// Copyright (c) 2014-2016 Thomas Fussell
// Copyright (c) 2010-2015 openpyxl
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, WRISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE
//
// @license: http://www.opensource.org/licenses/mit-license.php
// @author: see AUTHORS file
#include <algorithm>
#include <cmath>
#include <limits>

#include <xlnt/cell/cell.hpp>
#include <xlnt/cell/cell_reference.hpp>
#include <xlnt/cell/index_types.hpp>
#include <xlnt/packaging/relationship.hpp>
#include <xlnt/utils/date.hpp>
#include <xlnt/utils/datetime.hpp>
#include <xlnt/utils/exceptions.hpp>
#include <xlnt/workbook/named_range.hpp>
#include <xlnt/workbook/workbook.hpp>
#include <xlnt/worksheet/cell_iterator.hpp>
#include <xlnt/worksheet/const_cell_iterator.hpp>
#include <xlnt/worksheet/const_range_iterator.hpp>
#include <xlnt/worksheet/range.hpp>
#include <xlnt/worksheet/range_iterator.hpp>
#include <xlnt/worksheet/range_reference.hpp>
#include <xlnt/worksheet/worksheet.hpp>

#include <detail/cell_impl.hpp>
#include <detail/constants.hpp>
#include <detail/workbook_impl.hpp>
#include <detail/worksheet_impl.hpp>

namespace xlnt {

worksheet::worksheet() : d_(nullptr)
{
}

worksheet::worksheet(detail::worksheet_impl *d) : d_(d)
{
}

worksheet::worksheet(const worksheet &rhs) : d_(rhs.d_)
{
}

worksheet::worksheet(workbook &parent, const std::string &title)
    : d_(title == "" ? parent.create_sheet().d_ : parent.create_sheet(title).d_)
{
}

bool worksheet::has_frozen_panes() const
{
    return get_frozen_panes() != cell_reference("A1");
}

std::string worksheet::unique_sheet_name(const std::string &value) const
{
    auto names = get_workbook().get_sheet_names();
    auto match = std::find(names.begin(), names.end(), value);
    std::size_t append = 0;
    while (match != names.end())
    {
        append++;
        match = std::find(names.begin(), names.end(), value + std::to_string(append));
    }
    return append == 0 ? value : value + std::to_string(append);
}

void worksheet::create_named_range(const std::string &name, const std::string &reference_string)
{
    create_named_range(name, range_reference(reference_string));
}

void worksheet::create_named_range(const std::string &name, const range_reference &reference)
{
    std::vector<named_range::target> targets;
    targets.push_back({ *this, reference });
    d_->named_ranges_[name] = named_range(name, targets);
}

range worksheet::operator()(const xlnt::cell_reference &top_left, const xlnt::cell_reference &bottom_right)
{
    return get_range(range_reference(top_left, bottom_right));
}

cell worksheet::operator[](const cell_reference &ref)
{
    return get_cell(ref);
}

std::vector<range_reference> worksheet::get_merged_ranges() const
{
    return d_->merged_cells_;
}

page_margins &worksheet::get_page_margins()
{
    return d_->page_margins_;
}

const page_margins &worksheet::get_page_margins() const
{
    return d_->page_margins_;
}

void worksheet::auto_filter(const std::string &reference_string)
{
    auto_filter(range_reference(reference_string));
}

void worksheet::auto_filter(const range_reference &reference)
{
    d_->auto_filter_ = reference;
}

void worksheet::auto_filter(const xlnt::range &range)
{
    auto_filter(range.get_reference());
}

range_reference worksheet::get_auto_filter() const
{
    return d_->auto_filter_;
}

bool worksheet::has_auto_filter() const
{
    return d_->auto_filter_.get_width() > 0;
}

void worksheet::unset_auto_filter()
{
    d_->auto_filter_ = range_reference(1, 1, 1, 1);
}

page_setup &worksheet::get_page_setup()
{
    return d_->page_setup_;
}

const page_setup &worksheet::get_page_setup() const
{
    return d_->page_setup_;
}

std::string worksheet::to_string() const
{
    return "<Worksheet \"" + d_->title_ + "\">";
}

workbook &worksheet::get_workbook()
{
    return *d_->parent_;
}

const workbook &worksheet::get_workbook() const
{
	return *d_->parent_;
}

void worksheet::garbage_collect()
{
    auto cell_map_iter = d_->cell_map_.begin();

    while (cell_map_iter != d_->cell_map_.end())
    {
        auto cell_iter = cell_map_iter->second.begin();

        while (cell_iter != cell_map_iter->second.end())
        {
            cell current_cell(&cell_iter->second);

            if (current_cell.garbage_collectible())
            {
                cell_iter = cell_map_iter->second.erase(cell_iter);
                continue;
            }

            cell_iter++;
        }

        if (cell_map_iter->second.empty())
        {
            cell_map_iter = d_->cell_map_.erase(cell_map_iter);
            continue;
        }

        cell_map_iter++;
    }
}

std::string worksheet::get_title() const
{
    if (d_ == nullptr)
    {
        throw std::runtime_error("null worksheet");
    }
    return d_->title_;
}

void worksheet::set_title(const std::string &title)
{
    d_->title_ = title;
}

cell_reference worksheet::get_frozen_panes() const
{
    return d_->view_.get_pane().top_left_cell;
}

void worksheet::freeze_panes(xlnt::cell top_left_cell)
{
    freeze_panes(top_left_cell.get_reference().to_string());
}

void worksheet::freeze_panes(const std::string &top_left_coordinate)
{
    auto ref = cell_reference(top_left_coordinate);
    d_->view_.get_pane().top_left_cell = ref;
    d_->view_.get_pane().state = pane_state::frozen;
    
    d_->view_.get_selections().clear();
    d_->view_.get_selections().push_back(selection());
    
    if (ref.get_column_index() == 1
        && ref.get_row() == 1)
    {
        d_->view_.get_selections().back().set_pane(pane_corner::top_left);
        d_->view_.get_pane().active_pane = pane_corner::top_left;
        d_->view_.get_pane().state = pane_state::normal;
    }
    else if (ref.get_column_index() == 1)
    {
        d_->view_.get_selections().back().set_pane(pane_corner::bottom_left);
        d_->view_.get_pane().active_pane = pane_corner::bottom_left;
        d_->view_.get_pane().y_split = ref.get_row() - 1;
    }
    else if (ref.get_row() == 1)
    {
        d_->view_.get_selections().back().set_pane(pane_corner::top_right);
        d_->view_.get_pane().active_pane = pane_corner::top_right;
        d_->view_.get_pane().x_split = ref.get_column_index().index - 1;
    }
    else
    {
        d_->view_.get_selections().push_back(selection());
        d_->view_.get_selections().push_back(selection());
        d_->view_.get_selections()[0].set_pane(pane_corner::top_right);
        d_->view_.get_selections()[1].set_pane(pane_corner::bottom_left);
        d_->view_.get_selections()[2].set_pane(pane_corner::bottom_right);
        d_->view_.get_pane().active_pane = pane_corner::bottom_right;
        d_->view_.get_pane().x_split = ref.get_column_index().index - 1;
        d_->view_.get_pane().y_split = ref.get_row() - 1;
    }
}

void worksheet::unfreeze_panes()
{
    d_->view_.get_pane().top_left_cell = cell_reference("A1");
    d_->view_.get_pane().state = pane_state::normal;
}

cell worksheet::get_cell(const cell_reference &reference)
{
    if (d_->cell_map_.find(reference.get_row()) == d_->cell_map_.end())
    {
        d_->cell_map_[reference.get_row()] = std::unordered_map<column_t, detail::cell_impl>();
    }

    auto &row = d_->cell_map_[reference.get_row()];

    if (row.find(reference.get_column_index()) == row.end())
    {
        row[reference.get_column_index()] = detail::cell_impl(d_, reference.get_column_index(), reference.get_row());
    }

    return cell(&row[reference.get_column_index()]);
}

const cell worksheet::get_cell(const cell_reference &reference) const
{
    return cell(&d_->cell_map_.at(reference.get_row()).at(reference.get_column_index()));
}

bool worksheet::has_cell(const cell_reference &reference) const
{
    const auto row = d_->cell_map_.find(reference.get_row());
    if(row == d_->cell_map_.cend())
        return false;
    
    const auto col = row->second.find(reference.get_column_index());
    if(col == row->second.cend())
        return false;
    
    return true;
}

bool worksheet::has_row_properties(row_t row) const
{
    return d_->row_properties_.find(row) != d_->row_properties_.end();
}

range worksheet::get_named_range(const std::string &name)
{
    if (!get_workbook().has_named_range(name))
    {
        throw key_error();
    }
    
    if (!has_named_range(name))
    {
        throw named_range_error();
    }

    return get_range(d_->named_ranges_[name].get_targets()[0].second);
}

column_t worksheet::get_lowest_column() const
{
    if (d_->cell_map_.empty())
    {
        return constants::min_column();
    }

    column_t lowest = constants::max_column();

    for (auto &row : d_->cell_map_)
    {
        for (auto &c : row.second)
        {
            lowest = std::min(lowest, c.first);
        }
    }

    return lowest;
}

row_t worksheet::get_lowest_row() const
{
    if (d_->cell_map_.empty())
    {
        return constants::min_row();
    }

    row_t lowest = constants::max_row();

    for (auto &row : d_->cell_map_)
    {
        lowest = std::min(lowest, row.first);
    }

    return lowest;
}

row_t worksheet::get_highest_row() const
{
    row_t highest = constants::min_row();

    for (auto &row : d_->cell_map_)
    {
        highest = std::max(highest, row.first);
    }

    return highest;
}

column_t worksheet::get_highest_column() const
{
    column_t highest = constants::min_column();

    for (auto &row : d_->cell_map_)
    {
        for (auto &c : row.second)
        {
            highest = std::max(highest, c.first);
        }
    }

    return highest;
}

range_reference worksheet::calculate_dimension() const
{
    auto lowest_column = get_lowest_column();
    auto lowest_row = get_lowest_row();

    auto highest_column = get_highest_column();
    auto highest_row = get_highest_row();

    return range_reference(lowest_column, lowest_row, highest_column, highest_row);
}

range worksheet::get_range(const std::string &reference_string)
{
    return get_range(range_reference(reference_string));
}

range worksheet::get_range(const range_reference &reference)
{
    return range(*this, reference);
}

const range worksheet::get_range(const std::string &reference_string) const
{
    return get_range(range_reference(reference_string));
}

const range worksheet::get_range(const range_reference &reference) const
{
    return range(*this, reference);
}

range worksheet::get_squared_range(column_t min_col, row_t min_row, column_t max_col, row_t max_row)
{
    range_reference reference(min_col, min_row, max_col, max_row);
    return get_range(reference);
}

const range worksheet::get_squared_range(column_t min_col, row_t min_row, column_t max_col, row_t max_row) const
{
    range_reference reference(min_col, min_row, max_col, max_row);
    return get_range(reference);
}

const std::vector<relationship> &worksheet::get_relationships() const
{
    return d_->relationships_;
}

relationship worksheet::create_relationship(relationship::type type, const std::string &target_uri)
{
    std::string r_id = "rId" + std::to_string(d_->relationships_.size() + 1);
    d_->relationships_.push_back(relationship(type, r_id, target_uri));
    return d_->relationships_.back();
}

void worksheet::merge_cells(const std::string &reference_string)
{
    merge_cells(range_reference(reference_string));
}

void worksheet::unmerge_cells(const std::string &reference_string)
{
    unmerge_cells(range_reference(reference_string));
}

void worksheet::merge_cells(const range_reference &reference)
{
    d_->merged_cells_.push_back(reference);
    bool first = true;

    for (auto row : get_range(reference))
    {
        for (auto cell : row)
        {
            cell.set_merged(true);

            if (!first)
            {
                if (cell.get_data_type() == cell::type::string)
                {
                    cell.set_value("");
                }
                else
                {
                    cell.clear_value();
                }
            }

            first = false;
        }
    }
}

void worksheet::merge_cells(column_t start_column, row_t start_row, column_t end_column, row_t end_row)
{
    merge_cells(xlnt::range_reference(start_column, start_row, end_column, end_row));
}

void worksheet::unmerge_cells(const range_reference &reference)
{
    auto match = std::find(d_->merged_cells_.begin(), d_->merged_cells_.end(), reference);

    if (match == d_->merged_cells_.end())
    {
        throw std::runtime_error("cells not merged");
    }

    d_->merged_cells_.erase(match);

    for (auto row : get_range(reference))
    {
        for (auto cell : row)
        {
            cell.set_merged(false);
        }
    }
}

void worksheet::unmerge_cells(column_t start_column, row_t start_row, column_t end_column, row_t end_row)
{
    unmerge_cells(xlnt::range_reference(start_column, start_row, end_column, end_row));
}

void worksheet::append()
{
    get_cell(cell_reference(1, get_next_row()));
}

void worksheet::append(const std::vector<std::string> &cells)
{
    xlnt::cell_reference next(1, get_next_row());

    for (auto cell : cells)
    {
        get_cell(next).set_value(cell);
        next.set_column_index(next.get_column_index() + 1);
    }
}

row_t worksheet::get_next_row() const
{
    auto row = get_highest_row() + 1;

    if (row == 2 && d_->cell_map_.size() == 0)
    {
        row = 1;
    }

    return row;
}

void worksheet::append(const std::vector<int> &cells)
{
    xlnt::cell_reference next(1, get_next_row());

    for (auto cell : cells)
    {
        get_cell(next).set_value(cell);
        next.set_column_index(next.get_column_index() + 1);
    }
}

void worksheet::append(const std::unordered_map<std::string, std::string> &cells)
{
    auto row = get_next_row();

    for (auto cell : cells)
    {
        get_cell(cell_reference(cell.first, row)).set_value(cell.second);
    }
}

void worksheet::append(const std::unordered_map<int, std::string> &cells)
{
    auto row = get_next_row();

    for (auto cell : cells)
    {
        get_cell(cell_reference(static_cast<column_t>(cell.first), row)).set_value(cell.second);
    }
}

void worksheet::append(const std::vector<int>::const_iterator begin, const std::vector<int>::const_iterator end)
{
    xlnt::cell_reference next(1, get_next_row());

    for (auto i = begin; i != end; i++)
    {
        get_cell(next).set_value(*i);
        next.set_column_index(next.get_column_index() + 1);
    }
}

xlnt::range worksheet::rows() const
{
    return get_range(calculate_dimension());
}

xlnt::range worksheet::rows(const std::string &range_string) const
{
    return get_range(range_reference(range_string));
}

xlnt::range worksheet::rows(const std::string &range_string, int row_offset, int column_offset) const
{
    range_reference reference(range_string);
    return get_range(reference.make_offset(column_offset, row_offset));
}

xlnt::range worksheet::rows(int row_offset, int column_offset) const
{
    range_reference reference(calculate_dimension());
    return get_range(reference.make_offset(column_offset, row_offset));
}

xlnt::range worksheet::columns() const
{
    return range(*this, calculate_dimension(), major_order::column);
}

bool worksheet::operator==(const worksheet &other) const
{
    return compare(other, true);
}

bool worksheet::compare(const worksheet &other, bool reference) const
{
    if(reference)
    {
        return d_ == other.d_;
    }
    
    if(d_->parent_ != other.d_->parent_) return false;
    
    for(auto &row : d_->cell_map_)
    {
        if(other.d_->cell_map_.find(row.first) == other.d_->cell_map_.end())
        {
            return false;
        }
        
        for(auto &cell : row.second)
        {
            if(other.d_->cell_map_[row.first].find(cell.first) == other.d_->cell_map_[row.first].end())
            {
                return false;
            }
            
            auto this_cell = cell.second.self();
            auto other_cell = other.d_->cell_map_[row.first][cell.first].self();

            if (this_cell.get_data_type() != other_cell.get_data_type())
            {
                return false;
            }

            if (this_cell.get_data_type() == xlnt::cell::type::numeric && this_cell.get_value<long double>() != other_cell.get_value<long double>())
            {
                return false;
            }
        }
    }
    
    // todo: missing some comparisons
    
    if(d_->auto_filter_ == other.d_->auto_filter_
        && d_->comment_count_ == other.d_->comment_count_
        && d_->view_.get_pane().top_left_cell == other.d_->view_.get_pane().top_left_cell
        && d_->merged_cells_ == other.d_->merged_cells_
        && d_->relationships_ == other.d_->relationships_)
    {
        return true;
    }
    
    return false;
}

bool worksheet::operator!=(const worksheet &other) const
{
    return !(*this == other);
}

bool worksheet::operator==(std::nullptr_t) const
{
    return d_ == nullptr;
}

bool worksheet::operator!=(std::nullptr_t) const
{
    return d_ != nullptr;
}

void worksheet::operator=(const worksheet &other)
{
    d_ = other.d_;
}

const cell worksheet::operator[](const cell_reference &ref) const
{
    return get_cell(ref);
}

range worksheet::operator[](const range_reference &ref)
{
    return get_range(ref);
}

range worksheet::operator[](const std::string &name)
{
    if (has_named_range(name))
    {
        return get_named_range(name);
    }
    return get_range(range_reference(name));
}

bool worksheet::has_named_range(const std::string &name)
{
    return d_->named_ranges_.find(name) != d_->named_ranges_.end();
}

void worksheet::remove_named_range(const std::string &name)
{
    if (!has_named_range(name))
    {
        throw std::runtime_error("worksheet doesn't have named range");
    }

    d_->named_ranges_.erase(name);
}

void worksheet::reserve(std::size_t n)
{
    d_->cell_map_.reserve(n);
}

void worksheet::increment_comments()
{
    d_->comment_count_++;
}

void worksheet::decrement_comments()
{
    d_->comment_count_--;
}

std::size_t worksheet::get_comment_count() const
{
    return d_->comment_count_;
}

header_footer &worksheet::get_header_footer()
{
    return d_->header_footer_;
}

const header_footer &worksheet::get_header_footer() const
{
    return d_->header_footer_;
}

header_footer::header_footer()
{
}

header::header() : default_(true), font_size_(12)
{
}

footer::footer() : default_(true), font_size_(12)
{
}

void worksheet::set_parent(xlnt::workbook &wb)
{
    d_->parent_ = &wb;
}

std::vector<std::string> worksheet::get_formula_attributes() const
{
    return {};
}

cell_reference worksheet::get_point_pos(int left, int top) const
{
    static const double DefaultColumnWidth = 51.85;
    static const double DefaultRowHeight = 15.0;

    auto points_to_pixels = [](long double value, long double dpi)
    {
        return static_cast<int>(std::ceil(value * dpi / 72));
    };

    auto default_height = points_to_pixels(DefaultRowHeight, 96.0);
    auto default_width = points_to_pixels(DefaultColumnWidth, 96.0);

    column_t current_column = 1;
    row_t current_row = 1;

    int left_pos = 0;
    int top_pos = 0;

    while (left_pos <= left)
    {
        current_column++;

        if (has_column_properties(current_column))
        {
            auto cdw = get_column_properties(current_column).width;

            if (cdw >= 0)
            {
                left_pos += points_to_pixels(cdw, 96.0);
                continue;
            }
        }

        left_pos += default_width;
    }

    while (top_pos <= top)
    {
        current_row++;

        if (has_row_properties(current_row))
        {
            auto cdh = get_row_properties(current_row).height;

            if (cdh >= 0)
            {
                top_pos += points_to_pixels(cdh, 96.0);
                continue;
            }
        }

        top_pos += default_height;
    }

    return { current_column - 1, current_row - 1 };
}

cell_reference worksheet::get_point_pos(const std::pair<int, int> &point) const
{
    return get_point_pos(point.first, point.second);
}

void worksheet::set_sheet_state(sheet_state state)
{
    get_page_setup().set_sheet_state(state);
}

void worksheet::add_column_properties(column_t column, const xlnt::column_properties &props)
{
    d_->column_properties_[column] = props;
}

bool worksheet::has_column_properties(column_t column) const
{
    return d_->column_properties_.find(column) != d_->column_properties_.end();
}

column_properties &worksheet::get_column_properties(column_t column)
{
    return d_->column_properties_[column];
}

const column_properties &worksheet::get_column_properties(column_t column) const
{
    return d_->column_properties_.at(column);
}

row_properties &worksheet::get_row_properties(row_t row)
{
    return d_->row_properties_[row];
}

const row_properties &worksheet::get_row_properties(row_t row) const
{
    return d_->row_properties_.at(row);
}

worksheet::iterator worksheet::begin()
{
    auto dimensions = calculate_dimension();
    cell_reference top_right(dimensions.get_bottom_right().get_column_index(), dimensions.get_top_left().get_row());
    range_reference row_range(dimensions.get_top_left(), top_right);
    
    return iterator(*this, row_range, major_order::row);
}

worksheet::iterator worksheet::end()
{
    auto dimensions = calculate_dimension();
    auto past_end_row_index = dimensions.get_bottom_right().get_row() + 1;
    cell_reference bottom_left(dimensions.get_top_left().get_column_index(), past_end_row_index);
    cell_reference bottom_right(dimensions.get_bottom_right().get_column_index(), past_end_row_index);
    
    return iterator(*this, range_reference(bottom_left, bottom_right), major_order::row);
}

worksheet::const_iterator worksheet::cbegin() const
{
    auto dimensions = calculate_dimension();
    cell_reference top_right(dimensions.get_bottom_right().get_column_index(), dimensions.get_top_left().get_row());
    range_reference row_range(dimensions.get_top_left(), top_right);
    
    return const_iterator(*this, row_range, major_order::row);
}

worksheet::const_iterator worksheet::cend() const
{
    auto dimensions = calculate_dimension();
    auto past_end_row_index = dimensions.get_bottom_right().get_row() + 1;
    cell_reference bottom_left(dimensions.get_top_left().get_column_index(), past_end_row_index);
    cell_reference bottom_right(dimensions.get_bottom_right().get_column_index(), past_end_row_index);
    
    return const_iterator(*this, range_reference(bottom_left, bottom_right), major_order::row);
}

worksheet::const_iterator worksheet::begin() const
{
    return cbegin();
}

worksheet::const_iterator worksheet::end() const
{
    return cend();
}

range worksheet::iter_cells(bool skip_null)
{
    return range(*this, calculate_dimension(), major_order::row, skip_null);
}

void worksheet::add_print_title(int i)
{
    add_print_title(i, "rows");
}

void worksheet::add_print_title(int i, const std::string &rows_or_cols)
{
    if(rows_or_cols == "cols")
    {
        set_print_title_cols("A:" + column_t::column_string_from_index(i));
    }
    else
    {
        set_print_title_rows("1:" + std::to_string(i));
    }
}

void worksheet::set_print_title_rows(const std::string &rows)
{
    d_->print_title_rows_ = rows;
}

void worksheet::set_print_title_cols(const std::string &cols)
{
    d_->print_title_cols_ = cols;
}

std::string worksheet::get_print_titles() const
{
    if (!d_->print_title_rows_.empty() && !d_->print_title_cols_.empty())
    {
        return d_->title_ + "!" + d_->print_title_rows_ + "," + d_->title_ + "!" + d_->print_title_cols_;
    }
    else if (!d_->print_title_cols_.empty())
    {
        return d_->title_ + "!" + d_->print_title_cols_;
    }
    else
    {
        return d_->title_ + "!" + d_->print_title_rows_;
    }
}

void worksheet::set_print_area(const std::string &print_area)
{
    d_->print_area_ = range_reference::make_absolute(range_reference(print_area));
}

range_reference worksheet::get_print_area() const
{
    return d_->print_area_;
}

sheet_view worksheet::get_sheet_view() const
{
    return d_->view_;
}

std::size_t worksheet::next_custom_number_format_id()
{
    return get_workbook().d_->stylesheet_.next_custom_format_id++;
}

} // namespace xlnt