belt-analyzer fix: we are presenting the percent of the belt, not the…

… percent of an item relative to other items

locale/en/ui-belt-analyzer.cfg

@@ -14,4 +14,4 @@ ui-belt-analyzer-empty=empty
 ui-belt-analyzer-left-lane=Left Lane
 ui-belt-analyzer-right-lane=Right Lane
 
-ui-belt-analyzer-aggregation=__1__, __2__ percent
+ui-belt-analyzer-aggregation=__1__, __2__ percent of the belt

scripts/transport-belts.lua

@@ -555,6 +555,29 @@ end
 ---@class fa.TransportBelts.BeltAnalyzerData
 ---@field left { upstream: fa.NQC, downstream: fa.NQC, total: fa.NQC }
 ---@field right { upstream: fa.NQC, downstream: fa.NQC, total: fa.NQC }
+---@field upstream_length number in "slots", always a multiple of 4.
+---@field downstream_length number
+---@field total_length number
+
+---@param ent LuaEntity
+---@return number
+local function belt_length_in_slots(ent)
+   -- Underground belt exits are also special: they have 0.5-length lines which are used, and two lines left empty.
+   if ent.type == "underground-belt" and ent.belt_to_ground_type == "output" then return 2 end
+
+   -- Underground belt entrances are where we get the length of the underground part from.
+   if ent.type == "underground-belt" and ent.belt_to_ground_type == "input" then
+      local l1 = ent.get_transport_line(1).line_length
+      local l2 = ent.get_transport_line(3).line_length
+      return (l1 + l2) * 4
+   end
+
+   if ent.type == "loader" then return 0 end
+
+   -- Everything else is 4: transport belts for the obvious reason and splitters
+   -- because they are complicated and 4 is a good enough approximation.
+   return 4
+end
 
 --[[
 Run the belt analyzer algorithm: collect the left and right lane contents for
@@ -575,6 +598,10 @@ function Node:belt_analyzer_algo()
          total = {},
       },
       right = { upstream = {}, downstream = {}, total = {} },
+      upstream_length = 0,
+      downstream_length = 0,
+      -- There is always at least this belt.
+      total_length = 0,
    }
 
    ---@param tab fa.NQC
@@ -629,13 +656,23 @@ function Node:belt_analyzer_algo()
 
    self:walk_single_parents(function(e)
       local n = Node.create(e)
-      return add_node(n, "upstream")
+      if add_node(n, "upstream") then
+         ret.upstream_length = ret.upstream_length + belt_length_in_slots(e)
+         return true
+      end
+      return false
    end)
 
    self:walk_single_child(function(e)
-      return add_node(Node.create(e), "downstream")
+      if add_node(Node.create(e), "downstream") then
+         ret.downstream_length = ret.downstream_length + belt_length_in_slots(e)
+         return true
+      end
+      return false
    end)
 
+   ret.total_length = belt_length_in_slots(self.entity) + ret.upstream_length + ret.downstream_length
+
    return ret
 end
 

scripts/ui/belt-analyzer.lua

@@ -15,6 +15,9 @@ local mod = {}
 ---@field upstream fa.BeltAnalyzer.SortedEntries[]
 ---@field downstream fa.BeltAnalyzer.SortedEntries[]
 ---@field total fa.BeltAnalyzer.SortedEntries[]
+---@field upstream_length number
+---@field downstream_length number
+---@field total_length number
 
 ---@class fa.ui.BeltAnalyzer.SharedState
 ---@field node fa.TransportBelts.Node
@@ -97,7 +100,9 @@ local LocalTab = Grid.declare_grid(LocalGrid)
 -- The only difference between the upstream/total/downstream tabs is which
 -- field of the analysis they reference, so this returns the grids referencing
 -- the proper field.  All other logic is 100% identical.
-local function aggregate_grid_builder(field)
+---@param field "upstream"|"downstream"|"total"
+---@param length_field "upstream_length" | "downstream_length" | "total_length"
+local function aggregate_grid_builder(field, length_field)
    ---@class fa.BeltAnalyzer.AggregateTabCallbacks:  fa.ui.GridCallbacks
    local TabCallbacks = {}
 
@@ -119,22 +124,17 @@ local function aggregate_grid_builder(field)
       local ent = ctx.shared_state.analysis[field][x][y]
       if not ent then return { "fa.ui-belt-analyzer-empty" } end
 
-      local total = 0
-      for i = 1, #ctx.shared_state.analysis[field][x] do
-         local c = ctx.shared_state.analysis[field][x][i].count
-         total = total + c
-      end
-      local percent = string.format("%.1f", 100 * ent.count / total)
+      local percent = string.format("%.1f", 100 * ent.count / ctx.shared_state.analysis[length_field])
 
       return { "fa.ui-belt-analyzer-aggregation", Localising.localise_item(ent), percent }
    end
 
    return Grid.declare_grid(TabCallbacks)
 end
 
-local TotalTab = aggregate_grid_builder("total")
-local UpstreamTab = aggregate_grid_builder("upstream")
-local DownstreamTab = aggregate_grid_builder("downstream")
+local TotalTab = aggregate_grid_builder("total", "total_length")
+local UpstreamTab = aggregate_grid_builder("upstream", "upstream_length")
+local DownstreamTab = aggregate_grid_builder("downstream", "downstream_length")
 
 ---@param params fa.ui.BeltAnalyzer.Parameters
 ---@return fa.ui.BeltAnalyzer.SharedState
@@ -154,6 +154,9 @@ local function state_setup(_pindex, params)
          upstream = { up_left, up_right },
          total = { tot_left, tot_right },
          downstream = { down_left, down_right },
+         upstream_length = ad.upstream_length,
+         downstream_length = ad.downstream_length,
+         total_length = ad.total_length,
       },
    }
 end