From aaaa0c0c68aec3937410d85a8680244e53e178c1 Mon Sep 17 00:00:00 2001
From: Graham <gpe@openrs2.dev>
Date: Sat, 7 Mar 2020 16:18:07 +0000
Subject: [PATCH] Fix appending fields to javax.media.opengl.GL

Signed-off-by: Graham <gpe@openrs2.dev>
---
 .../ast/transform/GlConstantTransformer.kt    | 47 ++++++++++++++++---
 1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/GlConstantTransformer.kt b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/GlConstantTransformer.kt
index 2f3e55d5..371fe8b2 100644
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/GlConstantTransformer.kt
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/GlConstantTransformer.kt
@@ -60,14 +60,13 @@ class GlConstantTransformer : Transformer() {
         val glUnit = units[GL_CLASS] ?: return
         val glInterface = glUnit.primaryType.get()
 
-        // remove existing declarations first to maintain sort order
-        for (enum in enums) {
-            val declaration = glInterface.getFieldByName(enum.name)
-            declaration.ifPresent { it.remove() }
-        }
+        // add missing fields
+        val fields = enums.filter { !glInterface.getFieldByName(it.name).isPresent }
+            .map { it.toDeclaration() }
+        glInterface.members.addAll(fields)
 
-        val fields = enums.sortedBy(GlEnum::value).map { it.toDeclaration() }
-        glInterface.members.addAll(0, fields)
+        // sort fields by value for consistency
+        glInterface.members.sortWith(FIELD_METHOD_COMPARATOR.thenComparing(GL_FIELD_VALUE_COMPARATOR))
     }
 
     private fun transformCall(unit: CompilationUnit, expr: MethodCallExpr) {
@@ -203,5 +202,39 @@ class GlConstantTransformer : Transformer() {
         private const val GL_CLASS = "javax.media.opengl.$GL_CLASS_UNQUALIFIED"
         private val REGISTRY = GlRegistry.parse()
         private val VENDORS = setOf("ARB", "EXT")
+
+        private val FIELD_METHOD_COMPARATOR = Comparator<BodyDeclaration<*>> { a, b ->
+            when {
+                a.isFieldDeclaration && !b.isFieldDeclaration -> -1
+                !a.isFieldDeclaration && b.isFieldDeclaration -> 1
+                else -> 0
+            }
+        }
+
+        private fun BodyDeclaration<*>.getIntValue(): Int? {
+            if (!isFieldDeclaration) {
+                return null
+            }
+
+            val variable = asFieldDeclaration().variables.firstOrNull() ?: return null
+            return variable.initializer.map {
+                if (it.isIntegerLiteralExpr) {
+                    it.asIntegerLiteralExpr().checkedAsInt()
+                } else {
+                    null
+                }
+            }.orElse(null)
+        }
+
+        private val GL_FIELD_VALUE_COMPARATOR = Comparator<BodyDeclaration<*>> { a, b ->
+            val aValue = a.getIntValue()
+            val bValue = b.getIntValue()
+            when {
+                aValue != null && bValue != null -> aValue - bValue
+                aValue != null && bValue == null -> -1
+                aValue == null && bValue != null -> 1
+                else -> 0
+            }
+        }
     }
 }