From 610875070f7facae1ec4281b52c3511a5a2aa2a8 Mon Sep 17 00:00:00 2001
From: MewMew <mail@mewmew.net>
Date: Fri, 27 Mar 2020 12:57:47 +0100
Subject: [PATCH] new module

---
 modules/sticky_landfill.lua | 65 +++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 modules/sticky_landfill.lua

diff --git a/modules/sticky_landfill.lua b/modules/sticky_landfill.lua
new file mode 100644
index 00000000..aa521764
--- /dev/null
+++ b/modules/sticky_landfill.lua
@@ -0,0 +1,65 @@
+-- landfill is sticky, making it difficult to isolate
+
+local table_insert = table.insert
+
+local vectors = {}
+table_insert(vectors, {0, 0})
+for r = 1, 64, 1 do
+	table_insert(vectors, {0, r})
+	table_insert(vectors, {0, r * -1})
+	table_insert(vectors, {r, 0})
+	table_insert(vectors, {r * -1, 0})
+end
+
+local vectors_2 = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}}
+
+local function is_position_sticky(surface, position)
+	local tile = surface.get_tile(position)
+	if not tile.collides_with("resource-layer") then return end
+	
+	for _, v in pairs(vectors_2) do
+		tile = surface.get_tile({position.x + v[1], position.y + v[2]})
+		if not tile.collides_with("resource-layer") then
+			return true
+		end
+	end
+end
+
+local function move_tile(surface, tile_name, position)	
+	for key, v in pairs(vectors) do
+		local p = {x = position.x + v[1], y = position.y + v[2]}
+
+		if is_position_sticky(surface, p) then
+			surface.set_tiles({{name = tile_name, position = p}}, true)
+			return
+		end
+	end
+end
+	
+local function sticky(surface, tiles, tile_name)
+	local revert_tiles = {}
+	local i = 1
+	for _, placed_tile in pairs(tiles) do
+		revert_tiles[i] = {name = placed_tile.old_tile.name, position = placed_tile.position}
+		i = i + 1	
+	end
+	surface.set_tiles(revert_tiles, true)
+	
+	for _, placed_tile in pairs(tiles) do
+		move_tile(surface, tile_name, placed_tile.position)
+	end		
+end
+
+local function on_player_built_tile(event)
+	if event.item.name ~= "landfill" then return end
+	sticky(game.surfaces[event.surface_index], event.tiles, event.tile.name)
+end
+
+local function on_robot_built_tile(event)
+	if event.item.name ~= "landfill" then return end
+	sticky(event.robot.surface, event.tiles, event.tile.name)
+end
+
+local Event = require 'utils.event'
+Event.add(defines.events.on_robot_built_tile, on_robot_built_tile)
+Event.add(defines.events.on_player_built_tile, on_player_built_tile)
\ No newline at end of file