From cdd47315643f3051d0c9e74487944641b797828c Mon Sep 17 00:00:00 2001
From: xuwei-k <6b656e6a69@gmail.com>
Date: Thu, 8 Jun 2023 08:25:13 +0900
Subject: [PATCH] RemoveIf

---
 input/src/main/scala/fix/RemoveIfTest.scala  | 43 ++++++++++++
 output/src/main/scala/fix/RemoveIfTest.scala | 23 +++++++
 rules/src/main/scala/fix/RemoveIf.scala      | 70 ++++++++++++++++++++
 3 files changed, 136 insertions(+)
 create mode 100644 input/src/main/scala/fix/RemoveIfTest.scala
 create mode 100644 output/src/main/scala/fix/RemoveIfTest.scala
 create mode 100644 rules/src/main/scala/fix/RemoveIf.scala

diff --git a/input/src/main/scala/fix/RemoveIfTest.scala b/input/src/main/scala/fix/RemoveIfTest.scala
new file mode 100644
index 0000000..5da6df2
--- /dev/null
+++ b/input/src/main/scala/fix/RemoveIfTest.scala
@@ -0,0 +1,43 @@
+/*
+rule = RemoveIf
+ */
+package fix
+
+class RemoveIfTest {
+  def f1[A](a1: A, a2: A): Boolean = {
+    if (a1 == a2) {
+      true
+    } else {
+      false
+    }
+  }
+
+  def f2[A](a1: A, a2: A): Boolean = {
+    if (a1 != a2) {
+      false
+    } else {
+      true
+    }
+  }
+
+  def f3[A](a1: A, a2: A): Boolean = {
+    if (a1 == a2)
+      false
+    else
+      true
+  }
+
+  def f4[A](a1: Seq[A]): Boolean = {
+    if (a1.isEmpty)
+      true
+    else
+      false
+  }
+
+  def f5[A](a1: Seq[A]): Boolean = {
+    if (a1.nonEmpty)
+      false
+    else
+      true
+  }
+}
diff --git a/output/src/main/scala/fix/RemoveIfTest.scala b/output/src/main/scala/fix/RemoveIfTest.scala
new file mode 100644
index 0000000..10c1ce3
--- /dev/null
+++ b/output/src/main/scala/fix/RemoveIfTest.scala
@@ -0,0 +1,23 @@
+package fix
+
+class RemoveIfTest {
+  def f1[A](a1: A, a2: A): Boolean = {
+    a1 == a2
+  }
+
+  def f2[A](a1: A, a2: A): Boolean = {
+    a1 == a2
+  }
+
+  def f3[A](a1: A, a2: A): Boolean = {
+    a1 != a2
+  }
+
+  def f4[A](a1: Seq[A]): Boolean = {
+    a1.isEmpty
+  }
+
+  def f5[A](a1: Seq[A]): Boolean = {
+    a1.isEmpty
+  }
+}
diff --git a/rules/src/main/scala/fix/RemoveIf.scala b/rules/src/main/scala/fix/RemoveIf.scala
new file mode 100644
index 0000000..0ec056c
--- /dev/null
+++ b/rules/src/main/scala/fix/RemoveIf.scala
@@ -0,0 +1,70 @@
+package fix
+
+import scala.meta.Lit
+import scala.meta.Term
+import scalafix.Patch
+import scalafix.v1.SyntacticDocument
+import scalafix.v1.SyntacticRule
+
+object RemoveIf {
+  object True {
+    def unapply(t: Term): Boolean = PartialFunction.cond(t) {
+      case Lit.Boolean(true) =>
+        true
+      case Term.Block(Lit.Boolean(true) :: Nil) =>
+        true
+    }
+  }
+
+  object False {
+    def unapply(t: Term): Boolean = PartialFunction.cond(t) {
+      case Lit.Boolean(false) =>
+        true
+      case Term.Block(Lit.Boolean(false) :: Nil) =>
+        true
+    }
+  }
+}
+
+class RemoveIf extends SyntacticRule("RemoveIf") {
+  override def fix(implicit doc: SyntacticDocument): Patch = {
+    doc.tree.collect {
+      case x @ Term.If.After_4_4_0(
+            cond,
+            RemoveIf.True(),
+            RemoveIf.False(),
+            _
+          ) =>
+        Patch.replaceTree(x, cond.toString)
+      case x @ Term.If.After_4_4_0(cond, RemoveIf.False(), RemoveIf.True(), _) =>
+        cond match {
+          case Term.ApplyInfix.Initial(
+                a1,
+                Term.Name("=="),
+                _,
+                a2 :: Nil
+              ) =>
+            Patch.replaceTree(x, s"${a1} != ${a2}")
+          case Term.ApplyInfix.Initial(
+                a1,
+                Term.Name("!="),
+                _,
+                a2 :: Nil
+              ) =>
+            Patch.replaceTree(x, s"${a1} == ${a2}")
+          case Term.Select(
+                a1,
+                Term.Name("isEmpty")
+              ) =>
+            Patch.replaceTree(x, s"${a1}.nonEmpty")
+          case Term.Select(
+                a1,
+                Term.Name("nonEmpty")
+              ) =>
+            Patch.replaceTree(x, s"${a1}.isEmpty")
+          case _ =>
+            Patch.replaceTree(x, s"!($cond)")
+        }
+    }.asPatch
+  }
+}