/**
 * Answer Picker — preset follow-up prompts as clickable buttons in the pane frame.
 *
 * Puts the short prompts you type over and over ("continue", "yes", "run the
 * tests", ...) into the bottom frame row of pi's own pane, via the sl0p zellij
 * fork's OSC 5577 pane-status-bar protocol. Click one, or press alt+<N>, and it
 * is sent to the agent as a real user message.
 *
 *   ╭───────────────────────── pi ─────────────────────────╮
 *   │ transcript, editor, …                                │
 *   ╰ alt+N · ready ──[continue]─[yes]─[no]─[explain]───────╯
 *      ^ status text        ^ zellij-drawn, clickable
 *
 * ── WHERE THE ANSWERS COME FROM ──────────────────────────────────────────────
 * Two sources, with the file winning outright when it exists:
 *
 *   1. DEFAULTS below — the built-in set, used when no file is present.
 *   2. <cwd>/.pi-answers.md — per-project answers, read at session start.
 *
 * The file is authoritative rather than additive: it is SEEDED with DEFAULTS the
 * first time anything writes it, so "file wins" and "you still get the defaults"
 * are the same statement. That keeps precedence trivial to reason about (there is
 * no merge order to remember) while making the defaults editable — delete a line
 * from the file and that button is gone, which an additive model could not do.
 *
 * `/answers add <label> [text…]` appends and persists in one step, creating the
 * file (defaults + the new answer) if it does not exist yet. Hand-editing the
 * file is equally supported; `/answers reload` re-reads it.
 *
 * File format — a markdown list, label in backticks so the text may contain any
 * punctuation (including the em dash used as separator):
 *
 *     - `continue` — continue
 *     - `no` — no — don't do that
 *
 * Parsing takes the label from between the backticks and everything after the
 * first separator as the text, so a dash inside the text is not a problem. A
 * looser `- label: text` / `- label -> text` form is also accepted for
 * hand-written files.
 *
 * ── WHY OSC 5577 RATHER THAN DRAWING OUR OWN BUTTONS ─────────────────────────
 * v1 drew its own button row and enabled terminal mouse reporting inside pi.
 * Mouse reporting is per-terminal, not per-region — the wheel is just another
 * button in that protocol — so pi's pane lost native wheel scrolling and
 * click-drag selection as the price of clickable buttons. v2 moved the buttons to
 * a second pane to confine the tracking, which restored scrolling but cost an
 * extra pane, a picker process and a unix socket.
 *
 * OSC 5577 removes the tradeoff instead of relocating it: zellij draws the
 * buttons in the frame it already owns, hit-tests them itself, and reports a
 * click as a fixed-format sequence on our stdin. No mouse reporting anywhere, no
 * second pane, no socket. The frame row also does not shrink the content area, so
 * setting or clearing it never resizes the PTY nor sends SIGWINCH.
 *
 *   we send:   ESC ] 5577;1;buttons;ans-continue:continue;ans-yes:yes ESC \
 *              ESC ] 5577;1;status;alt+N · ready                      ESC \
 *   we get:    ESC ] 5577;1;click;ans-continue                        ESC \
 *
 * ── CONSEQUENCES OF THE PROTOCOL WE HAVE TO HANDLE ───────────────────────────
 *   - Click reports arrive INTERLEAVED with ordinary stdin, like a cursor-position
 *     or OSC 11 reply. We scan for them and strip them, because anything left in
 *     the stream would be typed into the editor as garbage. We do get whole
 *     reports: pi-tui's StdinBuffer holds an `ESC ]` sequence until its ST/BEL
 *     terminator arrives (isCompleteOscSequence), so a report split across
 *     read() boundaries is reassembled before it reaches us.
 *   - Ids are validated against the buttons we actually declared. They are
 *     DERIVED FROM THE LABEL (ans-<slug>) rather than positional, so that when
 *     the answer list changes, a click report for a button that no longer exists
 *     simply fails to match instead of resolving to whatever now occupies that
 *     index. Positional ids would silently fire the wrong prompt.
 *   - These are in-band escapes, so anything that writes to the pane (a `cat` of
 *     a hostile file) can declare buttons and draw a misleading bar. A click
 *     report is a hint that a user pressed something, not proof that we put it
 *     there — hence the allow-list, and hence keeping the action non-destructive
 *     (it sends a prompt; it does not deploy anything).
 *   - The bar survives detach/reattach AND session resurrection, so a restored
 *     pane can come back showing a stale bar. We re-assert on every session_start
 *     and clear on shutdown rather than trusting the screen.
 *   - Buttons are click-only; the protocol has no keyboard access. alt+1..9 is
 *     ours, is registered once against a live lookup (so answers added at runtime
 *     get a working key immediately), and works even with frames off — including
 *     mid-run, when the buttons themselves are deliberately withdrawn.
 *
 * ── BUTTONS ONLY EXIST BETWEEN TURNS ───────────────────────────────────────
 * While a run is in flight the buttons are withdrawn and only the status text
 * remains, so a click cannot queue a second answer behind the one already
 * working. They come back when the run settles — completed, errored, or
 * cancelled. That relies on agent_settled as much as agent_end: agent_settled is
 * what fires on the abort/error paths where agent_end never arrives, so an
 * escape-key cancel or a provider blow-up still restores them rather than
 * leaving the frame permanently bare.
 *
 * Withdrawing means sending `buttons` with an empty payload (an empty list),
 * NOT `clear` — `clear` would take the status text with it. Verified against the
 * fork: the buttons verb assigns parse_status_bar_buttons(payload), which
 * filter_maps away every field lacking an `id:label`, and only `clear` touches
 * status_bar.
 *   - The bar needs pane frames. With pane_frame_style "none"/"titles", or after
 *     TogglePaneFrames, it is simply not drawn — nothing breaks.
 *   - Protocol limits: 8 buttons, 512-char status, control chars stripped.
 *     Answers past the 8th stay keyboard-only rather than being silently dropped.
 */

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { truncateToWidth, visibleWidth, wrapTextWithAnsi } from "@earendil-works/pi-tui";
import fs from "node:fs";
import path from "node:path";

type Answer = { label: string; text: string };

/** Payload for the /answers list transcript entry. */
type AnswersListData = {
  answers: Answer[];
  source: "file" | "defaults";
  path: string;
  maxButtons: number;
};

/** Built-in set. Used until a .pi-answers.md exists, and seeds it when created. */
const DEFAULTS: readonly Answer[] = [
  { label: "continue", text: "continue" },
  { label: "yes", text: "yes, go ahead" },
  { label: "no", text: "no — don't do that" },
  { label: "explain", text: "explain what you just did, and why" },
  { label: "tests", text: "run the tests and fix anything that fails" },
  { label: "commit", text: "commit this with a clear message" },
];

/** Per-project answers, looked up in the cwd pi was started in. */
const ANSWERS_FILE = ".pi-answers.md";

const NUDGE_KEYS = ["alt+1", "alt+2", "alt+3", "alt+4", "alt+5", "alt+6", "alt+7", "alt+8", "alt+9"] as const;
const MIDRUN_DELIVERY: "steer" | "followUp" = "followUp";
const DEBOUNCE_MS = 250;

// Protocol ceilings (zellij drops the excess itself; we cap to stay predictable).
const MAX_BUTTONS = 8;
const MAX_STATUS = 512;
const MAX_LABEL = 24;

const OSC = "\x1b]5577;1;";
const ST = "\x1b\\";
const CLICK_RE = /\x1b\]5577;1;click;([A-Za-z0-9_-]{1,32})(?:\x1b\\|\x07)/g;

/** Button fields are `;`-separated, so `;` `:` `%` must be %-escaped in labels. */
const escLabel = (s: string) => s.replace(/%/g, "%25").replace(/;/g, "%3B").replace(/:/g, "%3A");
// eslint-disable-next-line no-control-regex
const stripCtl = (s: string) => s.replace(/[\x00-\x1f\x7f]/g, "");

/**
 * Labels are delimited by backticks in the file, so a backtick inside one would
 * corrupt the format on the next write. Strip them here rather than at the write
 * site, so a hand-written ``- `` — x`` (empty backticks) also collapses to an
 * empty label and gets dropped instead of becoming a junk `` `` `` button.
 */
const cleanLabel = (s: string) => stripCtl(s).replace(/`/g, "").slice(0, MAX_LABEL).trim();

/** Markdown list item: canonical ``- `label` — text`` plus looser fallbacks. */
function parseAnswers(md: string): Answer[] {
  const out: Answer[] = [];
  const seen = new Set<string>();
  for (const raw of md.split(/\r?\n/)) {
    const line = raw.trim();
    if (!line.startsWith("-") && !line.startsWith("*")) continue;
    const item = line.replace(/^[-*]\s*/, "");
    if (!item) continue;

    let label: string;
    let text: string;
    const backticked = /^`([^`]{1,64})`\s*(.*)$/.exec(item);
    if (backticked) {
      label = backticked[1].trim();
      text = backticked[2].replace(/^\s*(?:—|--|->|:)\s*/, "").trim();
    } else {
      const sep = /\s+(?:—|--|->)\s+|:\s+/.exec(item);
      if (sep) {
        label = item.slice(0, sep.index).trim();
        text = item.slice(sep.index + sep[0].length).trim();
      } else {
        label = item.trim();
        text = label;
      }
    }
    label = cleanLabel(label);
    text = stripCtl(text).trim() || label;
    if (!label || seen.has(label.toLowerCase())) continue;
    seen.add(label.toLowerCase());
    out.push({ label, text });
  }
  return out;
}

function renderAnswers(list: readonly Answer[]): string {
  return [
    "# pi answer buttons",
    "",
    "<!-- Clickable buttons in this pane's zellij frame row (OSC 5577), also alt+1..9.",
    "     Format:  - `label` — text sent to the agent",
    "     This file is authoritative: it was seeded with answer-picker.ts defaults,",
    "     so deleting a line removes that button. `/answers reload` re-reads it. -->",
    "",
    ...list.map((a) => `- \`${a.label}\` — ${a.text}`),
    "",
  ].join("\n");
}

/**
 * Stable, label-derived button id. Deliberately not positional: if the answer
 * list changes, an in-flight click for a vanished button must fail the allow-list
 * rather than resolve to whatever took its index.
 */
function buttonId(label: string, idx: number, taken: Set<string>): string {
  const slug = label
    .toLowerCase()
    .replace(/[^a-z0-9_-]+/g, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 24);
  let id = slug ? `ans-${slug}` : `ans-${idx}`;
  if (taken.has(id)) id = `${id}-${idx}`.slice(0, 32);
  return id;
}

export default function (pi: ExtensionAPI) {
  let answers: Answer[] = DEFAULTS.map((a) => ({ ...a }));
  /** id -> index allow-list for the buttons currently declared. */
  const declared = new Map<string, number>();
  let filePath: string | undefined;
  let fromFile = false;
  let barActive = false;
  let buttonsShown = false;
  let isRunning = false;
  let turn = 0;
  let lastFireAt = 0;
  let unsubInput: (() => void) | undefined;

  const inZellij = () => !!process.env.ZELLIJ || !!process.env.ZELLIJ_SESSION_NAME;

  function write(s: string) {
    try {
      process.stdout.write(s);
    } catch {
      /* closed stdout */
    }
  }

  // ── answers file ──────────────────────────────────────────────────────────
  function resolvePath(ctx: any): string {
    return path.join(ctx?.cwd || process.cwd(), ANSWERS_FILE);
  }

  function loadAnswers(ctx: any): { source: "file" | "defaults"; count: number; error?: string } {
    filePath = resolvePath(ctx);
    try {
      if (fs.existsSync(filePath)) {
        const parsed = parseAnswers(fs.readFileSync(filePath, "utf8"));
        if (parsed.length > 0) {
          answers = parsed;
          fromFile = true;
          return { source: "file", count: parsed.length };
        }
        // Present but unparseable: fall back rather than leave the user with no
        // buttons, and say so instead of failing silently.
        answers = DEFAULTS.map((a) => ({ ...a }));
        fromFile = false;
        return { source: "defaults", count: answers.length, error: `${ANSWERS_FILE} has no readable entries` };
      }
    } catch (err: any) {
      answers = DEFAULTS.map((a) => ({ ...a }));
      fromFile = false;
      return { source: "defaults", count: answers.length, error: err?.message ?? String(err) };
    }
    answers = DEFAULTS.map((a) => ({ ...a }));
    fromFile = false;
    return { source: "defaults", count: answers.length };
  }

  /** Persist current answers, creating the file (seeded with defaults) if needed. */
  function saveAnswers(ctx: any): string | undefined {
    const p = filePath ?? resolvePath(ctx);
    try {
      fs.writeFileSync(p, renderAnswers(answers), "utf8");
      filePath = p;
      fromFile = true;
      return undefined;
    } catch (err: any) {
      return err?.message ?? String(err);
    }
  }

  // ── OSC 5577 bar ──────────────────────────────────────────────────────────
  function showButtons() {
    if (!inZellij()) return;
    declared.clear();
    const spec: string[] = [];
    answers.slice(0, MAX_BUTTONS).forEach((a, idx) => {
      const id = buttonId(a.label, idx, new Set(declared.keys()));
      declared.set(id, idx);
      spec.push(`${id}:${escLabel(a.label)}`);
    });
    if (spec.length === 0) {
      hideButtons();
      return;
    }
    write(`${OSC}buttons;${spec.join(";")}${ST}`);
    buttonsShown = true;
    barActive = true;
  }

  /**
   * Drop ONLY the buttons, keeping the status text. `buttons` with no id:label
   * field parses to an empty list in the fork (parse_status_bar_buttons
   * filter_maps every field lacking a ':'), whereas `clear` is the one verb that
   * would also wipe the status.
   *
   * Clearing `declared` matters as much as the redraw: a click report already in
   * flight when the run started must not fire against a button that is no longer
   * on screen.
   */
  function hideButtons() {
    declared.clear();
    if (!inZellij() || !buttonsShown) return;
    buttonsShown = false;
    write(`${OSC}buttons${ST}`);
    barActive = true;
  }

  function setStatus() {
    if (!inZellij()) return;
    const state = isRunning ? "working" : "ready";
    const extra = answers.length > MAX_BUTTONS ? ` · +${answers.length - MAX_BUTTONS} via alt+N` : "";
    write(`${OSC}status;${stripCtl(`alt+N · ${state}${turn ? ` · #${turn}` : ""}${extra}`).slice(0, MAX_STATUS)}${ST}`);
    barActive = true;
  }

  function clearBar() {
    if (!barActive) return;
    barActive = false;
    buttonsShown = false;
    declared.clear();
    write(`${OSC}clear${ST}`);
  }

  /**
   * Assert the bar for the current state. Buttons exist only between turns:
   * while the agent is working they are withdrawn, so a click cannot queue a
   * second answer behind the one already in flight. The status text stays up
   * throughout, which is also what advertises that alt+N still works.
   */
  function refresh() {
    if (isRunning) hideButtons();
    else showButtons();
    setStatus();
  }

  function fire(idx: number) {
    const a = answers[idx];
    if (!a) return;
    const now = Date.now();
    if (now - lastFireAt < DEBOUNCE_MS) return;
    lastFireAt = now;
    if (isRunning) pi.sendUserMessage(a.text, { deliverAs: MIDRUN_DELIVERY });
    else pi.sendUserMessage(a.text);
  }

  function onInput(data: string): { consume?: boolean; data?: string } | undefined {
    if (!data.includes("5577")) return undefined;
    let residual = "";
    let cursor = 0;
    let saw = false;
    CLICK_RE.lastIndex = 0;
    let m: RegExpExecArray | null;
    while ((m = CLICK_RE.exec(data)) !== null) {
      saw = true;
      residual += data.slice(cursor, m.index);
      cursor = m.index + m[0].length;
      const idx = declared.get(m[1]);
      if (idx !== undefined) fire(idx); // unknown id: swallowed, never acted on
    }
    if (!saw) return undefined;
    residual += data.slice(cursor);
    return residual.length === 0 ? { consume: true } : { data: residual };
  }

  // ── /answers list rendering ───────────────────────────────────────────────
  // A ▪ marks an answer that has a clickable button; · marks one only reachable
  // by alt+N, because the protocol's 8-button row is full. Bodies are truncated
  // to the pane width and wrapped in full when the entry is expanded (ctrl+o).
  pi.registerEntryRenderer<AnswersListData>("answers-list", (entry, { expanded }, theme) => {
    const d = entry.data;
    if (!d) return undefined;
    return {
      render(width: number): string[] {
        const IND = "  ";
        const srcLabel = d.source === "file" ? path.basename(d.path) : "built-in defaults";
        const lines: string[] = [];

        lines.push(
          `${IND}${theme.fg("accent", "◈")} ${theme.fg("accent", theme.bold("answers"))}` +
            theme.fg("dim", `  ${d.answers.length} · ${srcLabel}`),
        );
        lines.push("");

        if (d.answers.length === 0) {
          lines.push(`${IND}${theme.fg("warning", "(none)")} ${theme.fg("dim", "— /answers init restores the defaults")}`);
        } else {
          const idxW = String(d.answers.length).length;
          const labelW = Math.min(20, Math.max(...d.answers.map((a) => a.label.length)));
          d.answers.forEach((a, i) => {
            const isBtn = i < d.maxButtons;
            const marker = isBtn ? theme.fg("accent", "▪") : theme.fg("dim", "·");
            const num = String(i + 1).padStart(idxW);
            const label = a.label.length > labelW ? `${a.label.slice(0, labelW - 1)}…` : a.label.padEnd(labelW);
            const prefix = `${IND}${marker} ${theme.fg("dim", num)}  ${theme.fg(isBtn ? "accent" : "muted", label)}  `;
            const avail = Math.max(8, width - visibleWidth(prefix) - 2);
            if (expanded) {
              const wrapped = wrapTextWithAnsi(a.text, avail);
              lines.push(prefix + theme.fg("muted", wrapped[0] ?? ""));
              for (const cont of wrapped.slice(1)) {
                lines.push(" ".repeat(visibleWidth(prefix)) + theme.fg("muted", cont));
              }
            } else {
              lines.push(prefix + theme.fg("muted", truncateToWidth(a.text, avail, "…")));
            }
          });
        }

        lines.push("");
        lines.push(
          `${IND}${theme.fg("dim", d.source === "file" ? d.path : `${d.path}  (created on first add)`)}`,
        );
        if (d.answers.length > d.maxButtons) {
          lines.push(`${IND}${theme.fg("dim", `▪ button  · alt+N only — the frame row holds ${d.maxButtons}`)}`);
        }
        lines.push(`${IND}${theme.fg("dim", "/answers add <label> [text…] · rm <label> · reload")}`);
        // Safety net: the header, footer and legend are fixed strings, so on a
        // narrow pane they would wrap and visually break the entry. Clamp every
        // line to the width (ANSI-aware) rather than trusting each producer.
        return lines.map((l) => (visibleWidth(l) > width ? truncateToWidth(l, width, "…") : l));
      },
      invalidate() {},
    };
  });

  // ── /answers ──────────────────────────────────────────────────────────────
  const SUBS = [
    { value: "list", label: "list", description: "show current answers and their source" },
    { value: "add", label: "add <label> [text…]", description: "add an answer and persist it" },
    { value: "rm", label: "rm <label>", description: "remove an answer and persist it" },
    { value: "reload", label: "reload", description: `re-read ${ANSWERS_FILE}` },
    { value: "init", label: "init", description: `create ${ANSWERS_FILE} from the defaults` },
    { value: "refresh", label: "refresh", description: "re-assert the buttons in the frame" },
  ];

  function summary(): string {
    const src = fromFile ? ANSWERS_FILE : "built-in defaults";
    const shown = Math.min(answers.length, MAX_BUTTONS);
    return `${answers.length} answers from ${src} (${shown} as buttons)`;
  }

  /**
   * Render the list into the transcript rather than a one-line notification:
   * the bodies are the useful part and they do not fit on one row. appendEntry
   * keeps it out of the LLM context while staying scrollable and copyable.
   */
  function showList(ctx: any) {
    pi.appendEntry<AnswersListData>("answers-list", {
      answers: answers.map((a) => ({ ...a })),
      source: fromFile ? "file" : "defaults",
      path: filePath ?? resolvePath(ctx),
      maxButtons: MAX_BUTTONS,
    });
  }

  pi.registerCommand("answers", {
    description: "Manage the clickable answer buttons (list/add/rm/reload/init)",
    getArgumentCompletions: (prefix: string) => {
      const first = prefix.trimStart();
      if (first.includes(" ")) {
        // completing a label for rm
        const [sub, ...rest] = first.split(/\s+/);
        if (sub === "rm" || sub === "remove" || sub === "del") {
          const p = (rest[0] ?? "").toLowerCase();
          return answers
            .filter((a) => a.label.toLowerCase().startsWith(p))
            .map((a) => ({ value: `rm ${a.label}`, label: a.label, description: a.text }));
        }
        return null;
      }
      return SUBS.filter((s) => s.value.startsWith(first));
    },
    handler: async (args: string, ctx: any) => {
      const notify = (msg: string, kind: "info" | "warning" | "error" = "info") => {
        if (ctx.hasUI) ctx.ui.notify(msg, kind);
      };
      const parts = args.trim().split(/\s+/).filter(Boolean);
      const sub = (parts[0] ?? "list").toLowerCase();
      const rest = parts.slice(1);

      if (sub === "list") {
        showList(ctx);
        return;
      }

      if (sub === "refresh") {
        refresh();
        notify(isRunning ? "bar re-asserted — buttons return when this turn settles" : `answer buttons re-asserted (${declared.size})`);
        return;
      }

      if (sub === "reload") {
        const res = loadAnswers(ctx);
        refresh();
        if (res.error) notify(`${res.error} — using defaults`, "warning");
        showList(ctx);
        return;
      }

      if (sub === "init") {
        if (fs.existsSync(resolvePath(ctx))) {
          notify(`${ANSWERS_FILE} already exists — use /answers reload`, "warning");
          return;
        }
        const err = saveAnswers(ctx);
        refresh();
        notify(err ? `could not write ${ANSWERS_FILE}: ${err}` : `wrote ${filePath} with ${answers.length} defaults`, err ? "error" : "info");
        return;
      }

      if (sub === "add") {
        const label = cleanLabel(rest[0] ?? "");
        if (!label) {
          notify("usage: /answers add <label> [text…]  (text defaults to the label)", "warning");
          return;
        }
        const text = stripCtl(rest.slice(1).join(" ")).trim() || label;
        // First write seeds the file with the defaults + this answer, which is
        // what makes "the file always wins" safe to state without caveats.
        const existing = answers.findIndex((a) => a.label.toLowerCase() === label.toLowerCase());
        if (existing >= 0) answers[existing] = { label, text };
        else answers.push({ label, text });
        const err = saveAnswers(ctx);
        refresh();
        if (err) {
          notify(`added "${label}" for this session, but could not write ${ANSWERS_FILE}: ${err}`, "error");
          return;
        }
        const overflow = answers.length > MAX_BUTTONS ? ` (button row is full — reachable via alt+${answers.length})` : "";
        notify(`${existing >= 0 ? "updated" : "added"} "${label}" → ${filePath}${overflow}`);
        return;
      }

      if (sub === "rm" || sub === "remove" || sub === "del") {
        const label = (rest[0] ?? "").toLowerCase();
        const at = answers.findIndex((a) => a.label.toLowerCase() === label);
        if (at < 0) {
          notify(`no answer labelled "${rest[0] ?? ""}"`, "warning");
          return;
        }
        const [gone] = answers.splice(at, 1);
        // Persist even when removing a default: the file is the record of intent,
        // so a removed default must be written down or it returns next session.
        const err = saveAnswers(ctx);
        refresh();
        notify(err ? `removed "${gone.label}" for this session, but could not write ${ANSWERS_FILE}: ${err}` : `removed "${gone.label}" → ${filePath}`, err ? "error" : "info");
        return;
      }

      notify(`unknown subcommand "${sub}" — try list / add / rm / reload / init / refresh`, "warning");
    },
  });

  // Registered once against a live lookup, so answers added at runtime work
  // immediately without re-registering shortcuts.
  NUDGE_KEYS.forEach((key, idx) => {
    pi.registerShortcut(key, { description: `Answer #${idx + 1}`, handler: () => fire(idx) });
  });

  pi.on("input", async (event) => {
    if (!event.text) return;
    turn++;
    setStatus();
  });

  // Withdraw the buttons for the whole in-flight window, and put them back when
  // the run settles. agent_settled is the important half of that pair: it fires
  // on the abort/error paths where agent_end never arrives, so an escape-key
  // cancel or a provider failure still gets the buttons back.
  pi.on("agent_start", async () => {
    isRunning = true;
    refresh();
  });
  const settle = () => {
    isRunning = false;
    refresh();
  };
  pi.on("agent_end", async () => settle());
  pi.on("agent_settled", async () => settle());

  pi.on("session_start", async (_e, ctx) => {
    isRunning = false;
    turn = 0;
    const res = loadAnswers(ctx);
    if (!ctx.hasUI || ctx.mode !== "tui") return;

    unsubInput?.();
    unsubInput = ctx.ui.onTerminalInput?.(onInput);

    refresh();
    if (res.error) ctx.ui.notify(`answer picker: ${res.error} — using defaults`, "warning");
  });

  pi.on("session_shutdown", async () => {
    clearBar();
    unsubInput?.();
    unsubInput = undefined;
  });
}