<?php
/** DomFramework
    @package domframework
    @author Dominique Fournier <dominique@fournier38.fr> */

// dblayer.php

/* Documentation :
The dbLayer provide an abstraction layer on PDO to be easier on all the CRUD
(Create, Read, Update, Delete) operations, accross all the databases engines.
To use it, extends in your code this class, and define the attributes :
- public $table : name of the table you want to use
- public $fields : description of all the fields in the database like :
  public $fields = array (
    "id"=>array ("integer", "not null", "autoincrement"),
    "zone"=>array ("varchar", "255", "not null"),
    "viewname"=>array ("varchar", "255"),
    "viewclients"=>array ("varchar", "255"),
    "comment"=>array ("varchar", "1024"),
    "opendate"=>array ("datetime", "not null"),
    "closedate"=>array ("datetime"),
  );
- public $primary = "id" ; the primary key of the table (in text). Actually
  the dbLayer abstraction don't supports primary key on multiples columns
- public $unique = array ("column", array ("column1", "column2");)
- public $foreign : Add the support of foreign keys. Must be defined like :
  public $foreign = array (
    "localfield"=>array ("foreign Table", "foreign key",
                         "ON UPDATE CASCADE ON DELETE CASCADE"),
  );

Optionnaly, you can add the
- public $debug = TRUE : enable the debug on screen (NOT FOR PROD !!)
*/

require_once ("domframework/verify.php");

/** Permit abstraction on the differents SQL databases available */
class dblayer extends PDO
{
  /** The table name to use */
  public $table = null;
  /** The tableprefix text to prepend to table name (Should finish by _)
      Just allow chars ! */
  public $tableprefix = "";
  /** The fields with the definition of type, and special parameters */
  public $fields = array ();
  /** The primary field */
  public $primary = null;
  /** An array to define the unique fields (or array of unique fields) */
  public $unique = null;
  /** An array to define the foreign keys of the field */
  public $foreign = array ();
  /** The verify unitary stack
      @param string $field The name of the field to test
      @param string $val The value of the field to test */
  public function verifyOne ($field, $val) {}
  /** The verify global stack
      @param array $datas The associative array of contents */
  public function verifyAll ($datas) {}
  /** Debug of the SQL */
  public $debug = FALSE;
  /** The connecting DSN */
  private $dsn = null;
  /** The field group delimiter */
  private $sep = "";
  /** Titles */
  public $titles = array ();

  // TODO !!
  /** Create Table creation from $this->fields with engine abstraction
      Example in sqlite3 id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
              in MySQL   id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT, */

  // TODO !!
  /** Create automatic creation of $fields from .schema of sqlite3/
      show create table `NomTable`; for MySQL
      SQLite3 : PRAGMA TABLE_INFO('yourtable');
      MYSQL : SHOW COLUMNS FROM yourtable;*/

  // TODO !!
  /** Allow to modify tables if the definition is changed
      Attention : SQLite don't supports adding Foreign keys without deleting all
      the table, and re-import the datas (http://www.sqlite.org/omitted.html) */

  /** Limit to one instance of the connection to the same database */
  private static $instance = null;

  /** Connection to the database engine
      See http://fr2.php.net/manual/en/pdo.construct.php for the $dsn format
      @param string $dsn PDO Data Source Name
      @param string|null $username Username to connect
      @param string|null $password Password to connect
      @param string|null $driver_options Driver options to the database */
  public function __construct ($dsn, $username=null, $password=null,
                               $driver_options=null)
  {
    $driver = @explode (":", $dsn);
    if (! isset ($driver[0]))
      throw new Exception (_("No valid DSN provided"), 500);
    // Force specifics initialisations
    switch ($driver[0])
    {
    case "sqlite":
      // Look at the right to write in database and in the directory
      $file = substr ($dsn, 7);
      if (! is_writeable (dirname ($file)))
        throw new Exception (dgettext("domframework",
                        "The directory for SQLite database is write protected"),
                        500);
      if (file_exists ($file) && ! is_writeable ($file))
        throw new Exception (dgettext("domframework",
                             "The SQLite database file is write protected"),
                             500);
      if (function_exists ("posix_getuid") &&
          fileowner ($file) === posix_getuid ())
        chmod ($file, 0666);
      try
      {
        parent::__construct ($dsn, $username, $password, $driver_options);
        parent::setAttribute (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
      }
      catch (Exception $e)
      {
        throw new Exception ("PDO error : ".$e->getMessage(), 500);
      }

      // Force ForeignKeys support (disabled by default)
      $this->exec("PRAGMA foreign_keys = ON");
      $this->sep = "`";
      break;
    case "mysql":
      try
      {
        $driver_options[PDO::MYSQL_ATTR_FOUND_ROWS] = 1;
        parent::__construct ($dsn, $username, $password, $driver_options);
        parent::setAttribute (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
      }
      catch (Exception $e)
      {
        throw new Exception ("PDO error : ".$e->getMessage(), 500);
      }

      // Set the coding to UTF8
      $this->exec("SET CHARACTER SET utf8");
      $this->sep = "`";
      break;
    case "pgsql":
      try
      {
        parent::__construct ($dsn, $username, $password, $driver_options);
        parent::setAttribute (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
      }
      catch (Exception $e)
      {
        throw new Exception ("PDO error : ".$e->getMessage(), 500);
      }

      // Set the coding to UTF8
      $this->exec("SET NAMES 'utf8'");
      $this->sep = "\"";
      break;
    default:
      throw new Exception (dgettext("domframework",
                                    "Unknown PDO driver provided"), 500);
    }
    $this->dsn = $dsn;
  }

  /** Return the connected database name from DSN used to connect */
  public function databasename ()
  {
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    $vals = explode (";", substr (strstr ($this->dsn, ":"), 1));
    $dsnExplode = array ();
    foreach ($vals as $val)
    {
      @list ($k, $v) = explode ("=", $val);
      $dsnExplode[$k] = $v;
    }
    if (isset ($dsnExplode["dbname"]))
      return $dsnExplode["dbname"];
    return NULL;
  }

  /** Return all the tables available in the database */
  public function listTables ()
  {
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    switch ($this->getAttribute(PDO::ATTR_DRIVER_NAME))
    {
    case "sqlite":
      $req = "SELECT name FROM sqlite_master WHERE type='table'";
      $st = $this->prepare ($req);
      $st->execute ();
      $res = array ();
      while ($d = $st->fetch (PDO::FETCH_ASSOC))
        $res[] = $d["name"];
      break;
    case "mysql":
      $req = "SELECT TABLE_NAME
              FROM information_schema.tables
              WHERE TABLE_SCHEMA='".$this->databasename()."'";
      $st = $this->prepare ($req);
      $st->execute ();
      $res = array ();
      while ($d = $st->fetch (PDO::FETCH_ASSOC))
        $res[] = $d["TABLE_NAME"];
      break;
    case "pgsql":
      $req = "SELECT *
              FROM pg_tables
              WHERE schemaname = 'public'";
      $st = $this->prepare ($req);
      $st->execute ();
      $res = array ();
      while ($d = $st->fetch (PDO::FETCH_ASSOC))
        $res[] = $d["tablename"];
      break;
    default:
      throw new Exception (dgettext("domframework",
                           "Unknown database driver in listTables"), 500);
    }
    return $res;
  }

  /** Verify if the provided datas can be inserted/updated in the database.
      @param $datas An array containing the datas to verify with keys 
      @param $updatekey the key to update
      @return an array with the errors in array($key=>array($priority,$message))
    */
  public function verify ($datas, $updatekey=false)
  {
    if ($this->debug) echo "== Entering verify\n";
    $errors = array ();
    foreach ($this->fields as $key=>$params)
    {
      if ($this->debug) echo "      verify ($key)\n";
      if ($updatekey === false)
      {
        // Don't check if there is an update : the database is already filled
        // For autoincrement, in INSERT mode, force the value to null
        if (in_array ("autoincrement", $params))
          $datas[$key] = null;
        if (in_array ("not null", $params) && !array_key_exists ($key, $datas))
        {
          $errors[$key] = array ("error", sprintf (dgettext("domframework",
                                        "Mandatory field '%s' not provided"),
                                        $key));
          continue;
        }
        if (in_array ("not null", $params) && $datas[$key] === "")
        {
          $errors[$key] = array ("error", sprintf (dgettext("domframework",
                                        "Mandatory field '%s' is empty"),
                                        $key));
          continue;
        }
      }

      // Do not verify the non provided datas (if they are not mandatory)
      if (!array_key_exists ($key, $datas))
        continue;

      // Verify the fields, if $verify is defined, before doing insertion
      $verify = $this->verifyOne ($key, $datas[$key]);
      if (is_array ($verify) && count ($verify))
      {
        $errors[$key] = array ($verify[0], $verify[1]);
        //." ". dgettext("domframework","in")." ".$key);
        continue;
      }
   
      // Check for type inconsistencies if the value is provided
      if (is_null ($datas[$key]))
      {
        // Skipped the removed autoincrement keys
        continue;
      }
      elseif (! is_string ($datas[$key]))
      {
        $errors[$key] = array ("error", sprintf (
                            dgettext("domframework",
                       "Errors in consistency : '%s' is not an string [is %s]"),
                            $key, gettype ($datas[$key])));
        continue;
      }
      elseif ($datas[$key] !== "" && $params[0] === "integer")
      {
        if (strspn ($datas[$key], "0123456789") !== strlen ($datas[$key]))
        {
          $errors[$key] = array ("error", sprintf (
                            dgettext("domframework",
                            "Errors in consistency : '%s' is not an integer"),
                            $key));
          continue;
        }
      }
      elseif ($datas[$key] !== "" && $params[0] === "varchar")
      {
        if (! isset ($params[1]))
        {
          $errors[$key] = array ("error", sprintf (
                          dgettext("domframework",
                          "The length of varchar field '%s' is not provided"),
                          $key));
          continue;
        }
        if (strlen ($datas[$key]) > $params[1])
        {
          $errors[$key] = array ("error", sprintf (
                               dgettext("domframework",
                               "Errors in consistency : '%s' data is too long"),
                               $key));
          continue;
        }
      }
      elseif ($datas[$key] !== "" && $params[0] === "datetime")
      {
        // The date format must be in ANSI SQL : YYYY-MM-DD HH:MM:SS
        $d = DateTime::createFromFormat("Y-m-d H:i:s", $datas[$key]);
        if (!$d || $d->format("Y-m-d H:i:s") !== $datas[$key])
        {
          $errors[$key] = array ("error", sprintf (
                               dgettext("domframework",
                               "Incorrect datetime provided for field '%s'"),
                               $key));
          continue;
        }
      }
      elseif ($datas[$key] !== "" && $params[0] === "date")
      {
        // The date format must be in ANSI SQL : YYYY-MM-DD
        $d = DateTime::createFromFormat("Y-m-d", $datas[$key]);
        if (!$d || $d->format("Y-m-d") !== $datas[$key])
        {
          $errors[$key] = array ("error", sprintf (
                               dgettext("domframework",
                               "Incorrect date provided for field '%s'"),
                               $key));
          continue;
        }
      }
      elseif ($datas[$key] !== "")
      {
        $errors[$key] = array ("error", sprintf (dgettext("domframework",
                                 "Unknown field type for '%s'"), $key));
        continue;
      }
      else
      {
        // Nothing to do if the value is empty : just save it
      }
    }

    if (count ($errors) !== 0)
      return $errors;

    if ($this->debug) echo "   verify inconsistency\n";
    // Check for inconsistency
    $verify = $this->verifyAll ($datas);
    if (count ($verify))
      return $verify;

    $datasOK = array ();
    foreach ($this->fields as $field=>$desc)
    {
      if (isset ($datas[$field]))
        $datasOK[$field] = $datas[$field];
    }

    if ($updatekey !== false)
    {
      if ($this->debug) echo "   verify in updatekey\n";
      // Check if the unique constrain is valid before doing the insertion
      // 1. Read the actual state
      $before = $this->read (array (array ($this->primary, $updatekey)));
      if (count ($before) === 0)
        return array ("error", dgettext("domframework",
                      "Entry to modify unavailable"));
      $before = reset ($before);
      // 2. Map the proposal entries into the before state
      $after = $before;
      foreach ($datasOK as $field=>$val)
        $after[$field] = $val;
    }
    else
    {
      if ($this->debug) echo "   verify NO updatekey\n";
      $after = $datasOK;

    }
    // Check if the unique constrain is valid before doing the insertion
    if ($this->unique === null && $this->primary !== null)
      $this->unique = array ($this->primary);
    // TODO : If Unique is not defined nor primary
    // FIXME : If unique is defined, could I test if the primary key is defined
    // in a parameter of the unique and if it is not add it automatically 
    foreach ($this->unique as $k=>$columns)
    {
      if ($this->primary === null)
      {
        return array (dgettext("domframework", 
                              "No field primary defined for tests in primary"));
      }

      if (is_array ($columns))
      {
        // Multiple columns in unique
        if ($this->debug) echo "   verify unique multiple $k\n";
        $select = array ();
        if ($updatekey !== false)
          $select[] = array ($this->primary, $updatekey, "!=");
        foreach ($columns as $col)
        {
          if (!array_key_exists ($col, $after)) continue;
          $select[] = array ($col, $after[$col]);
        }
        // If there is only the primary key, there is no chance to have a
        // conflict
        // Before updating, check if the new values are not creating an error
        $rc = $this->read ($select, array ($this->primary));
        if (count ($rc) > 0)
        {
          $errors[] = array ("error", dgettext("domframework",
                             "An entry with these values already exists"));
          continue;
        }
      }
      else
      {
        // One column in unique
        if ($this->debug) echo "   verify unique one column $k\n";
        if (!array_key_exists ($columns, $after)) continue;
        $select = array ();
        if ($updatekey !== false)
        {
          // This line have a problem to update a tuple with the same values
          //  if ($columns === $this->primary)
            $select[] = array ($this->primary, $updatekey, "!=");
        }
        $select[] = array ($columns, $after[$columns]);
        $rc = $this->read ($select,
                           array ($this->primary));
        if (count ($rc) > 0)
        {
          $errors[] = array ("error", dgettext("domframework",
                             "An entry with this value already exists"));
          continue;
        }
      }
    }

    // Check if the foreign keys constrains are valid before doing the insertion
    foreach ($this->foreign as $foreign=>$data)
    {
      if ($updatekey === false)
      {
        // Before doing the insert, check the foreign keys. In update, they are
        // not mandatory and are not checked for existancy.
        if ($this->debug) echo "   verify foreign $foreign\n";
        if (! isset ($datas[$foreign]))
        {
          $errors[] = array ("error", sprintf (dgettext("domframework",
                               "The foreign column '%s' is not provided"),
                               $foreign));
          return $errors;
        }
        if (! isset ($datas[$foreign][0]))
        {
          $errors[] = array ("error", sprintf (dgettext("domframework",
                             "The field type for column '%s' is not provided"),
                             $foreign));
          return $errors;
          continue;
        }
      }
      else
      {
        if (! array_key_exists ($foreign, $data))
          continue;
      }
      $table = $data[0];
      $column = $data[1];
      $req = "SELECT $this->sep$column$this->sep ".
             "FROM $this->sep$this->tableprefix$table$this->sep ".
             "WHERE $this->sep$column$this->sep=:".md5 ($column);
      if ($this->debug) echo "DEBUG : $req\n";
      $st = $this->prepare ($req);
      $val = $datas[$foreign];
      $key = $column;
      if ($this->debug) echo "DEBUG BIND : ".$this->fields[$foreign][0]."\n";
      if ($this->debug) echo "DEBUG BIND : $column(".md5 ($column)."->".
                             var_export ($val, TRUE)."\n";
      if ($val === null)
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_NULL);
      elseif ($this->fields[$foreign][0] === "integer")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_INT);
      elseif ($this->fields[$foreign][0] === "varchar")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      elseif ($this->fields[$foreign][0] === "datetime")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      elseif ($this->fields[$foreign][0] === "date")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      else
      {
        throw new Exception ("TO BE DEVELOPPED : ".$this->fields[$foreign][0],
                             500);
      }
      $st->execute ();
      $res = array ();
      while ($d = $st->fetch (PDO::FETCH_ASSOC))
        $res[] = $d;
      if (count ($res) === 0)
      {
        $errors[] = array ("error", sprintf (dgettext("domframework",
                                      "The foreign key '%s' doesn't exists"),
                                      $column));
        continue;
      }
    }
    return $errors;
  }

  /** Create a new entry in the table. Datas must be an indexed array
      @param array $datas Datas to be recorded (column=>value)
      @obsolete 0.5 */
  public function create ($datas)
  {
    return $this->insert ($datas);
  }

  /** Insert a new line of datas in the table. Datas must be an indexed array
      @param array $datas Datas to be recorded (column=>value)*/
  public function insert ($datas)
  {
    if ($this->debug) echo "== Entering insert\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    if ($this->unique === null)
      throw new Exception (dgettext("domframework",
                           "Unique fields of table are not defined"), 500);
    if (! is_array ($this->unique))
      throw new Exception (dgettext("domframework",
                           "The unique configuration is not an array"), 500);
    if (!is_array ($datas))
      throw new Exception (dgettext("domframework",
                           "The datas provided to create are not array"),
                           405);
    foreach ($this->fields as $key=>$params)
    {
      if (in_array ("autoincrement", $params))
        $datas[$key] = null;
    }
    if (!in_array ($this->primary, $this->unique))
      $this->unique[] = $this->primary;
    $datasOK = array ();
    $errors = $this->verify ($datas);
    if (count ($errors) !== 0)
    {
      $errors = reset ($errors);
      throw new Exception ($errors[1], 405);
    }
    foreach ($this->fields as $field=>$desc)
    {
      if (isset ($datas[$field]))
        $datasOK[$field] = $datas[$field];
    }
    $binds = array_keys ($datasOK);
    array_walk ($binds, function(&$value, $key) {
      $value = md5 ($value);
    });
    $datasOK = $this->hookpreinsert ($datasOK);
    $req = "INSERT INTO $this->sep$this->tableprefix$this->table$this->sep ";
    $req .= "($this->sep".
            implode ("$this->sep,$this->sep", array_keys ($datasOK)).
            "$this->sep)";
    $req .= " VALUES ";
    $req .= "(:".implode (",:", $binds).")";
    if ($this->debug) echo "DEBUG : $req\n";
    $st = $this->prepare ($req);
    foreach ($datasOK as $key=>$val)
    {
      if ($this->debug) echo "DEBUG BIND : $key(".md5 ($key).")->".
                             var_export ($val, TRUE)."\n";
      if ($val === null)
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_NULL);
      elseif ($this->fields[$key][0] === "integer")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_INT);
      elseif ($this->fields[$key][0] === "varchar")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      elseif ($this->fields[$key][0] === "datetime")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      elseif ($this->fields[$key][0] === "date")
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      else
        throw new Exception ("TO BE DEVELOPPED : ".$this->fields[$key][0], 500);
    }

    try
    {
      $st->execute ();
    }
    catch (Exception $e)
    {
      echo "dblayer execute exception : ".$e->getMessage()."\n";
      exit;
    }
    $lastID = $this->lastInsertId();
    $lastID = $this->hookpostinsert ($datasOK, $lastID);
    return $lastID;
  }

  /** Read the table content based on a select filter, ordered by order
      operator and the associated select value
      @param array|null $select Rows to select with
         $select = array (array ($key, $val, $operator), ...)
         $key=>column, $val=>value to found, $operator=>'LIKE', =...
      @param array|null $display Columns displayed
         $display = array ($col1, $col2...);
      @param array|null $order Sort the columns by orientation
         $order = array (array ($key, $orientation), ...)
         $key=>column, $orientation=ASC/DESC
      @param bool|null $whereOr The WHERE parameters are separated by OR instead
                                of AND
      @param array|null $foreignSelect Add a filter on foreign keys */
  public function read ($select=null, $display=null, $order=null,
                        $whereOr=false, $foreignSelect=null)
  {
    if ($this->debug) echo "== Entering read\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    if ($select !== null && !is_array ($select))
      throw new Exception (dgettext("domframework",
                           "Select information provided is not an array"),
                           405);
    if ($display !== null && !is_array ($display))
      throw new Exception (dgettext("domframework",
                           "Display information provided is not an array"),
                           405);
    if ($order !== null && !is_array ($order))
      throw new Exception (dgettext("domframework",
                           "Order information provided is not an array"),
                           405);
    if ($display !== null)
    {
      foreach ($display as $f)
      {
        if (!in_array ($f, array_keys ($this->fields)))
          throw new Exception (sprintf (dgettext("domframework",
                               "Field '%s' not allowed"), $f), 500);
      }
    }
    else
    {
      $display = array_keys ($this->fields);
    }

    $foreignSelectCols = array ();
    if ($foreignSelect !== null)
    {
      foreach ($foreignSelect as $s)
        $foreignSelectCols[] = $s[0];
    }
    $req = "SELECT $this->sep";
    $req .= implode ("$this->sep,$this->sep", $display);
    $req .= "$this->sep ";
    $req .= "FROM $this->sep$this->tableprefix$this->table$this->sep";
    if ($select !== null || $foreignSelect !== null)
    {
      $req .= " WHERE (";
    }
    if ($select !== null)
    {
      // TODO Allow a field=>value in plus of array("field","value")
      foreach ($select as $n=>$s)
      {
        // The foreign keys can not be in the select too (conflict)
        if (in_array ($s[0],$foreignSelectCols))
          continue;
        if ($n > 0)
        {
          if ($whereOr === false)
            $req .= " AND";
          else
            $req .= " OR ";
        }
        if (!isset ($s[2]))
          $s[2] = "=";
        if (!isset ($s[0]))
          throw new Exception (sprintf (dgettext("domframework",
                               "Select not found for id=%d"), $n), 500);
        // The double-quotes are added for sqlite to escape the column if its
        // name is 'group'
        // Don't put single quotes : don't work with SQLite
        // TODO : Test for PostgreSQL (Tested for SQLite and MySQL)
        $req .= " $this->sep".$s[0]."$this->sep ".$s[2]." :".md5 ($s[0]);
      }
      $req .=")";
    }
    if ($select !== null && $foreignSelect !== null)
      $req .= " AND (";
    if ($foreignSelect !== null)
    {
      // TODO Allow a field=>value in plus of array("field","value")
      foreach ($foreignSelect as $n=>$s)
      {
        if ($n > 0)
        {
          $req .= " AND";
        }
        if (!isset ($s[2]))
          $s[2] = "=";
        $req .= " $this->sep".$s[0]."$this->sep ".$s[2]." :".md5 ($s[0]);
      }
      $req .=")";
    }

    if ($order !== null)
    {
      $req .= " ORDER BY ";
      foreach ($order as $n=>$o)
      {
        if ($n > 0)
         $req .= ",";
        $req .= $this->sep.$o[0].$this->sep;
        if (isset ($o[1]) && $o[1] === "DESC")
          $req .= " DESC";
        else
          $req .= " ASC";
      }
    }

    if ($this->debug) echo "DEBUG : $req\n";
    try
    {
      $st = $this->prepare ($req);
    }
    catch (Exception $e)
    {
      if ($this->debug) echo "DEBUG : PREPARE ERROR ! Return FALSE".
         $e->getMessage()."\n";
      throw new Exception ($e->getMessage(), 500);     
    }

    if ($select !== NULL)
    {
      foreach ($select as $s)
      {
        if ($this->debug) echo "DEBUG BIND : ".$s[0]."(".md5 ($s[0]).")->".
                               var_export ($s[1], TRUE)."\n";
        $st->bindValue (":".md5 ($s[0]), $s[1]);
      }
    }
    if ($foreignSelect !== null)
    {
      foreach ($foreignSelect as $s)
      {
        if ($this->debug) echo "DEBUG BIND : ".$s[0]."(".md5 ($s[0]).")->".
                               var_export ($s[1], TRUE)."\n";
        $st->bindValue (":".md5 ($s[0]), $s[1]);
      }
    }

    $rc = $st->execute ();
    if ($rc === false)
    {
      if ($this->debug) echo "DEBUG : EXECUTE ERROR ! Return FALSE\n";
    }
    $res = array ();
    while ($d = $st->fetch (PDO::FETCH_ASSOC))
      $res[] = $d;
    return $res;
  }

  /** Update the key tuple with the provided datas
      Return the number of rows modified
      @param string|integer $updatekey The key applied on primary key to be
        updated
      @param array $datas The values to be updated 
      @return the number of lines modified */
  public function update ($updatekey, $datas)
  {
    if ($this->debug) echo "== Entering update\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    if (count ($this->fields) === 0)
      throw new Exception (dgettext("domframework", "No Field defined"), 500);
    if ($this->primary === null)
      throw new Exception (dgettext("domframework", "No Primary defined"), 500);
    if (count ($datas) === 0)
      throw new Exception (dgettext("domframework",
                                    "No data to update provided"), 500);
    $datasOK = array ();
    $errors = $this->verify ($datas, $updatekey);
    if (count ($errors) !== 0)
    {
      if (is_array ($errors))
        throw new Exception ($errors[0][1], 405);
      throw new Exception ($errors[1], 405);
    }
    foreach ($this->fields as $field=>$desc)
    {
      if (isset ($datas[$field]))
        $datasOK[$field] = $datas[$field];
    }

    $datasOK = $this->hookpreupdate ($updatekey, $datasOK);
    $req = "UPDATE $this->sep".$this->tableprefix."$this->table$this->sep SET ";
    $i = 0;
    foreach ($datasOK as $key=>$val)
    {
      if ($i>0) $req .= ",";
      $req .= "$this->sep$key$this->sep=:".md5 ($key);
      $i++;
    }

    $req .= " WHERE $this->sep$this->primary$this->sep=:".
              md5 ("PRIMARY".$this->primary);
    if ($this->debug) echo "DEBUG : $req\n";
    $st = $this->prepare ($req);
    // Add the primary key to field list temporaly. It will permit to update the
    // primary key
    $fields = $this->fields;
    $datasOK["PRIMARY".$this->primary] = $updatekey;
    $fields["PRIMARY".$this->primary] = $this->fields[$this->primary];
    foreach ($datasOK as $key=>$val)
    {
      if ($this->debug) echo "DEBUG BIND : $key(".md5 ($key).")->".
                             var_export ($val, TRUE)." ";
      if ($val === null)
      {
        if ($this->debug) echo "(null)\n";
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_NULL);
      }
      elseif ($fields[$key][0] === "integer")
      {
        if ($this->debug) echo "(integer)\n";
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_INT);
      }
      elseif ($fields[$key][0] === "varchar")
      {
        if ($this->debug) echo "(varchar)\n";
        $st->bindValue (":".md5 ($key), "$val", PDO::PARAM_STR);
      }
      elseif ($fields[$key][0] === "datetime")
      {
        if ($this->debug) echo "(datetime)\n";
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      }
      elseif ($fields[$key][0] === "date")
      {
        if ($this->debug) echo "(date)\n";
        $st->bindValue (":".md5 ($key), $val, PDO::PARAM_STR);
      }
      else
      {
        if ($this->debug) echo "(UNKNOWN)\n";
        throw new Exception ("TO BE DEVELOPPED : ".$fields[$key][0], 500);
      }
    }

    $st->execute ();
    $nbLinesUpdated = $st->rowCount ();
    $nbLinesUpdated = $this->hookpostupdate ($updatekey, $datasOK,
                                             $nbLinesUpdated);
    return $nbLinesUpdated;
  }

  /** Delete a tuple identified by its primary key
      Return the number of deleted rows (can be 0 !)
      @param strin|integer $deletekey The key of primary key to be deleted */
  public function delete ($deletekey)
  {
    if ($this->debug) echo "== Entering delete\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"));
    $deletekey = $this->hookpredelete ($deletekey);
    $req = "DELETE FROM $this->sep$this->tableprefix$this->table$this->sep ";
    $req .= "WHERE $this->primary = :primary";
    $st = $this->prepare ($req);
    if ($this->debug) echo "DEBUG : $req\n";
    if ($this->debug) echo "DEBUG BIND : primary->".
                           var_export ($deletekey, TRUE)."\n";
    $st->bindValue (":primary", $deletekey);
    $st->execute ();
    $nbLinesDeleted = $st->rowCount();
    $nbLinesDeleted = $this->hookpostdelete ($deletekey, $nbLinesDeleted);
    return $nbLinesDeleted;
  }

  /** Translation of fields */
  public function titles ()
  {
    if ($this->debug) echo "== Entering titles\n";
    if (count ($this->fields) === 0)
      throw new Exception (dgettext("domframework", "No Field defined"), 500);
    $arr = array ();
    if (count ($this->titles) !== 0)
    {
      foreach ($this->titles as $field=>$v)
        $arr[$field] = $field;
    }
    else
    {
      foreach ($this->fields as $field=>$v)
        $arr[$field] = $field;
    }
    return $arr;
  }

  /** Drop the table */
  public function dropTable ()
  {
    if ($this->debug) echo "== Entering dropTables\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"));
    $sql = "DROP TABLE $this->sep$this->tableprefix$this->table$this->sep";
    if ($this->debug)
      echo "$sql\n";
    return $this->exec($sql);
  }

  /** Create the table defined by the differents fields.
      Define the SQL syntax based on SQL engines
      $table = "dns zones";
      $fields = array (
        "id"=>array ("integer", "not null", "autoincrement"),
        "zo ne"=>array ("varchar", "255", "not null"),
        "vie wname"=>array ("varchar", "255"),
        "view clients"=>array ("varchar", "255"),
        "comme nt"=>array ("varchar", "1024"),
        "opendate"=>array ("datetime", "not null"),
        "closedate"=>array ("datetime"),
      );
      $primary = "id";
      $unique = array ("id", array ("zo ne", "vie wname"));
      $foreign = array ("zone"=>"table.field",...);
   */
  public function createTable ()
  {
    if ($this->debug) echo "== Entering createTable\n";
    if ($this->sep === "")
      throw new Exception (dgettext("domframework", "Database not connected"),
                           500);
    if (count ($this->fields) === 0)
      throw new Exception (dgettext("domframework", "No Field defined"), 500);
    switch ($this->getAttribute(PDO::ATTR_DRIVER_NAME))
    {
    case "sqlite":
      $sql = "CREATE TABLE $this->sep$this->tableprefix$this->table$this->sep ".
             "(\n";
      $i = 0;
      foreach ($this->fields as $field=>$params)
      {
        if ($i > 0)
          $sql .= ",\n";
        // Name of field
        $sql .= "$this->sep$field$this->sep ";
        // Type of field : in $params[0]
        if (!isset ($params[0]))
          throw new Exception (sprintf (
                               dgettext("domframework",
                               "No database type defined for field '%s'"),
                               $field), 500);

        switch ($params[0])
        {
        case "integer":
          $sql .= "INTEGER";
          $params  = array_slice ($params, 1);
          break;
        case "varchar":
          if (!isset ($params[1]))
            throw new Exception (dgettext("domframework",
                                 "No Size provided for varchar field"), 500);
          $sql .= "VARCHAR(".$params[1].")";
          $params  = array_slice ($params, 2);
          break;
        case "datetime":
          $sql .= "DATETIME";
          $params  = array_slice ($params, 1);
          break;
        case "date":
          $sql .= "DATE";
          $params  = array_slice ($params, 1);
          break;
        default:
          throw new Exception (sprintf (
                               dgettext("domframework",
                               "Unknown type '%s' provided for field '%s'"),
                               $params[0], $field), 500);
        }
        // Primary key
        if ($this->primary === $field)
          $sql .= " PRIMARY KEY";
        // Others parameters for field
        // Sort to put the autoincrement field in front of params, if it is
        // present
        sort ($params);
        foreach ($params as $p)
        {
          switch ($p)
          {
          case "not null": $sql .= " NOT NULL"; break;
          case "autoincrement": $sql .= " AUTOINCREMENT";break;
          default:
            throw new Exception (dgettext("domframework",
                                 "Unknown additionnal parameter for field"),
                                 500);
          }
        }
        $i ++;
      }
      // Unique fields
      if ($this->unique !== null)
      {
        if (!is_array ($this->unique))
          throw new Exception (dgettext("domframework",
                               "The Unique field definition is not an array"),
                               500);
        foreach ($this->unique as $u)
        {
          $sql .= ",\n  UNIQUE ($this->sep";
          if (is_array ($u))
            $sql .=implode ("$this->sep,$this->sep", $u);
          else
            $sql .= $u;
          $sql .="$this->sep)";
        }
      }
      // Foreign keys
      $i = 0;
      foreach ($this->foreign as $field=>$k)
      {
        $sql .= ",\n  FOREIGN KEY($this->sep$field$this->sep) ".
                "REFERENCES $this->sep".$k[0]."$this->sep($this->sep".
                $k[1]."$this->sep)";
        if (isset ($k[2]))
          $sql .= " ".$k[2];
        $i++;
      }
      $sql .=")";
      break;
    case "mysql":
      $sql = "CREATE TABLE $this->sep$this->tableprefix$this->table$this->sep ".
             "(\n";
      $i = 0;
      foreach ($this->fields as $field=>$params)
      {
        if ($i > 0)
          $sql .= ",\n";
        // Name of field
        $sql .= "$this->sep$field$this->sep ";
        // Type of field : in $params[0]
        if (!isset ($params[0]))
          throw new Exception (dgettext("domframework",
                               "No database type defined for field"), 500);
        switch ($params[0])
        {
        case "integer":
          $sql .= "INTEGER";
          $params  = array_slice ($params, 1);
          break;
        case "varchar":
          if (!isset ($params[1]))
            throw new Exception (dgettext("domframework",
                                 "No Size provided for varchar field"), 500);
          $sql .= "VARCHAR(".$params[1].")";
          $params  = array_slice ($params, 2);
          break;
        case "datetime":
          $sql .= "DATETIME";
          $params  = array_slice ($params, 1);
          break;
        case "date":
          $sql .= "DATE";
          $params  = array_slice ($params, 1);
          break;
        default:
          throw new Exception (sprintf (
                               dgettext("domframework",
                               "Unknown type provided for field '%s'"),
                               $field), 500);
        }
        // Primary key
        if ($this->primary === $field)
          $sql .= " PRIMARY KEY";
        // Others parameters for field
        // Sort to put the autoincrement field in front of params, if it is
        // present
        sort ($params);
        foreach ($params as $p)
        {
          switch ($p)
          {
          case "not null": $sql .= " NOT NULL"; break;
          case "autoincrement": $sql .= " AUTO_INCREMENT";break;
          default:
            throw new Exception (sprintf (
                                 dgettext("domframework",
                                "Unknown additionnal parameter for field '%s'"),
                                 $field), 500);
          }
        }
        $i ++;
      }
      // Unique fields
      if ($this->unique !== null)
      {
        foreach ($this->unique as $u)
        {
          $sql .= ",\n  UNIQUE ($this->sep";
          if (is_array ($u))
            $sql .=implode ("$this->sep,$this->sep", $u);
          else
            $sql .= $u;
          $sql .="$this->sep)";
        }
      }
      // Foreign keys
      $i = 0;
      foreach ($this->foreign as $field=>$k)
      {
        $sql .= ",\n  FOREIGN KEY($this->sep$field$this->sep) ".
                "REFERENCES $this->sep".$k[0]."$this->sep($this->sep".
                $k[1]."$this->sep)";
        if (isset ($k[2]))
          $sql .= " ".$k[2];
        if ($i > 0)
          $sql .= ",";
        $i++;
      }
      $sql .=")  ENGINE=InnoDB DEFAULT CHARSET=utf8;";
      break;
    case "pgsql":
      $sql = "CREATE TABLE \"$this->tableprefix$this->table\" (\n";
      $i = 0;
      foreach ($this->fields as $field=>$params)
      {
        if ($i > 0)
          $sql .= ",\n";
        // Name of field
        $sql .= "\"$field\" ";
        if (in_array ("autoincrement", $params))
          $sql .= "SERIAL";
        else
        {
          // Type of field : in $params[0]
          if (!isset ($params[0]))
            throw new Exception (sprintf (
                                 dgettext("domframework",
                                 "No database type defined for field '%s'"),
                                 $field), 500);
          switch ($params[0])
          {
          case "integer":
            $sql .= "INTEGER";
            $params  = array_slice ($params, 1);
            break;
          case "varchar":
            if (!isset ($params[1]))
              throw new Exception (sprintf (
                                   dgettext("domframework",
                                   "No Size provided for varchar field '%s'"),
                                   $field), 500);
            $sql .= "VARCHAR(".$params[1].")";
            $params  = array_slice ($params, 2);
            break;
          case "datetime":
            $sql .= "timestamp with time zone";
            $params  = array_slice ($params, 1);
            break;
        case "date":
          $sql .= "DATE";
          $params  = array_slice ($params, 1);
          break;
          default:
            throw new Exception (sprintf (
                                 dgettext("domframework",
                                 "Unknown type provided for field '%s'"),
                                 $field), 500);
          }
          // Primary key
          if ($this->primary === $field)
            $sql .= " PRIMARY KEY";
          // Others parameters for field
          // Sort to put the autoincrement field in front of params, if it is
          // present
          sort ($params);
          foreach ($params as $p)
          {
            switch ($p)
            {
            case "not null": $sql .= " NOT NULL"; break;
            default:
              throw new Exception (sprintf (
                                   dgettext("domframework",
                                "Unknown additionnal parameter for field '%s'"),
                                   $field), 500);
            }
          }
        }
        $i ++;
      }
      // Unique fields
      if ($this->unique !== null)
      {
        foreach ($this->unique as $u)
        {
          $sql .= ",\n  UNIQUE (\"";
          if (is_array ($u))
            $sql .=implode ("\",\"", $u);
          else
            $sql .= $u;
          $sql .="\")";
        }
      }
      // Foreign keys
      $i = 0;
      foreach ($this->foreign as $field=>$k)
      {
        $sql .= ",\n  FOREIGN KEY(\"$field\") REFERENCES \"".$k[0]."\"(\"".
                $k[1]."\")";
        if (isset ($k[2]))
          $sql .= " ".$k[2];
        if ($i > 0)
          $sql .= ",";
        $i++;
      }
      $sql .=")";
      break;
    default:
      throw new Exception (dgettext("domframework",
                           "PDO Engine not supported in dbLayer"), 500);
    }

    if ($this->debug)
      echo "$sql\n";
    return $this->exec($sql);
  }

  /** This function permit to send a SQL request to the database to do a SELECT
      Return the an array with the datas */
  public function directRead ($sql)
  {
    if ($this->debug) echo "== Entering directRead\n";
    $st = $this->prepare ($sql);
    $st->execute ();
    $res = array ();
    while ($d = $st->fetch (PDO::FETCH_ASSOC))
      $res[] = $d;
    return $res;
  }

  /** Hook preinsert
      This hook is run before inserting a new data in the database, after the 
      verification 
      @param array the data to insert in the database
      @return the modified datas */
  public function hookpreinsert ($data)
  {
    return $data;
  }

  /** Hook postinsert
      This hook is run after successfuly insert a new data in the database
      @return the modified lastID */
  public function hookpostinsert ($data, $lastID)
  {
    return $lastID;
  }

  /** Hook preupdate
      This hook is run before updating a data in the database, after the 
      verification 
      @return the modified datas */
  public function hookpreupdate ($updatekey, $data)
  {
    return $data;
  }

  /** Hook postupdate
      This hook is run after successfuly update a data in the database
      @return the modified $nbLinesUpdated */
  public function hookpostupdate ($updatekey, $data, $nbLinesUpdated)
  {
    return $nbLinesUpdated;
  }

  /** Hook predelete
      This hook is run before deleting a data in the database
      @return the modified $deletekey */
  public function hookpredelete ($deletekey)
  {
    return $deletekey;
  }

  /** Hook postdelete
      This hook is run after successfuly deleting a data in the database
      @return $nbLinesUpdated */
  public function hookpostdelete ($deletekey, $nbLinesDeleted)
  {
    return $nbLinesDeleted;
  }
}

/** POC :
error_reporting (E_ALL);
require_once  ("domframework/dbLayer.php");
class zone extends dbLayer
{
  // The database must be initialized with
  // CREATE TABLE `dns_zones` (id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
  //                           zone VARCHAR(255) NOT NULL,
  //                           viewname VARCHAR(255),
  //                           viewclients VARCHAR(255),
  //                           comment VARCHAR(1024),
  //                           opendate DATETIME NOT NULL,
  //                           closedate DATETIME,
  //                           UNIQUE (zone,viewname));
  protected $table = "dns_zones";
  protected $fields = array (
    "id"=>array ("integer", "not null", "autoincrement"),
    "zone"=>array ("varchar", "255", "not null"),
    "viewname"=>array ("varchar", "255"),
    "viewclients"=>array ("varchar", "255"),
    "comment"=>array ("varchar", "1024"),
    "opendate"=>array ("datetime", "not null"),
    "closedate"=>array ("datetime"),
  );
  protected $primary = "id";
  protected $unique = array ("id", array ("zone", "viewname"));
}

ini_set ("date.timezone", "Europe/Paris");
$zone = new zone ("sqlite:datas/database.db");
$last = $zone->create (array ("zone"=>"testZone",
                              "opendate"=>date("Y-m-d H:i:s")));
//print_r ($zone->read ());
$zone->update (2040, array ("zone"=>"testZone2"));
print_r ($zone->delete ($last));
*/