--[[
function Set(list)
	local set = {}
	for _, l in ipairs(list) do
		set[l] = true
	end
	return set
end

local sb, fsb, esb = "subterranean-belt", "fast-subterranean-belt", "express-subterranean-belt"
local sp = "subterranean-pipe"
local pipes = Set {sp, "stone-underground-pipe", "steel-underground-pipe"}
local underground_belts_bobs = Set {"green-underground-belt", "purple-underground-belt"}

local function getDistance(entity, ioEntity)
	return math.sqrt(
		math.pow(math.abs(math.floor(ioEntity.position.x) - math.floor(entity.position.x)), 2) +
			math.pow(math.abs(math.floor(ioEntity.position.y) - math.floor(entity.position.y)), 2)
	)
end

local function checkCount(character, count, what)
	if character.get_item_count(what) < count then
		return false
	else
		return true
	end
end

local function restoreDeniedItem(character, item)
	if not character.cursor_stack.valid_for_read then --if that was their last one
		character.cursor_stack.set_stack {name = item, count = 1}
	elseif character.cursor_stack.name == item then
		character.cursor_stack.count = character.cursor_stack.count + 1
	end
end

script.on_event(
	{defines.events.on_built_entity}, --run whenever the player builds an entity
	function(event)
		local entity = event.created_entity
		local player = game.players[event.player_index]
		local name = entity.name

		if name == sb or name == fsb or name == esb or underground_belts_bobs[name] then
			subterrainOnBuilt(event)
		elseif pipes[name] ~= nil then
			subterrainPipesOnBuilt(event)
		end
	end --ends event function
)

-- Actions for subterrain on built.
function subterrainOnBuilt(event)
	if settings.global["subterrain-belt-cost-multiplier"].value <= 0 then
		return nil
	end --don't cost belts
	local entity = event.created_entity
	local player = game.players[event.player_index]
	local eName = entity.name

	--check to see if the place is important
	if not entity.belt_to_ground_type == "output" or (entity.belt_to_ground_type == "input" and not entity.neighbours) then
		return
	end

	local otherEntity = entity.neighbours
	if not otherEntity then
		return
	end
	local distance = getDistance(entity, otherEntity)
	local cost = (math.floor(distance * settings.global["subterrain-belt-cost-multiplier"].value))
	local respectiveBelts = string.gsub(eName, "subterranean", "transport")
	local respectiveBelts_pretty = respectiveBelts:gsub("-", " ") .. "s"

	otherEntity.force = "player" --set the force of the other side to player, to allow refund

	if not checkCount(character, cost, respectiveBelts) then --they don't have enough of the aboveground belts for this distance
		entity.destroy()
		character.print("You don't have enough " .. respectiveBelts_pretty .. " in your inventory to create this length.")

		restoreDeniedItem(character, eName)
	else
		character.remove_item {name = respectiveBelts, count = cost} --deduct the required belts from their inventory
	end
end

--actions for subterrain pipes on built
function subterrainPipesOnBuilt(event)
	local entity = event.created_entity
	local character = game.players[event.player_index]
	entity.rotatable = false --Prevent rotation, as that can be used to game the system

	if settings.global["subterrain-pipe-cost-multiplier"].value <= 0 then
		return nil
	end --no pipe cost

	local otherPipe = entity.neighbours[1][1] or nil

	if not otherPipe then
		return nil --no need to do anything if this is the first placed
	end

	local distance = getDistance(entity, otherPipe)
	local calc = (math.floor(distance * settings.global["subterrain-pipe-cost-multiplier"].value))

	otherPipe.force = "player"

	if not checkCount(character, calc, "pipe") then
		entity.destroy()
		character.print("You don't have enough pipes in your inventory to create this length.")

		restoreDeniedItem(character, sp)
	else
		character.remove_item {name = "pipe", count = calc} --charge the player the pipes
	end
end

--actions for bob's logistics on built
-- function bobsLogisticsOnBuilt(event)
-- if settings.global["subterrain-belt-cost-multiplier"].value <= 0 then return nil end --don't cost belts
-- local entity = event.created_entity
-- local player = game.players[event.player_index]
-- local eName = entity.name

-- --check to see if the place is important
-- if not entity.belt_to_ground_type == "output" or (entity.belt_to_ground_type == "input" and not entity.neighbours) then
-- return
-- end

-- local otherEntity = entity.neighbours
-- local distance = getDistance(entity, otherEntity)
-- local cost = (math.floor(distance * settings.global["subterrain-belt-cost-multiplier"].value))
-- local respectiveBelts = string.gsub(eName, "underground", "transport")
-- local respectiveBelts_pretty = respectiveBelts:gsub("-", " ") .. "s"

-- otherEntity.force = "player" --set the force of the other side to player, to allow refund

-- if not checkCount(player, cost, respectiveBelts) then --they don't have enough of the aboveground belts for this distance
-- entity.destroy()
-- player.print("You don't have enough " .. respectiveBelts_pretty ..	" in your inventory to create this length.")

-- restoreDeniedItem(player,eName)
-- else
-- player.remove_item{name = respectiveBelts, count = cost} --deduct the required belts from their inventory
-- end
-- end

script.on_event(
	{defines.events.on_pre_player_mined_item}, --Called before the mined item is removed from the map
	function(event)
		local entity = event.entity
		local player = game.players[event.player_index]
		local name = entity.name

		if name == sb or name == fsb or name == esb or underground_belts_bobs[name] then
			subterrainOnMine(event)
		elseif pipes[name] ~= nil then
			subterrainOnMinePipes(event)
		end
	end
)

local function insert_items(character, name, count)
	if character.can_insert {name = name, count = count} then
		local inserted = character.insert {name = name, count = count}
		if inserted < count then
			character.surface.spill_item_stack(character.position, {name = name, count = count - inserted}, true)
		end
	else
		character.surface.spill_item_stack(character.position, {name = name, count = count}, true)
	end
end

--actions for subterrain pipes on mine
function subterrainOnMinePipes(event)
	if
		(not settings.global["subterrain-should-refund-pipes"].value) or
			(settings.global["subterrain-pipe-refund-multiplier"].value <= 0)
	 then --don't do any of this if not refunding pipes
		return
	end
	local entity = event.entity
	local otherEntity = entity.neighbours[1][1] or false --the opening end of the pair of pipes
	if not otherEntity then
		return
	end --pipe isnt connected to anything

	local distance = getDistance(entity, otherEntity)
	if (entity.force.name == "neutral") or (otherEntity.force.name == "neutral") then --a reward was already given
		return
	end

	otherEntity.force = "neutral"
	local calc =
		(math.floor(
		(distance * settings.global["subterrain-pipe-cost-multiplier"].value) *
			settings.global["subterrain-pipe-refund-multiplier"].value
	))
	if calc <= 0 then
		return
	end -- Exit if the return turns out to be 0.

	insert_items(game.players[event.player_index], "pipe", calc)
end

--Actions for subterrain on mine
function subterrainOnMine(event)
	if
		(not settings.global["subterrain-should-refund-belts"].value) or
			(settings.global["subterrain-belt-refund-multiplier"].value <= 0)
	 then
		return
	end

	local entity = event.entity
	local eName = entity.name
	local otherEntity = entity.neighbours or false
	if not otherEntity then
		return
	end

	local distance = getDistance(entity, otherEntity)

	--a reward was already given
	if (entity.force.name == "neutral") or (otherEntity.force.name == "neutral") then
		return
	end

	otherEntity.force = "neutral"
	local calc =
		(math.floor(
		(distance * settings.global["subterrain-belt-cost-multiplier"].value) *
			settings.global["subterrain-belt-refund-multiplier"].value
	))
	if calc <= 0 then
		return
	end -- Exit if the return turns out to be 0.
	local respectiveBelts = string.gsub(eName, "subterranean", "transport")

	insert_items(game.players[event.player_index], respectiveBelts, calc)
end

--Actions for bob's logistics on mine
function bobsLogisticsOnMine(event)
	if
		(not settings.global["subterrain-should-refund-belts"].value) or
			(settings.global["subterrain-belt-refund-multiplier"].value <= 0)
	 then
		return
	end

	local entity = event.entity
	local eName = entity.name
	local otherEntity = entity.neighbours or false
	if not otherEntity then
		return
	end
	local distance = getDistance(entity, otherEntity)

	--a reward was already given
	if (entity.force.name == "neutral") or (otherEntity.force.name == "neutral") then
		return
	end

	otherEntity.force = "neutral"
	local calc =
		(math.floor(
		(distance * settings.global["subterrain-belt-cost-multiplier"].value) *
			settings.global["subterrain-belt-refund-multiplier"].value
	))
	if calc <= 0 then
		return
	end -- Exit if the return turns out to be 0.
	local respectiveBelts = string.gsub(eName, "underground", "transport")

	insert_items(game.players[event.player_index], respectiveBelts, calc)
end
]]-- --drd