Fix explorer back and session usage selection

EXPLORER.md

@@ -215,9 +215,9 @@ be lost. The explorer draws over the session, which deliberately has no
 the session stays composed under it: its event stream keeps flowing, its
 scroll position and draft stay where they were, and returning from a file
 costs nothing. Back — the button and the platform gesture — clears `files`
-when set and goes to the list otherwise. Inside the explorer the same back
-steps one level: editor → viewer (with the unsaved question) → listing →
-parent directory, and only from the starting directory does it close. "Back
+and returns to the session from anywhere in the explorer. Directory navigation
+stays in the listing: `..` is an explicit row rather than a hidden second
+meaning for Back. An editor with unsaved changes asks before closing. "Back
 returns; it does not exit."
 
 Rejected: a `Screen.Files` beside `Screen.Session`. Every route back from a

PLAN.md

@@ -608,6 +608,14 @@ session now names its meter (`usageProvider`, from
 two lists cannot disagree) and `GET /usage` is matched on machine *and*
 provider. `None` is a session that meters nothing, and the phone draws
 nothing at all for it — not a zero, and not "unknown".
+The session's usage dialog applies the same machine-and-provider match and
+shows every billing pool for that provider; it does not turn opening one
+session into a comparison with the other providers on that machine.
+For a provider with several pools, the compact bar selects the pool named by
+the session's model (including Luna's `gpt-reserve` name), falling back to the
+provider's generic pool, and shows the shortest cycle that pool actually
+reports. A weekly-only pool therefore gets a weekly bar; it is never relabeled
+as five-hour merely because the provider called it `primary`.
 
 `DriverKind::Echo` names a meter of its own that exists only when a test has
 asked for one: `/usage` in an echo session sets an invented answer

app/androidApp/src/main/kotlin/com/example/aiapp/Api.kt

@@ -884,6 +884,8 @@ data class UsageWindow(
     val kind: String,
     val label: String,
     val percent: Double,
+    /** Length of this cycle, when the provider reported it. */
+    val durationMinutes: Long?,
     val resetsAt: String?,
     val active: Boolean,
 )
@@ -931,6 +933,10 @@ fun fetchUsage(settings: ServerSettings): List<UsageSnapshot> =
                             kind = window.optString("kind").ifEmpty { "unknown" },
                             label = window.getString("label"),
                             percent = window.getDouble("percent"),
+                            durationMinutes =
+                                if (window.has("durationMinutes")) {
+                                    window.getLong("durationMinutes")
+                                } else null,
                             resetsAt = window.optString("resetsAt").ifEmpty { null },
                             active = window.getBoolean("active"),
                         )

app/androidApp/src/main/kotlin/com/example/aiapp/FilesScreen.kt

@@ -61,9 +61,8 @@ private sealed class Spot(val path: String) {
  * The files on the machine a session runs on: browse them, read one, change one.
  *
  * Drawn **over** the session rather than instead of it (see [AppRoot]), so its event stream keeps
- * flowing and coming back from a file costs nothing. Back steps one level inside here -- editor to
- * viewer, viewer to the directory it came from, directory to the one above -- and only closes from
- * where it opened.
+ * flowing and coming back from a file costs nothing. Back always closes the explorer and returns to
+ * that session; directory navigation stays inside the listing, where its `..` row is explicit.
  *
  * Every directory that has been visited is kept for as long as this is open; the refresh glyph is
  * how one gets asked again on purpose, and creating something refetches the directory it was
@@ -72,7 +71,7 @@ private sealed class Spot(val path: String) {
 @Composable
 fun FilesScreen(settings: ServerSettings, target: FilesTarget, onClose: () -> Unit) {
     val scope = rememberCoroutineScope()
-    var stack by remember { mutableStateOf(listOf<Spot>(Spot.Dir(target.start))) }
+    var here by remember { mutableStateOf<Spot>(Spot.Dir(target.start)) }
     val listings = remember { mutableStateMapOf<String, LoadState<Listing>>() }
     var creating by remember { mutableStateOf(false) }
     // Edit mode and whether anything has been typed live here rather than in the pane below,
@@ -82,25 +81,14 @@ fun FilesScreen(settings: ServerSettings, target: FilesTarget, onClose: () -> Un
     var dirty by remember { mutableStateOf(false) }
     var askUnsaved by remember { mutableStateOf(false) }
 
-    val here = stack.last()
-
     fun go(spot: Spot) {
         editing = false
         dirty = false
-        stack = stack + spot
+        here = spot
     }
 
     fun back() {
-        when {
-            editing && dirty -> askUnsaved = true
-            editing -> editing = false
-            stack.size > 1 -> {
-                stack = stack.dropLast(1)
-                editing = false
-                dirty = false
-            }
-            else -> onClose()
-        }
+        if (editing && dirty) askUnsaved = true else onClose()
     }
 
     suspend fun load(path: String, again: Boolean) {
@@ -173,8 +161,7 @@ fun FilesScreen(settings: ServerSettings, target: FilesTarget, onClose: () -> Un
         UnsavedDialog(
             onDiscard = {
                 askUnsaved = false
-                editing = false
-                dirty = false
+                onClose()
             },
             onCancel = { askUnsaved = false },
         )

app/androidApp/src/main/kotlin/com/example/aiapp/SessionScreen.kt

@@ -1929,7 +1929,9 @@ fun SessionScreen(
     // is the screen's business rather than any row's. See [SessionImageViewer].
     fullImage?.let { ref -> SessionImageViewer(settings, summary.id, ref) { fullImage = null } }
     if (usageOpen) {
-        usageFeed?.let { UsageDialog(feed = it, onDismiss = { usageOpen = false }) }
+        usageFeed?.let {
+            UsageDialog(feed = it, session = summary, onDismiss = { usageOpen = false })
+        }
     }
     if (settingsOpen) {
         // Measured when the dialog opens rather than kept up to date: what the reader is being told

app/androidApp/src/main/kotlin/com/example/aiapp/SessionUsageBar.kt

@@ -83,7 +83,7 @@ class UsageFeed(
         return when (val state = snapshots) {
             is LoadState.Loading -> SessionUsage.Waiting
             is LoadState.Error -> SessionUsage.Unavailable(state.message)
-            is LoadState.Loaded -> usageFor(state.value, session.setup, provider)
+            is LoadState.Loaded -> usageFor(state.value, session.setup, provider, session.model)
         }
     }
 }
@@ -125,8 +125,8 @@ fun rememberUsageFeed(settings: ServerSettings): UsageFeed {
  *
  * Worst rather than the five-hour one, because the button it colours opens *all* of them, and a
  * blue icon over a weekly quota at 97% would be the interface answering a question nobody asked.
- * Taken over however many windows came back rather than the three Claude sends today -- the backend
- * passes windows it does not recognise straight through.
+ * Taken over however many windows this session's provider returned rather than the three Claude
+ * sends today -- the backend passes windows it does not recognise straight through.
  *
  * Every state that is not a measurement takes the ordinary control colour instead. That is the
  * point where colour stops being able to help: blue is the low end of a scale here, so colouring an
@@ -142,7 +142,7 @@ fun usageGlyphColour(usage: SessionUsage): Color =
     }
 
 /**
- * The five-hour window for the machine this session runs on, under the session's own header.
+ * The shortest usage window for the pool this session uses, under the session's own header.
  *
  * Here rather than only in the usage dialog because it is the number that decides whether to keep
  * going, and it was a screen away from the place that decision gets made. It reports on this
@@ -189,11 +189,11 @@ fun SessionUsageBar(usage: SessionUsage, modifier: Modifier = Modifier) {
             // Both handled above, before the row exists at all.
             SessionUsage.NotMetered,
             SessionUsage.Waiting -> Unit
-            is SessionUsage.Unavailable -> UsageNote("5-hour usage unknown -- ${state.why}")
+            is SessionUsage.Unavailable -> UsageNote("Usage unknown -- ${state.why}")
             is SessionUsage.Known -> {
-                val window = state.windows.firstOrNull { it.kind == "session" }
+                val window = shortestUsageWindow(state.windows)
                 if (window == null) {
-                    UsageNote("5-hour usage unknown -- no five-hour window reported")
+                    UsageNote("Usage unknown -- no window duration was reported")
                 } else {
                     LinearProgressIndicator(
                         progress = { (window.percent / 100.0).toFloat().coerceIn(0f, 1f) },
@@ -204,7 +204,7 @@ fun SessionUsageBar(usage: SessionUsage, modifier: Modifier = Modifier) {
                         modifier = Modifier.weight(1f),
                     )
                     Text(
-                        fiveHourLabel(window, now),
+                        usageWindowLabel(window, now),
                         style = MaterialTheme.typography.labelSmall,
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                         modifier = Modifier.padding(start = 8.dp),
@@ -234,11 +234,11 @@ private fun UsageNote(text: String) {
  * The window's end has two missing cases, worded differently on purpose; see [WindowEnd]. A window
  * that is not running gets the percentage and nothing else.
  */
-private fun fiveHourLabel(window: UsageWindow, now: OffsetDateTime): String {
-    val percent = "${window.percent.toInt()}%"
+private fun usageWindowLabel(window: UsageWindow, now: OffsetDateTime): String {
+    val percent = "${window.label} · ${window.percent.toInt()}%"
     return when (val end = windowEnd(window.resetsAt, now)) {
-        // Between blocks the five-hour window has no reset time, and saying so is a fact about
-        // nothing: there is no window to run out. The percentage is the whole answer.
+        // Between blocks a window can have no reset time, and saying so is a fact about nothing:
+        // there is no window to run out. The percentage is the whole answer.
         WindowEnd.NotRunning -> percent
         WindowEnd.Unreadable -> "$percent · reset time unreadable"
         is WindowEnd.Ends ->
@@ -260,14 +260,52 @@ private fun fiveHourLabel(window: UsageWindow, now: OffsetDateTime): String {
  * None of them may look like zero, and none may look like [SessionUsage.NotMetered], which is the
  * machine having no quota rather than the question going unanswered.
  */
-fun usageFor(snapshots: List<UsageSnapshot>, setup: String, provider: String): SessionUsage {
+fun usageFor(
+    snapshots: List<UsageSnapshot>,
+    setup: String,
+    provider: String,
+    model: String?,
+): SessionUsage {
     // No snapshot at all means the backend never asked, which it only does where there is nothing
     // to ask about. That is a different answer from having asked and failed.
+    val pools = usageSnapshotsFor(snapshots, setup, provider)
+    if (pools.isEmpty()) return SessionUsage.NotMetered
     val mine =
-        snapshots.firstOrNull { it.setup == setup && it.provider == provider }
-            ?: return SessionUsage.NotMetered
+        usagePoolFor(pools, model)
+            ?: return SessionUsage.Unavailable("couldn't tell which usage pool this session uses")
     if (mine.state != "ok") {
         return SessionUsage.Unavailable(mine.detail ?: mine.state)
     }
     return SessionUsage.Known(mine.windows)
 }
+
+/** Every billing pool reported for one provider on one machine. */
+internal fun usageSnapshotsFor(
+    snapshots: List<UsageSnapshot>,
+    setup: String,
+    provider: String?,
+): List<UsageSnapshot> =
+    if (provider == null) emptyList()
+    else snapshots.filter { it.setup == setup && it.provider == provider }
+
+/** The pool an explicit model names, or the provider's generic pool for every other model. */
+internal fun usagePoolFor(pools: List<UsageSnapshot>, model: String?): UsageSnapshot? {
+    if (pools.size == 1) return pools.first()
+    val normalizedModel = model?.normalizedPoolName()
+    val named = normalizedModel?.let { wanted ->
+        pools.firstOrNull { pool ->
+            val name = pool.limitName?.normalizedPoolName()
+            name == wanted || (wanted.contains("luna") && name == "gptreserve")
+        }
+    }
+    return named ?: pools.firstOrNull { it.limitId == "codex" }
+}
+
+/** The shortest cycle the selected pool actually reported. */
+internal fun shortestUsageWindow(windows: List<UsageWindow>): UsageWindow? =
+    windows
+        .mapNotNull { window -> window.durationMinutes?.let { duration -> duration to window } }
+        .minByOrNull { it.first }
+        ?.second
+
+private fun String.normalizedPoolName(): String = lowercase().filter(Char::isLetterOrDigit)

app/androidApp/src/main/kotlin/com/example/aiapp/UsageDialog.kt

@@ -30,7 +30,7 @@ import java.time.OffsetDateTime
  * own, so the only thing its Back could ever have meant was "put this away".
  */
 @Composable
-fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
+fun UsageDialog(feed: UsageFeed, session: SessionSummary, onDismiss: () -> Unit) {
     // A plain Dialog rather than an AlertDialog, for the spacing alone. AlertDialog fixes the gaps
     // between its title, content and buttons at sizes meant for a sentence of prose and a decision;
     // this is a dense read-out, and those gaps left a band of empty dialog above Close that was
@@ -45,10 +45,6 @@ fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
                     verticalAlignment = Alignment.CenterVertically,
                     modifier = Modifier.fillMaxWidth(),
                 ) {
-                    // Deliberately not subtitled with the provider this was opened from. These
-                    // numbers belong to an account on a particular machine -- naming the session's
-                    // provider here made an echo session's screen read "echo" above a line reading
-                    // "claude". Each machine names itself and the service it came from.
                     Text(
                         "Usage",
                         style = MaterialTheme.typography.headlineSmall,
@@ -65,10 +61,24 @@ fun UsageDialog(feed: UsageFeed, onDismiss: () -> Unit) {
                 }
                 Spacer(Modifier.height(8.dp))
                 // Scrolls rather than being trimmed: a machine can report any number of windows and
-                // there can be any number of machines, and a dialog is the one place where running
-                // out of room is silent. `fill = false` so a short read-out keeps a short dialog.
+                // a provider can report several billing pools, and a dialog is the one place where
+                // running out of room is silent. `fill = false` so a short read-out keeps a short
+                // dialog.
                 Column(Modifier.weight(1f, fill = false).verticalScroll(rememberScrollState())) {
-                    UsageBody(feed.snapshots)
+                    val state =
+                        when (val snapshots = feed.snapshots) {
+                            is LoadState.Loading -> LoadState.Loading
+                            is LoadState.Error -> snapshots
+                            is LoadState.Loaded ->
+                                LoadState.Loaded(
+                                    usageSnapshotsFor(
+                                        snapshots.value,
+                                        session.setup,
+                                        session.usageProvider,
+                                    )
+                                )
+                        }
+                    UsageBody(state)
                 }
                 TextButton(onClick = onDismiss, modifier = Modifier.align(Alignment.End)) {
                     Text("Close")
@@ -87,18 +97,18 @@ private fun UsageBody(state: LoadState<List<UsageSnapshot>>) {
             is LoadState.Error -> Text(current.message, color = MaterialTheme.colorScheme.error)
             is LoadState.Loaded ->
                 if (current.value.isEmpty()) {
-                    // Not an error and not a blank screen: no machine offers a paid service, so
+                    // Not an error and not a blank screen: this provider has no paid quota, so
                     // there is genuinely nothing to report and saying so is the answer.
                     Text(
-                        "No machine here runs anything with usage limits.",
+                        "This session's provider has no usage limits.",
                         style = MaterialTheme.typography.bodyMedium,
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                     )
                 } else {
-                    // No card around each machine. A card is a step up the surface ladder, and
-                    // inside a dialog -- itself a raised surface -- the step barely renders while
-                    // costing 16dp on every side. What separates one machine from the next is the
-                    // line naming it.
+                    // No card around each pool. A card is a step up the surface ladder, and inside
+                    // a dialog -- itself a raised surface -- the step barely renders while costing
+                    // 16dp on every side. What separates one pool from the next is the line naming
+                    // it.
                     current.value.forEachIndexed { index, snapshot ->
                         if (index > 0) {
                             Spacer(Modifier.height(20.dp))

app/androidApp/src/test/kotlin/com/example/aiapp/SessionUsageTest.kt

@@ -0,0 +1,90 @@
+package com.example.aiapp
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class SessionUsageTest {
+    @Test
+    fun `usage snapshots stay with the session's machine and provider`() {
+        val claude = snapshot("machine", "claude", null)
+        val codex = snapshot("machine", "codex", "codex")
+        val reserve = snapshot("machine", "codex", "gpt-reserve")
+        val elsewhere = snapshot("other", "codex", "codex")
+
+        assertEquals(
+            listOf(codex, reserve),
+            usageSnapshotsFor(
+                listOf(claude, codex, reserve, elsewhere),
+                setup = "machine",
+                provider = "codex",
+            ),
+        )
+    }
+
+    @Test
+    fun `a session without a meter has no usage snapshots`() {
+        assertEquals(
+            emptyList(),
+            usageSnapshotsFor(
+                listOf(snapshot("machine", "claude", null)),
+                setup = "machine",
+                provider = null,
+            ),
+        )
+    }
+
+    @Test
+    fun `the model selects its named pool and other models use the generic pool`() {
+        val generic = snapshot("machine", "codex", "codex")
+        val spark =
+            snapshot(
+                "machine",
+                "codex",
+                "codex_bengalfox",
+                limitName = "GPT-5.3-Codex-Spark",
+            )
+        val reserve =
+            snapshot("machine", "codex", "base_model_inference", limitName = "gpt-reserve")
+        val pools = listOf(generic, spark, reserve)
+
+        assertEquals(spark, usagePoolFor(pools, "gpt-5.3-codex-spark"))
+        assertEquals(reserve, usagePoolFor(pools, "gpt-5.6-luna"))
+        assertEquals(generic, usagePoolFor(pools, "gpt-6-astra"))
+    }
+
+    @Test
+    fun `the bar uses the shortest reported cycle`() {
+        val weekly = window("Weekly", 10_080)
+        val hourly = window("5-hour window", 300)
+
+        assertEquals(hourly, shortestUsageWindow(listOf(weekly, hourly)))
+        assertEquals(null, shortestUsageWindow(listOf(window("unknown", null))))
+    }
+
+    private fun snapshot(
+        setup: String,
+        provider: String,
+        limitId: String?,
+        limitName: String? = null,
+    ) =
+        UsageSnapshot(
+            provider = provider,
+            setup = setup,
+            setupName = setup,
+            limitId = limitId,
+            limitName = limitName,
+            state = "ok",
+            detail = null,
+            windows = emptyList(),
+        )
+
+    private fun window(label: String, durationMinutes: Long?) =
+        UsageWindow(
+            kind = "test",
+            label = label,
+            percent = 12.0,
+            durationMinutes = durationMinutes,
+            resetsAt = null,
+            active = false,
+        )
+}

server/src/resume.rs

@@ -282,6 +282,7 @@ mod tests {
             kind: "session".to_string(),
             label: "5-hour window".to_string(),
             percent,
+            duration_minutes: Some(300),
             resets_at: resets_at.map(str::to_string),
             active: true,
         }

server/src/usage.rs

@@ -60,6 +60,9 @@ pub struct UsageWindow {
     pub label: String,
     /// 0-100.
     pub percent: f64,
+    /// Length of the cycle when the provider reports one.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub duration_minutes: Option<u64>,
     /// ISO-8601, as the API sends it; absent for windows that never reset.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub resets_at: Option<String>,
@@ -361,11 +364,18 @@ fn parse_codex_windows(limits: &Value) -> Vec<UsageWindow> {
                 None => "Secondary window".to_string(),
             };
             Some(UsageWindow {
-                // Common semantic names: the phone's compact bar asks for
-                // `session`, and auto-resume treats all windows alike.
-                kind: if primary { "session" } else { "weekly_all" }.to_string(),
+                // Keep the common semantic names where the duration establishes them. `primary`
+                // is only the protocol's position and can itself be a weekly window.
+                kind: match minutes {
+                    Some(300) => "session",
+                    Some(10_080) => "weekly_all",
+                    _ if primary => "primary",
+                    _ => "secondary",
+                }
+                .to_string(),
                 label,
                 percent: window.get("usedPercent")?.as_f64()?,
+                duration_minutes: minutes,
                 resets_at: window
                     .get("resetsAt")
                     .and_then(Value::as_i64)
@@ -374,7 +384,8 @@ fn parse_codex_windows(limits: &Value) -> Vec<UsageWindow> {
                         at.format(&time::format_description::well_known::Rfc3339)
                             .ok()
                     }),
-                active: primary,
+                // Unlike Claude's response, Codex does not say which window is binding.
+                active: false,
             })
         })
         .collect()
@@ -528,6 +539,11 @@ fn parse_windows(body: &Value) -> Vec<UsageWindow> {
                 kind: kind.to_string(),
                 label,
                 percent,
+                duration_minutes: match kind {
+                    "session" => Some(300),
+                    "weekly_all" | "weekly_scoped" => Some(10_080),
+                    _ => None,
+                },
                 resets_at: limit
                     .get("resets_at")
                     .and_then(Value::as_str)
@@ -662,6 +678,7 @@ fn fixture_windows(percent: f64, reset: Option<&str>) -> Vec<UsageWindow> {
             kind: "session".to_string(),
             label: "5-hour window".to_string(),
             percent,
+            duration_minutes: Some(300),
             resets_at: resets_at.clone(),
             active: true,
         },
@@ -669,6 +686,7 @@ fn fixture_windows(percent: f64, reset: Option<&str>) -> Vec<UsageWindow> {
             kind: "weekly_all".to_string(),
             label: "Weekly (all models)".to_string(),
             percent: percent / 2.0,
+            duration_minutes: Some(10_080),
             resets_at: resets_at.as_ref().map(|_| reset_in(FIXTURE_MINUTES * 40)),
             active: false,
         },
@@ -676,6 +694,7 @@ fn fixture_windows(percent: f64, reset: Option<&str>) -> Vec<UsageWindow> {
             kind: "weekly_scoped".to_string(),
             label: "Weekly (Echo)".to_string(),
             percent: percent / 4.0,
+            duration_minutes: Some(10_080),
             resets_at: resets_at.as_ref().map(|_| reset_in(FIXTURE_MINUTES * 40)),
             active: false,
         },
@@ -1107,9 +1126,11 @@ mod tests {
         assert_eq!(windows.len(), 2);
         assert_eq!(windows[0].label, "5-hour window");
         assert_eq!(windows[0].percent, 10.0);
-        assert!(windows[0].active);
+        assert_eq!(windows[0].duration_minutes, Some(300));
+        assert!(!windows[0].active);
         assert_eq!(windows[1].kind, "weekly_all");
         assert_eq!(windows[1].label, "Weekly");
+        assert_eq!(windows[1].duration_minutes, Some(10_080));
         assert!(
             windows[1]
                 .resets_at
@@ -1141,6 +1162,8 @@ mod tests {
         assert_eq!(snapshot.limit_id.as_deref(), Some("base_model_inference"));
         assert_eq!(snapshot.limit_name.as_deref(), Some("gpt-reserve"));
         assert_eq!(snapshot.windows.len(), 1);
+        assert_eq!(snapshot.windows[0].kind, "weekly_all");
         assert_eq!(snapshot.windows[0].label, "Weekly");
+        assert_eq!(snapshot.windows[0].duration_minutes, Some(10_080));
     }
 }