<?php
/**
 * Copyright (C) 2019-2022 Graham Breach
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
/**
 * For more information, please contact <graham@goat1000.com>
 */

namespace Goat1000\SVGGraph;

trait BarGraphTrait {

  // these are filled in by barSetup()
  protected $calculated_bar_width;
  protected $calculated_bar_space;

  /**
   * Draws the graph
   */
  protected function draw()
  {
    $this->setup();

    $body = $this->grid();
    $bars = $this->drawBars();
    $bar_group = $this->barGroup();
    if(!empty($bar_group))
      $bars = $this->element('g', $bar_group, null, $bars);

    $body .= $this->underShapes();
    $body .= $bars;
    $body .= $this->overShapes();
    $body .= $this->axes();
    return $body;
  }

  /**
   * Draws the bars
   */
  protected function drawBars()
  {
    $dataset = $this->getOption(['dataset', 0], 0);
    $this->barSetup();

    $bars = '';
    foreach($this->values[$dataset] as $bnum => $item) {
      $this->setBarLegendEntry($dataset, $bnum, $item);
      $bars .= $this->drawBar($item, $bnum, 0, null, $dataset);
    }
    return $bars;
  }

  /**
   * Returns the width of a bar
   */
  protected function barWidth()
  {
    $bw = $this->getOption('bar_width');
    if(is_numeric($bw) && $bw >= 1)
      return $bw;
    $unit_w = $this->x_axes[$this->main_x_axis]->unit();
    $bw = $unit_w - $this->getOption('bar_space');
    return max(1, $bw, $this->getOption('bar_width_min'));
  }

  /**
   * Initialize bars
   */
  protected function barSetup()
  {
    $width = $this->barWidth();
    $space = $this->barSpace($width);
    $this->setBarWidth($width, $space);
  }

  /**
   * Sets up the width of the bar and the spacing
   */
  protected function setBarWidth($width, $space)
  {
    $this->calculated_bar_width = $width;
    $this->calculated_bar_space = $this->getOption('datetime_keys') ? 0 : $space;
  }

  /**
   * Returns an array of attributes for whole group of bars
   */
  protected function barGroup()
  {
    $group = [];
    if($this->getOption('semantic_classes'))
      $group['class'] = 'series';
    $shadow_id = $this->defs->getShadow();
    if($shadow_id !== null)
      $group['filter'] = 'url(#' . $shadow_id . ')';
    return $group;
  }

  /**
   * Sets the legend entry for a bar
   */
  protected function setBarLegendEntry($dataset, $index, DataItem $item)
  {
    $bar = ['fill' => $this->getColour($item, $index, $dataset)];
    $this->setStroke($bar, $item, $index, $dataset);
    $this->setLegendEntry($dataset, $index, $item, $bar);
  }

  /**
   * Returns the SVG code for a bar
   */
  protected function drawBar(DataItem $item, $index, $start = 0, $axis = null,
    $dataset = 0, $options = [])
  {
    if($item->value === null)
      return '';

    $bar = $this->barDimensions($item, $index, $start, $axis, $dataset);
    if(empty($bar))
      return '';

    // if the bar is empty and no legend or labels to show give up now
    if((string)$bar['height'] == '0' && !$this->getOption('legend_show_empty') &&
      !$this->getOption('show_data_labels'))
      return '';

    $this->setStroke($bar, $item, $index, $dataset);
    $bar['fill'] = $this->getColour($item, $index, $dataset);

    if($this->getOption('semantic_classes'))
      $bar['class'] = 'series' . $dataset;

    $label_shown = $this->addDataLabel($dataset, $index, $bar, $item,
      $bar['x'], $bar['y'], $bar['width'], $bar['height']);

    if($this->getOption('show_tooltips'))
      $this->setTooltip($bar, $item, $dataset, $item->key, $item->value,
        $label_shown);
    if($this->getOption('show_context_menu'))
      $this->setContextMenu($bar, $dataset, $item, $label_shown);

    $round = max($this->getItemOption('bar_round', $dataset, $item), 0);
    if($round > 0) {
      // don't allow the round corner to be more than 1/2 bar width or height
      $bar['rx'] = $bar['ry'] = min($round, $bar['width'] / 2, $bar['height'] / 2);
    }

    $bar_part = $this->element('rect', $bar);
    return $this->getLink($item, $item->key, $bar_part);
  }

  /**
   * Returns the space before a bar
   */
  protected function barSpace($bar_width)
  {
    return max(0, ($this->x_axes[$this->main_x_axis]->unit() - $bar_width) / 2);
  }

  /**
   * Returns an array with x, y, width and height set
   */
  protected function barDimensions($item, $index, $start, $axis, $dataset)
  {
    $bar = [];
    $bar_x = $this->barX($item, $index, $bar, $axis, $dataset);
    if($bar_x === null)
      return [];

    $y_pos = $this->barY($item->value, $bar, $start, $axis);
    if($y_pos === null)
      return [];
    return $bar;
  }

  /**
   * Fills in the x and width of bar
   */
  protected function barX($item, $index, &$bar, $axis, $dataset)
  {
    $bar_x = $this->gridPosition($item, $index);
    if($bar_x === null)
      return null;

    $bar['x'] = $bar_x + $this->calculated_bar_space;
    $bar['width'] = $this->calculated_bar_width;
    return $bar_x;
  }

  /**
   * Fills in the y and height of a bar
   * @return number unclamped bar position
   */
  protected function barY($value, &$bar, $start = null, $axis = null)
  {
    if($start)
      $value += $start;

    $startpos = $start === null ? $this->originY($axis) :
      $this->gridY($start, $axis);
    if($startpos === null)
      $startpos = $this->originY($axis);
    $pos = $this->gridY($value, $axis);
    if($pos === null) {
      $bar['height'] = 0;
    } else {
      $l1 = $this->clampVertical($startpos);
      $l2 = $this->clampVertical($pos);
      $bar['y'] = min($l1, $l2);
      $bar['height'] = abs($l1-$l2);
    }
    return $pos;
  }

  /**
   * Override to check minimum space requirement
   */
  protected function addDataLabel($dataset, $index, &$element, &$item,
    $x, $y, $w, $h, $content = null, $duplicate = true)
  {
    if($h < $this->getOption(['data_label_min_space', $dataset]))
      return false;
    return parent::addDataLabel($dataset, $index, $element, $item, $x, $y,
      $w, $h, $content, $duplicate);
  }

  /**
   * Returns the position for a data label
   */
  public function dataLabelPosition($dataset, $index, &$item, $x, $y, $w, $h,
    $label_w, $label_h)
  {
    list($pos,$end) = parent::dataLabelPosition($dataset, $index, $item,
      $x, $y, $w, $h, $label_w, $label_h);
    $bpos = $this->getOption('bar_label_position');
    if(!empty($bpos))
      $pos = $bpos;

    if($label_h > $h && Graph::isPositionInside($pos))
      $pos = str_replace(['top','middle','bottom'], 'outside top inside ', $pos);

    // flip top/bottom for negative values
    if($item !== null && $item->value < 0) {
      if(strpos($pos, 'top') !== false)
        $pos = str_replace('top','bottom', $pos);
      elseif(strpos($pos, 'above') !== false)
        $pos = str_replace('above','below', $pos);
      elseif(strpos($pos, 'below') !== false)
        $pos = str_replace('below','above', $pos);
      elseif(strpos($pos, 'bottom') !== false)
        $pos = str_replace('bottom','top', $pos);
    }

    return [$pos, $end];
  }

  /**
   * Returns the style options for bar labels
   */
  public function dataLabelStyle($dataset, $index, &$item)
  {
    $style = parent::dataLabelStyle($dataset, $index, $item);

    // bar label settings can override global settings
    $opts = [
      'font' => 'bar_label_font',
      'font_size' => 'bar_label_font_size',
      'font_weight' => 'bar_label_font_weight',
      'colour' => 'bar_label_colour',
      'altcolour' => 'bar_label_colour_above',
      'space' => 'bar_label_space',
    ];
    foreach($opts as $key => $opt)
      if(isset($this->settings[$opt]))
        $style[$key] = $this->settings[$opt];
    return $style;
  }

  /**
   * Return box for legend
   */
  public function drawLegendEntry($x, $y, $w, $h, $entry)
  {
    $bar = ['x' => $x, 'y' => $y, 'width' => $w, 'height' => $h];
    return $this->element('rect', $bar, $entry->style);
  }
}