From 0e083ba8d662aed47006be95b5189eabf6629a61 Mon Sep 17 00:00:00 2001
From: JugadorXEI <eugeniom9@gmail.com>
Date: Mon, 17 Mar 2025 19:38:57 +0100
Subject: [PATCH] Expose footsteps[], footsteps.iterate and #footsteps to Lua

---
 src/lua_terrainlib.c | 79 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/src/lua_terrainlib.c b/src/lua_terrainlib.c
index 7588992d8..25aaaf706 100644
--- a/src/lua_terrainlib.c
+++ b/src/lua_terrainlib.c
@@ -304,6 +304,75 @@ static int footstep_num(lua_State *L)
 	return 1;
 }
 
+static int lib_iterateFootsteps(lua_State *L)
+{
+	size_t i;
+
+	if (lua_gettop(L) < 2)
+	{
+		lua_pushcfunction(L, lib_iterateFootsteps);
+		return 1;
+	}
+
+	lua_settop(L, 2);
+	lua_remove(L, 1); // state is unused.
+
+	if (!lua_isnil(L, 1))
+		i = K_GetFootstepHeapIndex(*(t_footstep_t **)luaL_checkudata(L, 1, META_FOOTSTEP)) + 1;
+	else
+		i = 0;
+
+	// footsteps are always valid, only added, never removed
+	if (i < K_GetNumFootstepDefs())
+	{
+		LUA_PushUserdata(L, K_GetFootstepByIndex(i), META_FOOTSTEP);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int lib_getFootstep(lua_State *L)
+{
+	const char *field;
+	size_t i;
+
+	// find footstep by number
+	if (lua_type(L, 2) == LUA_TNUMBER)
+	{
+		i = luaL_checkinteger(L, 2);
+		if (i >= K_GetNumFootstepDefs())
+			return luaL_error(L, "footsteps[] index %d out of range (0 - %d)", i, K_GetNumFootstepDefs()-1);
+		LUA_PushUserdata(L, K_GetFootstepByIndex(i), META_FOOTSTEP);
+		return 1;
+	}
+
+	field = luaL_checkstring(L, 2);
+
+	// special function iterate
+	if (fastcmp(field,"iterate"))
+	{
+		lua_pushcfunction(L, lib_iterateFootsteps);
+		return 1;
+	}
+
+	// find footstep by name
+	t_footstep_t *byname = K_GetFootstepByName(field);
+	if (byname != NULL)
+	{
+		LUA_PushUserdata(L, byname, META_FOOTSTEP);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int lib_numFootsteps(lua_State *L)
+{
+	lua_pushinteger(L, K_GetNumFootstepDefs());
+	return 1;
+}
+
 static int overlay_get(lua_State *L)
 {
 	t_overlay_t *overlay = *((t_overlay_t **)luaL_checkudata(L, 1, META_OVERLAY));
@@ -626,6 +695,16 @@ int LUA_TerrainLib(lua_State *L)
 		lua_pushcfunction(L, footstep_num);
 		lua_setfield(L, -2, "__len");
 	lua_pop(L,1);
+
+	lua_newuserdata(L, 0);
+		lua_createtable(L, 0, 2);
+			lua_pushcfunction(L, lib_getFootstep);
+			lua_setfield(L, -2, "__index");
+
+			lua_pushcfunction(L, lib_numFootsteps);
+			lua_setfield(L, -2, "__len");
+		lua_setmetatable(L, -2);
+	lua_setglobal(L, "footsteps");
 	
 	luaL_newmetatable(L, META_OVERLAY);
 		lua_pushcfunction(L, overlay_get);