/**
 * @file pty-run.js
 * @description Owns the tmux-backed run lifecycle for the dashboard's
 * terminal-run feature: Start (create-or-adopt), Resume (`--resume`), Kill,
 * and List. Unlike the old run-spawner.js, there is no in-memory handle Map —
 * `listRuns`/`getRun` are computed fresh from `tmux list-sessions` on every
 * call, the same "computed fact, never a stored one" principle this repo
 * already applies to lane runtime up/down (see CLAUDE.md). A session killed
 * out-of-band (crash, manual `tmux kill-session`, host reboot) self-corrects
 * on the next read instead of leaving a ghost "running" row.
 *
 * Every session is named `ccam-lane-<laneId>` so a real terminal can attach
 * to the exact same session (`tmux attach -t ccam-lane-<id>`, or
 * `ccam lanes shell`) — that's the whole point: the dashboard both creates
 * the session (one-click Start/Resume) and is just one of possibly several
 * attached clients tmux already keeps in sync.
 *
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const tmux = require("./tmux");

let dashboardRuns = null;
try {
  dashboardRuns = require("./dashboard-runs");
} catch {
  /* db-less environment, skip persistence */
}

const RUN_ID_RE = /^ccam-lane-(\d+)$/;
const EFFORT_LEVELS = new Set(["low", "medium", "high", "xhigh", "max"]);
const ALLOWED_PERMISSION_MODES = new Set(["acceptEdits", "default", "plan", "bypassPermissions"]);

function runIdForLane(laneId) {
  return `ccam-lane-${laneId}`;
}

function laneIdFromRunId(id) {
  const m = typeof id === "string" ? id.match(RUN_ID_RE) : null;
  return m ? Number(m[1]) : null;
}

function makeErr(code, message) {
  const err = new Error(message);
  err.code = code;
  return err;
}

/**
 * Build the pane's command argv. Unlike the old stream-json spawner there is
 * no headless/conversation split — every run is a live interactive pane, so
 * an initial prompt (when given) is a trailing POSITIONAL argument: `claude`
 * treats a bare positional as the first turn's message and stays interactive
 * afterward (unlike `-p`, which forces print-and-exit and closes stdin).
 */
function buildArgv({ model, permissionMode, effort, resumeSessionId, initialPrompt }) {
  const argv = ["claude"];
  argv.push("--permission-mode", permissionMode || "acceptEdits");
  if (model) argv.push("--model", model);
  if (effort && EFFORT_LEVELS.has(effort)) argv.push("--effort", effort);
  if (resumeSessionId) argv.push("--resume", resumeSessionId);
  if (initialPrompt) argv.push(initialPrompt);
  return argv;
}

/**
 * @param {object} args
 * @param {number} args.laneId
 * @param {string} args.cwd
 * @param {string} [args.model]
 * @param {string} [args.permissionMode]
 * @param {string} [args.effort]
 * @param {string} [args.resumeSessionId]
 * @param {string} [args.initialPrompt]
 */
function spawnRun(args) {
  const { laneId, cwd, model, permissionMode, effort, resumeSessionId, initialPrompt } = args || {};
  if (typeof laneId !== "number" || !Number.isInteger(laneId)) {
    throw makeErr("EBADLANE", "laneId must be an integer");
  }
  if (typeof cwd !== "string" || !cwd) {
    throw makeErr("EBADCWD", "cwd is required");
  }
  if (permissionMode != null && !ALLOWED_PERMISSION_MODES.has(permissionMode)) {
    throw makeErr(
      "EBADMODE",
      `permissionMode must be one of: ${Array.from(ALLOWED_PERMISSION_MODES).join(", ")}`
    );
  }
  if (effort != null && effort !== "" && !EFFORT_LEVELS.has(effort)) {
    throw makeErr("EBADEFFORT", `effort must be one of: ${Array.from(EFFORT_LEVELS).join(", ")}`);
  }
  if (
    resumeSessionId != null &&
    (typeof resumeSessionId !== "string" || !/^[A-Za-z0-9-]{8,}$/.test(resumeSessionId))
  ) {
    throw makeErr("EBADSESSION", "resumeSessionId is not a valid session id");
  }

  const id = runIdForLane(laneId);
  const startedAt = Date.now();

  if (!tmux.hasSession(id)) {
    const argv = buildArgv({ model, permissionMode, effort, resumeSessionId, initialPrompt });
    tmux.newSession({ name: id, cwd, argv });
    if (dashboardRuns) {
      dashboardRuns.recordRun({
        id,
        sessionId: resumeSessionId || null,
        mode: null,
        cwd,
        model: model || null,
        permissionMode: permissionMode || "acceptEdits",
        effort: effort || null,
        resumeSessionId: resumeSessionId || null,
        prompt: initialPrompt || "",
        status: "running",
        startedAt,
        endedAt: null,
        exitCode: null,
        laneId,
      });
    }
  }
  // Already running: adopt silently, same convention as this repo's server
  // port-adoption logic — no error, no duplicate session.

  return getRun(id);
}

function killRun(id) {
  if (!id || !tmux.hasSession(id)) return false;
  tmux.killSession(id);
  if (dashboardRuns) {
    dashboardRuns.patchRun({ id, status: "killed", endedAt: Date.now() });
  }
  return true;
}

function publicRun(id) {
  const laneId = laneIdFromRunId(id);
  const live = tmux.hasSession(id);
  const row = dashboardRuns ? dashboardRuns.getRun(id) : null;
  return {
    id,
    laneId,
    status: live ? "running" : "gone",
    cwd: row?.cwd || null,
    model: row?.model || null,
    permissionMode: row?.permission_mode || null,
    effort: row?.effort || null,
    resumeSessionId: row?.resume_session_id || null,
    sessionId: row?.session_id || null,
    startedAt: row?.started_at || null,
    promptPreview: row?.prompt_preview || null,
  };
}

function getRun(id) {
  if (!id) return null;
  return publicRun(id);
}

/** Computed fresh from tmux state every call — see file header. */
function listRuns() {
  return tmux.listSessions("ccam-lane-").map(publicRun);
}

module.exports = {
  spawnRun,
  killRun,
  getRun,
  listRuns,
  laneIdFromRunId,
  runIdForLane,
};