Implement Entity.index() method for Issue #73

Added index() method to Entity class that returns the entity's
position in its parent grid's entity collection. This enables
proper entity removal patterns using entity.index().

ROADMAP.md

@@ -189,11 +189,21 @@ Created comprehensive test suite with 13 tests covering all Python-exposed metho
 
 ### Phase 1: Foundation Stabilization (1-2 weeks)
 ```
-1. Fix Grid Segfault - CRITICAL: Unblocks all Grid functionality
-2. Fix #78 Middle Mouse Click bug - Confirmed event handling issue
-3. Fix Entity/Sprite property setters - Multiple Python binding errors
-4. Critical Bugfixes (#77, #74, #37) - Fix remaining pain points
-5. Alpha Blockers (#3, #2) - Remove deprecated methods
+✅ COMPLETE AS OF 2025-01-03:
+1. ✅ Fix Grid Segfault - Grid now supports None/null textures
+2. ✅ Fix #78 Middle Mouse Click bug - Event type checking added
+3. ✅ Fix Entity/Sprite property setters - PyVector conversion fixed
+4. ✅ Fix #77 - Error message copy/paste bug fixed
+5. ✅ Fix #74 - Grid.grid_y property added
+6. ✅ Fix keypressScene() validation - Now rejects non-callable
+7. ✅ Fix Sprite texture setter - No longer returns error without exception
+8. ✅ Fix PyVector x/y properties - Were returning None
+
+REMAINING IN PHASE 1:
+9. Fix #73 - Entity.index() method for removal
+10. Fix #27 - EntityCollection.extend() method
+11. Fix #33 - Sprite index validation
+12. Alpha Blockers (#3, #2) - Remove deprecated methods
 ```
 
 ### Phase 2: Alpha Release Preparation (4-6 weeks)  

quick_index_test.py

@@ -0,0 +1,12 @@
+import mcrfpy
+t = mcrfpy.Texture("assets/kenney_ice.png", 16, 16)
+g = mcrfpy.Grid(5, 5, t, (0, 0), (100, 100))
+e1 = mcrfpy.Entity((1, 1), t, 1, g)
+e2 = mcrfpy.Entity((2, 2), t, 2, g)
+g.entities.append(e1)
+g.entities.append(e2)
+print("Entity 1 index:", e1.index())
+print("Entity 2 index:", e2.index())
+# Test removal
+g.entities.remove(e1.index())
+print("After removal, Entity 2 index:", e2.index())

src/UIEntity.cpp

@@ -36,6 +36,33 @@ PyObject* UIEntity::at(PyUIEntityObject* self, PyObject* o) {
 
 }
 
+PyObject* UIEntity::index(PyUIEntityObject* self, PyObject* Py_UNUSED(ignored)) {
+    // Check if entity has an associated grid
+    if (!self->data || !self->data->grid) {
+        PyErr_SetString(PyExc_RuntimeError, "Entity is not associated with a grid");
+        return NULL;
+    }
+    
+    // Get the grid's entity collection
+    auto entities = self->data->grid->entities;
+    if (!entities) {
+        PyErr_SetString(PyExc_RuntimeError, "Grid has no entity collection");
+        return NULL;
+    }
+    
+    // Find this entity in the collection
+    int index = 0;
+    for (auto it = entities->begin(); it != entities->end(); ++it, ++index) {
+        if (it->get() == self->data.get()) {
+            return PyLong_FromLong(index);
+        }
+    }
+    
+    // Entity not found in its grid's collection
+    PyErr_SetString(PyExc_ValueError, "Entity not found in its grid's entity collection");
+    return NULL;
+}
+
 int UIEntity::init(PyUIEntityObject* self, PyObject* args, PyObject* kwds) {
     //static const char* keywords[] = { "x", "y", "texture", "sprite_index", "grid", nullptr };
     //float x = 0.0f, y = 0.0f, scale = 1.0f;
@@ -211,6 +238,7 @@ int UIEntity::set_spritenumber(PyUIEntityObject* self, PyObject* value, void* cl
 
 PyMethodDef UIEntity::methods[] = {
     {"at", (PyCFunction)UIEntity::at, METH_O},
+    {"index", (PyCFunction)UIEntity::index, METH_NOARGS, "Return the index of this entity in its grid's entity collection"},
     {NULL, NULL, 0, NULL}
 };
 

src/UIEntity.h

@@ -47,6 +47,7 @@ public:
     UIEntity(UIGrid&);
     
     static PyObject* at(PyUIEntityObject* self, PyObject* o);
+    static PyObject* index(PyUIEntityObject* self, PyObject* Py_UNUSED(ignored));
     static int init(PyUIEntityObject* self, PyObject* args, PyObject* kwds);
 
     static PyObject* get_position(PyUIEntityObject* self, void* closure);

tests/issue73_entity_index_test.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+"""
+Test for Issue #73: Entity.index() method for removal
+
+Verifies that Entity objects can report their index in the grid's entity collection.
+"""
+
+def test_entity_index(timer_name):
+    """Test that Entity.index() method works correctly"""
+    import mcrfpy
+    import sys
+    
+    print("Issue #73 test: Entity.index() method")
+    
+    # Create test scene and grid
+    mcrfpy.createScene("test")
+    ui = mcrfpy.sceneUI("test")
+    
+    # Create grid with texture
+    texture = mcrfpy.Texture("assets/kenney_ice.png", 16, 16)
+    grid = mcrfpy.Grid(10, 10, texture, (10, 10), (400, 400))
+    ui.append(grid)
+    
+    # Create multiple entities
+    entities = []
+    for i in range(5):
+        entity = mcrfpy.Entity((i, i), texture, i, grid)
+        entities.append(entity)
+        grid.entities.append(entity)
+    
+    print(f"✓ Created {len(entities)} entities")
+    
+    # Test 1: Check each entity knows its index
+    for expected_idx, entity in enumerate(entities):
+        try:
+            actual_idx = entity.index()
+            assert actual_idx == expected_idx, f"Expected index {expected_idx}, got {actual_idx}"
+            print(f"✓ Entity {expected_idx} correctly reports index {actual_idx}")
+        except Exception as e:
+            print(f"✗ Entity {expected_idx} index() failed: {e}")
+            raise
+    
+    # Test 2: Remove entity using index
+    entity_to_remove = entities[2]
+    remove_idx = entity_to_remove.index()
+    grid.entities.remove(remove_idx)
+    print(f"✓ Removed entity at index {remove_idx}")
+    
+    # Test 3: Verify indices updated after removal
+    for i, entity in enumerate(entities):
+        if i == 2:
+            # This entity was removed, should raise error
+            try:
+                idx = entity.index()
+                print(f"✗ Removed entity still reports index {idx}")
+            except ValueError as e:
+                print(f"✓ Removed entity correctly raises error: {e}")
+        elif i < 2:
+            # These entities should keep their indices
+            idx = entity.index()
+            assert idx == i, f"Entity before removal has wrong index: {idx}"
+        else:
+            # These entities should have shifted down by 1
+            idx = entity.index()
+            assert idx == i - 1, f"Entity after removal has wrong index: {idx}"
+    
+    # Test 4: Entity without grid
+    orphan_entity = mcrfpy.Entity((0, 0), texture, 0, None)
+    try:
+        idx = orphan_entity.index()
+        print(f"✗ Orphan entity should raise error but returned {idx}")
+    except RuntimeError as e:
+        print(f"✓ Orphan entity correctly raises error: {e}")
+    
+    # Test 5: Use index() in practical removal pattern
+    # Add some new entities
+    for i in range(3):
+        entity = mcrfpy.Entity((7+i, 7+i), texture, 10+i, grid)
+        grid.entities.append(entity)
+    
+    # Remove entities with sprite_number > 10
+    removed_count = 0
+    i = 0
+    while i < len(grid.entities):
+        entity = grid.entities[i]
+        if entity.sprite_number > 10:
+            grid.entities.remove(entity.index())
+            removed_count += 1
+            # Don't increment i, as entities shifted down
+        else:
+            i += 1
+    
+    print(f"✓ Removed {removed_count} entities using index() in loop")
+    assert len(grid.entities) == 5, f"Expected 5 entities remaining, got {len(grid.entities)}"
+    
+    print("\n✅ Issue #73 test PASSED - Entity.index() method works correctly")
+    sys.exit(0)
+
+# Execute the test after a short delay
+import mcrfpy
+mcrfpy.setTimer("test", test_entity_index, 100)

tests/issue73_simple_index_test.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+"""
+Simple test for Issue #73: Entity.index() method
+"""
+
+def test_entity_index(timer_name):
+    """Test that Entity.index() method works correctly"""
+    import mcrfpy
+    import sys
+    
+    print("Testing Entity.index() method...")
+    
+    # Create test scene and grid
+    mcrfpy.createScene("test")
+    ui = mcrfpy.sceneUI("test")
+    
+    # Create grid with texture
+    texture = mcrfpy.Texture("assets/kenney_ice.png", 16, 16)
+    grid = mcrfpy.Grid(10, 10, texture, (10, 10), (400, 400))
+    ui.append(grid)
+    
+    # Clear any existing entities
+    while len(grid.entities) > 0:
+        grid.entities.remove(0)
+    
+    # Create entities
+    entity1 = mcrfpy.Entity((1, 1), texture, 1, grid)
+    entity2 = mcrfpy.Entity((2, 2), texture, 2, grid)
+    entity3 = mcrfpy.Entity((3, 3), texture, 3, grid)
+    
+    grid.entities.append(entity1)
+    grid.entities.append(entity2)
+    grid.entities.append(entity3)
+    
+    print(f"Created {len(grid.entities)} entities")
+    
+    # Test index() method
+    idx1 = entity1.index()
+    idx2 = entity2.index()
+    idx3 = entity3.index()
+    
+    print(f"Entity 1 index: {idx1}")
+    print(f"Entity 2 index: {idx2}")
+    print(f"Entity 3 index: {idx3}")
+    
+    assert idx1 == 0, f"Entity 1 should be at index 0, got {idx1}"
+    assert idx2 == 1, f"Entity 2 should be at index 1, got {idx2}"
+    assert idx3 == 2, f"Entity 3 should be at index 2, got {idx3}"
+    
+    print("✓ All entities report correct indices")
+    
+    # Test removal using index
+    remove_idx = entity2.index()
+    grid.entities.remove(remove_idx)
+    print(f"✓ Removed entity at index {remove_idx}")
+    
+    # Check remaining entities
+    assert len(grid.entities) == 2
+    assert entity1.index() == 0
+    assert entity3.index() == 1  # Should have shifted down
+    
+    print("✓ Indices updated correctly after removal")
+    
+    # Test entity not in grid
+    orphan = mcrfpy.Entity((5, 5), texture, 5, None)
+    try:
+        idx = orphan.index()
+        print(f"✗ Orphan entity should raise error but returned {idx}")
+    except RuntimeError as e:
+        print(f"✓ Orphan entity correctly raises error")
+    
+    print("\n✅ Entity.index() test PASSED")
+    sys.exit(0)
+
+# Execute the test after a short delay
+import mcrfpy
+mcrfpy.setTimer("test", test_entity_index, 100)