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   1  <?php
   2  
   3  /**
   4   *  A helper function to do cross-database concatation of date parts
   5   *
   6   *  @param $array - an array of values to be concatonated in sql
   7   *  @return - correct sql string for database type
   8   */
   9  function date_sql_concat($array) {
  10    global $db_type;
  11    switch ($db_type) {
  12      case ('mysql'):
  13      case ('mysqli'):
  14        return "CONCAT(". implode(",", $array) .")";
  15      case ('pgsql'):
  16        return implode(" || ", $array);
  17    }
  18  }
  19  
  20  /**
  21   * Helper function to do cross-database NULL replacements
  22   *
  23   * @param an array of values to test for NULL values
  24   * @return SQL statement to return the first non-NULL value in the list.
  25   */
  26  function date_sql_coalesce($array) {
  27    global $db_type;
  28    switch ($db_type) {
  29      case ('mysql'):
  30      case ('mysqli'):
  31      case ('pgsql'):
  32        return "COALESCE(". implode(',', $array) .")";
  33    }  
  34  }
  35  
  36  /**
  37   *  A helper function to do cross-database padding of date parts
  38   *
  39   *  @param $str - a string to apply padding to
  40   *  @param $size - the size the final string should be
  41   *  @param $pad - the value to pad the string with
  42   *  @param $side - the side of the string to pad
  43   */
  44  function date_sql_pad($str, $size = 2, $pad = '0', $side = 'l') {
  45    switch ($side) {
  46    case ('r'):
  47      return "RPAD($str, $size, '$pad')";
  48    default:
  49      return "LPAD($str, $size, '$pad')";
  50    }
  51  }
  52  
  53  /**
  54   * A class to manipulate date SQL.
  55   */
  56  class date_sql_handler {
  57    var $db_type = 'mysql';
  58    var $date_type = DATE_DATETIME;
  59    var $db_timezone = 'UTC'; // A string timezone name.
  60    var $local_timezone = NULL; // A string timezone name.
  61    var $db_timezone_field = NULL; // Use if the db timezone is stored in a field.
  62    var $local_timezone_field = NULL; // Use if the local timezone is stored in a field.
  63    var $offset_field = NULL; // Use if the offset is stored in a field.
  64  
  65    function construct($date_type = DATE_DATETIME, $local_timezone = NULL) {
  66      $this->db_type = $GLOBALS['db_type'];
  67      $this->date_type = $date_type;
  68      $this->db_timezone = 'UTC';
  69      $this->local_timezone = isset($local_timezone) ? $local_timezone : date_default_timezone_name();
  70      if (isset($this->definition['content_field'])) {
  71        $this->date_handler->date_type = $this->definition['content_field']['type'];
  72      }
  73      date_api_set_db_timezone();
  74    }
  75  
  76    /**
  77     * See if the db has timezone name support.
  78     */
  79    function db_tz_support($reset = FALSE) {
  80      $has_support = variable_get('date_db_tz_support', -1);
  81      if ($has_support == -1 || $reset) {
  82        date_api_set_db_timezone();
  83        $has_support = FALSE;
  84        switch ($this->db_type) {
  85          case 'mysql':
  86          case 'mysqli':
  87            if (version_compare(db_version(), '4.1.3', '>=')) {
  88              $test = db_result(db_query("SELECT CONVERT_TZ('2008-02-15 12:00:00', 'UTC', 'US/Central')"));
  89              if ($test == '2008-02-15 06:00:00') {
  90                $has_support = TRUE;
  91              }
  92            }
  93            break;
  94          case 'pgsql':
  95            $test = db_result(db_query("SELECT '2008-02-15 12:00:00 UTC' AT TIME ZONE 'US/Central'"));
  96            if ($test == '2008-02-15 06:00:00') {
  97              $has_support = TRUE;
  98            }
  99          break;
 100        }
 101        variable_set('date_db_tz_support', $has_support);
 102      }
 103      return $has_support;
 104    }
 105  
 106    /**
 107     * Set the database timzone offset.
 108     * 
 109     * Setting the db timezone to UTC is done to ensure consistency in date 
 110     * handling whether or not the database can do proper timezone conversion.
 111     * 
 112     * Views filters that not exposed are cached and won't set the timezone
 113     * so views date filters should add 'cacheable' => 'no' to their 
 114     * definitions to ensure that the database timezone gets set properly 
 115     * when the query is executed.
 116     * 
 117     * @param $offset
 118     *   An offset value to set the database timezone to. This will only
 119     *   set a fixed offset, not a timezone, so any value other than
 120     *   '+00:00' should be used with caution.
 121     */
 122    function set_db_timezone($offset = '+00:00') {
 123      static $already_set = FALSE;
 124      $type = $GLOBALS['db_type'];
 125      if (!$already_set) {
 126        if (($type == 'mysqli' || $type == 'mysql') && version_compare(db_version(), '4.1.3', '>=')) {
 127          db_query("SET @@session.time_zone = '$offset'");
 128        }
 129        elseif ($type == 'pgsql') {
 130          db_query("SET TIME ZONE INTERVAL '$offset' HOUR TO MINUTE");
 131        }
 132        $already_set = true;
 133      }
 134    }
 135  
 136    /**
 137     * Return timezone offset for the date being processed.
 138     */
 139    function get_offset() {
 140      if (!empty($this->db_timezone) && !empty($this->local_timezone)) {
 141        if ($this->db_timezone != $this->local_timezone) {
 142          $date = date_now($this->db_timezone);
 143          date_timezone_set($date, timezone_open($this->local_timezone));
 144          return date_offset_get($date);
 145        }
 146      }
 147      return 0;
 148    }
 149  
 150    /**
 151     * Helper function to create cross-database SQL dates.
 152     *
 153     * @param $field
 154     *   The real table and field name, like 'tablename.fieldname'.
 155     * @param $offset
 156     *   The name of a field that holds the timezone offset or an
 157     *   offset value. If NULL, the normal Drupal timezone handling
 158     *   will be used, if $offset = 0 no adjustment will be made.
 159     * @return
 160     *   An appropriate SQL string for the db type and field type.
 161     */
 162    function sql_field($field, $offset = NULL) {
 163      if (strtoupper($field) == 'NOW') {
 164        // NOW() will be in UTC since that is what we set the db timezone to.
 165        $this->local_timezone = 'UTC';
 166        return $this->sql_offset('NOW()', $offset);
 167      }
 168      switch ($this->db_type) {
 169        case 'mysql':
 170        case 'mysqli':
 171          switch ($this->date_type) {
 172            case DATE_UNIX:
 173              $field = "FROM_UNIXTIME($field)";
 174              break;
 175            case DATE_ISO:
 176              if (version_compare(db_version(), '4.1.1', '>=')) {
 177                $field = "STR_TO_DATE($field, '%Y-%m-%%dT%T')";
 178              }
 179              else {
 180                $field = "REPLACE($field, 'T', ' ')";
 181              }
 182              break;
 183            case DATE_DATETIME:
 184              break;
 185          }
 186          break;
 187        case 'pgsql':
 188          switch ($this->date_type) {
 189            case DATE_UNIX:
 190              $field = "$field::ABSTIME";
 191              break;
 192            case DATE_ISO:
 193              $field = "TO_DATE($field, 'FMYYYY-FMMM-FMDDTFMHH24:FMMI:FMSS')";
 194              break;
 195            case DATE_DATETIME:
 196              break;
 197          }
 198        break;
 199      }
 200      // Adjust the resulting value to the right timezone/offset.
 201      return $this->sql_tz($field, $offset);
 202    }
 203  
 204    /**
 205     * Adjust a field value by an offset in seconds.
 206     */
 207    function sql_offset($field, $offset = NULL) {
 208      if (!empty($offset)) {
 209        switch ($this->db_type) {
 210          case 'mysql':
 211          case 'mysqli':
 212            if (version_compare(db_version(), '4.1.1', '>=')) {
 213              return "ADDTIME($field, SEC_TO_TIME($offset))";
 214            }
 215            else {
 216              return "DATE_ADD($field, INTERVAL $offset SECOND)";
 217            }
 218          case 'pgsql':
 219            return "($field + INTERVAL '$offset SECONDS')";;
 220        }
 221      }
 222      return $field;
 223    }
 224  
 225    /**
 226     * Adjust a field value by time interval.
 227     * 
 228     * @param $field
 229     *   The field to be adjusted.
 230     * @param $direction
 231     *   Either ADD or SUB.
 232     * @param $count
 233     *   The number of values to adjust.
 234     * @param $granularity
 235     *   The granularity of the adjustment, should be singular,
 236     *   like SECOND, MINUTE, DAY, HOUR.
 237     */
 238    function sql_date_math($field, $direction, $count, $granularity) {
 239      $granularity = strtoupper($granularity);
 240      switch ($this->db_type) {
 241        case 'mysql':
 242        case 'mysqli':
 243          switch ($direction) {
 244            case 'ADD':
 245              return "DATE_ADD($field, INTERVAL $count $granularity)";
 246            case 'SUB':
 247              return "DATE_SUB($field, INTERVAL $count $granularity)";
 248            }
 249  
 250        case 'pgsql':
 251          $granularity .= 'S';
 252          switch ($direction) {
 253            case 'ADD':
 254              return "($field + INTERVAL '$count $granularity')";
 255            case 'SUB':
 256              return "($field - INTERVAL '$count $granularity')";
 257          }
 258       }
 259       return $field;
 260    }  
 261  
 262    /**
 263     * Select a date value from the database, adjusting the value
 264     * for the timezone.
 265     * 
 266     * Check whether database timezone conversion is supported in
 267     * this system and use it if possible, otherwise use an
 268     * offset.
 269     * 
 270     * @param $offset
 271     *   Set a fixed offset or offset field to use for the date. 
 272     *   If set, no timezone conversion will be done and the 
 273     *   offset will be used.
 274     */
 275    function sql_tz($field, $offset = NULL) {
 276      // If the timezones are values they need to be quoted, but
 277      // if they are field names they do not.
 278      $db_zone   = $this->db_timezone_field ? $this->db_timezone_field : "'{$this->db_timezone}'";
 279      $localzone = $this->local_timezone_field ? $this->local_timezone_field : "'{$this->local_timezone}'"; 
 280  
 281      // If a fixed offset is required, use it.
 282      if ($offset !== NULL) {
 283        return $this->sql_offset($field, $offset);
 284      }
 285      // If the db and local timezones are the same, make no adjustment.
 286      elseif ($db_zone == $localzone) {
 287        return $this->sql_offset($field, 0);
 288      }
 289      // If the db has no timezone support, adjust by the offset,
 290      // could be either a field name or a value.
 291      elseif (!$this->db_tz_support()) {
 292        if (!empty($this->offset_field)) {
 293          return $this->sql_offset($field, $this->offset_field);
 294        }
 295        else {
 296          return $this->sql_offset($field, $this->get_offset());
 297        }
 298      }
 299      // Otherwise make a database timezone adjustment to the field.
 300      else {
 301        switch ($this->db_type) {
 302          case 'mysql':
 303          case 'mysqli':
 304            return "CONVERT_TZ($field, $db_zone, $localzone)";
 305          case 'pgsql':
 306            // WITH TIME ZONE assumes the date is using the system
 307            // timezone, which should have been set to UTC.
 308            return "$field::timestamp with time zone AT TIME ZONE $localzone";
 309        }
 310      }
 311    }
 312  
 313    /**
 314     * Helper function to create cross-database SQL date formatting.
 315     *
 316     * @param $format
 317     *   A format string for the result, like 'Y-m-d H:i:s'.
 318     * @param $field
 319     *   The real table and field name, like 'tablename.fieldname'.
 320     * @return
 321     *   An appropriate SQL string for the db type and field type.
 322     */
 323    function sql_format($format, $field) {
 324      switch ($this->db_type) {
 325        case 'mysql':
 326        case 'mysqli':
 327          $replace = array(
 328            'Y' => '%Y', 'y' => '%y',
 329            'm' => '%m', 'n' => '%c',
 330            'd' => '%%d', 'j' => '%e',
 331            'H' => '%H',
 332            'i' => '%i',
 333            's' => '%%s',
 334            '\WW' => 'W%U',
 335            );
 336          $format = strtr($format, $replace);
 337          return "DATE_FORMAT($field, '$format')";
 338        case 'pgsql':
 339          $replace = array(
 340            'Y' => 'YYYY', 'y' => 'Y',
 341            'm' => 'MM', 'n' => 'M',
 342            'd' => 'DD', 'j' => 'D',
 343            'H' => 'HH24',
 344            'i' => 'MI',
 345            's' => 'SS',
 346            '\T' => '"T"',
 347            //'\W' => // TODO, what should this be?
 348            );
 349          $format = strtr($format, $replace);
 350          return "TO_CHAR($field, '$format')";
 351      }
 352    }
 353  
 354    /**
 355     * Helper function to create cross-database SQL date extraction.
 356     *
 357     * @param $extract_type
 358     *   The type of value to extract from the date, like 'MONTH'.
 359     * @param $field
 360     *   The real table and field name, like 'tablename.fieldname'.
 361     * @return
 362     *   An appropriate SQL string for the db type and field type.
 363     */
 364    function sql_extract($extract_type, $field) {
 365      // Note there is no space after FROM to avoid db_rewrite problems
 366      // see http://drupal.org/node/79904.
 367      switch (strtoupper($extract_type)) {
 368      case ('DATE'):
 369        return $field;
 370      case ('YEAR'):
 371        return "EXTRACT(YEAR FROM($field))";
 372      case ('MONTH'):
 373        return "EXTRACT(MONTH FROM($field))";
 374      case ('DAY'):
 375        return "EXTRACT(DAY FROM($field))";
 376      case ('HOUR'):
 377        return "EXTRACT(HOUR FROM($field))";
 378      case ('MINUTE'):
 379        return "EXTRACT(MINUTE FROM($field))";
 380      case ('SECOND'):
 381        return "EXTRACT(SECOND FROM($field))";
 382      case ('WEEK'):  // ISO week number for date
 383        switch ($this->db_type) {
 384          case ('mysql'):
 385          case ('mysqli'):
 386            // WEEK using arg 3 in mysql should return the same value as postgres EXTRACT
 387            return "WEEK($field, 3)";
 388          case ('pgsql'):
 389            return "EXTRACT(WEEK FROM($field))";
 390        }
 391      case ('DOW'):
 392        switch ($this->db_type) {
 393          case ('mysql'):
 394          case ('mysqli'):
 395            // mysql returns 1 for Sunday through 7 for Saturday
 396            // php date functions and postgres use 0 for Sunday and 6 for Saturday
 397            return "INTEGER(DAYOFWEEK($field) - 1)";
 398          case ('pgsql'):
 399            return "EXTRACT(DOW FROM($field))";
 400        }
 401      case ('DOY'):
 402        switch ($this->db_type) {
 403          case ('mysql'):
 404          case ('mysqli'):
 405            return "DAYOFYEAR($field)";
 406          case ('pgsql'):
 407            return "EXTRACT(DOY FROM($field))";
 408        }
 409      }
 410    }
 411  
 412    /**
 413     * Create a where clause to compare a complete date field to a complete date value.
 414     *
 415     * @param string $type
 416     *   The type of value we're comparing to, could be another field
 417     *   or a date value.
 418     * @param string $field
 419     *   The db table and field name, like "$table.$field".
 420     * @param string $operator
 421     *   The db comparison operator to use, like '='.
 422     * @param int $value
 423     *   The value to compare the extracted date part to, could be a
 424     *   field name or a date string or NOW().
 425     * @return 
 426     *   SQL for the where clause for this operation.
 427     */
 428    function sql_where_date($type, $field, $operator, $value, $adjustment = 0) {
 429      $type = strtoupper($type);
 430      if (strtoupper($value) == 'NOW') {
 431        $value = $this->sql_field('NOW', $adjustment);
 432      }
 433      elseif ($type == 'FIELD') {
 434        $value = $this->sql_field($value, $adjustment);
 435      }    
 436      elseif ($type == 'DATE') {
 437        $date = date_make_date($value, date_default_timezone_name(), DATE_DATETIME);
 438        if (!empty($adjustment)) {
 439          date_modify($date, $adjustment .' seconds');
 440        }
 441        // When comparing a field to a date we can avoid doing timezone 
 442        // conversion by altering the comparison date to the db timezone.
 443        // This won't work if the timezone is a field instead of a value.
 444        if (empty($this->db_timezone_field) && empty($this->local_timezone_field) && $this->db_timezone_field != $this->local_timezone_field) {
 445          date_timezone_set($date, timezone_open($this->db_timezone));
 446          $this->local_timezone = $this->db_timezone;
 447        }
 448        $value = "'". date_format_date($date, 'custom', DATE_FORMAT_DATETIME) ."'";
 449      }    
 450      if ($this->local_timezone != $this->db_timezone) {
 451        $field = $this->sql_field($field);
 452      }
 453      else {
 454        $field = $this->sql_field($field, 0);
 455      }
 456      return "$field $operator $value";
 457    }
 458  
 459    /**
 460     * Create a where clause to compare an extracted part of a field to an integer value.
 461     *
 462     * @param string $part
 463     *   The part to extract, YEAR, MONTH, DAY, etc.
 464     * @param string $field
 465     *   The db table and field name, like "$table.$field".
 466     * @param string $operator
 467     *   The db comparison operator to use, like '='.
 468     * @param int $value
 469     *   The integer value to compare the extracted date part to.
 470     * @return 
 471     *   SQL for the where clause for this operation.
 472     */
 473    function sql_where_extract($part, $field, $operator, $value, $adjustment = 0) {
 474      $field = $this->sql_field($field, $adjustment);
 475      return $this->sql_extract($part, $field) ." $operator $value";
 476    }
 477  
 478    /**
 479     * Create a where clause to compare a formated field to a formated value.
 480     *
 481     * @param string $format
 482     *   The format to use on the date and the value when comparing them.
 483     * @param string $field
 484     *   The db table and field name, like "$table.$field".
 485     * @param string $operator
 486     *   The db comparison operator to use, like '='.
 487     * @param string $value
 488     *   The value to compare the extracted date part to, could be a
 489     *   field name or a date string or NOW().
 490     * @return 
 491     *   SQL for the where clause for this operation.
 492     */
 493    function sql_where_format($format, $field, $operator, $value, $adjustment = 0) {
 494      $field = $this->sql_field($field, $adjustment);
 495      return $this->sql_format($format, $field) ." $operator '$value'";
 496    }
 497  
 498    /**
 499     * An array of all date parts,
 500     * optionally limited to an array of allowed parts.
 501     */
 502    function date_parts($limit = NULL) {
 503      $parts =  array(
 504        'year' => date_t('Year', 'datetime'), 'month' => date_t('Month', 'datetime'), 'day' => date_t('Day', 'datetime'),
 505        'hour' => date_t('Hour', 'datetime'), 'minute' => date_t('Minute', 'datetime'), 'second' => date_t('Second', 'datetime'),
 506        );
 507      if (!empty($limit)) {
 508        $last = FALSE;
 509        foreach ($parts as $key => $part) {
 510          if ($last) {
 511            unset($parts[$key]);
 512          }
 513          if ($key == $limit) {
 514            $last = TRUE;
 515          }
 516        }
 517      }
 518      return $parts;
 519    }
 520  
 521    /**
 522     * Part information.
 523     *
 524     * @param $op
 525     *   'min', 'max', 'format', 'sep', 'empty_now', 'empty_min', 'empty_max'. 
 526     *   Returns all info if empty.
 527     * @param $part
 528     *   'year', 'month', 'day', 'hour', 'minute', or 'second.
 529     *   returns info for all parts if empty.
 530     */
 531    function part_info($op = NULL, $part = NULL) {
 532      $info = array();
 533      $info['min'] = array(
 534        'year' => 100, 'month' => 1, 'day' => 1,
 535        'hour' => 0, 'minute' => 0, 'second' => 0);
 536      $info['max'] = array(
 537        'year' => 4000, 'month' => 12, 'day' => 31,
 538        'hour' => 23, 'minute' => 59, 'second' => 59);
 539      $info['format'] = array(
 540        'year' => 'Y', 'month' => 'm', 'day' => 'd',
 541        'hour' => 'H', 'minute' => 'i', 'second' => 's');
 542      $info['sep'] = array(
 543        'year' => '', 'month' => '-', 'day' => '-',
 544        'hour' => ' ', 'minute' => ':', 'second' => ':');
 545      $info['empty_now'] = array(
 546        'year' => date('Y'), 'month' => date('m'), 'day' => min('28', date('d')),
 547        'hour' => date('H'), 'minute' => date('i'), 'second' => date('s'));  
 548      $info['empty_min'] = array(
 549        'year' => '1000', 'month' => '01', 'day' => '01',
 550        'hour' => '00', 'minute' => '00', 'second' => '00');  
 551      $info['empty_max'] = array(
 552        'year' => '9999', 'month' => '12', 'day' => '31',
 553        'hour' => '23', 'minute' => '59', 'second' => '59');  
 554      if (!empty($op)) {
 555        if (!empty($part)) {
 556          return $info[$op][$part];
 557        }
 558        else {
 559          return $info[$op];
 560        }
 561      }
 562      return $info;
 563    }
 564  
 565    /**
 566     * Create a complete datetime value out of an 
 567     * incomplete array of selected values.
 568     * 
 569     * For example, array('year' => 2008, 'month' => 05) will fill
 570     * in the day, hour, minute and second with the earliest possible
 571     * values if type = 'min', the latest possible values if type = 'max',
 572     * and the current values if type = 'now'.
 573     */
 574    function complete_date($selected, $type = 'now') {
 575      if (empty($selected)) {
 576        return '';
 577      }
 578      // Special case for weeks.
 579      if (array_key_exists('week', $selected)) {
 580        $dates = date_week_range($selected['week'], $selected['year']);
 581        switch ($type) {
 582          case 'empty_now':
 583          case 'empty_min':
 584          case 'min':
 585            return date_format($dates[0], 'Y-m-d H:i:s');
 586          case 'empty_max':
 587          case 'max':
 588            return date_format($dates[1], 'Y-m-d H:i:s');
 589          default:
 590            return;
 591        }
 592      }
 593  
 594      $compare = array_merge($this->part_info('empty_'. $type), $selected);
 595      // If this is a max date, make sure the last day of 
 596      // the month is the right one for this date.
 597      if ($type == 'max') {
 598        $compare['day'] = date_days_in_month($compare['year'], $compare['month']);
 599      }
 600      $value = '';
 601      $separators = $this->part_info('sep');
 602      foreach ($this->date_parts() as $key => $name) {
 603        $value .= $separators[$key] . (!empty($selected[$key]) ? $selected[$key] : $compare[$key]);
 604      }
 605      return $value;
 606    }
 607    /**
 608     * Convert a format string into help text,
 609     * i.e. 'Y-m-d' becomes 'YYYY-MM-DD'.
 610     *
 611     * @param unknown_type $format
 612     * @return unknown
 613     */
 614    function format_help($format) {
 615      $replace = array(
 616        'Y' => 'YYYY', 'm' => 'MM', 'd' => 'DD',
 617        'H' => 'HH', 'i' => 'MM', 's' => 'SS', '\T' => 'T');
 618      return strtr($format, $replace);
 619    }
 620  
 621    /**
 622     *  A function to test the validity of various date parts
 623     */
 624    function part_is_valid($value, $type) {
 625      if ( !preg_match('/^[0-9]*$/', $value) ) {
 626        return false;
 627      }
 628      $value = intval($value);
 629      if ($value <= 0) return false;
 630      switch ($type) {
 631        case 'year':
 632          if ($value < DATE_MIN_YEAR) return false;
 633          break;
 634        case 'month':
 635          if ($value < 0 || $value > 12) return false;
 636          break;
 637        case 'day':
 638          if ($value < 0 || $value > 31) return false;
 639          break;
 640        case 'week':
 641          if ($value < 0 || $value > 53) return false;
 642      }
 643      return true;
 644    }
 645  
 646    function views_formats($granularity, $type = 'sql') {
 647      $formats = array('display', 'sql');
 648      // Start with the site long date format and add seconds to it
 649      $long = str_replace(':i', ':i:s', variable_get('date_format_long',  'l, F j, Y - H:i'));
 650      switch ($granularity) {
 651        case ('year'):
 652          $formats['display'] = 'Y';
 653          $formats['sql'] = 'Y';
 654          break;
 655        case ('month'):
 656          $formats['display'] = date_limit_format($long, array('year', 'month'));
 657          $formats['sql'] = 'Y-m';
 658          break;
 659        case ('day'):
 660          $formats['display'] = date_limit_format($long, array('year', 'month', 'day'));
 661          $formats['sql'] = 'Y-m-d';
 662          break;
 663        case ('hour'):
 664          $formats['display'] = date_limit_format($long, array('year', 'month', 'day', 'hour'));
 665          $formats['sql'] = 'Y-m-d\TH';
 666          break;
 667        case ('minute'):
 668          $formats['display'] = date_limit_format($long, array('year', 'month', 'day', 'hour', 'minute'));
 669          $formats['sql'] = 'Y-m-d\TH:i';
 670          break;
 671        case ('second'):
 672          $formats['display'] = date_limit_format($long, array('year', 'month', 'day', 'hour', 'minute', 'second'));
 673          $formats['sql'] = 'Y-m-d\TH:i:s';
 674          break;
 675        case ('week'):
 676          $formats['display'] = 'F j Y (W)';
 677          $formats['sql'] = 'Y-\WW';
 678          break;
 679      }
 680      return $formats[$type];
 681    }
 682  
 683    function granularity_form($granularity) {
 684      $form = array(
 685        '#title' => t('Granularity'),
 686        '#type' => 'radios',
 687        '#default_value' => $granularity,
 688        '#options' => $this->date_parts(),
 689        );
 690      return $form;
 691    }
 692  
 693    /**
 694     * Parse date parts from an ISO date argument.
 695     * 
 696     * Based on ISO 8601 date duration and time interval standards.
 697     *
 698     * See http://en.wikipedia.org/wiki/ISO_8601#Week_dates for definitions of ISO weeks.
 699     * See http://en.wikipedia.org/wiki/ISO_8601#Duration for definitions of ISO duration and time interval.
 700     *
 701     * Parses a value like 2006-01-01--2006-01-15, or 2006-W24, or @P1W.
 702     * Separate from and to dates or date and period with a double hyphen (--).
 703     *
 704     * The 'to' portion of the argument can be eliminated if it is the same as the 'from' portion.
 705     * Use @ instead of a date to substitute in the current date and time.
 706     *
 707     * Use periods (P1H, P1D, P1W, P1M, P1Y) to get next hour/day/week/month/year from now.
 708     * Use date before P sign to get next hour/day/week/month/year from that date.
 709     * Use period then date to get a period that ends on the date.
 710     *
 711     */
 712    function arg_parts($argument) {
 713      $values = array();
 714      // Keep mal-formed arguments from creating errors.
 715      if (empty($argument) || is_array($argument)) {
 716        return array('date' => array(), 'period' => array());
 717      }
 718      $fromto = explode('--', $argument);
 719      foreach ($fromto as $arg) {
 720        $parts = array();
 721        if ($arg == '@') {
 722          $parts['date'] = date_array(date_now());
 723        }
 724        elseif (preg_match('/(\d{4})?-?(W)?(\d{1,2})?-?(\d{1,2})?[T\s]?(\d{1,2})?:?(\d{1,2})?:?(\d{1,2})?/', $arg, $matches)) {
 725          $date = array();
 726          if (!empty($matches[1])) $date['year'] = $matches[1];
 727          if (!empty($matches[3])) {
 728            if (empty($matches[2])) {
 729              $date['month'] = $matches[3];
 730            }
 731            else {
 732              $date['week'] = $matches[3];
 733            }    
 734          }
 735          if (!empty($matches[4])) $date['day'] = $matches[4];
 736          if (!empty($matches[5])) $date['hour'] = $matches[5];
 737          if (!empty($matches[6])) $date['minute'] = $matches[6];
 738          if (!empty($matches[7])) $date['second'] = $matches[7];
 739          $parts['date'] = $date;
 740        }
 741        if (preg_match('/^P(\d{1,4}[Y])?(\d{1,2}[M])?(\d{1,2}[W])?(\d{1,2}[D])?([T]{0,1})?(\d{1,2}[H])?(\d{1,2}[M])?(\d{1,2}[S])?/', $arg, $matches)) {
 742          $period = array();
 743          if (!empty($matches[1])) $period['year'] =  str_replace('Y', '', $matches[1]);
 744          if (!empty($matches[2])) $period['month'] = str_replace('M', '', $matches[2]);
 745          if (!empty($matches[3])) $period['week'] = str_replace('W', '', $matches[3]);
 746          if (!empty($matches[4])) $period['day'] = str_replace('D', '', $matches[4]);
 747          if (!empty($matches[6])) $period['hour'] = str_replace('H', '', $matches[6]);
 748          if (!empty($matches[7])) $period['minute'] = str_replace('M', '', $matches[7]);
 749          if (!empty($matches[8])) $period['second'] = str_replace('S', '', $matches[8]);
 750          $parts['period'] = $period;
 751        }
 752        $values[] = $parts;
 753      }
 754      return $values;
 755    }
 756  
 757    /**
 758     * Convert strings like '+1 day' to the ISO equivalent, like 'P1D'.
 759     */
 760    function arg_replace($arg) {
 761      if (!preg_match('/([+|-])\s?([0-9]{1,32})\s?([day(s)?|week(s)?|month(s)?|year(s)?|hour(s)?|minute(s)?|second(s)?]{1,10})/', $arg, $results)) {
 762        return str_replace('now', '@', $arg);
 763      }
 764      $direction = $results[1];
 765      $count = $results[2];
 766      $item = $results[3];
 767  
 768      $replace = array(
 769        'now' => '@',
 770        '+' => 'P',
 771        '-' => 'P-',
 772        'years' => 'Y',
 773        'year' => 'Y',
 774        'months' => 'M',
 775        'month' => 'M',
 776        'weeks' => 'W',
 777        'week' => 'W',
 778        'days' => 'D',
 779        'day' => 'D',
 780        'hours' => 'H',
 781        'hour' => 'H',
 782        'minutes' => 'M',
 783        'minute' => 'M',
 784        'seconds' => 'S',
 785        'second' => 'S',
 786        '  ' => '',
 787        ' ' => '',
 788        );
 789      $prefix = in_array($item, array('hours', 'hour', 'minutes', 'minute', 'seconds', 'second')) ? 'T' : '';  
 790      return $prefix . strtr($direction, $replace) . $count . strtr($item, $replace);  
 791    }
 792  
 793    /**
 794     * Use the parsed values from the ISO argument to determine the
 795     * granularity of this period.
 796     */
 797    function arg_granularity($arg) {
 798      $granularity = '';
 799      $parts = $this->arg_parts($arg);
 800      $date = !empty($parts[0]['date']) ? $parts[0]['date'] : (!empty($parts[1]['date']) ? $parts[1]['date'] : array());
 801      foreach ($date as $key => $part) {
 802        $granularity = $key;    
 803      }
 804      return $granularity;
 805    }
 806  
 807    /**
 808     * Use the parsed values from the ISO argument to determine the
 809     * min and max date for this period.
 810     */
 811    function arg_range($arg) {
 812      // Parse the argument to get its parts
 813      $parts = $this->arg_parts($arg);
 814  
 815      // Build a range from a period-only argument (assumes the min date is now.)
 816      if (empty($parts[0]['date']) && !empty($parts[0]['period']) && (empty($parts[1]))) {
 817        $min_date = date_now();
 818        $max_date = drupal_clone($min_date);
 819        foreach ($parts[0]['period'] as $part => $value) {
 820          date_modify($max_date, "+$value $part");
 821        }
 822        date_modify($max_date, '-1 second');
 823        return array($min_date, $max_date);
 824      }
 825      // Build a range from a period to period argument
 826      if (empty($parts[0]['date']) && !empty($parts[0]['period']) && !empty($parts[1]['period'])) {
 827        $min_date = date_now();
 828        $max_date = drupal_clone($min_date);
 829        foreach ($parts[0]['period'] as $part => $value) {
 830          date_modify($min_date, "+$value $part");
 831        }
 832        date_modify($min_date, '-1 second');
 833        foreach ($parts[1]['period'] as $part => $value) {
 834          date_modify($max_date, "+$value $part");
 835        }
 836        date_modify($max_date, '-1 second');
 837        return array($min_date, $max_date);
 838      }
 839      if (!empty($parts[0]['date'])) {
 840        $value = date_fuzzy_datetime($this->complete_date($parts[0]['date'], 'min'));
 841        $min_date = date_make_date($value, date_default_timezone_name(), DATE_ISO);
 842        // Build a range from a single date-only argument.
 843        if (empty($parts[1]) || (empty($parts[1]['date']) && empty($parts[1]['period']))) {
 844          $value = date_fuzzy_datetime($this->complete_date($parts[0]['date'], 'max'));
 845          $max_date = date_make_date($value, date_default_timezone_name(), DATE_ISO);
 846          return array($min_date, $max_date);
 847        }
 848        // Build a range from start date + period.
 849        elseif (!empty($parts[1]['period'])) {
 850          foreach ($parts[1]['period'] as $part => $value) {
 851            $max_date = drupal_clone($min_date);
 852            date_modify($max_date, "+$value $part");
 853          }
 854          date_modify($max_date, '-1 second');
 855          return array($min_date, $max_date);
 856        }
 857      }
 858      // Build a range from start date and end date.
 859      if (!empty($parts[1]['date'])) {
 860        $value = date_fuzzy_datetime($this->complete_date($parts[1]['date'], 'max'));
 861        $max_date = date_make_date($value, date_default_timezone_name(), DATE_ISO);
 862        if (isset($min_date)) {
 863          return array($min_date, $max_date);
 864        }
 865      }
 866      // Build a range from period + end date.
 867      if (!empty($parts[0]['period'])) {
 868        $min_date = date_now();
 869        foreach ($parts[0]['period'] as $part => $value) {
 870          date_modify($min_date, "$value $part");
 871        }
 872        return array($min_date, $max_date);
 873      }
 874       // Intercept invalid info and fall back to the current date.
 875      $now = date_now();
 876      return array($now, $now);
 877   }
 878  }