feat(tui): add replaceable prompt footer slot

packages/tui/src/feature-plugins/prompt/footer.tsx

@@ -0,0 +1,89 @@
+import { Plugin } from "@opencode-ai/plugin/tui"
+import { createMemo, Match, Show, Switch } from "solid-js"
+import { contextUsage, formatContextUsage } from "../../util/session"
+
+const money = new Intl.NumberFormat("en-US", {
+  style: "currency",
+  currency: "USD",
+})
+
+export function PromptFooter(props: { context: Plugin.Context; sessionID?: string; mode: "normal" | "shell" }) {
+  const activeSubagents = createMemo(() => {
+    if (!props.sessionID) return 0
+    return props.context.data.session
+      .family(props.sessionID)
+      .filter((id) => id !== props.sessionID && props.context.data.session.status(id) === "running").length
+  })
+  const runningShells = createMemo(() => {
+    if (!props.sessionID) return 0
+    return props.context.data.shell
+      .list(props.context.location)
+      .filter((shell) => shell.metadata.sessionID === props.sessionID).length
+  })
+  const subagents = createMemo(() => {
+    const count = activeSubagents()
+    return count ? `${count} subagent${count === 1 ? "" : "s"}` : undefined
+  })
+  const shells = createMemo(() => {
+    const count = runningShells()
+    return count ? `${count} shell${count === 1 ? "" : "s"}` : undefined
+  })
+  const status = createMemo(() => {
+    if (!props.sessionID) return []
+    const session = props.context.data.session.get(props.sessionID)
+    if (!session) return []
+    const usage = contextUsage(
+      props.context.data.session.message.list(props.sessionID),
+      props.context.data.location.model.list(session.location),
+      session.revert?.messageID,
+    )
+    const cost = props.context.data.session.cost(props.sessionID)
+    return [usage ? formatContextUsage(usage.tokens, usage.percent) : undefined, cost > 0 ? money.format(cost) : undefined]
+      .filter((item): item is string => Boolean(item))
+  })
+  const live = createMemo(() => Boolean(subagents() || shells()))
+  const shortcut = (id: string) => props.context.keymap.shortcuts(id)[0]
+
+  return (
+    <Switch>
+      <Match when={props.mode === "normal"}>
+        <Switch>
+          <Match when={live() || status().length > 0}>
+            <text fg={props.context.theme.text.subdued} wrapMode="none" truncate flexShrink={1}>
+              <Show when={live() && shortcut("session.child.first")}>
+                {(value) => <span style={{ fg: props.context.theme.text.default }}>{value()} </span>}
+              </Show>
+              <Show when={subagents()}>{(value) => <span>{value()}</span>}</Show>
+              <Show when={subagents() && shells()}> · </Show>
+              <Show when={shells()}>{(value) => <span>{value()}</span>}</Show>
+              <Show when={live() && status().length > 0}> · </Show>
+              <Show when={status().length > 0}>{status().join(" · ")}</Show>
+            </text>
+          </Match>
+          <Match when={true}>
+            <text fg={props.context.theme.text.default} flexShrink={0}>
+              {shortcut("agent.cycle")} <span style={{ fg: props.context.theme.text.subdued }}>agents</span>
+            </text>
+          </Match>
+        </Switch>
+        <text fg={props.context.theme.text.default} flexShrink={0}>
+          {shortcut("command.palette.show")} <span style={{ fg: props.context.theme.text.subdued }}>commands</span>
+        </text>
+      </Match>
+      <Match when={props.mode === "shell"}>
+        <text fg={props.context.theme.text.default} flexShrink={0}>
+          esc <span style={{ fg: props.context.theme.text.subdued }}>exit shell mode</span>
+        </text>
+      </Match>
+    </Switch>
+  )
+}
+
+export default Plugin.define({
+  id: "opencode.prompt-footer",
+  setup(context) {
+    context.ui.slot("prompt.footer.end", (props) => (
+      <PromptFooter context={context} sessionID={props.sessionID} mode={props.mode} />
+    ))
+  },
+})