import slick.codegen.SourceCodeGenerator
import slick.{model => m}

class TypedIdSourceCodeGenerator(
    singleSchemaModel: m.Model,
    databaseModel: m.Model,
    idType: Option[String],
    manualForeignKeys: Map[(String, String), (String, String)]
) extends SourceCodeGenerator(singleSchemaModel) {
  val manualReferences =
    SchemaParser.references(databaseModel, manualForeignKeys)

  val modelTypeToColumnMaper = Map(
    "java.util.UUID" -> "uuidKeyMapper",
    "String" -> "naturalKeyMapper",
    "Int" -> "serialKeyMapper"
  )

  val keyReferences: Map[m.Column, m.Column] = {
    val pks = databaseModel.tables.flatMap(_.columns)
      .filter(_.options.contains(slick.ast.ColumnOption.PrimaryKey))
      .map(c => (c -> c))

    val fks: Seq[(m.Column, m.Column)] = databaseModel.tables.flatMap(_.foreignKeys)
      .filter(_.referencedColumns.length == 1)
      .filter(_.referencedColumns.forall(
        _.options.contains(slick.ast.ColumnOption.PrimaryKey)))
      .flatMap(fk =>
      fk.referencingColumns.flatMap(from =>
        fk.referencedColumns.headOption.map(to => (from -> to))))

    (pks ++ fks).toMap
  }

  def pKeyTypeTag(columnRef: m.Column): String = {
    val schemaName = columnRef.table.schema.getOrElse("`public`")
    val tableName = entityName(columnRef.table.table)
    s"$schemaName.$tableName"
  }

  def pKeyType(columnRef: m.Column): String = {
    s"${idType.getOrElse("Id")}[${pKeyTypeTag(columnRef)}]"
  }

  class TypedIdTable(model: m.Table) extends Table(model) {
    class TypedIdColumn(override val model: m.Column) extends Column(model) {
      override def rawType: String = {
        keyReferences.get(model).fold(super.rawType)(pKeyType)
      }
    }

    class TypedIdPrimaryKey(override val model: m.PrimaryKey) extends PrimaryKey(model) { primaryKey =>
      def `super.code` = s"""val $name = primaryKey("$dbName", ${compoundValue(columns.map(_.name))})"""

      override def code = {
        val implicitKeyBaseMapper =
        primaryKey.columns.headOption
          .filter(_ => primaryKey.columns.length == 1)
          .map { column =>
            val name = termName(column.rawName + "KeyMapper")
            val tpe = s"BaseColumnType[column.rawName]"
            val mapping = s"${modelTypeToColumnMaper(column.model.tpe)}[${pKeyTypeTag(column.model)}]"
            s"implicit def $name: $tpe = $mapping\n"
        }
        implicitKeyBaseMapper.fold(super.code)(super.code + _)
      }
    }
  }
}