feat(spike): durable multiview host, gateway and remote client (P0)

package.json

@@ -6,7 +6,8 @@
   "type": "module",
   "workspaces": [
     "apps/*",
-    "packages/*"
+    "packages/*",
+    "spikes/*"
   ],
   "scripts": {
     "postinstall": "install-electron",

spikes/durable-multiview/cli/observe.ts

@@ -0,0 +1,58 @@
+#!/usr/bin/env node
+// A line-mode client of a running host: prints the shown conversation as it
+// streams, and sends each typed line. Run several to watch one host from many terminals.
+//
+//   node cli/observe.ts [--data-dir DIR] [--url ws://127.0.0.1:7420]
+//   typed lines: text (prompt; follow-up while busy), /steer text, /abort, /tasks, /quit
+import { readFile } from "node:fs/promises";
+import { join, resolve } from "node:path";
+import { createInterface } from "node:readline";
+import { parseArgs } from "node:util";
+import { getAgentDir } from "@earendil-works/pi-coding-agent";
+import { connectRemoteDurable } from "../protocol/remote-durable.ts";
+import type { DurableView } from "../protocol/view.ts";
+import { initialPrinter, printIncrement } from "./printer.ts";
+
+const { values } = parseArgs({
+  options: {
+    "data-dir": { type: "string" },
+    url: { type: "string", default: "ws://127.0.0.1:7420" },
+    token: { type: "string" },
+  },
+});
+const dataDir = resolve(values["data-dir"] ?? join(getAgentDir(), "experimental", "durable-multiview", "default"));
+const token = values.token ?? (await readFile(join(dataDir, "token"), "utf8")).trim();
+
+const remote = await connectRemoteDurable({ url: values.url, token });
+let printer = initialPrinter;
+let shown: DurableView | undefined;
+const render = (): void => {
+  const view = remote.view.current();
+  if (shown !== undefined && view.connection !== shown.connection) process.stdout.write(`\n[${view.connection}]\n`);
+  for (const notice of view.notices.slice(shown === undefined ? 0 : shown.notices.length)) {
+    process.stdout.write(`\n[${notice.level}] ${notice.message}\n`);
+  }
+  if (view.tasks !== shown?.tasks && view.tasks !== undefined) {
+    const nodes = Object.values(view.tasks.tasks).map((task) => `${task.id}:${task.kind}(${task.state.status})`);
+    process.stdout.write(`\n[tasks] ${nodes.length === 0 ? "none" : nodes.join(" ")}\n`);
+  }
+  shown = view;
+  const step = printIncrement(printer, view.conversation);
+  printer = step.state;
+  process.stdout.write(step.output);
+};
+remote.view.subscribe(render);
+process.stdout.write(`[connected to ${values.url}, session ${remote.view.current().session.id}]\n`);
+render();
+
+const input = createInterface({ input: process.stdin });
+for await (const line of input) {
+  const text = line.trim();
+  if (text === "") continue;
+  if (text === "/quit") break;
+  if (text === "/abort") await remote.controller.abort();
+  else if (text === "/tasks") await remote.controller.toggleTasks();
+  else if (text.startsWith("/steer ")) await remote.controller.submit(text.slice("/steer ".length), "steer");
+  else await remote.controller.submit(text, "followUp");
+}
+remote.close();

spikes/durable-multiview/cli/printer.ts

@@ -0,0 +1,47 @@
+import type { ConversationView } from "@earendil-works/pi-durable";
+import { streamingText, transcript, type TranscriptLine } from "../protocol/transcript.ts";
+
+/** What is already on the terminal: finished lines, and a partial left open on the last line. */
+export interface PrinterState {
+  readonly printed: readonly TranscriptLine[];
+  readonly streamed: string | undefined;
+}
+
+export const initialPrinter: PrinterState = { printed: [], streamed: undefined };
+
+const sameLine = (a: TranscriptLine, b: TranscriptLine): boolean => JSON.stringify(a) === JSON.stringify(b);
+
+const suffixOf = (line: TranscriptLine): string =>
+  line.role === "assistant" && line.stopReason !== "stop" ? ` [${line.stopReason}]` : "";
+
+const format = (line: TranscriptLine): string => `${line.role}: ${line.text}${suffixOf(line)}`;
+
+/** Append-only terminal output for the next view; a view that rewrites printed history is printed afresh. */
+export function printIncrement(state: PrinterState, view: ConversationView): { state: PrinterState; output: string } {
+  const lines = transcript(view);
+  let { printed, streamed } = state;
+  let output = "";
+
+  if (printed.length > lines.length || printed.some((line, i) => !sameLine(line, lines[i]!))) {
+    output += `${streamed === undefined ? "" : "\n"}--- view replaced ---\n`;
+    printed = [];
+    streamed = undefined;
+  }
+
+  for (const line of lines.slice(printed.length)) {
+    if (streamed === undefined) output += `${format(line)}\n`;
+    else if (line.role === "assistant" && line.text.startsWith(streamed)) output += `${line.text.slice(streamed.length)}${suffixOf(line)}\n`;
+    else output += `\n${format(line)}\n`;
+    streamed = undefined;
+  }
+  printed = lines;
+
+  const partial = streamingText(view);
+  if (partial !== undefined && partial !== "") {
+    if (streamed === undefined) output += `assistant: ${partial}`;
+    else if (partial.startsWith(streamed)) output += partial.slice(streamed.length);
+    else output += `\nassistant: ${partial}`;
+    streamed = partial;
+  }
+  return { state: { printed, streamed }, output };
+}