--[[
Stacking control
Fixes a bug in utils_ui that allowed things to stack incorectly when the full stacking rules are applied.
Provides a mechanisiam to invoke the full stacking rules on specified items under specified conditions 
06Jun2021
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
Author: RavenAscendant
--]]



local registered_rules = {}
local expanded_rules = {}
-- section_func is a function that when passed a section returns true, if that section should be exempted from the normal forced stack all and have more complex stacking rules applied including custom rules included in the functor
--obj_functor should take an object return true if that particualr object should have the complex staking rules applied, false if that object should not stack with other objects of the same section regardless of other stacking rules.  
-- if multiple rules for same 
  function register(section_func, obj_functor ) 	  
	  if not section_func  then return end    
	  registered_rules[section_func] = obj_functor 
	  expanded_rules = {} --clear caching on new rule
  end



local function get_rules(section)
	--printf("get_rules1:%s %s", section, type(expanded_rules[section]) )	
	if expanded_rules[section] or expanded_rules[section] == false then return expanded_rules[section] end --false indicates no rules for section, nil is section has not been evaluated
	expanded_rules[section] = {}
	for k,v in pairs(registered_rules) do
		--printf("get_rules2:%s %s", section, k(section) )
		if k(section) then
			
			expanded_rules[section][#expanded_rules[section]+1] = v or false --nil is not the same as false
		end
	end
	if #expanded_rules[section]<1 then expanded_rules[section] = false end --don't want to keep an empty list, as empty list is not false
	return expanded_rules[section]
end

local function check_rules(obj)
	--
	local rules = get_rules(obj:section())
	if not rules then return false end
	local stack = true
	for _,v in ipairs(rules) do
		stack = stack and (v and v(obj)) --any rule says don't stack it doesn't stack.  
	end
	return not stack
end


function utils_ui.UICellContainer:ValidateSimilar(obj, sec)
	if not (obj or sec) then	
		printe("!ERROR UICellContainer:ValidateSimilar | no data recieved!")
		return false
	end

	
	local sec = obj:section()
	
	if get_rules(sec) and check_rules(obj) then
		return false
	end

	
	-- Ignore search if multiuse item is used
	local max_uses = IsItem("multiuse",sec)
	if max_uses and obj:get_remaining_uses() ~= max_uses then
		return false
	end
	
	
	-- Ignore search if item has upgrades
	if utils_item.has_upgrades(obj) then
		return false
	end
	return true -- no opbjections let it go
end




function utils_ui.UICellContainer:FindSimilar(obj, sec)
	--printf("find similar")
	if not (obj or sec) then	
		printe("!ERROR UICellContainer:FindSimilar | no data recieved!")
		return false
	end

	-- Ignore search if item isn't meant to stack
	if SYS_GetParam(1,sec,"dont_stack") then
		return false
	end

	
	if self.disable_stack then
		return false
	end

	if  self.showcase or self.stack_all and (not get_rules(sec)) then
		return self:GetCell_SEC(sec)
	end
	
	local sec = obj:section() --not sure the importance of this, but tronex had it so make sure it fits.

	if not self:ValidateSimilar(obj, sec) then
		return false
	end
	
	
	-- items with no condition can stack, return a cell with same section
	local clsid = obj:clsid()
	local use_cond = SYS_GetParam(1,sec,"use_condition") or IsWeapon(nil,clsid) or IsOutfit(nil,clsid) or IsHeadgear(nil,clsid)
	if (not use_cond) and (not get_rules(sec)) then
		return self:GetCell_SEC(sec)
	end

	
	-- items with condition, full search
	for idx,ci in pairs(self.cell) do
		local obj_2 = ci.ID and level.object_by_id(ci.ID)
		if (ci.section == sec and obj_2 and self:ValidateSimilar(obj_2, ci.section)) then
			-- full multiuse item can stack
			if max_uses then
				return ci 
				
			-- item with similar condition can stack
			else
				local cond = obj:condition()
				if obj_2 and math.abs(obj_2:condition() - cond) < 0.1 then
					return ci
				end
			end
		end
	end
	
	-- no similar item found
	return false
end