From e0ebc7fc328c101d6fc20d64186e5ab5921f4e98 Mon Sep 17 00:00:00 2001
From: TheBrokenRail <connor24nolan@live.com>
Date: Sun, 6 Mar 2022 22:43:42 -0500
Subject: [PATCH] Fix Furnace Not Checking Item Auxiliary

---
 .../available-feature-flags                   |  1 +
 mods/src/misc/misc.c                          | 39 +++++++++++++++++++
 symbols/include/symbols/minecraft.h           | 12 ++++++
 3 files changed, 52 insertions(+)

diff --git a/launcher/client-data/lib/minecraft-pi-reborn-client/available-feature-flags b/launcher/client-data/lib/minecraft-pi-reborn-client/available-feature-flags
index c8b5788..fc49887 100644
--- a/launcher/client-data/lib/minecraft-pi-reborn-client/available-feature-flags
+++ b/launcher/client-data/lib/minecraft-pi-reborn-client/available-feature-flags
@@ -30,3 +30,4 @@ TRUE Load Language Files
 TRUE Implement Sound Engine
 TRUE Close Current Screen On Death
 FALSE Disable Raw Mouse Motion (Not Recommended)
+TRUE Fix Furnace Not Checking Item Auxiliary
diff --git a/mods/src/misc/misc.c b/mods/src/misc/misc.c
index 16c8ced..b00a070 100644
--- a/mods/src/misc/misc.c
+++ b/mods/src/misc/misc.c
@@ -145,6 +145,40 @@ static void LocalPlayer_die_injection(unsigned char *entity, unsigned char *caus
     (*LocalPlayer_die)(entity, cause);
 }
 
+// Fix Furnace Not Checking Item Auxiliary When Inserting New Item
+static int32_t FurnaceScreen_handleAddItem_injection(unsigned char *furnace_screen, int32_t slot, ItemInstance const *item) {
+    // Get Existing Item
+    unsigned char *tile_entity = *(unsigned char **) (furnace_screen + FurnaceScreen_tile_entity_property_offset);
+    unsigned char *tile_entity_vtable = *(unsigned char **) tile_entity;
+    FurnaceTileEntity_getItem_t FurnaceTileEntity_getItem = *(FurnaceTileEntity_getItem_t *) (tile_entity_vtable + FurnaceTileEntity_getItem_vtable_offset);
+    ItemInstance *existing_item = (*FurnaceTileEntity_getItem)(tile_entity, slot);
+
+    // Check Item
+    int valid;
+    if (item->id == existing_item->id && item->auxiliary == existing_item->auxiliary) {
+        // Item Matches, Is Valid
+        valid = 1;
+    } else {
+        // Item Doesn't Match, Check If Existing Item Is Empty
+        if ((existing_item->id | existing_item->count | existing_item->auxiliary) == 0) {
+            // Existing Item Is Empty, Is Valid
+            valid = 1;
+        } else {
+            // Existing Item Isn't Empty, Isn't Valid
+            valid = 0;
+        }
+    }
+
+    // Call Original Method
+    if (valid) {
+        // Valid
+        return (*FurnaceScreen_handleAddItem)(furnace_screen, slot, item);
+    } else {
+        // Invalid
+        return 0;
+    }
+}
+
 // Init
 void init_misc() {
     // Remove Invalid Item Background (A Red Background That Appears For Items That Are Not Included In The gui_blocks Atlas)
@@ -177,6 +211,11 @@ void init_misc() {
         patch_address(LocalPlayer_die_vtable_addr, (void *) LocalPlayer_die_injection);
     }
 
+    // Fix Furnace Not Checking Item Auxiliary When Inserting New Item
+    if (feature_has("Fix Furnace Not Checking Item Auxiliary", 1)) {
+        overwrite_calls((void *) FurnaceScreen_handleAddItem, (void *) FurnaceScreen_handleAddItem_injection);
+    }
+
     // Init C++ And Logging
     _init_misc_cpp();
     _init_misc_logging();
diff --git a/symbols/include/symbols/minecraft.h b/symbols/include/symbols/minecraft.h
index 334a4eb..5e79e10 100644
--- a/symbols/include/symbols/minecraft.h
+++ b/symbols/include/symbols/minecraft.h
@@ -401,6 +401,18 @@ static ProgressScreen_t ProgressScreen = (ProgressScreen_t) 0x37044;
 
 static void *OptionsScreen_handleBackEvent_vtable_addr = (void *) 0x10499c;
 
+// FurnaceScreen
+
+typedef int32_t (*FurnaceScreen_handleAddItem_t)(unsigned char *furnace_screen, int32_t slot, ItemInstance const *item);
+static FurnaceScreen_handleAddItem_t FurnaceScreen_handleAddItem = (FurnaceScreen_handleAddItem_t) 0x327a0;
+
+static uint32_t FurnaceScreen_tile_entity_property_offset = 0x1d0; // FurnaceTileEntity *
+
+// FurnaceTileEntity
+
+typedef ItemInstance *(*FurnaceTileEntity_getItem_t)(unsigned char *furnace_tile_entity, int32_t slot);
+static uint32_t FurnaceTileEntity_getItem_vtable_offset = 0x2c;
+
 // Screen
 
 typedef void (*Screen_updateEvents_t)(unsigned char *screen);