import net.liftweb.util.Helpers.{snakify, tryo}

import org.squeryl.{Schema, Session, Table}

import org.squeryl.internals.StatementWriter

import scala.collection.mutable.ListBuffer

  val entityTableName = "entity"

  val entities = new Table[EntityUnion](entityTableName) {

    val tables = new ListBuffer[String]

  }

  val codeListItems = entityTable[CodeListItem]("code_list_item")

  override def tableNameFromClass(c: Class[_]): String =

    snakify(c.getSimpleName)

  protected def entityTable[T <: Entity[_]](name: String)(implicit manifestT:

    Manifest[T]): Table[T] = {

    val tbl = table(name)(manifestT)

    on(tbl) { t => declare(t.id.is(autoIncremented("entity_id_seq"))) }

    entities.tables += name

    tbl

  }

  override def create = {

    table[EntityUnion](entityTableName) // register entity table as the last one

    super.create

  }

  override protected def drop = {

    val dba = Session.currentSession.databaseAdapter

    val sw = new StatementWriter(dba)

    sw.write("drop view " + entityTableName + " cascade")

    ex(sw)

    super.drop

  }

  private def ex(sw: StatementWriter) = {

    val sql = sw.statement

    val cs = Session.currentSession

    cs.log(sql)

    val s = cs.connection.createStatement

    tryo { s.execute(sql) }

    tryo { s.close }

class EntityViewH2Adapter extends SeqIdH2Adapter {

  override def writeCreateTable[T](t: Table[T], sw: StatementWriter,

    schema: Schema) = schema match {

    case sch: BaseSchema if t.name == sch.entityTableName =>

      sw.write("create view " + t.name + " as ")

      val it = sch.entities.tables.iterator

      while (it.hasNext) {

        sw.write("select id, name, note from " + it.next)

        if (it.hasNext)

          sw.write(" union ")

      }

    case _ => super.writeCreateTable(t, sw, schema)

  }

}