options/options"));
  return (int)options.get_int("Recordset:FloatingPointVisibleScale");
}

//--------------------------------------------------------------------------------------------------

boost::shared_ptr<sqlite::connection> VarGridModel::data_swap_db() const
{
  if (_grtm->in_main_thread())
    return (_data_swap_db) ? _data_swap_db : _data_swap_db= create_data_swap_db_connection();
  else
    return create_data_swap_db_connection();
}

//--------------------------------------------------------------------------------------------------

boost::shared_ptr<sqlite::connection> VarGridModel::create_data_swap_db_connection() const
{
  boost::shared_ptr<sqlite::connection> data_swap_db;
  if (!_data_swap_db_path.empty())
  {
    data_swap_db.reset(new sqlite::connection(_data_swap_db_path));
    sqlide::optimize_sqlite_connection_for_speed(data_swap_db.get());
  }
  return data_swap_db;
}

//--------------------------------------------------------------------------------------------------

int VarGridModel::refresh_ui()
{
  if (_grtm->in_main_thread())
    refresh_ui_signal();
  else
    _refresh_connection = _grtm->run_once_when_idle(this, boost::bind(&VarGridModel::refresh_ui, this));
  return 0;
}

//--------------------------------------------------------------------------------------------------

size_t VarGridModel::count()
{
  return _row_count + (_readonly ? 0 : 1);
}

//--------------------------------------------------------------------------------------------------

class VarType
{
public:
  typedef VarGridModel::ColumnType result_type;
  result_type operator()(const sqlite::blob_ref_t &) const { return VarGridModel::BlobType; }
  result_type operator()(int) const { return VarGridModel::NumericType; }
  result_type operator()(const boost::int64_t &) const { return VarGridModel::NumericType; }
  result_type operator()(const long double &) const { return VarGridModel::FloatType; }
  template<typename T> result_type operator()(const T &v) const { return VarGridModel::StringType; }
};

//--------------------------------------------------------------------------------------------------

VarGridModel::ColumnType VarGridModel::get_column_type(ColumnId column)
{
  static VarType vt;
  return boost::apply_visitor(vt, _column_types[column]);
}

//--------------------------------------------------------------------------------------------------

VarGridModel::ColumnType VarGridModel::get_real_column_type(ColumnId column)
{
  static VarType vt;
  return boost::apply_visitor(vt, _real_column_types[column]);
}

//--------------------------------------------------------------------------------------------------

std::string VarGridModel::get_column_caption(ColumnId column)
{
  return _column_names.at(column);
}


VarGridModel::Cell VarGridModel::cell(RowId row, ColumnId column)
{
  if (row >= _row_count)
    return _data.end();

  // cache rows if needed
  if ((_data_frame_begin > row) || (_data_frame_end <= row) || ((_data_frame_end == _data_frame_begin) && _row_count))
    cache_data_frame(row, false);

  // translate to absolute cell address
  RowId cell_index= (row - _data_frame_begin) * _column_count + column;
  return _data.begin() + cell_index;
}


bool VarGridModel::get_cell(VarGridModel::Cell &cell, const NodeId &node, ColumnId column, bool allow_new_row)
{
  if (!node.is_valid())
    return false;

  RowId row= node[0];

  if ( (row > _row_count)
    || (column >= _column_count)
    || (!allow_new_row && (_row_count == row)))
    return false;

  cell= this->cell(row, column);
  return true;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::is_field_null(const NodeId &node, ColumnId column)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);

  // returns true for out of the range addresses
  Cell cell;
  if (get_cell(cell, node, column, false))
  {
    if (_optimized_blob_fetching && sqlide::is_var_blob(_real_column_types[column]))
      return false;
    else
      return sqlide::is_var_null(*cell);
  }
  else
  {
    return true;
  }
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::set_field_null(const bec::NodeId &node, ColumnId column)
{
  return is_field_null(node, column) ? true : set_field(node, column, sqlite::null_t());
}

//--------------------------------------------------------------------------------------------------

IconId VarGridModel::get_field_icon(const NodeId &node, ColumnId column, IconSize size)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);

  Cell cell;
  static const sqlite::variant_t null_value= sqlite::null_t();
  if (((ssize_t)column < 0) || (column + 1 >= _column_types.size()))
    return 0;
  const sqlite::variant_t &var= get_cell(cell, node, column, false) ? *cell : null_value;
  return boost::apply_visitor(*_icon_for_val, _column_types[column], var);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field(const NodeId &node, ColumnId column, std::string &value)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);
  return get_field_(node, column, value);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_(const NodeId &node, ColumnId column, std::string &value)
{
  Cell cell;
  bool res= get_cell(cell, node, column, false);
  if (res)
    value= boost::apply_visitor(_var_to_str, *cell);
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_repr(const NodeId &node, ColumnId column, std::string &value)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);
  return get_field_repr_(node, column, value);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_repr_no_truncate(const bec::NodeId &node, ColumnId column, std::string &value)
{
  Cell cell;
  bool res= get_cell(cell, node, column, false);
  if (res)
    value= boost::apply_visitor(_var_to_str_repr, *cell);
  return res;  
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_repr_(const NodeId &node, ColumnId column, std::string &value)
{
  Cell cell;
  bool res= get_cell(cell, node, column, false);
  if (res)
  {
    if (_is_field_value_truncation_enabled)
    {
      size_t row= node[0];
      _var_to_str_repr.is_truncation_enabled= (row != _edited_field_row) || (column != _edited_field_col);
    }
    value= boost::apply_visitor(_var_to_str_repr, *cell);
  }
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field(const NodeId &node, ColumnId column, sqlite::variant_t &value)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);
  return get_field_(node, column, value);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_(const NodeId &node, ColumnId column, sqlite::variant_t &value)
{
  Cell cell;
  bool res= get_cell(cell, node, column, false);
  if (res)
    value= *cell;
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field(const NodeId &node, ColumnId column, ssize_t &value)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);
  return get_field_(node, column, value);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_(const NodeId &node, ColumnId column, ssize_t &value)
{
  Cell cell;
  bool res = get_cell(cell, node, column, false);
  if (res)
    value = (ssize_t)boost::apply_visitor(_var_to_int, *cell);
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field(const NodeId &node, ColumnId column, double &value)
{
  base::RecMutexLock data_mutex UNUSED (_data_mutex);
  return get_field_(node, column, value);
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_(const NodeId &node, ColumnId column, double &value)
{
  Cell cell;
  bool res= get_cell(cell, node, column, false);
  if (res)
    value= (double)boost::apply_visitor(_var_to_long_double, *cell);
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::get_field_grt(const NodeId &node, ColumnId column, grt::ValueRef &value)
{
  std::string val;
  bool res= get_field(node, column, val);
  if (res)
    value= grt::StringRef(val);
  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::set_field(const NodeId &node, ColumnId column, const sqlite::variant_t &value)
{
  bool res= false;

  {
    base::RecMutexLock data_mutex UNUSED (_data_mutex);

    Cell cell;
    res= get_cell(cell, node, column, true);
    if (res)
    {
      bool is_blob_column= sqlide::is_var_blob(_real_column_types[column]);
      if (!_optimized_blob_fetching || !is_blob_column)
      {
        static const sqlide::VarEq var_eq;
        if (!is_blob_column)
          res= !boost::apply_visitor(var_eq, value, *cell);
        if (res)
          *cell= value;
      }
    }
  }

  if (res)
    after_set_field(node, column, value);

  return res;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::set_field(const NodeId &node, ColumnId column, const std::string &value)
{
  return set_field(node, column, sqlite::variant_t(value));
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::set_field(const NodeId &node, ColumnId column, double value)
{
  return set_field(node, column, sqlite::variant_t((long double)value));
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::set_field(const NodeId &node, ColumnId column, ssize_t value)
{
  return set_field(node, column, sqlite::variant_t((boost::int64_t)value));
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::add_column(const std::string &name, const sqlite::variant_t &type)
{
  _column_names.push_back(name);
  _column_types.push_back(type);
  _real_column_types.push_back(type);
  ++_column_count;
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::cache_data_frame(RowId center_row, bool force_reload)
{
  static const RowId half_row_count= 500; //! load from options
  RowId row_count= half_row_count * 2;

  // center_row of -1 means only to forcibly reload current data frame
  if (-1 != (int)center_row)
  {
    RowId starting_row= (center_row < half_row_count) ? 0 : (center_row - half_row_count);

    // adjust range borders to comply with row count & cache frame size
    // e.g. shift back and/or resize requested cache frame
    if (starting_row + row_count > _row_count)
    {
      if (row_count < _row_count)
      {
        starting_row= _row_count - row_count;
      }
      else
      {
        starting_row= 0;
        row_count= _row_count;
      }
    }

    if (!force_reload &&
      (_data_frame_begin == starting_row) &&
      (_data_frame_begin != _data_frame_end) &&
      (_data_frame_end - _data_frame_begin == row_count))
    {
      return;
    }

    _data_frame_begin= starting_row;
    _data_frame_end= starting_row + row_count;
  }
  else
  {
    row_count= _data_frame_end - _data_frame_begin;
  }

  _data.clear();

  // load data
  {
    boost::shared_ptr<sqlite::connection> data_swap_db= this->data_swap_db();
    const size_t partition_count= data_swap_db_partition_count();

    std::list<boost::shared_ptr<sqlite::query> > data_queries(partition_count);
    prepare_partition_queries(data_swap_db.get(), "select d.* from `data%s` d inner join `data_index` di on (di.`id`=d.`id`) order by di.`rowid` limit ? offset ?", data_queries);
    std::list<sqlite::variant_t> bind_vars;
    bind_vars.push_back((int)row_count);
    bind_vars.push_back((int)_data_frame_begin);
    std::vector<boost::shared_ptr<sqlite::result> > data_results(data_queries.size());
    if (emit_partition_queries(data_swap_db.get(), data_queries, data_results, bind_vars))
    {
      bool next_row_exists= true;

      std::vector<bool> blob_columns(_column_count);
      for (ColumnId col= 0; _column_count > col; ++col)
        blob_columns[col]= sqlide::is_var_blob(_real_column_types[col]);

      _data.reserve(row_count * _column_count);
      do
      {
        for (size_t partition= 0; partition < partition_count; ++partition)
        {
          boost::shared_ptr<sqlite::result> &data_rs= data_results[partition];
          for (ColumnId col_begin= partition * DATA_SWAP_DB_TABLE_MAX_COL_COUNT, col= col_begin,
            col_end= std::min<ColumnId>(_column_count, (partition + 1) * DATA_SWAP_DB_TABLE_MAX_COL_COUNT); col < col_end; ++col)
          {
            sqlite::variant_t v;
            if (_optimized_blob_fetching && blob_columns[col])
            {
              v= sqlite::null_t();
            }
            else
            {
              ColumnId partition_column= col - col_begin;
              v = data_rs->get_variant((int)partition_column);
              v= boost::apply_visitor(_var_cast, _column_types[col], v);
            }
            _data.push_back(v);
          }
        }
        BOOST_FOREACH (boost::shared_ptr<sqlite::result> &data_rs, data_results)
          next_row_exists= data_rs->next_row();
      }
      while (next_row_exists);
    }
  }
}

//--------------------------------------------------------------------------------------------------

size_t VarGridModel::data_swap_db_partition_count() const
{
  return data_swap_db_partition_count(_column_count);
}

//--------------------------------------------------------------------------------------------------

size_t VarGridModel::data_swap_db_partition_count(ColumnId column_count)
{
  std::div_t d = std::div((int)column_count, DATA_SWAP_DB_TABLE_MAX_COL_COUNT);
  return d.quot + (size_t)(d.rem > 0);
}

//--------------------------------------------------------------------------------------------------

std::string VarGridModel::data_swap_db_partition_suffix(size_t partition_index)
{
  return (partition_index > 0) ? strfmt("_%u", (unsigned int) partition_index) : std::string("");
}

//--------------------------------------------------------------------------------------------------

size_t VarGridModel::data_swap_db_column_partition(ColumnId column)
{
  std::div_t d = std::div((int)column, DATA_SWAP_DB_TABLE_MAX_COL_COUNT);
  return d.quot;
}

//--------------------------------------------------------------------------------------------------

bec::ListModel::ColumnId VarGridModel::translate_data_swap_db_column(ListModel::ColumnId column, size_t *partition)
{
  std::div_t d = std::div((int)column, DATA_SWAP_DB_TABLE_MAX_COL_COUNT);
  if (partition)
    *partition= d.quot;
  return d.rem;
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::prepare_partition_queries(sqlite::connection *data_swap_db, const std::string &query_text_template, std::list<boost::shared_ptr<sqlite::query> > &queries)
{
  size_t partition= 0;
  BOOST_FOREACH (boost::shared_ptr<sqlite::query> &query, queries)
  {
    std::string partition_suffix= data_swap_db_partition_suffix(partition);
    query.reset(new sqlite::query(*data_swap_db, strfmt(query_text_template.c_str(), partition_suffix.c_str())));
    ++partition;
  }
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::emit_partition_queries(sqlite::connection *data_swap_db, std::list<boost::shared_ptr<sqlite::query> > &queries, std::vector<boost::shared_ptr<sqlite::result> > &results, const std::list<sqlite::variant_t> &bind_vars)
{
//  bool no_results_returned= false;
  size_t partition= 0;
  BOOST_FOREACH (boost::shared_ptr<sqlite::query> &query, queries)
  {
    query->clear();
    sqlide::BindSqlCommandVar bind_sql_command_var(query.get());
    BOOST_FOREACH (const sqlite::variant_t &var, bind_vars)
      boost::apply_visitor(bind_sql_command_var, var);
    if (!query->emit())
    {
//      no_results_returned= true;
      return false;
    }
    results[partition]= query->get_result();
    ++partition;
  }
  return true;
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::emit_partition_commands(sqlite::connection *data_swap_db, size_t partition_count, const std::string &command_text_template, const std::list<sqlite::variant_t> &bind_vars)
{
  for (size_t partition= 0; partition < partition_count; ++partition)  
  {
    std::string partition_suffix= data_swap_db_partition_suffix(partition);
    sqlite::command command(*data_swap_db, strfmt(command_text_template.c_str(), partition_suffix.c_str()));
    sqlide::BindSqlCommandVar bind_sql_command_var(&command);
    BOOST_FOREACH (const sqlite::variant_t &var, bind_vars)
      boost::apply_visitor(bind_sql_command_var, var);
    command.emit();
  }
}

//--------------------------------------------------------------------------------------------------

void VarGridModel::set_edited_field(RowId row_index, ColumnId col_index)
{
  _edited_field_row = row_index;
  _edited_field_col = col_index;
}

//--------------------------------------------------------------------------------------------------

bool VarGridModel::is_field_value_truncation_enabled(bool val)
{
  _is_field_value_truncation_enabled= val;
  if (_is_field_value_truncation_enabled)
  {
    grt::DictRef options= grt::DictRef::cast_from(_grtm->get_grt()->get("/wb/options/options"));
    ssize_t field_value_truncation_threshold = options.get_int("Recordset:FieldValueTruncationThreshold", 256);
    if (field_value_truncation_threshold < 0)
      _var_to_str_repr.is_truncation_enabled= _is_field_value_truncation_enabled= false;
    else
      _var_to_str_repr.truncation_threshold= field_value_truncation_threshold;
  }
  else
    _var_to_str_repr.is_truncation_enabled= _is_field_value_truncation_enabled;

  return _is_field_value_truncation_enabled;
}

//--------------------------------------------------------------------------------------------------
