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/*
* Copyright 2021 Kári Magnússon
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package kuzminki.render
import kuzminki.api.{Model, Join, KuzminkiError}
import kuzminki.column.ColInfo
sealed trait Prefix {
import Prefix.az
val prefixWrap = "\"%s\".\"%s\""
val tableWrap = "\"%s\" \"%s\""
def pick(info: ColInfo): String
def table(table: String): String
def forSubquery(prefix: Prefix): Prefix
def next(char: String) = {
val az = Prefix.az
az(az.indexOf(char) + 1)
}
def next2(char: String) = {
val az = Prefix.az
az(az.indexOf(char) + 2)
}
}
object Prefix {
def az = Vector("a", "b", "c", "d",
"e", "f", "g", "h",
"i", "k", "l", "m",
"n", "o", "p", "q",
"r", "s", "t", "v",
"x", "y", "z")
def forModel[M <: Model](model: M) =
new ModelPrefix(model.__name)
def forJoin[A <: Model, B <: Model](join: Join[A, B]): Prefix =
new JoinPrefix(join.a.__name, join.b.__name, "a", "b")
}
case class ModelPrefix(table: String) extends Prefix with Wrap {
def pick(info: ColInfo) = wrap(info.name)
def table(table: String) = wrap(table)
def forSubquery(prefix: Prefix) = prefix match {
case ModelPrefix(_) => new SubqueryPrefix(table, "a")
case SubqueryPrefix(_, last) => new SubqueryPrefix(table, next(last))
case JoinPrefix(_, _, _, last) => new SubqueryPrefix(table, next(last))
}
}
case class SubqueryPrefix(table: String, c: String) extends Prefix {
def pick(info: ColInfo) = prefixWrap.format(c, info.name)
def table(table: String) = tableWrap.format(table, c)
def forSubquery(prefix: Prefix) = prefix match {
case ModelPrefix(_) => new SubqueryPrefix(table, next(c))
case SubqueryPrefix(_, last) => new SubqueryPrefix(table, next(last))
case JoinPrefix(_, _, _, last) => new SubqueryPrefix(table, next(last))
}
}
case class JoinPrefix(tableA: String, tableB: String, a: String, b: String) extends Prefix {
def pick(info: ColInfo) = info match {
case ColInfo(name, table) if info.table == tableA =>
prefixWrap.format(a, name)
case ColInfo(name, table) if info.table == tableB =>
prefixWrap.format(b, name)
case ColInfo(name, table) =>
throw KuzminkiError(
s"column $name of table $table is not found in join($tableA, $tableB)"
)
}
def table(table: String) = table match {
case table if table == tableA =>
tableWrap.format(table, a)
case table if table == tableB =>
tableWrap.format(table, b)
case table =>
throw KuzminkiError(
s"table $table is not a member of join($tableA, $tableB)"
)
}
def forSubquery(prefix: Prefix) = {
val (na, nb) = prefix match {
case ModelPrefix(_) => (a, b)
case SubqueryPrefix(_, last) => (next(last), next2(last))
case JoinPrefix(_, _, la, lb) => (next2(la), next2(lb))
}
JoinPrefix(tableA, tableB, na, nb)
}
}
