#!/usr/bin/env -S bun --no-env-file --config=/dev/null
/**
 * gstack-regen — the generated-file registry `.gstack/generated.json` (plan C4).
 *
 *   gstack-regen check [--allow-repo-commands] [--base <ref>] [--registry-from base|head] [--only <id,..>] [--touched <path,..>] [--json]
 *   gstack-regen write [--allow-repo-commands] [--base <ref>] [--registry-from base|head] [--only <id,..>] [--json]
 *   gstack-regen list | validate | init [--explain] [--force]
 *
 * `check` regenerates every selected entry in a scratch `git worktree` seeded
 * from the working tree (node_modules linked, never copied) and reports stale
 * outputs without touching the tree; `write` regenerates in place. Commands
 * are read from the committed copy on origin/<base>; they run only with
 * --allow-repo-commands (what /ship passes). Standalone, `check`/`write` list
 * the commands and exit 3 (REPO_COMMANDS_NOT_ALLOWED). Workflow commands end
 * with the GSTACK_RESULT line. Logic: lib/regen.ts.
 */
import { spawnSync } from 'node:child_process';
import * as fs from 'node:fs';
import * as path from 'node:path';
import { EXIT, exitTableHelp, formatResult } from '../lib/headless-artifacts';
import {
  GENERATED_PATH, exampleRegistryJson, isRegistryUnavailable, loadRegistryFromBase, loadRegistryFromHead, renderEntry, runRegen,
  type RegistryLoad,
} from '../lib/regen';
import { RESULT_CODES, resultLine } from '../lib/result-codes';
import { policyUnavailableLine, resolveBaseBranch } from '../lib/ship-policy';

const HELP = `gstack-regen — generated files regenerate, never hand-merge (docs/pregate.md#generated)

  check     regenerate in a scratch git worktree; report stale entries (exit 1) without touching the tree
  write     regenerate in place (the restamp and the Step 3 conflict rule)
  list      print every entry: id, command, outputs, inputs
  validate  schema and containment check of the working-tree ${GENERATED_PATH}
  init [--explain] [--force]   write an example registry

  --allow-repo-commands      run the registry's commands (what /ship passes); without it, check/write list them and exit 3
  --registry-from base|head  base (default, reviewed: origin/<base>) or head (unreviewed; needs --allow-repo-commands)
  --base <ref>               base branch (default: origin/HEAD, else main)
  --only <id,...>            restrict to these entries
  --touched <path,...>       restrict to entries whose inputs or outputs intersect these paths
  --json                     JSON only on stdout

Prints one \`regen <id>: fresh|stale|failed|listed|written\` line per entry and
GSTACK_RESULT: skill=regen status=complete|incomplete|refused run=<wtree>.
${exitTableHelp()}`;

function flag(args: string[], name: string): string | undefined {
  const i = args.indexOf(name);
  return i >= 0 ? args[i + 1] : undefined;
}
function list(v: string | undefined): string[] | undefined {
  return v === undefined ? undefined : v.split(',').map(s => s.trim()).filter(Boolean);
}
function repoRoot(): string {
  const r = spawnSync('git', ['rev-parse', '--show-toplevel'], { encoding: 'utf8', timeout: 15_000 });
  return r.status === 0 && r.stdout.trim() ? r.stdout.trim() : process.cwd();
}

function load(root: string, rest: string[], defaultFrom: 'base' | 'head'): RegistryLoad | number {
  const from = flag(rest, '--registry-from') ?? defaultFrom;
  if (from !== 'base' && from !== 'head') { process.stderr.write(`gstack-regen: --registry-from needs base or head\n`); return EXIT.usage; }
  if (from === 'head') {
    if (defaultFrom === 'base' && !rest.includes('--allow-repo-commands')) { process.stderr.write('gstack-regen: --registry-from head needs --allow-repo-commands (the working-tree registry is unreviewed)\n'); return EXIT.refused; }
    return loadRegistryFromHead(root);
  }
  const base = resolveBaseBranch(root, flag(rest, '--base'));
  const loaded = loadRegistryFromBase(root, base);
  if (isRegistryUnavailable(loaded)) { process.stderr.write(policyUnavailableLine('gstack-regen', base, loaded.detail).replace('.gstack/ship-policy.json', GENERATED_PATH) + '\n'); return EXIT.refused; }
  return loaded;
}

function main(argv: string[]): number {
  const [cmd, ...rest] = argv;
  const json = rest.includes('--json');
  if (!cmd || cmd === '--help' || cmd === '-h' || cmd === 'help') { process.stdout.write(HELP + '\n'); return cmd ? EXIT.ok : EXIT.usage; }
  const root = repoRoot();

  if (cmd === 'init') {
    if (rest.includes('--explain')) {
      process.stdout.write('entries[].id: stable id ([a-z0-9][a-z0-9_.-]*), used by --only and the pre-gate\nentries[].command: the one command that regenerates the outputs; null lists outputs regenerated by hand\nentries[].outputs: repo-relative globs the command writes (non-empty)\nentries[].inputs: repo-relative globs that feed it; empty or absent means always regenerate\nentries[].note: free text shown in list and --explain\n');
      if (rest.length === 1) return EXIT.ok;
    }
    const file = path.join(root, GENERATED_PATH);
    if (fs.existsSync(file) && !rest.includes('--force')) { process.stderr.write(resultLine('gstack-regen init', 'POLICY_EXISTS', file) + '\n'); return EXIT.refused; }
    fs.mkdirSync(path.dirname(file), { recursive: true });
    fs.writeFileSync(file, exampleRegistryJson());
    process.stdout.write(`REGISTRY_WRITTEN: ${GENERATED_PATH} (edit it, then gstack-regen validate; commit it on the base branch before /ship reads it)\n`);
    return EXIT.ok;
  }

  if (cmd === 'validate' || cmd === 'list') {
    const fromBase = cmd === 'list' && flag(rest, '--registry-from') === 'base';
    const loaded = fromBase ? loadRegistryFromBase(root, resolveBaseBranch(root, flag(rest, '--base'))) : loadRegistryFromHead(root);
    if (isRegistryUnavailable(loaded)) { process.stderr.write(policyUnavailableLine('gstack-regen', loaded.base, loaded.detail).replace('.gstack/ship-policy.json', GENERATED_PATH) + '\n'); return EXIT.refused; }
    for (const e of loaded.errors) process.stderr.write(resultLine(`gstack-regen ${cmd}`, e.code, `${e.message} at ${e.path || GENERATED_PATH}`) + '\n');
    if (json) { process.stdout.write(JSON.stringify({ valid: loaded.errors.length === 0, present: loaded.present, source: loaded.source, entries: loaded.registry.entries, errors: loaded.errors }) + '\n'); return loaded.errors.length ? EXIT.fail : EXIT.ok; }
    if (cmd === 'validate') { process.stdout.write(loaded.errors.length ? `REGISTRY_INVALID: ${loaded.errors.length} error(s)\n` : `REGISTRY_VALID: ${loaded.present ? GENERATED_PATH : `no ${GENERATED_PATH} (nothing registered)`}\n`); return loaded.errors.length ? EXIT.fail : EXIT.ok; }
    process.stdout.write(`registry: ${loaded.source.label}\n`);
    for (const e of loaded.registry.entries) process.stdout.write(`${e.id}: command=${e.command === null ? 'null (by hand)' : JSON.stringify(e.command)} outputs=${e.outputs.join(',')} inputs=${e.inputs.join(',') || '(always)'}${e.note ? ` note=${JSON.stringify(e.note)}` : ''}\n`);
    return loaded.errors.length ? EXIT.fail : EXIT.ok;
  }

  if (cmd !== 'check' && cmd !== 'write') { process.stderr.write(`gstack-regen: unknown command ${cmd}\n${HELP}\n`); return EXIT.usage; }
  const loaded = load(root, rest, 'base');
  if (typeof loaded === 'number') return loaded;
  if (isRegistryUnavailable(loaded)) return EXIT.refused;
  if (loaded.errors.length) {
    for (const e of loaded.errors) process.stderr.write(resultLine(`gstack-regen ${cmd}`, e.code, `${e.message} at ${e.path || GENERATED_PATH} (${loaded.source.label})`) + '\n');
    process.stdout.write(formatResult('regen', 'refused', loaded.source.label) + '\n');
    return EXIT.refused;
  }
  const commands = loaded.registry.entries.filter(e => e.command);
  if (commands.length && !rest.includes('--allow-repo-commands')) {
    process.stderr.write(`gstack-regen ${cmd}: ${RESULT_CODES.REPO_COMMANDS_NOT_ALLOWED.summary.replace('the policy declares commands', `${GENERATED_PATH} declares ${commands.length} command(s)`)}; fix: pass --allow-repo-commands (what /ship does) (REPO_COMMANDS_NOT_ALLOWED)\n`);
    for (const e of commands) process.stdout.write(`COMMAND: ${e.id}=${JSON.stringify(e.command)} outputs=${e.outputs.join(',')}\n`);
    process.stdout.write(formatResult('regen', 'refused', loaded.source.label) + '\n');
    return EXIT.refused;
  }
  let outcome;
  try { outcome = runRegen({ repoRoot: root, registry: loaded.registry, mode: cmd, only: list(flag(rest, '--only')), touched: list(flag(rest, '--touched')) }); }
  catch (e: any) { process.stderr.write(resultLine(`gstack-regen ${cmd}`, 'PREGATE_INCOMPLETE', e.message) + '\n'); process.stdout.write(formatResult('regen', 'incomplete', loaded.source.label) + '\n'); return EXIT.fail; }
  const bad = outcome.results.filter(r => r.status === 'stale' || r.status === 'failed' || r.status === 'deps-missing');
  const status = outcome.results.some(r => r.status === 'failed' || r.status === 'deps-missing') ? 'incomplete' : 'complete';
  if (json) { process.stdout.write(JSON.stringify({ mode: cmd, registry: loaded.source.label, wtree: outcome.wtree, results: outcome.results, ok: bad.length === 0 }) + '\n'); return bad.length ? EXIT.fail : EXIT.ok; }
  process.stdout.write(`registry: ${loaded.source.label}\n`);
  for (const r of outcome.results) process.stdout.write(renderEntry(r) + '\n');
  process.stdout.write(`REGEN: ${cmd} ${bad.length ? `${bad.length} stale or failed` : 'fresh'} (${outcome.results.length} entries)\n`);
  process.stdout.write(formatResult('regen', status, outcome.wtree ?? loaded.source.label) + '\n');
  return bad.length ? EXIT.fail : EXIT.ok;
}

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