VoxeLibre/mods/ENTITIES/mcl_mobs/pathfinding.lua

local math, vector, minetest, mcl_mobs = math, vector, minetest, mcl_mobs
local mob_class = mcl_mobs.mob_class

local LOGGING_ON = minetest.settings:get_bool("mcl_logging_mobs_villager",false)

local LOG_MODULE = "[Mobs]"
local function mcl_log (message)
	if LOGGING_ON and message then
		minetest.log(LOG_MODULE .. " " .. message)
	end
end

function output_table (wp)
	if not wp then return end
	mcl_log("wp items: ".. tostring(#wp))
	for a,b in pairs(wp) do
		mcl_log(a.. ": ".. tostring(b))
	end
end

function append_paths (wp1, wp2)
	mcl_log("Start append")
	if not wp1 or not wp2 then
		mcl_log("Cannot append wp's")
		return
	end
	output_table(wp1)
	output_table(wp2)
	for _,a in pairs (wp2) do
		table.insert(wp1, a)
	end
	mcl_log("End append")
end

local function output_enriched (wp_out)
	mcl_log("Output enriched path")
	local i = 0
	for _,outy in pairs (wp_out) do
		i = i + 1
		mcl_log("Pos ".. i ..":" .. minetest.pos_to_string(outy["pos"]))

		local action =  outy["action"]
		if action then
			mcl_log("type: " .. action["type"])
			mcl_log("action: " .. action["action"])
			mcl_log("target: " .. minetest.pos_to_string(action["target"]))
		end
		mcl_log("failed attempts: " .. outy["failed_attempts"])
	end
end

-- This function will take a list of paths, and enrich it with:
-- a var for failed attempts
-- an action, such as to open or close a door where we know that pos requires that action
local function generate_enriched_path(wp_in, door_open_pos, door_close_pos, cur_door_pos)
	local wp_out = {}
	for i, cur_pos in pairs(wp_in) do
		local action = nil

		local one_down = vector.new(0,-1,0)
		local cur_pos_to_add = vector.add(cur_pos, one_down)
		if door_open_pos and vector.equals (cur_pos, door_open_pos) then
			mcl_log ("Door open match")
			--action = {type = "door", action = "open"}
			action = {}
			action["type"] = "door"
			action["action"] = "open"
			action["target"] = cur_door_pos
			cur_pos_to_add = vector.add(cur_pos, one_down)
		elseif door_close_pos and vector.equals(cur_pos, door_close_pos) then
			mcl_log ("Door close match")
			--action = {type = "door", action = "closed"}
			action = {}
			action["type"] = "door"
			action["action"] = "close"
			action["target"] = cur_door_pos
			cur_pos_to_add = vector.add(cur_pos, one_down)
		elseif cur_door_pos and vector.equals(cur_pos, cur_door_pos) then
			mcl_log("Current door pos")
			cur_pos_to_add = vector.add(cur_pos, one_down)
			action = {}
			action["type"] = "door"
			action["action"] = "open"
			action["target"] = cur_door_pos
		else
			cur_pos_to_add = cur_pos
			--mcl_log ("Pos doesn't match")
		end

		wp_out[i] = {}
		wp_out[i]["pos"] = cur_pos_to_add
		wp_out[i]["failed_attempts"] = 0
		wp_out[i]["action"] = action

		--wp_out[i] = {"pos" = cur_pos, "failed_attempts" = 0, "action" = action}
		--output_pos(cur_pos, i)
	end
	output_enriched(wp_out)
	return wp_out
end

local plane_adjacents = {
	vector.new(1,0,0),
	vector.new(-1,0,0),
	vector.new(0,0,1),
	vector.new(0,0,-1),
}

-- This function is used to see if we can path. We could use to check a route, rather than making people move.
local function calculate_path_through_door (p, t, target)
	-- target is the same as t, just 1 square difference. Maybe we don't need target
	mcl_log("Plot route from mob: " .. minetest.pos_to_string(p) .. ", to target: " .. minetest.pos_to_string(t))

	local enriched_path = nil

	local cur_door_pos = nil
	local pos_closest_to_door = nil
	local other_side_of_door = nil

	--Path to door first
	local wp = minetest.find_path(p,t,150,1,4)
	if not wp then
		mcl_log("No direct path. Path through door")

		-- This could improve. There could be multiple doors. Check you can path from door to target first.
		local cur_door_pos = minetest.find_node_near(target,16,{"group:door"})
		if cur_door_pos then
			mcl_log("Found a door near: " .. minetest.pos_to_string(cur_door_pos))
			for _,v in pairs(plane_adjacents) do
				pos_closest_to_door = vector.add(cur_door_pos,v)

				local n = minetest.get_node(pos_closest_to_door)
				if n.name == "air" then
					wp = minetest.find_path(p,pos_closest_to_door,150,1,4)
					if wp then
						mcl_log("Found a path to next to door".. minetest.pos_to_string(pos_closest_to_door))
						other_side_of_door = vector.add(cur_door_pos,-v)
						mcl_log("Opposite is: ".. minetest.pos_to_string(other_side_of_door))

						local wp_otherside_door_to_target = minetest.find_path(other_side_of_door,t,150,1,4)
						if wp_otherside_door_to_target and #wp_otherside_door_to_target > 0 then
							table.insert(wp, cur_door_pos)
							append_paths (wp, wp_otherside_door_to_target)
							enriched_path = generate_enriched_path(wp, pos_closest_to_door, other_side_of_door, cur_door_pos)
							mcl_log("We have a path from outside door to target")
						else
							mcl_log("We cannot path from outside door to target")
						end
						break
					else
						mcl_log("This block next to door doesn't work.")
					end
				else
					mcl_log("Block is not air, it is: ".. n.name)
				end

			end
		else
			mcl_log("No door found")
		end
	else
		mcl_log("We have a direct route")
	end

	if wp and not enriched_path then
		enriched_path = generate_enriched_path(wp)
	end
	return enriched_path
end

local gopath_last = os.time()
function mob_class:gopath(target,callback_arrived)
	if self.state == PATHFINDING then mcl_log("Already pathfinding, don't set another until done.") return end

	if self._pf_last_failed and (os.time() - self._pf_last_failed) < 30 then
		mcl_log("We are not ready to path as last fail is less than threshold: " .. (os.time() - self._pf_last_failed))
		return
	else
		mcl_log("We are ready to pathfind, no previous fail or we are past threshold")
	end

	--if os.time() - gopath_last < 5 then
	--	mcl_log("Not ready to path yet")
	--	return
	--end
	--gopath_last = os.time()

	self.order = nil

	local p = self.object:get_pos()
	local t = vector.offset(target,0,1,0)

	local wp = calculate_path_through_door(p, t, target)
	if not wp then
		mcl_log("Could not calculate path")
		self._pf_last_failed = os.time()
		-- Cover for a flaw in pathfind where it chooses the wrong door and gets stuck. Take a break, allow others.
	end
	--output_table(wp)

	if wp and #wp > 0 then
		self._target = t
		self.callback_arrived = callback_arrived
		local current_location = table.remove(wp,1)
		if current_location and current_location["pos"] then
			mcl_log("Removing first co-ord? " .. tostring(current_location["pos"]))
		else
			mcl_log("Nil pos")
		end
		self.current_target = current_location
		self.waypoints = wp
		self.state = PATHFINDING
		return true
	else
		self.state = "walk"
		self.waypoints = nil
		self.current_target = nil
		--	minetest.log("no path found")
	end
end

local gowp_etime = 0

function mob_class:check_gowp(dtime)
	gowp_etime = gowp_etime + dtime

	-- 0.1 is optimal.
	--less frequently = villager will get sent back after passing a point.
	--more frequently = villager will fail points they shouldn't they just didn't get there yet

	--if gowp_etime < 0.05 then return end
	--gowp_etime = 0
	local p = self.object:get_pos()

	-- no destination
	if not p or not self._target then
		mcl_log("p: ".. tostring(p))
		mcl_log("self._target: ".. tostring(self._target))
		return
	end

	-- arrived at location, finish gowp
	local distance_to_targ = vector.distance(p,self._target)
	--mcl_log("Distance to targ: ".. tostring(distance_to_targ))
	if distance_to_targ < 2 then
		mcl_log("Arrived at _target")
		self.waypoints = nil
		self._target = nil
		self.current_target = nil
		self.state = "stand"
		self.order = "stand"
		self.object:set_velocity({x = 0, y = 0, z = 0})
		self.object:set_acceleration({x = 0, y = 0, z = 0})
		if self.callback_arrived then return self.callback_arrived(self) end
		return true
	end

	-- More pathing to be done
	local distance_to_current_target = 50
	if self.current_target and self.current_target["pos"] then
		distance_to_current_target = vector.distance(p,self.current_target["pos"])
	end

	-- 0.6 is working but too sensitive. sends villager back too frequently. 0.7 is quite good, but not with heights
	-- 0.8 is optimal for 0.025 frequency checks and also 1... Actually. 0.8 is winning
	-- 0.9 and 1.0 is also good. Stick with unless door open or closing issues
	if self.waypoints and #self.waypoints > 0 and ( not self.current_target or not self.current_target["pos"] or distance_to_current_target < 0.9 ) then
		-- We have waypoints, and no current target, or we're at it. We need a new current_target.
		self:do_pathfind_action (self.current_target["action"])

		local failed_attempts = self.current_target["failed_attempts"]
		mcl_log("There after " .. failed_attempts .. " failed attempts. current target:".. minetest.pos_to_string(self.current_target["pos"]) .. ". Distance: " ..  distance_to_current_target)

		self.current_target = table.remove(self.waypoints, 1)
		self:go_to_pos(self.current_target["pos"])
		return
	elseif self.current_target and self.current_target["pos"] then
		-- No waypoints left, but have current target. Potentially last waypoint to go to.
		self.current_target["failed_attempts"] = self.current_target["failed_attempts"] + 1
		local failed_attempts = self.current_target["failed_attempts"]
		if failed_attempts >= 50 then
			mcl_log("Failed to reach position (" .. minetest.pos_to_string(self.current_target["pos"]) .. ") too many times. Abandon route. Times tried: " .. failed_attempts)
			self.state = "stand"
			self.current_target = nil
			self.waypoints = nil
			self._target = nil
			self._pf_last_failed = os.time()
			self.object:set_velocity({x = 0, y = 0, z = 0})
			self.object:set_acceleration({x = 0, y = 0, z = 0})
			return
		end

		--mcl_log("Not at pos with failed attempts ".. failed_attempts ..": ".. minetest.pos_to_string(p) .. "self.current_target: ".. minetest.pos_to_string(self.current_target["pos"]) .. ". Distance: ".. distance_to_current_target)
		self:go_to_pos(self.current_target["pos"])
		-- Do i just delete current_target, and return so we can find final path.
	else
		-- Not at target, no current waypoints or current_target. Through the door and should be able to path to target.
		-- Is a little sensitive and could take 1 - 7 times. A 10 fail count might be a good exit condition.

		mcl_log("We don't have waypoints or a current target. Let's try to path to target")
		local final_wp = minetest.find_path(p,self._target,150,1,4)
		if final_wp then
			mcl_log("We might be able to get to target here.")
		--	self.waypoints = final_wp
			self:go_to_pos(self._target)
		else
			-- Abandon route?
			mcl_log("Cannot plot final route to target")
		end
	end

	-- I don't think we need the following anymore, but test first.
	-- Maybe just need something to path to target if no waypoints left
	if self.current_target and self.current_target["pos"] and (self.waypoints and #self.waypoints == 0) then
		local updated_p = self.object:get_pos()
		local distance_to_cur_targ = vector.distance(updated_p,self.current_target["pos"])

		mcl_log("Distance to current target: ".. tostring(distance_to_cur_targ))
		mcl_log("Current p: ".. minetest.pos_to_string(updated_p))

		-- 1.6 is good. is 1.9 better? It could fail less, but will it path to door when it isn't after door
		if distance_to_cur_targ > 1.9 then
			mcl_log("not close to current target: ".. minetest.pos_to_string(self.current_target["pos"]))
			self:go_to_pos(self._current_target)
		else
			mcl_log("close to current target: ".. minetest.pos_to_string(self.current_target["pos"]))
			self.current_target = nil
		end

		return
	end
end