From 988367a2817155ee9d7d519711d6ca46025aa1aa Mon Sep 17 00:00:00 2001
From: eikek <eike.kettner@posteo.de>
Date: Sat, 26 Jun 2021 21:12:02 +0200
Subject: [PATCH] Extend query builder to compare results from subselects

---
 .../main/scala/docspell/store/qb/Condition.scala    |  3 +++
 .../src/main/scala/docspell/store/qb/DSL.scala      | 13 +++++++++++++
 .../docspell/store/qb/impl/ConditionBuilder.scala   | 13 +++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/modules/store/src/main/scala/docspell/store/qb/Condition.scala b/modules/store/src/main/scala/docspell/store/qb/Condition.scala
index 9a329033..cfe156a2 100644
--- a/modules/store/src/main/scala/docspell/store/qb/Condition.scala
+++ b/modules/store/src/main/scala/docspell/store/qb/Condition.scala
@@ -19,6 +19,9 @@ object Condition {
       val P: Put[A]
   ) extends Condition
 
+  case class CompareSelect(sel: SelectExpr, op: Operator, subSelect: Select)
+      extends Condition
+
   case class CompareCol[A](col1: Column[A], op: Operator, col2: Column[A])
       extends Condition
 
diff --git a/modules/store/src/main/scala/docspell/store/qb/DSL.scala b/modules/store/src/main/scala/docspell/store/qb/DSL.scala
index d6f32d9c..671d4e71 100644
--- a/modules/store/src/main/scala/docspell/store/qb/DSL.scala
+++ b/modules/store/src/main/scala/docspell/store/qb/DSL.scala
@@ -215,6 +215,19 @@ trait DSL extends DoobieMeta {
     def in(subsel: Select): Condition =
       Condition.InSubSelect(col, subsel)
 
+    def >(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Gt, subsel)
+    def <(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Lt, subsel)
+    def >=(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Gte, subsel)
+    def <=(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Lte, subsel)
+    def ===(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Eq, subsel)
+    def !==(subsel: Select): Condition =
+      Condition.CompareSelect(col.s, Operator.Neq, subsel)
+
     def notIn(subsel: Select): Condition =
       in(subsel).negate
 
diff --git a/modules/store/src/main/scala/docspell/store/qb/impl/ConditionBuilder.scala b/modules/store/src/main/scala/docspell/store/qb/impl/ConditionBuilder.scala
index c9e50575..665ca476 100644
--- a/modules/store/src/main/scala/docspell/store/qb/impl/ConditionBuilder.scala
+++ b/modules/store/src/main/scala/docspell/store/qb/impl/ConditionBuilder.scala
@@ -100,6 +100,19 @@ object ConditionBuilder {
         }
         c1Frag ++ operator(op) ++ c2Frag
 
+      case Condition.CompareSelect(col, op, subsel) =>
+        val opFrag = operator(op)
+        val colFrag = op match {
+          case Operator.LowerLike =>
+            lower(col)
+          case Operator.LowerEq =>
+            lower(col)
+          case _ =>
+            SelectExprBuilder.build(col)
+        }
+        val sub = SelectBuilder(subsel)
+        colFrag ++ opFrag ++ sql"(" ++ sub ++ sql")"
+
       case Condition.InSubSelect(col, subsel) =>
         val sub = SelectBuilder(subsel)
         SelectExprBuilder.column(col) ++ sql" IN (" ++ sub ++ parenClose