<?php


require_once 'DBSchema/Generic.php';

class MTrackDBSchema_mysql extends MTrackDBSchema_Generic 
{
    var $typemap = array(
        'autoinc' =>  'INT(11) NOT NULL AUTO_INCREMENT',
        'timestamp' => 'datetime',
        'blob' => 'longtext', // eak what blob is stored?
        'text' => 'VARCHAR(128)',
    );


    function determineVersion() {
        $ret = parent::determineVersion();
        if ($ret) {
            return $ret;
        }
        parse_str(str_replace(array(";",":"), "&", $this->db->dsn), $dsn);
        
        try {
            $this->db->query("CREATE DATABASE {$dsn['dbname']}");
        } catch (Exception $e) {
            // technically this should not get here..
            // as pdo's dsn design is borked..
        }
         
         
        // assume we need to create database..
        return null;
    }
    
    
    function computeFieldCreate($f)
    {
        $str = "\t`$f->name` ";
        $str .= isset($this->typemap[$f->type]) ? $this->typemap[$f->type] : $f->type;
        if (isset($f->nullable) && $f->nullable == '0') {
          $str .= ' NOT NULL ';
        }
        if (!isset($f->default)) {
            return $str;
        }
        if (!strlen($f->default)) {
            return $str . " DEFAULT ''";
        }
        
        return $str . ($f->default == 'CURRENT_TIMESTAMP' ? '' : 'DEFAULT '. $f->default);
    }
    
    // may as well rewrite this.. as we have too loop throug hit anyway..
    function createTable(MTrackDBSchema_Table $table)
    {
        echo "Create $table->name\n";

        $pri_key = null;
        $sql = array();
        foreach ($table->fields as $f) {
          if ($f->type == 'autoinc') {
            $pri_key = $f->name;
            
          }
          $str = $this->computeFieldCreate($f);
          $sql[] = $str;
        }
        if (is_array($table->keys)) {
            
            foreach ($table->keys as $kn=>$k) {
              if ($k->type != 'primary') continue;
             //   if ($pri_key !== null) continue;
                $sql[] = "\tprimary key (`" . join('`, `', $k->fields) . "`)";
            }
        }

        $sql = "CREATE TABLE $table->name (\n" .
          join(",\n", $sql) .
          ")\n";

        echo $sql;

        $this->db->exec($sql);
    }
  function alterTable(MTrackDBSchema_Table $from, MTrackDBSchema_Table $to)
  {
    $sql = array();
    $actions = array();
    
    //print_r($to);
    /* if keys have changed, we drop the old key definitions before changing the columns */
    if (is_array($from->keys)) foreach ($from->keys as $k) {
      if (!isset($to->keys[$k->name]) || $to->keys[$k->name] != $k) {
        if ($k->type == 'primary') {
          $actions[] = "DROP PRIMARY KEY";
        } else {
          $actions[] = "DROP INDEX $k->name";
        }
      }
    }

    foreach ($from->fields as $f) {
        
        if (isset($to->fields[$f->name])) {
            continue;
        }
        // let's check to see if it got renamed..
        $found = false;
        foreach($to->fields as $ff) {
            
            if ($ff->oldname == $f->name) {
                $actions[] = "CHANGE COLUMN `$f->name` " .  $this->computeFieldCreate($ff);
                unset($to->fields[$ff->name]);
                $found = true;
            }
        }
        if ($found) continue;
        $actions[] = "DROP COLUMN $f->name";
         
      
    }
    foreach ($to->fields as $f) {
      if (isset($from->fields[$f->name])) continue;
      $actions[] = "ADD COLUMN " . $this->computeFieldCreate($f);
    }

    /* changed and new keys */
    if (is_array($from->keys)) foreach ($from->keys as $k) {
      if (isset($to->keys[$k->name]) && $to->keys[$k->name] != $k) {
        if ($k->type == 'primary') {
          $actions[] = "ADD primary key (" . join(', ', $k->fields) . ")";
        } else {
          $sql[] = $this->computeIndexCreate($to, $k);
        }
      }
    }
    if (is_array($to->keys)) foreach ($to->keys as $k) {
      if (isset($from->keys[$k->name])) continue;
      if ($k->type == 'primary') {
        $actions[] = "ADD primary key (" . join(', ', $k->fields) . ")";
      } else {
        $sql[] = $this->computeIndexCreate($to, $k);
      }
    }

    if (count($actions)) {
      $sql[] = "ALTER TABLE $from->name " . join(",\n", $actions);
    }
    echo "Need to alter $from->name\n";
    echo "SQL:\n";
    var_dump($sql);
    foreach ($sql as $s) {
      $this->db->exec($s);
    }
  }
}