-- set name, description and owner of the NPC
-- (owner can only be set if the player has the npc_talk_master
--  priv - not with npc_talk_owner priv alone)
yl_speak_up.input_fs_initial_config = function(player, formname, fields)
	local pname = player:get_player_name()
	local n_id = yl_speak_up.speak_to[pname].n_id

	if(fields.back_from_error_msg) then
		-- no point in showing the formspec or error message again if we did so already
		if(not(yl_speak_up.may_edit_npc(player, n_id))) then
			return
		end
		-- show this formspec again
		yl_speak_up.show_fs(player, "initial_config",
			{n_id = n_id, d_id = yl_speak_up.speak_to[pname].d_id, false})
		return
	end

	if(not(fields.save_initial_config) or (fields and fields.exit)) then
		-- is the player editing the npc? then leaving this config
		-- dialog has to lead back to the talk dialog
		if(yl_speak_up.edit_mode[pname] == n_id and n_id) then
			yl_speak_up.show_fs(player, "talk",
				{n_id = n_id, d_id = yl_speak_up.speak_to[pname].d_id})
		end
		-- else we can quit here
		return
	end

	local error_msg = nil
	-- remove leading and tailing spaces from the potential new NPC name in order to avoid
	-- confusing names where a player's name (or that of another NPC) is beginning/ending
	-- with blanks
	if(fields.n_npc) then
		fields.n_npc = fields.n_npc:match("^%s*(.-)%s*$")
	end
	local dialog = yl_speak_up.speak_to[pname].dialog
	-- the player is trying to save the initial configuration
	-- is the player allowed to initialize this npc?
	if(not(yl_speak_up.may_edit_npc(player, n_id))) then
		error_msg = "You are not allowed to edit this NPC."
	elseif(not(fields.n_npc) or string.len(fields.n_npc) < 2) then
		error_msg = "The name of your NPC needs to be\nat least two characters long."
	elseif(minetest.check_player_privs(fields.n_npc, {interact=true})) then
		error_msg = "You cannot name your NPC\nafter an existing player."
	elseif(not(fields.n_description) or string.len(fields.n_description) < 2) then
		error_msg = "Please provide a description of your NPC!"
	-- sensible length limit
	elseif(string.len(fields.n_npc)>40 or string.len(fields.n_description)>40) then
		error_msg = "The name and description of your NPC\ncannot be longer than 40 characters."
	-- want to change the owner?
	elseif(fields.n_owner and fields.n_owner ~= yl_speak_up.npc_owner[ n_id ]) then
		if(    not(minetest.check_player_privs(player, {npc_talk_master=true}))) then
			error_msg = "You need the \"npc_talk_master\" priv\nin order to change the owner."
		elseif(not(minetest.check_player_privs(fields.n_owner, {npc_talk_owner=true}))) then
			error_msg = "The NPC can only be owned by players that\n"..
				    "have the \"npc_talk_owner\" priv. Else the\n"..
				    "new owner could not edit his own NPC."
		end
	-- want to change who may edit this npc?
	-- delete a player from the list of those allowed to edit the NPC
	elseif(fields.delete_may_edit and fields.delete_may_edit ~= ""
	   and fields.list_may_edit and fields.list_may_edit ~= "") then
		if(pname ~= yl_speak_up.npc_owner[ n_id ]) then
			error_msg = "Only the owner of the NPC\ncan change this."
		elseif(not(dialog)) then
			error_msg = "Please set a name for your NPC first!"
		else
			-- actually delete the player from the list
			dialog.n_may_edit[ fields.list_may_edit ] = nil
			-- show the next entry
			yl_speak_up.speak_to[pname].tmp_index = math.max(1,
					yl_speak_up.speak_to[pname].tmp_index-1)
		end
	-- add a player who may edit this NPC
	elseif(fields.add_may_edit and fields.add_may_edit ~= "") then
		if(pname ~= yl_speak_up.npc_owner[ n_id ]) then
			error_msg = "Only the owner of the NPC\ncan change this."
		elseif(fields.add_may_edit == pname) then
			error_msg = "You are already the owner of this NPC!\nNo need to add you extra here."
		elseif(not(minetest.check_player_privs(fields.add_may_edit, {interact=true}))) then
			error_msg = "Player \""..minetest.formspec_escape(fields.add_may_edit)..
				"\" not found."
		elseif(not(dialog)) then
			error_msg = "Please set a name for the NPC first!"
		else
			if(not(dialog.n_may_edit)) then
				dialog.n_may_edit = {}
			end
			dialog.n_may_edit[ fields.add_may_edit ] = true
			-- jump to the index with this player so that the player sees that he has been added
			local tmp_list = yl_speak_up.sort_keys(dialog.n_may_edit, true)
			local index = table.indexof(tmp_list, fields.add_may_edit)
			if(index and index > 0) then
				-- "Add player:" is added before all other names, so +1
				yl_speak_up.speak_to[pname].tmp_index = index + 1
			end
		end
	-- selected a player name in the why may edit this NPC dropdown?
	elseif(fields.list_may_edit and fields.list_may_edit ~= "") then
		local tmp_list = yl_speak_up.sort_keys(dialog.n_may_edit, true)
		local index = table.indexof(tmp_list, fields.list_may_edit)
		if(fields.list_may_edit == "Add player:") then
			index = 0
		end
		if(index and index > -1) then
			yl_speak_up.speak_to[pname].tmp_index = index + 1
		end
	end
	if(error_msg) then
		yl_speak_up.show_fs(player, "msg", { input_to = "yl_speak_up:initial_config",
			formspec = "size[6,2]"..
				"label[0.2,0.0;"..tostring(error_msg).."]"..
				"button[2,1.5;1,0.9;back_from_error_msg;Back]"})
		return
	end

	local d_id = yl_speak_up.speak_to[pname].d_id
	local count = 0
	if(dialog and dialog.n_dialogs) then
		for k,v in pairs(dialog.n_dialogs) do
			count = count + 1
		end
	end


	-- we checked earlier if the player doing this change and the
	-- player getting the NPC have appropriate privs
	if(fields.n_owner ~= yl_speak_up.npc_owner[ n_id ]) then
		yl_speak_up.log_change(pname, n_id,
			"Owner changed from "..tostring(yl_speak_up.npc_owner[ n_id ])..
			" to "..tostring(fields.n_owner).." for "..
			"NPC name: \""..tostring(fields.n_npc))
		-- the owner will actually be changed further down, at the end of this function
		yl_speak_up.npc_owner[ n_id ] = fields.n_owner
	end

	-- give the NPC its first dialog
	if(not(dialog) or count==0) then
		local f = {}
		-- create a new dialog
		f.d_id = yl_speak_up.text_new_dialog_id
		-- ...with this text
		f.d_text = "$GOOD_DAY$ $PLAYER_NAME$,\nI am $NPC_NAME$. I don't know much yet.\n"..
			"Hopefully $OWNER_NAME$ will teach me to talk soon."
		-- it is the first, initial dialog
		f.d_sort = "0"
		f.n_npc = fields.n_npc
		f.n_description = fields.n_description
		f.npc_owner = yl_speak_up.npc_owner[ n_id ]
		-- create and save the first dialog for this npc
		local dialog = yl_speak_up.fields_to_dialog(pname, f)
		yl_speak_up.save_dialog(n_id, dialog)
		yl_speak_up.speak_to[pname].dialog = dialog
		dialog.n_may_edit = {}

		yl_speak_up.log_change(pname, n_id,
			"Initial config saved. "..
			"NPC name: \""..tostring(fields.n_npc)..
			"\" Description: \""..tostring(fields.n_description).."\".")
	-- just change name and description
	elseif((fields.n_npc and fields.n_npc ~= "")
	   or (fields.n_description and fields.n_description ~= "")) then
		dialog = yl_speak_up.speak_to[pname].dialog
		dialog.n_npc = fields.n_npc
		dialog.n_description = fields.n_description
		yl_speak_up.save_dialog(n_id, dialog)

		yl_speak_up.log_change(pname, n_id,
			"Name and/or description changed. "..
			"NPC name: \""..tostring(fields.n_npc)..
			"\" Description: \""..tostring(fields.n_description)..
			"\" May be edited by: \""..
			table.concat(yl_speak_up.sort_keys(dialog.n_may_edit, true), " ").."\".")
	end

	dialog = yl_speak_up.speak_to[pname].dialog

	-- show nametag etc.
	if yl_speak_up.speak_to[pname].obj then
		local obj = yl_speak_up.speak_to[pname].obj
		local ent = obj:get_luaentity()
		if ent ~= nil then
			ent.yl_speak_up.npc_name = dialog.n_npc
			ent.yl_speak_up.npc_description = dialog.n_description
			ent.owner = yl_speak_up.npc_owner[ n_id ] or dialog.npc_owner
			local i_text = dialog.n_npc .. "\n" .. 
					dialog.n_description .. "\n" ..
					yl_speak_up.infotext
			obj:set_properties({infotext = i_text})
                               yl_speak_up.update_nametag(ent)
		end
	end

	if(not(fields.save_initial_config)) then
		yl_speak_up.show_fs(player, "initial_config",
			{n_id = n_id, d_id = yl_speak_up.speak_to[pname].d_id, false})
		return
	end
	-- actually start a chat with our new npc
	yl_speak_up.show_fs(player, "talk", {n_id = n_id, d_id = d_id})
end


-- initialize the npc without having to use a staff;
-- returns true when initialization possible
yl_speak_up.get_fs_initial_config = function(player, n_id, d_id, is_initial_config)
	local pname = player:get_player_name()

	-- is the player allowed to edit this npc?
	if(not(yl_speak_up.may_edit_npc(player, n_id))) then
		return "size[6,2]"..
			"label[0.2,0.0;Sorry. You are not authorized\nto edit this NPC.]"..
			"button_exit[2,1.5;1,0.9;back_from_error_msg;Exit]"
	end

	local tmp_name = n_id
	local tmp_descr = "A new NPC without description"
	local tmp_text = "Please provide your new NPC with a name and description!"
	local tmp_owner = (yl_speak_up.npc_owner[ n_id ] or "- none -")
	local table_of_names = {}
	local may_be_edited_by = ""
	-- use existing name and description as presets when just editing
	if(not(is_initial_config)) then
		local dialog = yl_speak_up.speak_to[pname].dialog
		tmp_name = (dialog.n_npc or tmp_name)
		tmp_descr = (dialog.n_description or tmp_descr)
		tmp_text = "You can change the name and description of your NPC."
		-- dialog.n_may_edit was a string for a short time in development
		if(not(dialog.n_may_edit) or type(dialog.n_may_edit) ~= "table") then
			dialog.n_may_edit = {}
		end
		table_of_names = dialog.n_may_edit
		may_be_edited_by =
			-- who can edit this NPC?
			"label[0.2,4.05;May be edited by:]"..
			-- offer a dropdown list and a text input field for player names for adding
			yl_speak_up.create_dropdown_playerlist(player, pname,
				table_of_names, yl_speak_up.speak_to[pname].tmp_index,
				2.5, 3.9, 0.0, "list_may_edit", "player", "Remove player from list",
				"add_may_edit",
					"Enter the name of the player whom you\n"..
					"want to grant the right to edit your NPC.\n"..
					"The player needs at least the npc_talk_owner priv\n"..
					"in order to actually edit the NPC.",
				"delete_may_edit",
					"If you click here, the player will no\n"..
					"longer be able to edit your NPC."
			)
	end
	local formspec = "size[10,6]"..
		"label[0.2,0.2;"..tmp_text.."]"..
		-- name of the npc
		"label[0.2,1.05;Name:]"..
		"field[2.0,1.2;4,0.9;n_npc;;"..minetest.formspec_escape(tmp_name).."]"..
		"label[7.0,1.05;NPC ID: "..minetest.colorize("#FFFF00",tostring(n_id)).."]"..
		"tooltip[n_npc;n_npc: The name of the NPC;#FFFFFF;#000000]"..
		-- description of the npc
		"label[0.2,2.05;Description:]"..
		"field[2.0,2.2;8,0.9;n_description;;"..minetest.formspec_escape(tmp_descr).."]"..
		"tooltip[n_description;n_description: A description for the NPC;#FFFFFF;#000000]"..
		-- the owner of the NPC
		"label[0.2,3.05;Owner:]"..
		"field[2.0,3.2;8,0.9;n_owner;;"..minetest.formspec_escape(tmp_owner).."]"..
		"tooltip[n_owner;The owner of the NPC. This can only be changed\n"..
			"if you have the npc_talk_master priv.;#FFFFFF;#000000]"..
		may_be_edited_by..
		-- save and exit buttons
		"button_exit[3.2,5.2;2,0.9;save_initial_config;Save]"..
		"button_exit[5.4,5.2;2,0.9;exit;Exit]"
	-- show the formspec to the player
	return formspec
end