#!/usr/bin/env node
// Usage:
//   mosaic launch <seat|seat-dir> [--task TEXT] [--project NAME] [--workspace PATH]
//                 [--harness NAME] [--repo PATH] [--config PATH] [-- args...]
//   mosaic seat task <seat> <text> [--by NAME] [--layout repo|fleet|unknown] [--config PATH]
//
// `seat task` records who set the task as taskSetBy: `--by NAME`, else
// $MOSAIC_AGENT_NAME, else "unknown". This is what the caller claimed; it is
// not verified and it authorizes nothing.
//
// `launch` writes <dataRoot>/seats/<layout>/<seat>/registration.json, then replaces
// itself with the seat's launch.sh, unchanged, with everything after `--` as
// its arguments and MOSAIC_LAUNCH_REGISTERED set to the record path. A launch
// script that sees that variable is already registered and must not call
// mosaic launch again. The exit code is the launch script's own.
//
// Exit codes: the launch script's code (launch); 0 ok; 1 operation failed;
// 2 invalid data or configuration; 4 usage.
import { rmSync } from "node:fs";
import {
  SeatError, defaultConfigPath, loadDataRoot, seatsDir, resolveSeat, tmuxContext,
  makeRegistration, writeRegistration, updateTask, resolveSetBy,
} from "./seat.mjs";

const USAGE = [
  "usage: mosaic launch <seat|seat-dir> [--task TEXT] [--project NAME] [--workspace PATH] [--harness NAME] [--repo PATH] [--config PATH] [-- args...]",
  "       mosaic seat task <seat> <text> [--by NAME] [--layout repo|fleet|unknown] [--config PATH]",
].join("\n");

export const REGISTERED_ENV = "MOSAIC_LAUNCH_REGISTERED";

function parseLaunch(argv) {
  const opts = { seat: null, task: "", project: undefined, workspace: undefined, harness: null, repo: process.cwd(), config: defaultConfigPath(), args: [] };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    const next = () => {
      if (i + 1 >= argv.length) throw new SeatError(`missing value for ${a}`, 4);
      return argv[++i];
    };
    if (a === "--") { opts.args = argv.slice(i + 1); break; }
    else if (a === "--task") opts.task = next();
    else if (a === "--project") opts.project = next();
    else if (a === "--workspace") opts.workspace = next();
    else if (a === "--harness") opts.harness = next();
    else if (a === "--repo") opts.repo = next();
    else if (a === "--config") opts.config = next();
    else if (a.startsWith("--")) throw new SeatError(`unknown argument: ${a}\n${USAGE}`, 4);
    else if (opts.seat === null) opts.seat = a;
    else throw new SeatError(`unexpected argument: ${a} (put launch script arguments after --)`, 4);
  }
  if (opts.seat === null) throw new SeatError(USAGE, 4);
  return opts;
}

function parseSeatTask(argv) {
  const opts = { seat: null, task: null, layout: null, by: null, config: defaultConfigPath() };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a === "--config" || a === "--layout" || a === "--by") {
      if (i + 1 >= argv.length) throw new SeatError(`missing value for ${a}`, 4);
      opts[a.slice(2)] = argv[++i];
    } else if (a.startsWith("--")) throw new SeatError(`unknown argument: ${a}\n${USAGE}`, 4);
    else if (opts.seat === null) opts.seat = a;
    else if (opts.task === null) opts.task = a;
    else throw new SeatError(`unexpected argument: ${a}`, 4);
  }
  if (opts.seat === null || opts.task === null) throw new SeatError(USAGE, 4);
  return opts;
}

function launch(argv) {
  const opts = parseLaunch(argv);
  const resolved = resolveSeat(opts.seat, { repo: opts.repo });
  const seats = seatsDir(loadDataRoot(opts.config));
  // Register first, then replace this process with the launch script (same
  // pid, same terminal, same process group). The launch script's exit code
  // and signals are then the shell's to see directly, and the tmux pane's
  // foreground command stays the harness itself, which the control board's
  // liveness check depends on.
  const record = makeRegistration({
    resolved, task: opts.task, project: opts.project, workspace: opts.workspace,
    harness: opts.harness, tmux: tmuxContext(), pid: process.pid,
  });
  const path = writeRegistration(seats, record);
  process.stderr.write(`mosaic launch: registered ${resolved.seat} (${resolved.layout} layout) at ${path}\n`);
  try {
    process.execve(resolved.launchScript, [resolved.launchScript, ...opts.args], { ...process.env, [REGISTERED_ENV]: path });
  } catch (err) {
    rmSync(path, { force: true });
    throw new SeatError(`could not run ${resolved.launchScript}: ${err.message}`, 1);
  }
  return 0;
}

function seatTask(argv) {
  const opts = parseSeatTask(argv);
  // Attribution is resolved (and an invalid value refused) before any read
  // or write, so a refusal leaves the record exactly as it was.
  const setBy = resolveSetBy({ by: opts.by, env: process.env });
  const seats = seatsDir(loadDataRoot(opts.config));
  const record = updateTask(seats, opts.seat, opts.task, { layout: opts.layout, setBy });
  process.stdout.write(`mosaic seat task: ${opts.seat} (${record.layout} layout) task set (${opts.task.length} characters, set by ${setBy})\n`);
  return 0;
}

function main(argv) {
  if (process.env[REGISTERED_ENV] && argv[0] === "launch") {
    throw new SeatError(`${REGISTERED_ENV} is already set; refusing to register a seat from inside a registered launch`, 4);
  }
  if (argv[0] === "launch") return launch(argv.slice(1));
  if (argv[0] === "seat" && argv[1] === "task") return seatTask(argv.slice(2));
  throw new SeatError(USAGE, 4);
}

try {
  process.exitCode = main(process.argv.slice(2));
} catch (err) {
  if (!(err instanceof SeatError)) throw err;
  process.stderr.write(`refused: ${err.message}\n`);
  process.exitCode = err.exitCode;
}