<?php
  /*
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * This software consists of voluntary contributions made by many individuals
   * and is licensed under the MIT license. For more information, see
   * <http://www.doctrine-project.org>.
   */
  
  namespace Doctrine\DBAL\Schema;
  
  use Doctrine\DBAL\Schema\Visitor\Visitor;
  
  class Index extends AbstractAsset implements Constraint
  {
      /**
       * @var array
       */
      protected $_columns;
  
      /**
       * @var bool
       */
      protected $_isUnique = false;
  
      /**
       * @var bool
       */
      protected $_isPrimary = false;
  
      /**
       * Platform specific flags for indexes.
       *
       * @var array
       */
      protected $_flags = array();
  
      /**
       * @param string $indexName
       * @param array $column
       * @param bool $isUnique
       * @param bool $isPrimary
       */
      public function __construct($indexName, array $columns, $isUnique = false, $isPrimary = false, array $flags = array())
      {
          $isUnique = ($isPrimary)?true:$isUnique;
  
          $this->_setName($indexName);
          $this->_isUnique = $isUnique;
          $this->_isPrimary = $isPrimary;
  
          foreach ($columns as $column) {
              $this->_addColumn($column);
          }
          foreach ($flags as $flag) {
              $this->addFlag($flag);
          }
      }
  
      /**
       * @param string $column
       */
      protected function _addColumn($column)
      {
          if(is_string($column)) {
              $this->_columns[] = $column;
          } else {
              throw new \InvalidArgumentException("Expecting a string as Index Column");
          }
      }
  
      /**
       * @return array
       */
      public function getColumns()
      {
          return $this->_columns;
      }
  
      /**
       * @return array
       */
      public function getUnquotedColumns()
      {
          return array_map(array($this, 'trimQuotes'), $this->getColumns());
      }
  
      /**
       * Is the index neither unique nor primary key?
       *
       * @return bool
       */
      public function isSimpleIndex()
      {
          return !$this->_isPrimary && !$this->_isUnique;
      }
  
      /**
       * @return bool
       */
      public function isUnique()
      {
          return $this->_isUnique;
      }
  
      /**
       * @return bool
       */
      public function isPrimary()
      {
          return $this->_isPrimary;
      }
  
      /**
       * @param  string $columnName
       * @param  int $pos
       * @return bool
       */
      public function hasColumnAtPosition($columnName, $pos = 0)
      {
          $columnName   = $this->trimQuotes(strtolower($columnName));
          $indexColumns = array_map('strtolower', $this->getUnquotedColumns());
          return array_search($columnName, $indexColumns) === $pos;
      }
  
      /**
       * Check if this index exactly spans the given column names in the correct order.
       *
       * @param array $columnNames
       * @return boolean
       */
      public function spansColumns(array $columnNames)
      {
          $sameColumns = true;
          for ($i = 0; $i < count($this->_columns); $i++) {
              if (!isset($columnNames[$i]) || $this->trimQuotes(strtolower($this->_columns[$i])) != $this->trimQuotes(strtolower($columnNames[$i]))) {
                  $sameColumns = false;
              }
          }
          return $sameColumns;
      }
  
      /**
       * Check if the other index already fullfills all the indexing and constraint needs of the current one.
       *
       * @param Index $other
       * @return bool
       */
      public function isFullfilledBy(Index $other)
      {
          // allow the other index to be equally large only. It being larger is an option
          // but it creates a problem with scenarios of the kind PRIMARY KEY(foo,bar) UNIQUE(foo)
          if (count($other->getColumns()) != count($this->getColumns())) {
              return false;
          }
  
          // Check if columns are the same, and even in the same order
          $sameColumns = $this->spansColumns($other->getColumns());
  
          if ($sameColumns) {
              if ( ! $this->isUnique() && !$this->isPrimary()) {
                  // this is a special case: If the current key is neither primary or unique, any uniqe or
                  // primary key will always have the same effect for the index and there cannot be any constraint
                  // overlaps. This means a primary or unique index can always fullfill the requirements of just an
                  // index that has no constraints.
                  return true;
              } else if ($other->isPrimary() != $this->isPrimary()) {
                  return false;
              } else if ($other->isUnique() != $this->isUnique()) {
                  return false;
              }
              return true;
          }
          return false;
      }
  
      /**
       * Detect if the other index is a non-unique, non primary index that can be overwritten by this one.
       *
       * @param Index $other
       * @return bool
       */
      public function overrules(Index $other)
      {
          if ($other->isPrimary()) {
              return false;
          } else if ($this->isSimpleIndex() && $other->isUnique()) {
              return false;
          }
  
          if ($this->spansColumns($other->getColumns()) && ($this->isPrimary() || $this->isUnique())) {
              return true;
          }
          return false;
      }
  
      /**
       * Add Flag for an index that translates to platform specific handling.
       *
       * @example $index->addFlag('CLUSTERED')
       * @param string $flag
       * @return Index
       */
      public function addFlag($flag)
      {
          $this->flags[strtolower($flag)] = true;
          return $this;
      }
  
      /**
       * Does this index have a specific flag?
       *
       * @param string $flag
       * @return bool
       */
      public function hasFlag($flag)
      {
          return isset($this->flags[strtolower($flag)]);
      }
  
      /**
       * Remove a flag
       *
       * @param string $flag
       * @return void
       */
      public function removeFlag($flag)
      {
          unset($this->flags[strtolower($flag)]);
      }
  }