<?php

namespace Drupal\Core\Field\Plugin\Field\FieldType;

use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\TypedData\DataDefinition;

/**
 * Defines the 'float' field type.
 *
 * @FieldType(
 *   id = "float",
 *   label = @Translation("Number (float)"),
 *   description = {
 *     @Translation("In most instances, it is best to use Number (decimal) instead, as decimal numbers stored as floats may contain errors in precision"),
 *     @Translation("This type of field offers faster processing and more compact storage, but the differences are typically negligible on modern sites"),
 *     @Translation("For example, 123.4 km when used in imprecise contexts such as a walking trail distance"),
 *   },
 *   category = "number",
 *   weight = -10,
 *   default_widget = "number",
 *   default_formatter = "number_decimal"
 * )
 */
class FloatItem extends NumericItemBase {

  /**
   * {@inheritdoc}
   */
  public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
    $properties['value'] = DataDefinition::create('float')
      ->setLabel(t('Float'))
      ->setRequired(TRUE);

    return $properties;
  }

  /**
   * {@inheritdoc}
   */
  public static function schema(FieldStorageDefinitionInterface $field_definition) {
    return [
      'columns' => [
        'value' => [
          'type' => 'float',
        ],
      ],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
    $element = parent::fieldSettingsForm($form, $form_state);

    $element['min']['#step'] = 'any';
    $element['max']['#step'] = 'any';

    return $element;
  }

  /**
   * {@inheritdoc}
   */
  public static function generateSampleValue(FieldDefinitionInterface $field_definition) {
    $settings = $field_definition->getSettings();
    $precision = rand(10, 32);
    $scale = rand(0, 2);
    $max = is_numeric($settings['max']) ? $settings['max'] : pow(10, ($precision - $scale)) - 1;
    $min = is_numeric($settings['min']) ? $settings['min'] : -pow(10, ($precision - $scale)) + 1;
    // @see "Example #1 Calculate a random floating-point number" in
    // http://php.net/manual/function.mt-getrandmax.php
    $random_decimal = $min + mt_rand() / mt_getrandmax() * ($max - $min);
    $values['value'] = self::truncateDecimal($random_decimal, $scale);
    return $values;
  }

}
