neiam /apollos_crib

It's Apollo's Crib

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Show a line only at the nearest stop it calls at

3402380 · Gabriel Morell · 2026-09-03 18:52

20 files +157 -1

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{commit_body(@commit)}

Files changed

modified PLANI.md

+18 −0

@@ -83,6 +83,24 @@ and a foci id otherwise. `weather`, `ephem`, `pollen` and `icarus` relocate;

83	83	`cronos` uses its foci for a timezone rather than a position, and `calendar`
84	84	for filtering, so neither moves.
85	85
	86	+### What "nearest" over-answers
	87	+
	88	+An areal query asks every stop inside the radius, and a route calls at
	89	+several of them — so the 87 toward Arlington arrives once per stop, all of them
	90	+the same bus. One stop per line (`nearest_per_route`) keeps a route only at
	91	+the nearest stop that has it.
	92	+
	93	+Two things it deliberately does not do. It claims per stop, not per arrival,
	94	+so the winning stop keeps all of that line's departures — showing one time for
	95	+the nearest stop would be the wrong half of the point. And direction is part of
	96	+the key, so the two sides of a street stay separate: those are genuinely
	97	+different departures, and merging them would send somebody the wrong way. The
	98	+key is route-and-direction rather than headsign, since a short turn gets a sign
	99	+of its own and is still the same line.
	100	+
	101	+This applies to both blended and broken-out modes, since it happens before the
	102	+split.
	103	+
86	104	Sources with no location. `github`, `gitlab`, `packages`, `mailbox`,
87	105	`treasury`, `bourse`. A Plani should either refuse these or pass them through
88	106	untouched; "the nearest CI job" is not a thing. Worth deciding explicitly

modified apps/room_sanctum/lib/room_sanctum/configuration/plani.ex

+7 −1

@@ -42,6 +42,11 @@ defmodule RoomSanctum.Configuration.Plani do

42	42	# and asks the client to render a list of its own.
43	43	field :break_out, :boolean, default: false
44	44
	45	+ # Show a line only at the nearest stop it calls at. An areal query asks
	46	+ # every stop in the radius and a route calls at several, so without this
	47	+ # the same bus is listed once per stop.
	48	+ field :nearest_per_route, :boolean, default: false
	49	+
45	50	timestamps()
46	51	end
47	52

@@ -58,7 +63,8 @@ defmodule RoomSanctum.Configuration.Plani do

58	63	:follow_tint,
59	64	:radius,
60	65	:limit,
61		− :break_out
	66	+ :break_out,
	67	+ :nearest_per_route
62	68	])
63	69	\|> validate_required([:name, :home_foci_id])
64	70	# The same bounds an area query keeps, and for the same reason: past a

modified apps/room_sanctum/lib/room_sanctum/workers/plani_worker.ex

+47 −0

@@ -220,6 +220,7 @@ defmodule RoomSanctum.Worker.Plani do

220	220
221	221	{stop, arrivals}
222	222	end)
	223	+ \|> nearest_per_route(plani)
223	224
224	225	entries =
225	226	if plani.break_out do

@@ -309,6 +310,52 @@ defmodule RoomSanctum.Worker.Plani do

309	310	# so a Plani hands them something query-shaped. The id has to match the key
310	311	# the data went under -- that is how the two are paired again -- so a broken
311	312	# out entry carries its own, or its name is dropped on the way out.
	313	+ # Keep a line only at the nearest stop it calls at.
	314	+ #
	315	+ # An areal query asks every stop inside the radius, and a bus route calls at
	316	+ # several of them -- so the 87 toward Arlington turns up three times, once
	317	+ # per stop, all of them the same bus. Nobody walks to the second-nearest stop
	318	+ # to catch it.
	319	+ #
	320	+ # Claimed per stop rather than per arrival: the nearest stop keeps all of
	321	+ # that line's departures, which is the point -- it is the next two or three
	322	+ # times that make a departure board worth reading. Claiming as each arrival
	323	+ # went past would have left the winning stop showing one time.
	324	+ #
	325	+ # Direction is part of the key, so the two sides of a street stay separate.
	326	+ # Those are genuinely different departures, and collapsing them would send
	327	+ # somebody the wrong way.
	328	+ @doc false
	329	+ # Public only so a test can reach it; nothing outside calls this.
	330	+ def nearest_per_route(by_stop, %{nearest_per_route: true}) do
	331	+ {kept, _claimed} =
	332	+ Enum.map_reduce(by_stop, MapSet.new(), fn {stop, arrivals}, claimed ->
	333	+ # Stops arrive nearest-first, so a first claim is the closest one.
	334	+ mine = arrivals \|> Enum.map(&line_of/1) \|> Enum.uniq() \|> Enum.reject(&(&1 in claimed))
	335	+
	336	+ {{stop, Enum.filter(arrivals, &(line_of(&1) in mine))},
	337	+ MapSet.union(claimed, MapSet.new(mine))}
	338	+ end)
	339	+
	340	+ kept
	341	+ end
	342	+
	343	+ def nearest_per_route(by_stop, _plani), do: by_stop
	344	+
	345	+ # A route in a direction. Not the headsign: a short turn gets a sign of its
	346	+ # own and is still the same line calling at the same stop. A feed that does
	347	+ # not say which direction leaves it nil, which groups them -- the honest
	348	+ # answer when there is nothing to tell them apart by.
	349	+ defp line_of(arrival) do
	350	+ direction =
	351	+ case arrival.trip.direction do
	352	+ %{direction: direction} -> direction
	353	+ _ -> nil
	354	+ end
	355	+
	356	+ {arrival.trip.route_id, direction}
	357	+ end
	358	+
312	359	defp described(source), do: described(source, source.id, source.name)
313	360
314	361	defp described(source, id, name) do

modified apps/room_sanctum/lib/room_sanctum_web/live/cfg_plani_live/form_component.ex

+12 −0

@@ -146,6 +146,18 @@ defmodule RoomSanctumWeb.PlaniLive.FormComponent do

146	146	into one entry per source.
147	147	</p>
148	148
	149	+ <.input
	150	+ field={@form[:nearest_per_route]}
	151	+ type="checkbox"
	152	+ label="One stop per line"
	153	+ />
	154	+ <p class="text-xs text-base-content/60">
	155	+ A route that calls at several stops inside the radius is shown only at
	156	+ the nearest one — otherwise the same bus is listed once per stop. The
	157	+ two sides of a street stay separate, since those are different
	158	+ departures.
	159	+ </p>
	160	+
149	161	<:actions>
150	162	<.button phx-disable-with="Saving...">Save Plani</.button>
151	163	</:actions>

added apps/room_sanctum/priv/repo/migrations/20260903170000_add_nearest_per_route_to_plani.exs

+17 −0

@@ -0,0 +1,17 @@

	1	+defmodule RoomSanctum.Repo.Migrations.AddNearestPerRouteToPlani do
	2	+ use Ecto.Migration
	3	+
	4	+ @moduledoc """
	5	+ Whether a line is shown only at the nearest stop it calls at.
	6	+
	7	+ An areal query asks every stop inside the radius, and a bus route calls at
	8	+ several of them -- so the same departure appears once per stop. Nobody walks
	9	+ to the second-nearest stop to catch a bus that is also stopping at the first.
	10	+ """
	11	+
	12	+ def change do
	13	+ alter table(:cfg_plani) do
	14	+ add :nearest_per_route, :boolean, default: false, null: false
	15	+ end
	16	+ end
	17	+end

added apps/room_sanctum/test/room_sanctum/plani_nearest_per_route_test.exs

+56 −0

@@ -0,0 +1,56 @@

	1	+defmodule RoomSanctum.PlaniNearestPerRouteTest do
	2	+ use ExUnit.Case, async: true
	3	+
	4	+ alias RoomSanctum.Worker.Plani
	5	+
	6	+ defp arrival(route, direction, time) do
	7	+ %{arrival_time: time, trip: %{route_id: route, direction: %{direction: direction}}}
	8	+ end
	9	+
	10	+ # Nearest first, the order `nearby_stops/4` returns.
	11	+ defp by_stop do
	12	+ [
	13	+ {%{stop_id: "a", stop_name: "Nearest"},
	14	+ [arrival("87", "In", "08:00"), arrival("87", "In", "08:12")]},
	15	+ {%{stop_id: "b", stop_name: "Across the street"},
	16	+ [arrival("87", "Out", "08:03"), arrival("87", "In", "08:01")]},
	17	+ {%{stop_id: "c", stop_name: "Furthest"},
	18	+ [arrival("87", "In", "08:02"), arrival("96", "In", "08:30")]}
	19	+ ]
	20	+ end
	21	+
	22	+ test "a line is kept only at the nearest stop that has it" do
	23	+ [_, _, {_, furthest}] = Plani.nearest_per_route(by_stop(), %{nearest_per_route: true})
	24	+
	25	+ # The 87 belongs to the nearest stop; the 96 stops nowhere nearer.
	26	+ assert Enum.map(furthest, & &1.trip.route_id) == ["96"]
	27	+ end
	28	+
	29	+ test "the winning stop keeps every departure of that line, not just the first" do
	30	+ # Claiming per arrival rather than per stop would leave one time here,
	31	+ # which is the wrong half of the point -- a board is worth reading because
	32	+ # it shows the next two.
	33	+ [{_, nearest} \| _] = Plani.nearest_per_route(by_stop(), %{nearest_per_route: true})
	34	+
	35	+ assert Enum.map(nearest, & &1.arrival_time) == ["08:00", "08:12"]
	36	+ end
	37	+
	38	+ test "the other side of the street is a different departure and survives" do
	39	+ [_, {_, across}, _] = Plani.nearest_per_route(by_stop(), %{nearest_per_route: true})
	40	+
	41	+ assert Enum.map(across, & &1.trip.direction.direction) == ["Out"]
	42	+ end
	43	+
	44	+ test "a feed that names no direction groups rather than raising" do
	45	+ stops = [
	46	+ {%{stop_id: "a"}, [%{arrival_time: "08:00", trip: %{route_id: "87", direction: nil}}]},
	47	+ {%{stop_id: "b"}, [%{arrival_time: "08:05", trip: %{route_id: "87", direction: nil}}]}
	48	+ ]
	49	+
	50	+ assert [{_, [_]}, {_, []}] = Plani.nearest_per_route(stops, %{nearest_per_route: true})
	51	+ end
	52	+
	53	+ test "off, it changes nothing" do
	54	+ assert Plani.nearest_per_route(by_stop(), %{nearest_per_route: false}) == by_stop()
	55	+ end
	56	+end

Parents: b14afb0