Merge red and green circuit values for monitors

The monitors shouldn't be terribly expensive, so there's no reason to
keep their number down (I might change my mind if it turns out terribly
expensive to keep reading circuit networks, but it probably won't be).

Author: narc0tiq

Diff for: control.lua

@@ -45,30 +45,51 @@ events.on_entity_died = on_entity_remove
 events.on_robot_pre_mined = on_entity_remove
 
 
-local function update_signals(tick)
-    log("Update signals")
+local function merged_signals_from(entity)
+    local red_network = entity.get_circuit_network(defines.wire_type.red)
+    local green_network = entity.get_circuit_network(defines.wire_type.green)
 
-    for name, combi in combinators.each() do
-        local red_network = combi.get_circuit_network(defines.wire_type.red)
-        local green_network = combi.get_circuit_network(defines.wire_type.green)
+    local merged = {}
+    if red_network and red_network.signals then
+        for _, s in pairs(red_network.signals) do
+            if not merged[s.signal.type] then merged[s.signal.type] = {} end
 
-        local red_name = name.." red"
-        local green_name = name.." green"
+            local old_val = merged[s.signal.type][s.signal.name] or 0
+            merged[s.signal.type][s.signal.name] = old_val +  s.count
+        end
+    end
+    if green_network and green_network.signals then
+        for _, s in pairs(green_network.signals) do
+            if not merged[s.signal.type] then merged[s.signal.type] = {} end
 
-        gui.remove_data_rows(red_name)
-        gui.remove_data_rows(green_name)
+            local old_val = merged[s.signal.type][s.signal.name] or 0
+            merged[s.signal.type][s.signal.name] = old_val +  s.count
+        end
+    end
 
-        if red_network and red_network.signals then
-            for _, s in pairs(red_network.signals) do
-                signals.add_sample(tick, s)
-                gui.set_data_row(red_name, s)
-            end
+    local merged_signals = {}
+    for type, sig in pairs(merged) do
+        for name, count in pairs(sig) do
+            local new_sig = {
+                signal = { type = type, name = name },
+                count = count
+            }
+            table.insert(merged_signals, new_sig)
         end
-        if green_network and green_network.signals then
-            for _, s in pairs(green_network.signals) do
-                signals.add_sample(tick, s)
-                gui.set_data_row(green_name, s)
-            end
+    end
+
+    return pairs(merged_signals)
+end
+
+
+local function update_signals(tick)
+    log("Update signals")
+
+    for name, combi in combinators.each() do
+        gui.remove_data_rows(name)
+        for _, s in merged_signals_from(combi) do
+            signals.add_sample(tick, s)
+            gui.set_data_row(name, s)
         end
     end
 end