added quest_step_possible check in preconditions

exec_eval_preconditions.lua

@@ -24,7 +24,7 @@ yl_speak_up.calculate_displayable_options = function(pname, d_options, in_edit_m
 	if(not(in_edit_mode)) then
 		local o_v = d_options[ o_k ]
 		-- Can we display this option?
-		retval[o_k] = yl_speak_up.eval_all_preconditions(player, o_v.o_prerequisites, o_k, retval)
+		retval[o_k] = yl_speak_up.eval_all_preconditions(player, o_v.o_prerequisites, o_k, retval,o_v)
 		-- do we need to take care of an automatic autoanswer?
 		if(retval[o_k] and retval[o_k] == true and o_v.o_autoanswer and o_v.o_autoanswer == 1
 		   and allow_recursion) then
@@ -46,9 +46,28 @@ end
 -- Important: If something cannot be determined (i.e. the node is nil),
 --            *both* the condition and its inverse condition may be
 --            true (or false).
-yl_speak_up.eval_all_preconditions = function(player, prereq, o_id, other_options_true_or_false)
+yl_speak_up.eval_all_preconditions = function(player, prereq, o_id, other_options_true_or_false, d_option)
 	local pname = player:get_player_name()
 	local n_id = yl_speak_up.speak_to[pname].n_id
+
+	-- if this is a quest step: check if its preconditions are fulfilled
+	-- (that way there doesn't have to be a manual precondition set for quests)
+	if(d_option and d_option.quest_id and d_option.quest_step) then
+		local d_id = yl_speak_up.speak_to[pname].d_id
+		yl_speak_up.debug_msg(player, n_id, o_id, "..checking quest step \""..
+			tostring(d_option.quest_step).."\" of quest \""..
+			tostring(d_option.quest_id).."\".")
+		if(not(yl_speak_up.quest_step_possible(player, d_option.quest_step, d_option.quest_id,
+				n_id, d_id, o_id))) then
+			yl_speak_up.debug_msg(player, n_id, o_id, "Quest step not available. Aborting.")
+			-- no need to look any further - once we hit a false, it'll stay false
+			return false
+		else
+			yl_speak_up.debug_msg(player, n_id, o_id, "OK. Quest step available.")
+		end
+	end
+
+
 	if(not(prereq)) then
 		yl_speak_up.debug_msg(player, n_id, o_id, "No preconditions given.")
 		-- no prerequirements? then they are automaticly fulfilled

quest_api.lua

@@ -682,6 +682,38 @@ yl_speak_up.add_quest = function(owner_name, variable_name, quest_name, descr_lo
 end
 
 
+-- delete a quest if possible
+yl_speak_up.del_quest = function(q_id, pname)
+	local quest = yl_speak_up.load_quest(q_id)
+	if(not(data)) then
+		return "Quest "..tostring(q_id).." does not exist."
+	end
+	if(quest.owner ~= pname) then
+		return "Quest "..tostring(q_id).." is owned by "..tostring(quest.owner)..
+			".\n You can't delete it."
+	end
+	if(quest.state ~= "created" and quest.state ~= "testing") then
+		return "Quest "..tostring(q_id).." is in stage \""..tostring(quest.state)..
+			"\".\n Only quests in state \"created\" or \"testing\" can be deleted."
+	end
+	if(#quest.is_subquest_of > 0) then
+		return "Quest "..tostring(q_id).." is used by the following subquests:\n"..
+			table.concat(quest.subquests, ", ")..
+			".\nPlease remove the subquests first!"
+	end
+	local quest_data = yl_speak_up.get_variable_metadata(k_long, "quest_data", true) or {}
+	if(quest_data and quest_data.steps and #quest_data.steps > 2) then
+		return "Quest "..tostring(q_id).." contains more than two steps:\n"..
+			table.concat(quest_data.steps, ", ")..
+			".\nPlease remove all steps apart from \"start\" and \"finish\" first!"
+	end
+	-- TODO: actually delete the file?
+	-- TODO: set the quest variable back to no type
+	-- TODO: delete quest variable?
+	return "OK"
+end
+
+
 -- returns a list of all quest IDs to which the player has write access
 yl_speak_up.get_quest_owner_list = function(pname)
 	local var_list = yl_speak_up.get_quest_variables_with_write_access(pname)
@@ -712,3 +744,16 @@ yl_speak_up.get_sorted_quest_list = function(pname)
 	table.sort(quest_list)
 	return quest_list
 end
+
+
+-- called for example by yl_speak_up.eval_all_preconditions to see if the player
+-- can reach quest_step in quest quest_id
+yl_speak_up.quest_step_possible = function(player, quest_step, quest_id, n_id, d_id, o_id)
+	-- TODO: evaluate that
+	-- TODO: the *previous* quest step needs to have been reached
+	-- TODO: the quest step *after* this quest step hasn't been reached (does that work?)
+	-- TODO: the quest needs to be owned by the player, the player be an authorized tester,
+	--       or the quest be in the official released stage
+--	minetest.chat_send_player("singleplayer", "TESTING quest step "..tostring(quest_step).." for quest "..tostring(quest_id))
+	return true
+end