Color boxes in the random order selection formspec.

white/gray: not yet completed boxes
green: completed boxes

Display the box numbers, since the order numbers may be confusing.

mods/boxes/nodes.lua

@@ -114,12 +114,20 @@ local function series_enter_choice(player, id)
 
 	f = f .. "textlist[0.2,0.5;5.4,7.4;in_series;"
 	local boxes = db.series_get_boxes(id)
+	local player_id = db.player_get_id(name)
+	local completed = db.player_get_series_boxes(player_id, id)
 	for k, box_id in pairs(boxes) do
-		-- TODO: color box depending on completed status
 		local bmeta = db.box_get_meta(box_id)
 		local bname = bmeta.meta.box_name or "[unnamed]"
-		--f = f .. "#00FF00"
-		f = f .. minetest.formspec_escape("[" .. k .. "] " .. bname)
+		local color = "#c0c0c0"
+		for _, v in ipairs(completed) do
+			if v == box_id then
+				color = "#00ff00"
+				break
+			end
+		end
+		f = f .. color
+		f = f .. minetest.formspec_escape("[" .. box_id .. "] " .. bname)
 		if k ~= #boxes then
 			f = f .. ","
 		end

mods/db/init.lua

@@ -278,6 +278,27 @@ function db.player_get_players()
 	return players
 end
 
+function db.player_get_series_boxes(player_id, series_id)
+	local stmt = itb_db:prepare[[
+		SELECT box_id FROM points WHERE player_id=:player_id AND type="time" AND box_id
+			IN (SELECT box_id FROM series_box WHERE series_id=:series_id)
+	]]
+	stmt:bind_names{
+		player_id = player_id,
+		series_id = series_id
+	}
+	local completed = {}
+	local completed_count = 1
+	for row in stmt:nrows() do
+		completed[completed_count] = row.box_id
+		completed_count = completed_count + 1
+	end
+
+	stmt:finalize()
+
+	return completed
+end
+
 function db.series_create(name)
 	assert(name ~= "")
 	local stmt = itb_db:prepare[[