From 322655f48337c447501b8847e7b9b63ebbfbeb6d Mon Sep 17 00:00:00 2001
From: mrkubax10 <mrkubax10@onet.pl>
Date: Mon, 12 May 2025 21:44:33 +0200
Subject: [PATCH] Implement cable melting

---
 api/network.lua | 129 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 127 insertions(+), 2 deletions(-)

diff --git a/api/network.lua b/api/network.lua
index c5df7ff..584779a 100644
--- a/api/network.lua
+++ b/api/network.lua
@@ -41,6 +41,102 @@ local function clampFlow(pos,flow)
 	return math.min(flow,newFlow)
 end
 
+-- \brief Finds path from pos to dest in network. Function finished if either dest is found or every node was visited
+-- \param pos Vector
+-- \param dest Vector
+-- \returns table or nil
+function industrialtest.api.findPathInNetwork(pos,dest)
+	local connections=industrialtest.api.getConnections(pos,"i")
+	if #connections==0 then
+		return nil
+	end
+
+	local workers={}
+	local serializedSourcePos=pos.x..","..pos.y..","..pos.z
+	local visitedNodes={[serializedSourcePos]=true}
+	for _,conn in ipairs(connections) do
+		local sideVector=vector.subtract(conn,pos)
+		table.insert(workers,{
+			position=conn,
+			direction=sideVector,
+			path={[1]=conn}
+		})
+	end
+
+	while #workers>0 do
+		for i=1,#workers do
+			local worker=workers[i]
+			local serializedPos=worker.position.x..","..worker.position.y..","..worker.position.z
+			if visitedNodes[serializedPos] then
+				table.remove(workers,i)
+				break
+			end
+			visitedNodes[serializedPos]=true
+
+			if worker.position.x==dest.x and worker.position.y==dest.y and worker.position.z==dest.z then
+				return worker.path
+			end
+
+			local def=minetest.registered_nodes[minetest.get_node(worker.position).name]
+			if def and def.groups and def.groups._industrialtest_cable then
+				connections=industrialtest.api.getConnections(worker.position,"i")
+				for j=1,#connections do
+					local direction=vector.subtract(connections[j],worker.position)
+					local oppositeDirection=vector.multiply(worker.direction,vector.new(-1,-1,-1))
+					if direction.x~=oppositeDirection.x or direction.y~=oppositeDirection.y or direction.z~=oppositeDirection.z then
+						if worker.direction.x~=direction.x or worker.direction.y~=direction.y or worker.direction.z~=direction.z then
+							table.insert(worker.path,worker.position)
+						end
+						for c=1,#connections do
+							local nextDirection=vector.subtract(connections[c],worker.position)
+							if c~=j and (nextDirection.x~=oppositeDirection.x or nextDirection.y~=oppositeDirection.y or nextDirection.z~=oppositeDirection.z) then
+								local newWorker={
+									position=connections[c],
+									direction=nextDirection,
+									path=table.copy(worker.path)
+								}
+								table.insert(newWorker.path,worker.position)
+								table.insert(workers,newWorker)
+							end
+						end
+						worker.direction=direction
+						worker.position=connections[j]
+						break
+					end
+				end
+
+				if #connections>2 then
+					break
+				end
+			else
+				table.remove(workers,i)
+				break
+			end
+		end
+	end
+
+	return nil
+end
+
+-- \brief Goes through path vertices specified by path running callback on each node.
+--        Function finishes if either callback returns false or entire path is went over.
+-- \param path table
+-- \param callback function
+-- \returns nil
+function industrialtest.api.walkPath(path,callback)
+	local pos=path[1]
+	for i=2,#path do
+		local pathNode=path[i]
+		local direction=vector.normalize(vector.subtract(pathNode,pos))
+		while pos.x~=pathNode.x or pos.y~=pathNode.y or pos.z~=pathNode.z do
+			if not callback(pos) then
+				return
+			end
+			pos=vector.add(pos,direction)
+		end
+	end
+end
+
 -- \brief Transfers power from source node to it's network, if sides is set then power will be only transfered to network connected to that sides
 -- \param pos Vector with position of source node
 -- \param (optional) sides table with Vectors
@@ -100,8 +196,36 @@ function industrialtest.api.powerFlow(pos,sides,flowOverride)
 					roomAvailable=true
 				end
 			else
-				minetest.remove_node(endpoint.position)
-				industrialtest.internal.explode(endpoint.position,2)
+				local path=industrialtest.api.findPathInNetwork(pos,endpoint.position)
+				if path and #path>0 then
+					table.insert(path,endpoint.position)
+					local removed=false
+					industrialtest.api.walkPath(path,function(pathPos)
+						local def=minetest.registered_nodes[minetest.get_node(pathPos).name]
+						if not def or not def.groups or not def.groups._industrialtest_cable then
+							return false
+						end
+						if powerDistribution>def._industrialtest_cableFlow then
+							removed=true
+							minetest.swap_node(pathPos,{
+								name="air"
+							})
+							minetest.remove_node(pathPos)
+							minetest.check_for_falling(pathPos)
+							minetest.sound_play("default_cool_lava",{
+								pos=pathPos,
+								max_hear_distance=5,
+								gain=0.7
+							})
+						end
+						return true
+					end)
+					if not removed and powerDistribution>endpoint.originalFlow then
+						minetest.remove_node(endpoint.position)
+						industrialtest.internal.explode(endpoint.position,2)
+					end
+					industrialtest.api.createNetworkMapForNode(pos)
+				end
 			end
 		end
 	end
@@ -199,6 +323,7 @@ function industrialtest.api.createNetworkMap(pos,addCables,omit)
 					position=worker.position,
 					distance=worker.distance,
 					flow=math.min(worker.flow,flow),
+					originalFlow=flow,
 					side=connectionSide,
 					sourceSide=worker.sourceSide
 				})