-- just some handling of variables

-- TODO: handle read (and write?) access for other players
-- TODO: add a function to check if the player has read/write access
-- TODO: mark some vars as "need to be saved" while others are less important (i.e. timestamps)
-- TODO: save state whenever a new variable is added - or else if the last change was more than x minutes ago?

-- the keys are of the form:
-- 	<player name> <blank> <variable name> (makes it easier to grant read access)
-- the values are of the form:
-- 	<current player name as key> : <value of variable for that player as value>
yl_speak_up.player_vars = {}


-- new variables have to be added somehow
yl_speak_up.add_quest_variable = function(owner_name, variable_name)
	local k = tostring(owner_name).." "..tostring(variable_name)
	if(not(owner_name) or not(variable_name)) then
		return false
	end
	-- create a new empty table;
	-- keys will be the names of players for which values are set
	yl_speak_up.player_vars[ k ] = {}
	return true
end


-- accidentally created or no longer needed variables need to be deleted somehow
yl_speak_up.del_quest_variable = function(owner_name, variable_name)
	local k = tostring(owner_name).." "..tostring(variable_name)
	if(not(owner_name) or not(variable_name)) then
		return false
	end
	yl_speak_up.player_vars[ k ] = nil
end


-- set the value of a variable used by a player in an NPC;
-- returns false if the variable cannot be set (i.e. does not exist)
yl_speak_up.set_quest_variable_value = function(player_name, variable_name, new_value)
	-- the owner name is alrady encoded in the variable name
	local k = tostring(variable_name)
	if(not(variable_name) or not(player_name) or not(yl_speak_up.player_vars[ k ])) then
		return false
	end
	yl_speak_up.player_vars[ k ][ player_name ] = new_value
	return true
end


-- get the value of a variable used by a player in an NPC;
-- returns nil if the variable does not exist
yl_speak_up.get_quest_variable_value = function(player_name, variable_name)
	-- the owner name is alrady encoded in the variable name
	local k = tostring(variable_name)
	if(not(variable_name) or not(player_name) or not(yl_speak_up.player_vars[ k ])) then
		return nil
	end
	return yl_speak_up.player_vars[ k ][ player_name ]
end


-- which variables can player pname read and use in preconditions?
-- returns a sorted list
yl_speak_up.get_quest_variables_with_read_access = function(pname)
	if(not(pname)) then
		return {}
	end
	local liste = {}
	for k, v in pairs(yl_speak_up.player_vars) do
		local parts = string.split(k, " ")
		if(parts and parts[1] and parts[1] == pname) then
			table.insert(liste, k)
		end
	end
	-- TODO: insert those vars owned by other players where this one has read access to
	table.sort(liste)
	return liste
end


-- which variables can player pname write and use in effects/results?
yl_speak_up.get_quest_variables_with_write_access = function(pname)
	if(not(pname)) then
		return {}
	end
	local liste = {}
	for k, v in pairs(yl_speak_up.player_vars) do
		local parts = string.split(k, " ")
		if(parts and parts[1] and parts[1] == pname) then
			table.insert(liste, k)
		end
	end
	-- TODO: insert those vars owned by other players where this one has write access to
	table.sort(liste)
	return liste
end


yl_speak_up.input_fs_manage_variables = function(player, formname, fields)
	local pname = player:get_player_name()
	if(fields and fields.back_from_msg) then
		yl_speak_up.show_fs(player, "manage_variables")
		return
	end
	-- add a new variable?
	if(fields and fields.add_variable) then
		if(not(fields.add_variable_name) or fields.add_variable_name == ""
		  or fields.add_variable_name:trim() == "") then
			yl_speak_up.show_fs(player, "msg", {
				input_to = "yl_speak_up:manage_variables",
				formspec = "size[6,2]"..
					"label[0.2,0.5;Please enter the name of your variable!]"..
					"button[1.5,1.5;2,0.9;back_from_msg;Back]"})
			return
		end
		-- TODO: limit names to something more sensible?
		fields.add_variable_name = fields.add_variable_name:trim()
		local res = yl_speak_up.add_quest_variable(pname, fields.add_variable_name)
		local text = "A new variable named\n     \""..tostring(fields.add_variable_name)..
			"\"\nhas been created."
		if(not(res)) then
			text = "Failed to create variable named\n      \""..
				tostring(fields.add_variable_name).."\"."
		end
		yl_speak_up.show_fs(player, "msg", {
			input_to = "yl_speak_up:manage_variables",
			formspec = "size[6,2]"..
				"label[0.2,0.0;"..minetest.formspec_escape(text).."]"..
				"button[1.5,1.5;2,0.9;back_from_msg;Back]"})
		return

	end
	-- try to go back to the last formspec shown before this one
	if(not(yl_speak_up.speak_to[pname])) then
		return
	end
	local last_fs = yl_speak_up.speak_to[pname][ "working_at" ]
	yl_speak_up.show_fs(player, last_fs)
end


yl_speak_up.get_fs_manage_variables = function(player, param)
	return "size[12,4]"..
		"label[2.0,-0.2;* Manage your variables *]"..
		"label[0.2,1.0;Create this new variable:]"..
		"field[3.7,1.3;6.0,0.6;add_variable_name;;]"..
		"button[9.4,1.0;2.5,0.6;add_variable;Create variable]"..
		"tooltip[add_variable;Enter the name of your new variable.]"..
		-- TODO: delete variable
		"button[2.0,3.5;1.0,0.6;back;Back]"
end