<?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\Cache;
  
  use Doctrine\DBAL\Driver\Statement;
  use Doctrine\DBAL\Driver\ResultStatement;
  use Doctrine\DBAL\Connection;
  use Doctrine\Common\Cache\Cache;
  use PDO;
  
  /**
   * Cache statement for SQL results.
   *
   * A result is saved in multiple cache keys, there is the originally specified
   * cache key which is just pointing to result rows by key. The following things
   * have to be ensured:
   *
   * 1. lifetime of the original key has to be longer than that of all the individual rows keys
   * 2. if any one row key is missing the query has to be re-executed.
   *
   * Also you have to realize that the cache will load the whole result into memory at once to ensure 2.
   * This means that the memory usage for cached results might increase by using this feature.
   */
  class ResultCacheStatement implements \IteratorAggregate, ResultStatement
  {
      /**
       * @var \Doctrine\Common\Cache\Cache
       */
      private $resultCache;
  
      /**
       *
       * @var string
       */
      private $cacheKey;
  
      /**
       * @var string
       */
      private $realKey;
  
      /**
       * @var int
       */
      private $lifetime;
  
      /**
       * @var Doctrine\DBAL\Driver\Statement
       */
      private $statement;
  
      /**
       * Did we reach the end of the statement?
       *
       * @var bool
       */
      private $emptied = false;
  
      /**
       * @var array
       */
      private $data;
  
      /**
       * @var int
       */
      private $defaultFetchMode = PDO::FETCH_BOTH;
  
      /**
       * @param Statement $stmt
       * @param Cache $resultCache
       * @param string $cacheKey
       * @param string $realKey
       * @param int $lifetime
       */
      public function __construct(Statement $stmt, Cache $resultCache, $cacheKey, $realKey, $lifetime)
      {
          $this->statement = $stmt;
          $this->resultCache = $resultCache;
          $this->cacheKey = $cacheKey;
          $this->realKey = $realKey;
          $this->lifetime = $lifetime;
      }
  
      /**
       * Closes the cursor, enabling the statement to be executed again.
       *
       * @return boolean              Returns TRUE on success or FALSE on failure.
       */
      public function closeCursor()
      {
          $this->statement->closeCursor();
          if ($this->emptied && $this->data !== null) {
              $data = $this->resultCache->fetch($this->cacheKey);
              if ( ! $data) {
                  $data = array();
              }
              $data[$this->realKey] = $this->data;
  
              $this->resultCache->save($this->cacheKey, $data, $this->lifetime);
              unset($this->data);
          }
      }
  
      /**
       * columnCount
       * Returns the number of columns in the result set
       *
       * @return integer              Returns the number of columns in the result set represented
       *                              by the PDOStatement object. If there is no result set,
       *                              this method should return 0.
       */
      public function columnCount()
      {
          return $this->statement->columnCount();
      }
  
      public function setFetchMode($fetchMode, $arg2 = null, $arg3 = null)
      {
          $this->defaultFetchMode = $fetchMode;
      }
  
      public function getIterator()
      {
          $data = $this->fetchAll();
          return new \ArrayIterator($data);
      }
  
      /**
       * fetch
       *
       * @see Query::HYDRATE_* constants
       * @param integer $fetchMode            Controls how the next row will be returned to the caller.
       *                                      This value must be one of the Query::HYDRATE_* constants,
       *                                      defaulting to Query::HYDRATE_BOTH
       *
       * @return mixed
       */
      public function fetch($fetchMode = null)
      {
          if ($this->data === null) {
              $this->data = array();
          }
  
          $row = $this->statement->fetch(PDO::FETCH_ASSOC);
          if ($row) {
              $this->data[] = $row;
  
              $fetchMode = $fetchMode ?: $this->defaultFetchMode;
  
              if ($fetchMode == PDO::FETCH_ASSOC) {
                  return $row;
              } else if ($fetchMode == PDO::FETCH_NUM) {
                  return array_values($row);
              } else if ($fetchMode == PDO::FETCH_BOTH) {
                  return array_merge($row, array_values($row));
              } else if ($fetchMode == PDO::FETCH_COLUMN) {
                  return reset($row);
              } else {
                  throw new \InvalidArgumentException("Invalid fetch-style given for caching result.");
              }
          }
          $this->emptied = true;
          return false;
      }
  
      /**
       * Returns an array containing all of the result set rows
       *
       * @param integer $fetchMode            Controls how the next row will be returned to the caller.
       *                                      This value must be one of the Query::HYDRATE_* constants,
       *                                      defaulting to Query::HYDRATE_BOTH
       *
       * @return array
       */
      public function fetchAll($fetchMode = null)
      {
          $rows = array();
          while ($row = $this->fetch($fetchMode)) {
              $rows[] = $row;
          }
          return $rows;
      }
  
      /**
       * fetchColumn
       * Returns a single column from the next row of a
       * result set or FALSE if there are no more rows.
       *
       * @param integer $columnIndex          0-indexed number of the column you wish to retrieve from the row. If no
       *                                      value is supplied, PDOStatement->fetchColumn()
       *                                      fetches the first column.
       *
       * @return string                       returns a single column in the next row of a result set.
       */
      public function fetchColumn($columnIndex = 0)
      {
          $row = $this->fetch(PDO::FETCH_NUM);
          if (!isset($row[$columnIndex])) {
              // TODO: verify this is correct behavior
              return false;
          }
          return $row[$columnIndex];
      }
  
      /**
       * rowCount
       * rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement
       * executed by the corresponding object.
       *
       * If the last SQL statement executed by the associated Statement object was a SELECT statement,
       * some databases may return the number of rows returned by that statement. However,
       * this behaviour is not guaranteed for all databases and should not be
       * relied on for portable applications.
       *
       * @return integer                      Returns the number of rows.
       */
      public function rowCount()
      {
          return $this->statement->rowCount();
      }
  }