/**
 * @file Safety-net reminder for codex lanes whose auto-detected stage has
 * clearly moved past the last stage the session actually *declared* (see
 * `server/lib/stage-detect.js` / `server/lib/codex-ingest.js`). A codex
 * session only declares a stage when it calls `ccam stage` on its own —
 * there is no hook or wrapper that does it for it — so a lane can sit with a
 * stale declared stage indefinitely even while its pipeline map keeps
 * painting fresh amber "detected" badges.
 *
 * This module never writes `stage` or `detected_stage` itself — the
 * declared-wins / inferred-never-`done` invariants in lanes.js are untouched.
 * It only types a plain-text reminder into the lane's own live tmux pane
 * (`tmux.sendText`), the same way a human watching the dashboard would nudge
 * the agent — so any stage change that results is still a REAL declaration
 * the codex session made itself.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const NUDGE_DELAY_MS = 120_000; // give the session 2 min to declare on its own first

// Per-lane memory of the last detected_stage already nudged for, so the 60s
// sweep doesn't retype the same reminder every pass. Cleared implicitly: once
// the session declares (setStage nulls detected_stage) or detection advances
// again, the value here no longer matches and a fresh nudge is due.
// ponytail: in-memory, resets on server restart — worst case one duplicate
// nudge after a restart, not worth a DB column for.
const nudgedFor = new Map();

/**
 * One sweep pass: nudge every codex lane whose fresh detection sits ahead of
 * its declared stage, has held for at least NUDGE_DELAY_MS, and hasn't
 * already been nudged for that exact detected stage.
 * @returns {number} How many lanes were nudged.
 */
function sweepCodexNudges() {
  const lanes = require("./lanes");
  const tmux = require("./tmux");
  const { SHELL_COMMANDS, runIdForLane } = require("./pty-run");

  let codexLanes = [];
  try {
    codexLanes = lanes.listLanes().filter((l) => l.tool === "codex" && l.run_id);
  } catch {
    return 0;
  }

  let nudged = 0;
  for (const lane of codexLanes) {
    try {
      if (!lane.detected_stage || lane.detected_stage === lane.stage) {
        nudgedFor.delete(lane.id);
        continue;
      }
      if (lanes.detectionIsStale(lane.detected_at)) continue;
      const detectedAt = Date.parse(lane.detected_at);
      if (!Number.isFinite(detectedAt) || Date.now() - detectedAt < NUDGE_DELAY_MS) continue;
      if (nudgedFor.get(lane.id) === lane.detected_stage) continue;

      const runId = runIdForLane(lane.id);
      if (!tmux.hasSession(runId)) continue;
      // A bare shell prompt has no chat turn to submit into — pressing Enter
      // there would run the reminder text as a shell command instead.
      if (SHELL_COMMANDS.has(tmux.paneCommand(runId) || "")) continue;

      tmux.sendText(
        runId,
        `[ccam] You appear to have moved on to "${lane.detected_stage}" — run: ccam stage ${lane.detected_stage} --tool codex --evidence "..."`
      );
      nudgedFor.set(lane.id, lane.detected_stage);
      nudged += 1;
    } catch {
      /* one lane's failure must not abort the sweep */
    }
  }
  return nudged;
}

/** Unref'd so it never blocks shutdown; disable with DASHBOARD_CODEX_NUDGE_MS=0. */
function startCodexNudge() {
  const POLL_MS = process.env.DASHBOARD_CODEX_NUDGE_MS
    ? Number(process.env.DASHBOARD_CODEX_NUDGE_MS)
    : 60_000;
  if (!Number.isFinite(POLL_MS) || POLL_MS <= 0) return;
  const timer = setInterval(() => {
    try {
      sweepCodexNudges();
    } catch {
      /* a sweep pass never throws into the event loop */
    }
  }, POLL_MS);
  if (timer.unref) timer.unref();
}

function __resetNudgeState() {
  nudgedFor.clear();
}

module.exports = {
  sweepCodexNudges,
  startCodexNudge,
  __resetNudgeState,
};