#!/usr/bin/env -S bun --no-env-file --config=/dev/null
/**
 * gstack-gate — render and parse the one gate list (plan B9).
 *
 *   gstack-gate render <gate.json> [--page N | --all]
 *   gstack-gate parse <gate.json> --reply "<text>" --gate-rev N [--json]
 *   gstack-gate decisions <gate.json> [--reply "<text>" --gate-rev N] [--answered-at ISO]
 *
 * Logic: lib/gate-list.ts. Codes: lib/result-codes.ts (GATE_REV_STALE, GATE_REPLY_UNPARSED).
 */
import * as fs from 'node:fs';
import { EXIT, exitTableHelp } from '../lib/headless-artifacts';
import { applyReply, decisionRows, parseReply, renderGate, validateGateList, type GateList } from '../lib/gate-list';
import { resultLine } from '../lib/result-codes';

const HELP = `gstack-gate — one gate list, one reply grammar

  render <gate.json> [--page N | --all]                 numbered items with stable ids, auto/approval, the reply shape;
                                                        --all prints every item on one page (relay every page)
  parse <gate.json> --reply "<text>" --gate-rev N [--json]
                                                        resolved choices as JSON; unparsed tokens are listed, never guessed
  decisions <gate.json> [--reply "<text>" --gate-rev N] [--answered-at ISO]
                                                        decisions.jsonl rows (pending, or applied when a reply is given)

Reply grammar: \`rec\` (alias \`all\`) · \`rec except <tokens>\` · \`<id><option>\` tokens (\`d3b uc1a\`) · \`as-is\` (the plan as written). Bare yes/no is rejected.
gate.json: {"schema_version":1,"run":"<id>","gate_rev":1,"items":[{"id":"d1","title":"…","kind":"auto|approval","recommended":"a","options":[{"key":"a","text":"…"},…]}]}
${exitTableHelp()}`;

function flag(args: string[], name: string): string | undefined {
  const i = args.indexOf(name);
  return i >= 0 ? args[i + 1] : undefined;
}
function usage(message: string): number {
  process.stderr.write(`gstack-gate: ${message}\n${HELP}\n`);
  return EXIT.usage;
}
function loadList(file: string | undefined): GateList | number {
  if (!file) return usage('a gate.json path is required');
  let list: unknown;
  try { list = JSON.parse(fs.readFileSync(file, 'utf8')); } catch (e: any) { process.stderr.write(`gstack-gate: ${file}: ${e.message}\n`); return EXIT.fail; }
  const problems = validateGateList(list);
  if (problems.length) { process.stderr.write(`gstack-gate: ${file} is not a gate list:\n  ${problems.join('\n  ')}\n`); return EXIT.fail; }
  return list as GateList;
}

function parseWith(list: GateList, rest: string[], json: boolean) {
  const reply = flag(rest, '--reply');
  const revText = flag(rest, '--gate-rev');
  if (reply === undefined) return { code: usage('--reply "<text>" is required') };
  if (revText === undefined) {
    process.stderr.write(resultLine('gstack-gate parse', 'GATE_REV_STALE', `no --gate-rev given; current gate_rev=${list.gate_rev}`) + '\n');
    return { code: EXIT.refused };
  }
  const parsed = parseReply(reply, list, Number(revText));
  if (json) process.stdout.write(JSON.stringify(parsed) + '\n');
  if (parsed.error === 'GATE_REV_STALE') {
    process.stderr.write(resultLine('gstack-gate parse', 'GATE_REV_STALE', `reply names gate_rev=${revText}, current gate_rev=${list.gate_rev}`) + '\n');
    return { code: EXIT.refused, parsed };
  }
  if (!parsed.valid) {
    const detail = parsed.error === 'GATE_EMPTY' ? 'empty reply' : `unparsed: ${parsed.unparsed.join(', ')}`;
    process.stderr.write(resultLine('gstack-gate parse', 'GATE_REPLY_UNPARSED', detail) + '\n');
    return { code: EXIT.fail, parsed };
  }
  return { code: EXIT.ok, parsed };
}

function main(argv: string[]): number {
  const [cmd, ...rest] = argv;
  if (!cmd || cmd === '--help' || cmd === '-h' || cmd === 'help') { process.stdout.write(HELP + '\n'); return cmd ? EXIT.ok : EXIT.usage; }
  const positional = rest.filter((a, i) => !a.startsWith('--') && !(i > 0 && rest[i - 1]!.startsWith('--') && !['--json', '--all'].includes(rest[i - 1]!)));
  const list = loadList(positional[0]);
  if (typeof list === 'number') return list;

  if (cmd === 'render') {
    const page = flag(rest, '--page');
    if (page !== undefined && !/^[0-9]+$/.test(page)) return usage('--page needs a number');
    if (page !== undefined && rest.includes('--all')) return usage('--page and --all are exclusive');
    process.stdout.write(rest.includes('--all') ? renderGate(list, 1, list.items.length) : renderGate(list, page ? Number(page) : 1));
    return EXIT.ok;
  }
  if (cmd === 'parse') {
    const { code, parsed } = parseWith(list, rest, rest.includes('--json'));
    if (code === EXIT.ok && !rest.includes('--json')) {
      process.stdout.write(JSON.stringify(parsed) + '\n');
    }
    return code;
  }
  if (cmd === 'decisions') {
    let rows = decisionRows(list);
    if (flag(rest, '--reply') !== undefined || flag(rest, '--gate-rev') !== undefined) {
      const { code, parsed } = parseWith(list, rest, false);
      if (code !== EXIT.ok) return code;
      rows = applyReply(rows, parsed!, flag(rest, '--answered-at') ?? new Date().toISOString());
    }
    process.stdout.write(rows.map(r => JSON.stringify(r)).join('\n') + '\n');
    return EXIT.ok;
  }
  return usage(`unknown command ${cmd}`);
}

process.exitCode = main(process.argv.slice(2));