/**
 * capy/skill/gstack/: the vendored Capy skill. scripts/install.sh is the
 * frozen bootstrapper the Drive copy holds: it prints its wrapper revision
 * first, learns the supported minimum from origin's default branch
 * (`git show FETCH_HEAD:capy/support.env`), fast-forwards a clean, unpinned
 * checkout below that minimum in install mode only (--check never moves the
 * checkout), and execs the checkout's own full wrapper, bin/gstack-capy-session,
 * handing over the held install lock (GSTACK_CAPY_LOCK_HELD=1). Pinned on the
 * machine lines (`gstack-capy-skill: wrapper|upgraded|owner action`, the
 * `gstack:` trailer as the last line), exit codes and HEAD before/after.
 * Fixture: a bare remote whose main moves from A (1.0.0, no capy/ directory:
 * an old checkout) to B (1.0.1, capy/support.env minimum 1.0.1, the vendored
 * scripts and a stub bin/gstack-capy-install that logs argv and env), a
 * depth-1 file:// clone at A, on the simulated Capy host.
 */
import { afterEach, describe, expect, test } from 'bun:test';
import { spawnSync } from 'child_process';
import * as fs from 'fs';
import * as path from 'path';
import { RESULT_CODES } from '../lib/result-codes';
import { capyHost, type CapyHost } from './helpers/capy-host';

const REPO = path.resolve(import.meta.dir, '..');
const SKILL = path.join(REPO, 'capy/skill/gstack');
const BOOT = path.join(SKILL, 'scripts/install.sh');
const hosts: CapyHost[] = [];
afterEach(() => { for (const h of hosts.splice(0)) h.cleanup(); });

const write = (file: string, text: string, mode = 0o644) => {
  fs.mkdirSync(path.dirname(file), { recursive: true });
  fs.writeFileSync(file, text, { mode });
};
const envValue = (text: string, key: string) => text.match(new RegExp(`^${key}=([0-9.]+)`, 'm'))?.[1] ?? '';
const below = (a: string, b: string) => {
  const x = a.split('.').map(Number), y = b.split('.').map(Number);
  for (let i = 0; i < Math.max(x.length, y.length); i++) if ((x[i] ?? 0) !== (y[i] ?? 0)) return (x[i] ?? 0) < (y[i] ?? 0);
  return false;
};

const STUB_INSTALLER = [
  '#!/usr/bin/env bash',
  'echo "installer $* lock=${GSTACK_CAPY_LOCK_HELD:-} rev=${GSTACK_CAPY_WRAPPER_REV:-} min=${GSTACK_CAPY_REMOTE_MIN:-} from=${GSTACK_CAPY_UPGRADED_FROM:-}" >> "$WRAP_LOG"',
  'cd "$(dirname "$0")/.."',
  'if [ "${1:-}" != --check ] && [ -f "$WRAP_FAIL_ONCE" ]; then rm -f "$WRAP_FAIL_ONCE"; echo "gstack: fail claude"; exit 1; fi',
  'echo "GSTACK_LAUNCH: GSTACK_SESSION_KIND=unattended GSTACK_CAPY=1"',
  'echo "gstack: ok $(cat VERSION) for=autoplan"',
].join('\n') + '\n';

function fixture(opts: { minWrapper?: number } = {}) {
  const host = capyHost({ systemBun: '1.4.2' });
  hosts.push(host);
  const git = (args: string[], cwd: string) => {
    const r = spawnSync('git', args, { cwd, encoding: 'utf8', env: host.env, timeout: 30_000 });
    if (r.status !== 0) throw new Error(`git ${args.join(' ')}: ${r.stderr}`);
    return r.stdout.trim();
  };
  const log = path.join(host.base, 'wrap.log');
  const seed = path.join(host.base, 'seed');
  const bare = path.join(host.base, 'remote.git');
  fs.mkdirSync(seed, { recursive: true });
  git(['init', '-q', '-b', 'main'], seed);
  write(path.join(seed, 'VERSION'), '1.0.0\n');
  write(path.join(seed, 'README.md'), 'old gstack\n');
  write(path.join(seed, 'setup'), '#!/usr/bin/env bash\nexit 0\n', 0o755);
  git(['add', '-A'], seed);
  git(['commit', '-qm', 'A'], seed);
  const a = git(['rev-parse', 'HEAD'], seed);
  git(['init', '-q', '--bare', '-b', 'main', bare], host.base);
  git(['push', '-q', bare, 'main'], seed);
  const root = path.join(host.base, 'gstack');
  git(['clone', '-q', '--single-branch', '--depth', '1', `file://${bare}`, root], host.base);
  write(path.join(seed, 'VERSION'), '1.0.1\n');
  write(path.join(seed, 'capy/support.env'), `GSTACK_MIN_REVISION=1.0.1\nGSTACK_CAPY_MIN_WRAPPER=${opts.minWrapper ?? 1}\n`);
  for (const rel of ['capy/skill/gstack/scripts/install.sh', 'capy/skill/gstack/SKILL.md', 'bin/gstack-capy-session', 'bin/gstack-install-verdict.sh']) {
    if (fs.existsSync(path.join(REPO, rel))) write(path.join(seed, rel), fs.readFileSync(path.join(REPO, rel), 'utf8'), 0o755);
  }
  write(path.join(seed, 'bin/gstack-capy-install'), STUB_INSTALLER, 0o755);
  git(['add', '-A'], seed);
  git(['commit', '-qm', 'B'], seed);
  const b = git(['rev-parse', 'HEAD'], seed);
  git(['push', '-q', bare, 'main'], seed);
  const env = { ...host.env, GSTACK_CAPY_ROOT: root, GSTACK_CAPY_REPO: `file://${bare}`, WRAP_LOG: log, WRAP_FAIL_ONCE: path.join(host.base, 'fail-once') };
  const run = (args: string[] = [], extra: Record<string, string> = {}) => {
    const r = spawnSync('bash', [BOOT, ...args], { cwd: host.home, encoding: 'utf8', env: { ...env, ...extra }, timeout: 120_000 });
    const lines = r.stdout.trim().split('\n');
    return { ...r, lines, last: lines.at(-1) ?? '' };
  };
  return {
    host, root, bare, a, b, run, git: (args: string[]) => git(args, root),
    calls: () => fs.existsSync(log) ? fs.readFileSync(log, 'utf8').trim().split('\n').filter(Boolean) : [],
  };
}

describe('capy skill bootstrapper (capy/skill/gstack/scripts/install.sh)', () => {
  test('the first line names the wrapper revision and path; bash -n passes for the bootstrapper and the full wrapper', () => {
    for (const file of [BOOT, path.join(REPO, 'bin/gstack-capy-session')]) {
      expect(fs.existsSync(file), file).toBe(true);
      const r = spawnSync('bash', ['-n', file], { encoding: 'utf8', timeout: 30_000 });
      expect(r.status, `${file}: ${r.stderr}`).toBe(0);
    }
    const f = fixture();
    const r = f.run(['--check', '--for', 'autoplan']);
    expect(r.lines[0]).toMatch(new RegExp(`^gstack-capy-skill: wrapper \\d+ \\(${BOOT.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}\\)$`));
  });

  test('below the remote minimum: --check is read-only and names the fast-forwarding command; install fast-forwards, installs and ends ok; the next session start is ok without moving', () => {
    const f = fixture();
    expect(f.git(['rev-parse', '--is-shallow-repository'])).toBe('true');
    const check = f.run(['--check', '--for', 'autoplan']);
    expect(check.status, check.stdout + check.stderr).toBe(1);
    expect(check.last).toBe(`gstack: fail revision — installed 1.0.0 is below the supported minimum 1.0.1 (fast-forward available); fix: bash ${BOOT} --for autoplan (fast-forwards) (REVISION_BELOW_MINIMUM)`);
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.a);
    expect(f.calls()).toEqual([]);

    const install = f.run(['--for', 'autoplan']);
    expect(install.status, install.stdout + install.stderr).toBe(0);
    expect(install.stdout).toContain('gstack-capy-skill: upgraded 1.0.0 -> 1.0.1');
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.b);
    expect(f.git(['rev-parse', '--is-shallow-repository'])).toBe('true');
    expect(install.last).toBe('gstack: ok 1.0.1 for=autoplan');
    expect(f.calls()).toEqual([`installer --root ${f.root} --for autoplan lock=1 rev=1 min=1.0.1 from=1.0.0`]);

    const next = f.run(['--check', '--for', 'autoplan']);
    expect(next.status, next.stdout + next.stderr).toBe(0);
    expect(next.stdout).not.toContain('upgraded');
    expect(next.last).toBe('gstack: ok 1.0.1 for=autoplan');
    expect(f.calls().at(-1)).toBe(`installer --check --root ${f.root} --for autoplan lock= rev=1 min=1.0.1 from=`);
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.b);
  });

  test('dirty, pinned, diverged or auto-upgrade disabled: no change, fail revision names the cause and the exact commands', () => {
    const f = fixture();
    fs.writeFileSync(path.join(f.root, 'README.md'), 'local edit\n');
    const dirty = f.run(['--for', 'autoplan']);
    expect(dirty.status).toBe(1);
    expect(dirty.last).toMatch(/^gstack: fail revision — installed 1\.0\.0 is below the supported minimum 1\.0\.1 \(tracked files changed: README\.md\); fix: .*git -C \S+ status --short.*\(REVISION_BELOW_MINIMUM\)$/);
    expect(fs.readFileSync(path.join(f.root, 'README.md'), 'utf8')).toBe('local edit\n');
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.a);
    f.git(['checkout', '-q', '--', 'README.md']);

    const pinned = f.run(['--for', 'autoplan', '--revision', f.a]);
    expect(pinned.status).toBe(1);
    expect(pinned.last).toContain('(pinned by --revision');
    f.git(['checkout', '-q', '--detach', 'HEAD']);
    const detached = f.run(['--for', 'autoplan']);
    expect(detached.last).toContain('(pinned: HEAD is detached');
    f.git(['checkout', '-q', 'main']);

    const disabled = f.run(['--for', 'autoplan'], { GSTACK_CAPY_AUTO_UPGRADE: '0' });
    expect(disabled.status).toBe(1);
    expect(disabled.last).toContain('(auto-upgrade disabled)');
    expect(disabled.last).toContain('GSTACK_CAPY_AUTO_UPGRADE');

    fs.writeFileSync(path.join(f.root, 'README.md'), 'local commit\n');
    f.git(['commit', '-qam', 'local']);
    const head = f.git(['rev-parse', 'HEAD']);
    const diverged = f.run(['--for', 'autoplan']);
    expect(diverged.status).toBe(1);
    expect(diverged.last).toContain('(diverged: ');
    expect(f.git(['rev-parse', 'HEAD'])).toBe(head);
    expect(f.git(['stash', 'list'])).toBe('');
    expect(f.calls()).toEqual([]);
  });

  test('an interrupted install after the fast-forward leaves the trailer fail; the next install run completes it', () => {
    const f = fixture();
    write(path.join(f.host.base, 'fail-once'), '1');
    const first = f.run(['--for', 'autoplan']);
    expect(first.status).toBe(1);
    expect(first.last).toBe('gstack: fail claude');
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.b);
    const second = f.run(['--for', 'autoplan']);
    expect(second.status, second.stdout + second.stderr).toBe(0);
    expect(second.last).toBe('gstack: ok 1.0.1 for=autoplan');
  });

  test('offline: the remote minimum is unknown and said so; an old checkout is never ok', () => {
    const f = fixture();
    fs.renameSync(f.bare, `${f.bare}.gone`);
    const old = f.run(['--check', '--for', 'autoplan']);
    expect(old.status).toBe(1);
    expect(old.stdout).toContain('remote minimum unknown (fetch failed)');
    expect(old.last).toMatch(/^gstack: fail /);
    fs.renameSync(`${f.bare}.gone`, f.bare);
    expect(f.run(['--for', 'autoplan']).status).toBe(0);
    fs.renameSync(f.bare, `${f.bare}.gone`);
    const current = f.run(['--check', '--for', 'autoplan']);
    expect(current.stdout).toContain('remote minimum unknown (fetch failed)');
    expect(f.calls().at(-1)).toContain('min=unknown');
  });

  test('a stale bootstrapper still runs the checkout wrapper and names the owner action', () => {
    const f = fixture({ minWrapper: 99 });
    const r = f.run(['--for', 'autoplan']);
    expect(r.status, r.stdout + r.stderr).toBe(0);
    expect(r.stdout).toMatch(new RegExp(`^gstack-capy-skill: owner action — Drive copy is wrapper \\d+, minimum 99; copy ${f.root}/capy/skill/gstack/ \\(CAPY_WRAPPER_STALE\\)$`, 'm'));
    expect(r.last).toBe('gstack: ok 1.0.1 for=autoplan');
  });

  test('no checkout: --check records the not-installed trailer; install clones and runs the checkout wrapper', () => {
    const f = fixture();
    fs.rmSync(f.root, { recursive: true, force: true });
    const check = f.run(['--check', '--for', 'autoplan']);
    expect(check.status).toBe(1);
    expect(check.last).toBe(`gstack: fail not-installed — no gstack checkout at ${f.root}; fix: bash ${BOOT} --for autoplan (installs)`);
    const install = f.run(['--for', 'autoplan']);
    expect(install.status, install.stdout + install.stderr).toBe(0);
    expect(f.git(['rev-parse', 'HEAD'])).toBe(f.b);
    expect(install.last).toBe('gstack: ok 1.0.1 for=autoplan');
  });
});

describe('capy skill: vendored text and support file', () => {
  const support = fs.existsSync(path.join(REPO, 'capy/support.env')) ? fs.readFileSync(path.join(REPO, 'capy/support.env'), 'utf8') : '';
  test('the wrapper revision meets the checkout minimum; GSTACK_MIN_REVISION <= VERSION', () => {
    const wrapper = Number(fs.readFileSync(BOOT, 'utf8').match(/^GSTACK_CAPY_WRAPPER=(\d+)$/m)?.[1] ?? 0);
    expect(wrapper).toBeGreaterThanOrEqual(Number(envValue(support, 'GSTACK_CAPY_MIN_WRAPPER') || 999));
    const min = envValue(support, 'GSTACK_MIN_REVISION');
    expect(min).toMatch(/^\d+\.\d+\.\d+\.\d+$/);
    expect(below(fs.readFileSync(path.join(REPO, 'VERSION'), 'utf8').trim(), min)).toBe(false);
  });

  test('SKILL.md: frontmatter, line cap, the session protocol tokens, and every command it names exists', () => {
    const text = fs.readFileSync(path.join(SKILL, 'SKILL.md'), 'utf8');
    expect(text).toMatch(/^---\nname: gstack\ndescription: .+\n---\n/);
    expect(text.split('\n').length).toBeLessThanOrEqual(90);
    for (const token of ['--check', 'GSTACK_LAUNCH', '^gstack: ok', 'gstack: fail not-installed', 'gstack-pregate sealed', 'autoplan/DRIVER.md', 'first report']) {
      expect(text, token).toContain(token);
    }
    const named = [...text.matchAll(/\b(?:bin\/)?(gstack-[a-z0-9-]+)\b/g)].map(m => m[1]).filter(n => n !== 'gstack-capy-skill');
    const missing = [...new Set(named)].filter(n => !fs.existsSync(path.join(REPO, 'bin', n)) && n !== 'gstack-pregate');
    expect(missing).toEqual([]);
    expect(fs.existsSync(path.join(REPO, 'bin/gstack-pregate'))).toBe(true);
  });

  test('every (CODE) the install-side bash bins print resolves to a troubleshooting anchor', () => {
    const bins = ['bin/gstack-capy-install', 'bin/gstack-upgrade', 'bin/gstack-capy-session', 'bin/gstack-install-verdict.sh', 'capy/skill/gstack/scripts/install.sh'];
    const codes = new Set<string>();
    for (const rel of bins) for (const m of fs.readFileSync(path.join(REPO, rel), 'utf8').matchAll(/\(([A-Z][A-Z0-9]+_[A-Z0-9_]+)[;)]/g)) codes.add(m[1]);
    for (const m of fs.readFileSync(path.join(REPO, 'bin/gstack-install-verdict.sh'), 'utf8').matchAll(/code=([A-Z][A-Z0-9_]+)/g)) codes.add(m[1]);
    expect([...codes].sort()).toEqual(expect.arrayContaining(['CAPY_WRAPPER_STALE', 'INSTALL_UNVERIFIED', 'REVISION_BELOW_MINIMUM', 'RUNTIME_BELOW_MINIMUM', 'UPGRADE_FETCH_FAILED', 'UPGRADE_REFUSED']));
    expect([...codes].filter(c => !(c in RESULT_CODES))).toEqual([]);
  });
});