Issue #3060042: Provide migrate support to upgrade from Date module on D7

<?php

namespace Drupal\smart_date\Plugin\migrate\process;

use Drupal\Core\Database\Database;

use Drupal\migrate\MigrateExecutableInterface;

use Drupal\migrate\ProcessPluginBase;

use Drupal\migrate\Row;

use Drupal\smart_date_recur\Entity\SmartDateRule;

/**

 * Given Drupal 7 date ranges and/or repeating dates, or serialized values from Views, parse for a Smart Date field.

 * 

 * Three formats of incoming data are accepted:

 * - Drupal 7 Date values of the form `['value' => START, 'value2' => END, 'rrule' => STRING]` (where rrule is optional);

 * - Views' "Date and Time" format, which you might use in an XML data export

 *   `<span class="date-display-start" ...>START</span> to <span class="date-display-end" ...>END</span>`

 *   with an optional `<div class="date-repeat-rule">STRING</div>` if you enable that option in the field of the View;

 * - or plain text serialized `START to END`.

 * The date values themselves can be in any format that works with PHP's strtotime() function.

 * 

 * Example:

 * 

 * @code

 * process:

 *  field_smart_date:

 *    plugin: parse_dates

 *    source: field_date

 *    entity_type: node

 *    bundle: opportunity

 * @endcode

 * 

 * The entity_type and bundle are only necessary for repeating dates.

 * 

 * @MigrateProcessPlugin(

 *   id = "parse_dates"

 * )

 */

class ParseDates extends ProcessPluginBase {

  /**

   * {@inheritdoc}

   */

  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {

    if (!is_array($value)) {

      // Check for multiple serialized values.

      foreach(['|', ';', ', ', ','] as $delimiter) {

        if (strpos($value, $delimiter)) {

          $value = explode($delimiter, $value);

          break;

        }

      }

      $value = (array) $value;

    }

    $rrule = null;

    $ordinal = [

      'first' => '+1',

      'second' => '+2',

      'third' => '+3',

      'fourth' => '+4',

      'last' => '-1',

    ];

    $month = [

      'January' => 1,

      'February' => 2,

      'March' => 3,

      'April' => 4,

      'May' => 5,

      'June' => 6,

      'July' => 7,

      'August' => 8,

      'September' => 9,

      'October' => 10,

      'November' => 11,

      'December' => 12,

    ];

    $timezone = \Drupal::config('system.date')->get('timezone')['default'];

    foreach ($value as $k => $d) {

      // Put the values into a standard format so we can work with them below.

      if (!is_array($d)) {

        // The format we want is ['value' => START, 'value2' => END, 'rrule' => STRING].

        if (strpos($d, 'date-display')) {

          // Parse Views' "Date and Time" HTML format to a Drupal 7 style array.

          // Views changes the rrule from the standard format to human-readable text, so we have to change it back.

          if (preg_match('#Repeats every (\d*)? ?(day|week|month|year)s? +(on .*)? (\d+ times|until .*)\.#', $d, $m)) {

            $rrule = "FREQ=" . ($m[2] == 'day' ? 'DAI' : strtoupper($m[2])) . "LY;INTERVAL=" . ($m[1] ?: 1);

            if (preg_match_all('#(\w\w)\w+day#', $m[3], $y)) {

              $rrule .= ";BYDAY=" . strtoupper(implode(',', $y[1]));

            }

          }

          elseif (preg_match('#Repeats on the (\w+) (\w+) of the (week|month|year) (\d+ times|until .*)\.#', $d, $m)) {

            $rrule = "FREQ=" . ($m[3] == 'day' ? 'DAI' : strtoupper($m[3])) . "LY;INTERVAL=1";

            $rrule .= ";BYDAY=" . $ordinal[$m[1]] . strtoupper(substr($m[2],0,2));

          }

          elseif (preg_match('#Repeats on the (\w+) (\w+) of the month during (.*) (\d+ times|until .*)\.#', $d, $m)) {

            $rrule = "RRULE:FREQ=MONTHLY;INTERVAL=1";

            $months = [];

            foreach (explode(' ', $m[3]) as $mo) {

              $mo = trim($mo, ',');

              if (isset($month[$mo])) $months[] = $month[$mo];

            }

            $rrule .= ";BYDAY=" . $ordinal[$m[1]] . strtoupper(substr($m[2],0,2)) . ";BYMONTH=" . implode(',', $months);

          }

          elseif (preg_match('#Repeats on the (\d+)\w+ of (.*) (\d+ times|until .*)\.#', $d, $m)) {

            $rrule = "RRULE:FREQ=MONTHLY;INTERVAL=1";

            $months = [];

            foreach (explode(' ', $m[2]) as $mo) {

              $mo = trim($mo, ',');

              if (isset($month[$mo])) $months[] = $month[$mo];

            }

            $rrule .= ";BYMONTH=" . implode(',', $months) . ";BYMONTHDAY=" . $m[1];

            $m[4] = $m[3];

          }

          if (isset($m[4])) {

            if (strpos($m[4], 'times')) {

              $rrule .= ';COUNT=' . substr($m[4],0,-6);

            }

            else {

              $rrule .= ';UNTIL=' . $this->date('Ymd\THis\Z', strtotime(substr($m[4], 6)), $timezone);

            }

          }

          // In the "Date and Time" format, there are either "start" & "end" values, or a "single" value.

          if (!preg_match('#"date-display-start"[^>]*>([^<]*).*"date-display-end"[^>]*>([^<]*)#', $d, $m)) {

            preg_match('#"date-display-single"[^>]*>([^<]*)#', $d, $m);

            // A single time of midnight meant "all day" in Drupal 7 Date module.

            // The Smart Date equivalent requires an end_value of 23:59:00.

            $m[2] = ($this->date('H:i:s', $m[1], $timezone) == '00:00:00') ? ($m[1] + 23*60*60 + 59*60) : $m[1];

          }

          $d = [

            'value' => $m[1],

            'value2' => $m[2],

            'rrule' => $rrule,

          ];

        }

        else {

          // Parse plain text serialized values (with " to " between the START & END) to a Drupal 7 style array.

          // So much simpler than "Date and Time" format!

          $d = explode(' to ', $d);

          $d = [

            'value' => $d[0],

            'value2' => isset($d[1]) ? $d[1] : $d[0],

          ];

        }

      }

      // Now that we've sorted out the start & end values, we're finally ready to work with them.

      if ((int)$d['value'] != $d['value']) {

        // Convert string values to UNIX timestamps for consistent processing.

        $d['value'] = strtotime($d['value']);

        $d['value2'] = strtotime($d['value2']);

      }

      if ($d['value2'] > 2147483647) {

        // This value is out of range due to the Year 2038 Bug. https://en.wikipedia.org/wiki/Year_2038_problem

        // Although PHP is unfazed by the bug, MySQL and MariaDB are afflicted, so we can't store these values.

        unset($d);

        continue;

      }

      if (!isset($d['rrule']) && $d['value2'] - $d['value'] > 24*60*60) {

        // Change a multi-day event into a single day event that repeats.

        $end = $d['value2'];

        $d['rrule'] = 'RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=' . $this->date('Ymd\THis\Z', $end, $timezone);

        $d['value2'] = strtotime($this->date('Y-m-d', $d['value'], $timezone) . $this->date(' H:i:s', $d['value2'], $timezone));

        // If we accidentally wrapped to the previous morning due to the time zone, add a day back.

        if ($d['value2'] < $d['value']) {

          $d['value2'] += 24*60*60;

        }

        $value[$k] = $d;

        // Generate new values for the repetitions.

        while ($d['value2'] < $end) {

          $value[] = [

            'value' => $d['value'] += 24*60*60,

            'value2' => $d['value2'] += 24*60*60,

            'rrule' => $d['rrule'],

          ];

        }

        // Don't loop over the values we just created.

        break;

      }

      if (isset($d['rrule']) && $d['value2'] - $d['value'] > 86400) {

        // Durations of repeating events should also be no more than 24 hours.

        while ($d['value2'] - $d['value'] > 86400) $d['value2'] -= 24*60*60;

      }

      $value[$k] = $d;

    }

    // Now that the data is cleaned up, convert it to Smart Date format.

    $dates = $rdata = [];

    $counter = 0;

    foreach ($value as $k => $d) {

      // Skip any values that got unset above.

      if (!is_array($d)) continue;

      if (isset($d['rrule']) && $d['rrule'] > '') {

        if (isset($rdata['rule']) && $d['rrule'] != $rdata['rule']) {

          // Time for a new rrule. Save the old rule before continuing.

          $rrule = SmartDateRule::create([$rdata]);

          foreach($rdata as $f => $v) {

            $rrule->set($f, $v);

          }

          $rrule->save();

          // Now that we have an rrule ID, process the field values that belong to that rule.

          $ri = 1;

          for ($i = $counter; $i < $k; $i++) {

            $dates[$i] = [

              'value' => $value[$i]['value'],

              'end_value' => $value[$i]['value2'],

              'duration' => (int) round(($value[$i]['value2'] - $value[$i]['value']) / 60),

              'rrule' => $rrule->id(),

              'rrule_index' => $ri,

              'timezone' => $timezone,

            ];

          }

          $counter = $k;

        }

        if (!isset($rdata['rule']) || $d['rrule'] != $rdata['rule']) {

          // First check for length. Smart Date Rules are limited to 256 characters.

          if (strlen($d['rrule']) > 255 && preg_match('/EXDATE:[^;]+/', $d['rrule'], $m)) {

            preg_match_all('/\d{8}T\d{6}Z,?/', $m[0], $m);

            foreach ($m[0] as $t) {

              // Delete any EXDATEs in the past to reduce the rule length.

              if (substr($t, 0, 8) < date('Ymd')) {

                $d['rrule'] = str_replace($t, '', $d['rrule']);

              }

            }

          }

          $newrule = $d['rrule'];

          // Check the rrule for Year 2038 Bug compliance.

          preg_match('/FREQ=([^;]+).*((COUNT|UNTIL)=([^;])+)/', $d['rrule'], $m);

          $freq = [

            'DAILY' => 24*60*60,

            'WEEKLY' => 7*24*60*60,

            'MONTHLY' => 31*24*60*60,

            'YEARLY' => 366*24*60*60

          ];

          $limit = $m[2];

          if ($m[3] == 'COUNT') {

            $enddate = (int)$d['value2'] + $m[4] * $freq[$m[1]];

            if ($enddate > 2147483647) {

              $limit = 'COUNT=' . (int)((2147483647 - (int)$d['value2'])/$freq[$m[1]]);

              $newrule = str_replace($m[2], $limit, $d['rrule']);

            }

          }

          elseif ($m[3] == 'UNTIL') {

            $enddate = strtotime($m[4]);

            if ($enddate > 2147483647) {

              $limit = 'UNTIL=' . $this->date('Ymd\THis\Z', 2147483647, $timezone);

              $newrule = str_replace($m[2], $limit, $d['rrule']);

            }

          }

          elseif (!isset($m[2])) {

            $limit = 'UNTIL=' . $this->date('Ymd\THis\Z', 2147483647, $timezone);

            $newrule .= ';' . $limit;

          }

          if ($newrule != $d['rrule']) {

            // Change all instances of the noncompliant rrule to the newrule so we can reuse it.

            foreach ($value as &$i) {

              if ($i['rrule'] == $d['rrule']) $i['rrule'] = $newrule;

            }

            $d['rrule'] = $newrule;

          }

          // Create a new rule with this as the first instance.

          $rdata = [

            'start' => $d['value'],

            'end' => $d['value2'],

            'rule' => $d['rrule'],

            'freq' => $m[1],

            'limit' => $limit,

            'instances' => [

              'data' => [

                1 => [

                  'value' => $d['value'], 

                  'end_value' => $d['value2'],

                ],

              ],

            ],

            'entity_type' => $this->configuration['entity_type'],

            'bundle' => $this->configuration['bundle'],

            'field_name' => $destination_property,

          ];

        }

        else {

          // Add this instance to an existing rule.

          $rdata['instances']['data'][] = [

            'value' => $d['value'], 

            'end_value' => $d['value2'],

          ];

        }

      }

      else {

        // This date doesn't repeat.

        $dates[$k] = [

          'value' => $d['value'],

          'end_value' => $d['value2'],

          'duration' => (int) round(($d['value2'] - $d['value']) / 60),

          'timezone' => $timezone,

        ];

        $rdata = [];

        $counter = $k+1;

      }

    }

    if (isset($rdata['rule'])) {

      // Save the rule.

      $rrule = SmartDateRule::create([$rdata]);

      foreach($rdata as $f => $v) {

        $rrule->set($f, $v);

      }

      $rrule->save();

      // Process field values belonging to this rule.

      $ri = 1;

      for ($i = $counter; $i <= $k; $i++) {

        if (!is_array($value[$i])) continue;

        $dates[$i] = [

          'value' => $value[$i]['value'],

          'end_value' => $value[$i]['value2'],

          'duration' => (int) round(($value[$i]['value2'] - $value[$i]['value']) / 60),

          'rrule' => $rrule->id(),

          'rrule_index' => $ri,

          'timezone' => $timezone,

        ];

        $ri++;

      }

    }

    return $dates;

  }

  // Thanks to ivijan.stefan@gmail.com commenting at https://www.php.net/manual/en/function.date.php

  private function date($format="r", $timestamp=false, $timezone=false) {

    $userTimezone = new \DateTimeZone(!empty($timezone) ? $timezone : 'UTC');

    $gmtTimezone = new \DateTimeZone('UTC');

    $myDateTime = new \DateTime(($timestamp != false ? date("r", (int)$timestamp) : date("r")), $gmtTimezone);

    $offset = $userTimezone->getOffset($myDateTime);

    return date($format, ($timestamp != false ? (int)$timestamp : $myDateTime->format('U')) + $offset);

  }

}