<?php

require_once 'Interface/DBSchema_Driver.php';

class MTrackDBSchema_Generic implements IMTrackDBSchema_Driver {
  var $db;
  var $typemap = array();

  function setDB(PDO $db) {
    $this->db = $db;
  }

  function determineVersion() {
    //echo "RUNNING QUERY";
    try {
      $q = $this->db->query('select version from mtrack_schema');
      if ($q) {
        foreach ($q as $row) {
          return $row[0];
        }
      }
    } catch (Exception $e) {
       // print_r($e->toString());
    }
    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)) {
      if (!strlen($f->default)) {
        $str .= " DEFAULT ''";
      } else {
        $str .= " DEFAULT $f->default";
      }
    }
    return $str;
  }

  function computeIndexCreate($table, $k) {
    switch ($k->type) {
      case 'unique':
        $kt = ' UNIQUE ';
        break;
      case 'multiple':
      default:
        $kt = '';
    }
    return "CREATE $kt INDEX $k->name on $table->name (" . join(', ', $k->fields) . ")";
  }

  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 $k) {
            if ($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);

    if (is_array($table->keys)) foreach ($table->keys as $k) {
      if ($k->type == 'primary') continue;
      $this->db->exec();
    }
  }

  function alterTable(MTrackDBSchema_Table $from, MTrackDBSchema_Table $to)
  {
    /* if keys have changed, we drop the old key definitions before changing the columns */

    echo "Need to alter $from->name\n";
    throw new Exception("bang!");
  }

  function dropTable(MTrackDBSchema_Table $table)
  {
    echo "Drop $table->name\n";
    $this->db->exec("drop table $table->name");
  }
}