From e17cda925b7ab7d3d586ed1c40c591854704d770 Mon Sep 17 00:00:00 2001
From: ShadowNinja <shadowninja@minetest.net>
Date: Sat, 12 Jul 2014 16:37:54 -0400
Subject: [PATCH] Add canInteractInArea

---
 api.lua      | 31 +++++++++++++++++++++++++++++++
 internal.lua | 18 ++++++------------
 legacy.lua   |  5 +++--
 pos.lua      |  2 +-
 4 files changed, 41 insertions(+), 15 deletions(-)

diff --git a/api.lua b/api.lua
index d6a2cfd..bdb886a 100644
--- a/api.lua
+++ b/api.lua
@@ -39,3 +39,34 @@ function areas:getNodeOwners(pos)
 	return owners
 end
 
+--- Checks if the area intersects with an area that the player can't interact in.
+-- Note that this fails and returns false when the specified area is fully
+-- owned by the player, but with miltiple protection zones, none of which
+-- cover the entire checked area.
+-- @return Boolean indicating whether the player can interact in that area.
+-- @return Un-owned intersecting area id, if found.
+function areas:canInteractInArea(pos1, pos2, name)
+	areas:sortPos(pos1, pos2)
+	-- First check for a fully enclosing owned area
+	for id, area in pairs(self.areas) do
+		-- A little optimization: isAreaOwner isn't necessary here
+		-- since we're iterating through all areas.
+		if area.owner == name and self:isSubarea(pos1, pos2, id) then
+			return true
+		end
+	end
+	-- Then check for intersecting non-owned areas
+	for id, area in pairs(self.areas) do
+		local p1, p2 = area.pos1, area.pos2
+		if (p1.x <= pos2.x and p2.x >= pos1.x) and
+		   (p1.y <= pos2.y and p2.y >= pos1.y) and
+		   (p1.z <= pos2.z and p2.z >= pos1.z) then
+			-- Found an intersecting area
+			if not areas:isAreaOwner(id, name) then
+				return false, id
+			end
+		end
+	end
+	return true
+end
+
diff --git a/internal.lua b/internal.lua
index 93b873f..f032b1b 100644
--- a/internal.lua
+++ b/internal.lua
@@ -81,7 +81,7 @@ function areas:isSubarea(pos1, pos2, id)
 	if not area then
 		return false
 	end
-	p1, p2 = area.pos1, area.pos2
+	local p1, p2 = area.pos1, area.pos2
 	if (pos1.x >= p1.x and pos1.x <= p2.x) and
 	   (pos2.x >= p1.x and pos2.x <= p2.x) and
 	   (pos1.y >= p1.y and pos1.y <= p2.y) and
@@ -141,17 +141,11 @@ function areas:canPlayerAddArea(pos1, pos2, name)
 	end
 
 	-- Check intersecting areas
-	for id, area in pairs(self.areas) do
-		if (area.pos1.x <= pos2.x and area.pos2.x >= pos1.x) and
-		   (area.pos1.y <= pos2.y and area.pos2.y >= pos1.y) and
-		   (area.pos1.z <= pos2.z and area.pos2.z >= pos1.z) then
-			-- Found an area intersecting with the suplied area
-			if not areas:isAreaOwner(id, name) then
-				return false, ("The area intersects with"
-					.." %s [%u] owned by %s.")
-					:format(area.name, id, area.owner)
-			end
-		end
+	local can, id = self:canInteractInArea(pos1, pos2, name)
+	if not can then
+		local area = self.areas[id]
+		return false, ("The area intersects with %s [%u] owned by %s.")
+				:format(area.name, id, area.owner)
 	end
 
 	return true
diff --git a/legacy.lua b/legacy.lua
index 7eabf90..b689cc0 100644
--- a/legacy.lua
+++ b/legacy.lua
@@ -31,7 +31,7 @@ minetest.register_chatcommand("legacy_load_areas", {
 				nil, nil, nil, nil, nil, nil
 
 			-- Area positions sorting
-			area.pos1, area.pos2 = areas:sortPos(area.pos1, area.pos2)
+			areas:sortPos(area.pos1, area.pos2)
 
 			-- Add name
 			area.name = "unnamed"
@@ -43,7 +43,8 @@ minetest.register_chatcommand("legacy_load_areas", {
 
 		areas:save()
 		minetest.chat_send_player(name, "Converted areas saved. Done.")
-end})
+	end
+})
 
 function areas:node_ownership_load()
 	local filename = minetest.get_worldpath().."/owners.tbl"
diff --git a/pos.lua b/pos.lua
index e4f2d25..40f8360 100644
--- a/pos.lua
+++ b/pos.lua
@@ -168,7 +168,7 @@ end)
 
 -- Modifies positions `pos1` and `pos2` so that each component of `pos1`
 -- is less than or equal to its corresponding component of `pos2`,
--- returning two new positions
+-- returning the two positions.
 function areas:sortPos(pos1, pos2)
 	if pos1.x > pos2.x then
 		pos2.x, pos1.x = pos1.x, pos2.x