From db99cd71d3f066ea22632c1dfbf126ed414afc17 Mon Sep 17 00:00:00 2001
From: BlackMATov <blackmat@mail.ru>
Date: Wed, 22 Apr 2020 08:53:01 +0700
Subject: [PATCH] node: child_index function

---
 headers/enduro2d/high/node.hpp                |  3 ++
 .../bin/library/scripts/emmy/high/node.lua    |  5 +++
 .../high/bindings/high_binds/node_binds.cpp   |  4 ++
 sources/enduro2d/high/node.cpp                | 14 +++++++
 untests/sources/untests_high/node.cpp         | 42 +++++++++++++++++++
 5 files changed, 68 insertions(+)

diff --git a/headers/enduro2d/high/node.hpp b/headers/enduro2d/high/node.hpp
index d1e40f3e..ffcb4da0 100644
--- a/headers/enduro2d/high/node.hpp
+++ b/headers/enduro2d/high/node.hpp
@@ -129,6 +129,9 @@ namespace e2d
         node_iptr child_at(std::size_t index) noexcept;
         const_node_iptr child_at(std::size_t index) const noexcept;
 
+        std::pair<std::size_t, bool> child_index(
+            const const_node_iptr& child) const noexcept;
+
         node_iptr remove_child_at(std::size_t index) noexcept;
     protected:
         node() = default;
diff --git a/samples/bin/library/scripts/emmy/high/node.lua b/samples/bin/library/scripts/emmy/high/node.lua
index f60010d5..31f23034 100644
--- a/samples/bin/library/scripts/emmy/high/node.lua
+++ b/samples/bin/library/scripts/emmy/high/node.lua
@@ -145,6 +145,11 @@ function node.bring_to_front(self) end
 ---@return node
 function node.child_at(self, index) end
 
+---@param self node
+---@param child node
+---@return integer, boolean
+function node.child_index(self, child) end
+
 ---@param self node
 ---@param index integer
 ---@return node
diff --git a/sources/enduro2d/high/bindings/high_binds/node_binds.cpp b/sources/enduro2d/high/bindings/high_binds/node_binds.cpp
index d1bd51fd..240b9378 100644
--- a/sources/enduro2d/high/bindings/high_binds/node_binds.cpp
+++ b/sources/enduro2d/high/bindings/high_binds/node_binds.cpp
@@ -149,6 +149,10 @@ namespace e2d::bindings::high
                     : node_iptr();
             },
 
+            "child_index", [](node& n, const node_iptr& c) -> std::pair<std::size_t, bool> {
+                return n.child_index(c);
+            },
+
             "remove_child_at", [](node& n, i32 index) -> node_iptr {
                 return index >= 0
                     ? n.remove_child_at(math::numeric_cast<std::size_t>(index))
diff --git a/sources/enduro2d/high/node.cpp b/sources/enduro2d/high/node.cpp
index fd41bb1f..ae96c15e 100644
--- a/sources/enduro2d/high/node.cpp
+++ b/sources/enduro2d/high/node.cpp
@@ -431,6 +431,20 @@ namespace e2d
         return child;
     }
 
+    std::pair<std::size_t, bool> node::child_index(
+        const const_node_iptr& child) const noexcept
+    {
+        if ( !child || child->parent_ != this ) {
+            return {std::size_t(-1), false};
+        }
+
+        const auto distance = std::distance(
+            children_.begin(),
+            node_children::iterator_to(*child));
+
+        return {math::numeric_cast<std::size_t>(distance), true};
+    }
+
     node_iptr node::remove_child_at(std::size_t index) noexcept {
         node_iptr child = child_at(index);
         return remove_child(child)
diff --git a/untests/sources/untests_high/node.cpp b/untests/sources/untests_high/node.cpp
index 9bde1862..3b373524 100644
--- a/untests/sources/untests_high/node.cpp
+++ b/untests/sources/untests_high/node.cpp
@@ -450,6 +450,48 @@ TEST_CASE("node") {
             REQUIRE_FALSE(cp->child_at(3));
         }
     }
+    SECTION("child_index") {
+        auto p = node::create();
+
+        auto n1 = node::create(p);
+        auto n2 = node::create(p);
+        auto n3 = node::create(p);
+
+        auto p2 = node::create();
+        auto n4 = node::create(p2);
+
+        auto n5 = node::create();
+
+        REQUIRE(p->child_index(n1).second);
+        REQUIRE(p->child_index(n2).second);
+        REQUIRE(p->child_index(n3).second);
+        REQUIRE_FALSE(p->child_index(n4).second);
+        REQUIRE_FALSE(p->child_index(n5).second);
+
+        REQUIRE(p->child_index(n1).first == 0u);
+        REQUIRE(p->child_index(n2).first == 1u);
+        REQUIRE(p->child_index(n3).first == 2u);
+
+        {
+            const_node_iptr cp = p;
+
+            const_node_iptr cn1 = n1;
+            const_node_iptr cn2 = n2;
+            const_node_iptr cn3 = n3;
+            const_node_iptr cn4 = n4;
+            const_node_iptr cn5 = n5;
+
+            REQUIRE(cp->child_index(cn1).second);
+            REQUIRE(cp->child_index(cn2).second);
+            REQUIRE(cp->child_index(cn3).second);
+            REQUIRE_FALSE(cp->child_index(cn4).second);
+            REQUIRE_FALSE(cp->child_index(cn5).second);
+
+            REQUIRE(cp->child_index(cn1).first == 0u);
+            REQUIRE(cp->child_index(cn2).first == 1u);
+            REQUIRE(cp->child_index(cn3).first == 2u);
+        }
+    }
     SECTION("remove_child_at") {
         auto p = node::create();