neiam /apollos_crib

It's Apollo's Crib

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Let a Plani have several homes, and pick the nearest

bc42901 · Gabriel Morell · 2026-09-05 18:52

26 files +411 -21

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modified PLANI.md

+22 −0

@@ -29,6 +29,28 @@ memory there is nothing to fall back *from*, so the home foci answers.

29	29	└──no───▶ home foci's place (from the database)
30	30	```
31	31
	32	+### Which home
	33	+
	34	+A Plani may have several. `home_foci_id` is the first and the fallback;
	35	+`home_foci_ids` names others, and `home_tint` follows every foci wearing a
	36	+colour — the same shortcut sources have, and the reason foci now carry a tint
	37	+at all.
	38	+
	39	+With more than one, the anchor settles on **the one nearest to where the client
	40	+last was**, not the one configured first. A house and an office are both home;
	41	+which is the right answer depends on which you were last near.
	42	+
	43	+That last position is held in the worker and nowhere else, so it dies with the
	44	+process — a Plani that has just restarted goes to its first home, which is
	45	+where a Plani with one home has always gone. Keeping it anywhere durable would
	46	+be storing a location history, which is the thing this component exists to
	47	+avoid.
	48	+
	49	+`home_after_mins` is how long a client may say nothing first: 5 to 30 minutes
	50	+in five minute steps. The Ankyra keeps positions for the longest of those, and
	51	+still shows only five minutes on its page — keeping a position and displaying
	52	+one are different questions.
	53	+
32	54	## What already exists
33	55
34	56	More than it looks, because the pieces were built for other reasons.

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

+14 −1

@@ -5,6 +5,10 @@ defmodule RoomSanctum.Configuration.Foci do

5	5	schema "cfg_focis" do
6	6	field :name, :string
7	7	field :place, Geo.PostGIS.Geometry
	8	+
	9	+ # As on a source: a colour that says these belong together, without making
	10	+ # a group out of it. A Plani can follow a tint of foci as its homes.
	11	+ field :tint, :string
8	12	belongs_to :user, RoomSanctum.Accounts.User
9	13
10	14	timestamps()

@@ -13,8 +17,17 @@ defmodule RoomSanctum.Configuration.Foci do

13	17	@doc false
14	18	def changeset(foci, attrs) do
15	19	foci
16		− \|> cast(attrs, [:name, :place, :user_id])
	20	+ \|> cast(attrs, [:name, :place, :user_id, :tint])
17	21	\|> foreign_key_constraint(:user_id)
18	22	\|> validate_required([:name, :place])
	23	+ \|> validate_tint()
	24	+ end
	25	+
	26	+ # An unknown tint renders as an unstyled dot rather than failing, which is
	27	+ # the kind of wrong that goes unnoticed. Same rule as a Plani's follow_tint.
	28	+ defp validate_tint(changeset) do
	29	+ validate_change(changeset, :tint, fn :tint, tint ->
	30	+ if tint in [nil, ""] or RoomSanctum.Tints.valid?(tint), do: [], else: [tint: "is not a tint"]
	31	+ end)
19	32	end
20	33	end

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

+47 −0

@@ -19,7 +19,19 @@ defmodule RoomSanctum.Configuration.Plani do

19	19	belongs_to :user, RoomSanctum.Accounts.User
20	20
21	21	# Where it is when it does not know where it is.
	22	+ #
	23	+ # More than one is allowed, because more than one is true: a house and an
	24	+ # office are both home, and which one answers depends on where you were
	25	+ # last. `home_foci_id` is the first of them and the answer for a Plani
	26	+ # that has never heard a position at all.
22	27	field :home_foci_id, :integer
	28	+ field :home_foci_ids, {:array, :integer}, default: []
	29	+ field :home_tint, :string
	30	+
	31	+ # How long a client may say nothing before the anchor goes home. Five
	32	+ # minutes suits a phone in a pocket on a bus; half an hour suits one that
	33	+ # only reports when it is opened.
	34	+ field :home_after_mins, :integer, default: 5
23	35
24	36	# Whose position to follow. An Ankyra may carry several clients and only
25	37	# one of them is the one that travels.

@@ -62,6 +74,9 @@ defmodule RoomSanctum.Configuration.Plani do

62	74	:name,
63	75	:user_id,
64	76	:home_foci_id,
	77	+ :home_foci_ids,
	78	+ :home_tint,
	79	+ :home_after_mins,
65	80	:ankyra_id,
66	81	:client_id,
67	82	:sources,

@@ -80,7 +95,11 @@ defmodule RoomSanctum.Configuration.Plani do

80	95	# Looser than `limit`: loose bikes are counted rather than read one by one,
81	96	# so a larger number is still a sensible thing to ask for.
82	97	\|> validate_number(:bike_limit, greater_than_or_equal_to: 1, less_than_or_equal_to: 50)
	98	+ # Offered as a menu of five minute steps, so the number is never anything
	99	+ # but one of these -- but a form is not the only way in.
	100	+ \|> validate_inclusion(:home_after_mins, [5, 10, 15, 20, 25, 30])
83	101	\|> validate_tint()
	102	+ \|> validate_home_tint()
84	103	\|> foreign_key_constraint(:user_id)
85	104	\|> foreign_key_constraint(:home_foci_id)
86	105	end

@@ -97,6 +116,34 @@ defmodule RoomSanctum.Configuration.Plani do

97	116	end)
98	117	end
99	118
	119	+ defp validate_home_tint(changeset) do
	120	+ validate_change(changeset, :home_tint, fn :home_tint, tint ->
	121	+ if tint in [nil, ""] or RoomSanctum.Tints.valid?(tint),
	122	+ do: [],
	123	+ else: [home_tint: "is not a tint"]
	124	+ end)
	125	+ end
	126	+
	127	+ @doc """
	128	+ Every foci this Plani calls home: the first one, any others it names, and
	129	+ any wearing its home tint.
	130	+
	131	+ In that order and deduplicated, so `home_foci_id` stays the one a Plani with
	132	+ no position falls back to -- which is what it has always been, and what
	133	+ keeps every existing Plani behaving exactly as it did.
	134	+ """
	135	+ def homes_for(%__MODULE__{} = plani, all_foci) do
	136	+ tinted =
	137	+ case plani.home_tint do
	138	+ blank when blank in [nil, ""] -> []
	139	+ tint -> all_foci \|> Enum.filter(&(&1.tint == tint)) \|> Enum.map(& &1.id)
	140	+ end
	141	+
	142	+ ([plani.home_foci_id] ++ (plani.home_foci_ids \|\| []) ++ tinted)
	143	+ \|> Enum.reject(&is_nil/1)
	144	+ \|> Enum.uniq()
	145	+ end
	146	+
100	147	@doc """
101	148	Every source this Plani asks: the ones it names, and the ones wearing its
102	149	tint.

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

+21 −12

@@ -10,11 +10,17 @@ defmodule RoomSanctum.Worker.Ankyra do

10	10	# Asking is cheap and answering is not: a vision's queries all run again.
11	11	@request_floor_ms 1_000
12	12
13		− # How long a reported position is worth showing, and how many to keep. Five
14		− # minutes is a trail rather than a history: long enough to see which way
15		− # somebody is going, short enough that it is gone before it is a record.
16		− @positions_ttl_s 300
17		− @positions_kept 20
	13	+ # How long a reported position is worth showing. Five minutes is a trail
	14	+ # rather than a history: long enough to see which way somebody is going,
	15	+ # short enough that it is gone before it is a record.
	16	+ @positions_shown_s 300
	17	+
	18	+ # How long one is worth keeping, which is not the same question. A Plani
	19	+ # may wait up to half an hour before it gives up on a client and goes home,
	20	+ # and it cannot ask about a position that has already been dropped. Still a
	21	+ # trail rather than a record: nothing here outlives the process.
	22	+ @positions_ttl_s 1800
	23	+ @positions_kept 64
18	24
19	25	@registry :zeus
20	26	def start_link(opts) do

@@ -87,11 +93,11 @@ defmodule RoomSanctum.Worker.Ankyra do

87	93	trail. Nil when that client has not reported inside the window, which is the
88	94	signal to fall back to a home foci rather than an error.
89	95	"""
90		− def position(name, client_id) do
	96	+ def position(name, client_id, max_age_s \\ @positions_shown_s) do
91	97	try do
92	98	"ankyra#{name}"
93	99	\|> via_tuple()
94		− \|> GenServer.call({:position, client_id}, 5_000)
	100	+ \|> GenServer.call({:position, client_id, max_age_s}, 5_000)
95	101	rescue
96	102	# A registry that is not up raises from the lookup rather than exiting.
97	103	ArgumentError -> nil

@@ -110,10 +116,10 @@ defmodule RoomSanctum.Worker.Ankyra do

110	116
111	117	def topic(id), do: "ankyra:#{id}"
112	118
113		− def handle_call({:position, client_id}, _from, state) do
	119	+ def handle_call({:position, client_id, max_age_s}, _from, state) do
114	120	latest =
115	121	state.positions
116		− \|> prune()
	122	+ \|> prune(max_age_s)
117	123	\|> Enum.find(fn p -> is_nil(client_id) or p.client_id == client_id end)
118	124
119	125	{:reply, latest, state}

@@ -372,16 +378,19 @@ defmodule RoomSanctum.Worker.Ankyra do

372	378	end
373	379	end
374	380
375		− defp prune(positions) do
376		− cutoff = DateTime.add(DateTime.utc_now(), -@positions_ttl_s, :second)
	381	+ defp prune(positions, max_age_s \\ @positions_ttl_s) do
	382	+ cutoff = DateTime.add(DateTime.utc_now(), -max_age_s, :second)
377	383	Enum.filter(positions, fn p -> DateTime.compare(p.at, cutoff) == :gt end)
378	384	end
379	385
	386	+ # The page draws a five minute trail whatever the worker is holding for the
	387	+ # Plani's benefit -- keeping a position and showing it are different
	388	+ # questions, and the answer to the second did not change.
380	389	defp broadcast_positions(id, positions) do
381	390	Phoenix.PubSub.broadcast(
382	391	RoomSanctum.PubSub,
383	392	topic(id),
384		− {:ankyra_positions, positions}
	393	+ {:ankyra_positions, prune(positions, @positions_shown_s)}
385	394	)
386	395	end
387	396

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

+67 −8

@@ -60,7 +60,11 @@ defmodule RoomSanctum.Worker.Plani do

60	60	places: [],
61	61	notes: %{},
62	62	anchor: nil,
63		− anchored_to: :home
	63	+ anchored_to: :home,
	64	+ # The last position a client reported, for choosing which home to
	65	+ # settle on. Lost with the process, deliberately: a Plani that has just
	66	+ # restarted falls back to its first home, which is where it started.
	67	+ last_seen: nil
64	68	}}
65	69	end
66	70

@@ -119,7 +123,7 @@ defmodule RoomSanctum.Worker.Plani do

119	123	def handle_cast(:query, %{plani: nil} = state), do: {:noreply, state}
120	124
121	125	def handle_cast(:query, state) do
122		− {anchor, anchored_to} = anchor(state.plani)
	126	+ {anchor, anchored_to, last_seen} = anchor(state.plani, state.last_seen)
123	127
124	128	# Resolved on every tick rather than held: a source tinted since the last
125	129	# one should join without the Plani being edited, which is the whole point

@@ -165,7 +169,8 @@ defmodule RoomSanctum.Worker.Plani do

165	169	places: places,
166	170	notes: notes,
167	171	anchor: anchor,
168		− anchored_to: anchored_to
	172	+ anchored_to: anchored_to,
	173	+ last_seen: last_seen
169	174	}}
170	175	end
171	176

@@ -187,22 +192,76 @@ defmodule RoomSanctum.Worker.Plani do

187	192
188	193	def handle_info(_msg, state), do: {:noreply, state}
189	194
190		− # Where to ask from: the client if it has said recently, the home foci if not.
191		− defp anchor(plani) do
	195	+ # Where to ask from: the client if it has said recently, a home foci if not.
	196	+ #
	197	+ # Takes and returns the last position this worker saw, because "which home"
	198	+ # is answered by where you were, not by which was configured first. A house
	199	+ # and an office are both home; the useful one is the one you were last near.
	200	+ # Held here and nowhere else -- it does not outlive the process, which is the
	201	+ # same promise the position itself is under.
	202	+ defp anchor(plani, last_seen) do
	203	+ window = (plani.home_after_mins \|\| 5) * 60
	204	+
192	205	reported =
193	206	if plani.ankyra_id do
194		− RoomSanctum.Worker.Ankyra.position(to_string(plani.ankyra_id), plani.client_id)
	207	+ RoomSanctum.Worker.Ankyra.position(to_string(plani.ankyra_id), plani.client_id, window)
195	208	end
196	209
197	210	case reported do
198	211	%{lat: lat, lon: lon} ->
199		− {%Geo.Point{coordinates: {lon, lat}, srid: 4326}, :client}
	212	+ point = %Geo.Point{coordinates: {lon, lat}, srid: 4326}
	213	+ {point, :client, point}
200	214
201	215	_ ->
202		− {Configuration.get_foci!(plani.home_foci_id).place, :home}
	216	+ {home(plani, last_seen), :home, last_seen}
	217	+ end
	218	+ end
	219	+
	220	+ # The home to settle on: the nearest to where the client last was.
	221	+ #
	222	+ # With one home this is that home, which is every Plani that has not been
	223	+ # told otherwise. With several and nothing ever heard from a client, it is
	224	+ # `home_foci_id` -- the first, and what a Plani has always fallen back to.
	225	+ defp home(plani, last_seen) do
	226	+ all = Configuration.list_focis({:user, plani.user_id})
	227	+ ids = RoomSanctum.Configuration.Plani.homes_for(plani, all)
	228	+
	229	+ all
	230	+ \|> Enum.filter(&(&1.id in ids))
	231	+ \|> nearest_home(last_seen, plani.home_foci_id)
	232	+ end
	233	+
	234	+ @doc false
	235	+ # Public only so a test can reach it; the database read is the caller's.
	236	+ def nearest_home(foci, last_seen, fallback_id)
	237	+
	238	+ def nearest_home([], _last_seen, _fallback_id), do: nil
	239	+
	240	+ def nearest_home([only], _last_seen, _fallback_id), do: only.place
	241	+
	242	+ def nearest_home(foci, %Geo.Point{} = seen, fallback_id) do
	243	+ # A foci with no place cannot be measured against and cannot be an answer.
	244	+ case Enum.filter(foci, &match?(%Geo.Point{}, &1.place)) do
	245	+ [] -> nearest_home(foci, nil, fallback_id)
	246	+ placed -> placed \|> Enum.min_by(&distance(&1.place, seen)) \|> Map.get(:place)
203	247	end
204	248	end
205	249
	250	+ def nearest_home(foci, _last_seen, fallback_id) do
	251	+ # Never heard from anybody: the first home, which is where a Plani with
	252	+ # one home has always gone.
	253	+ Enum.find_value(foci, hd(foci).place, fn f -> if f.id == fallback_id, do: f.place end)
	254	+ end
	255	+
	256	+ # Close enough to order by. Squared degrees, scaled for longitude at this
	257	+ # latitude -- no square root because nothing here needs the number itself,
	258	+ # only which of two is smaller.
	259	+ defp distance(%Geo.Point{coordinates: {lon1, lat1}}, %Geo.Point{coordinates: {lon2, lat2}}) do
	260	+ d_lat = lat1 - lat2
	261	+ d_lon = (lon1 - lon2) * :math.cos(rad((lat1 + lat2) / 2))
	262	+ d_lat * d_lat + d_lon * d_lon
	263	+ end
	264	+
206	265	# What is near the anchor, for one source. The shape of the answer matches
207	266	# what the equivalent query would have returned, so the condensers need to
208	267	# know nothing about Plani.

modified apps/room_sanctum/lib/room_sanctum_web/live/cfg_foci_live/form_component.html.heex

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

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

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added apps/room_sanctum/priv/repo/migrations/20260905120000_add_tint_to_foci.exs

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added apps/room_sanctum/priv/repo/migrations/20260905121000_add_homes_to_plani.exs

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added apps/room_sanctum/test/room_sanctum/plani_homes_test.exs

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Parents: cd0e1e5