feat(tui): integrate with Herdr host

tui/src/host.ts

@@ -0,0 +1,174 @@
+export type HostAgentState = "idle" | "working" | "blocked" | "unknown"
+
+export interface HostMetadata {
+  model?: string
+  branch?: string
+  workspace?: string
+  task?: string
+  action?: string
+}
+
+export interface TuiHost {
+  readonly hosted: boolean
+  reportState(state: HostAgentState, message?: string): void
+  reportSession(sessionId: string): void
+  reportMetadata(metadata: HostMetadata): void
+  release(): void
+}
+
+export function currentGitBranch(workspace: string): string {
+  const path = workspace.trim()
+  if (!path) return ""
+  try {
+    const branch = spawnText(["git", "-C", path, "branch", "--show-current"])
+    if (branch) return branch
+    const revision = spawnText(["git", "-C", path, "rev-parse", "--short", "HEAD"])
+    return revision ? `@${revision}` : ""
+  } catch {
+    return ""
+  }
+}
+
+type Environment = Record<string, string | undefined>
+type CommandRunner = (command: readonly string[]) => Promise<void>
+
+const AGENT = "nanobot"
+const LIFECYCLE_SOURCE = "nanobot:tui"
+const METADATA_SOURCE = "nanobot:tui:metadata"
+const METADATA_KEYS = ["model", "branch", "workspace", "task", "action"] as const
+
+class StandaloneHost implements TuiHost {
+  readonly hosted = false
+  reportState(): void {}
+  reportSession(): void {}
+  reportMetadata(): void {}
+  release(): void {}
+}
+
+class HerdrHost implements TuiHost {
+  readonly hosted = true
+  private sequence = 0
+  private released = false
+  private lastState = ""
+  private lastSession = ""
+  private metadata: HostMetadata = {}
+  private queue: Promise<void> = Promise.resolve()
+
+  constructor(
+    private readonly paneId: string,
+    private readonly binary: string,
+    private readonly run: CommandRunner,
+  ) {}
+
+  reportState(state: HostAgentState, message = ""): void {
+    if (this.released) return
+    const cleanMessage = normalize(message)
+    const fingerprint = `${state}\0${cleanMessage}\0${this.lastSession}`
+    if (fingerprint === this.lastState) return
+    this.lastState = fingerprint
+    const args = [
+      "pane", "report-agent", this.paneId,
+      "--source", LIFECYCLE_SOURCE,
+      "--agent", AGENT,
+      "--state", state,
+      "--seq", String(this.nextSequence()),
+    ]
+    if (cleanMessage) args.push("--message", cleanMessage)
+    if (this.lastSession) args.push("--agent-session-id", this.lastSession)
+    this.enqueue(args)
+  }
+
+  reportSession(sessionId: string): void {
+    if (this.released) return
+    const cleanSession = normalize(sessionId, 256)
+    if (!cleanSession || cleanSession === this.lastSession) return
+    this.lastSession = cleanSession
+    this.lastState = ""
+    this.enqueue([
+      "pane", "report-agent-session", this.paneId,
+      "--source", LIFECYCLE_SOURCE,
+      "--agent", AGENT,
+      "--agent-session-id", cleanSession,
+      "--seq", String(this.nextSequence()),
+    ])
+  }
+
+  reportMetadata(next: HostMetadata): void {
+    if (this.released) return
+    const changed: Array<[typeof METADATA_KEYS[number], string]> = []
+    for (const key of METADATA_KEYS) {
+      const value = normalize(next[key])
+      if (value === normalize(this.metadata[key])) continue
+      changed.push([key, value])
+    }
+    if (!changed.length) return
+    this.metadata = { ...this.metadata, ...next }
+    const args = [
+      "pane", "report-metadata", this.paneId,
+      "--source", METADATA_SOURCE,
+      "--agent", AGENT,
+      "--display-agent", AGENT,
+      "--seq", String(this.nextSequence()),
+    ]
+    const task = normalize(this.metadata.task)
+    args.push(task ? "--title" : "--clear-title")
+    if (task) args.push(task)
+    for (const [key, value] of changed) {
+      args.push(value ? "--token" : "--clear-token", value ? `${key}=${value}` : key)
+    }
+    this.enqueue(args)
+  }
+
+  release(): void {
+    if (this.released) return
+    this.released = true
+    const clear = [
+      "pane", "report-metadata", this.paneId,
+      "--source", METADATA_SOURCE,
+      "--clear-title", "--clear-display-agent", "--clear-state-labels",
+      "--seq", String(this.nextSequence()),
+    ]
+    for (const key of METADATA_KEYS) clear.push("--clear-token", key)
+    this.enqueue(clear)
+    this.enqueue([
+      "pane", "release-agent", this.paneId,
+      "--source", LIFECYCLE_SOURCE,
+      "--agent", AGENT,
+      "--seq", String(this.nextSequence()),
+    ])
+  }
+
+  private nextSequence(): number {
+    this.sequence += 1
+    return this.sequence
+  }
+
+  private enqueue(args: string[]): void {
+    const command = [this.binary, ...args]
+    this.queue = this.queue.then(() => this.run(command)).catch(() => {})
+  }
+}
+
+function normalize(value: string | undefined, limit = 80): string {
+  return (value || "").replace(/[\u0000-\u001f\u007f]+/gu, " ").replace(/\s+/gu, " ").trim().slice(0, limit)
+}
+
+async function runCommand(command: readonly string[]): Promise<void> {
+  const child = Bun.spawn([...command], { stdout: "ignore", stderr: "ignore" })
+  await child.exited
+}
+
+function spawnText(command: readonly string[]): string {
+  const result = Bun.spawnSync([...command], { stdout: "pipe", stderr: "ignore" })
+  if (result.exitCode !== 0) return ""
+  return new TextDecoder().decode(result.stdout).trim()
+}
+
+export function createTuiHost(
+  environment: Environment = process.env,
+  run: CommandRunner = runCommand,
+): TuiHost {
+  const paneId = environment.HERDR_PANE_ID?.trim() || ""
+  if (environment.HERDR_ENV !== "1" || !paneId) return new StandaloneHost()
+  return new HerdrHost(paneId, environment.HERDR_BIN_PATH?.trim() || "herdr", run)
+}