#!/usr/bin/env python3
"""Attended custody child for CCR-2026-0033: KeyCape `secrets-engine-openbao` client secret.

SOURCE ONLY until the founder approves this exact child. One run generates one
value in process memory, compare-before-writes it as the authoritative KV-v2
version, writes the secrets-engine consumer copy in the same process, runs the
consumer's value-free acceptance check and writes a metadata-only receipt.

It never reads the KV value, never prints the value, never puts it in argv or
the environment, and does not touch policies, roles, ESO, KeyCape or the
cluster (later live steps, see CCR-2026-0033 live_order).
"""
from __future__ import annotations

import argparse
import hashlib
import importlib.util
import json
import os
from pathlib import Path
import re
import secrets
import stat
import sys
from datetime import datetime, timezone

sys.path.insert(0, str(Path(__file__).resolve().parent))
from state_hub_preflight_lane import ROOT, LaneError, bao, command, data  # noqa: E402

CCR_ID = 'CCR-2026-0033'
CCR_PATH = ROOT / 'credential-change-requests/CCR-2026-0033.yaml'
BOUNDARY_DECISION = '632a8893-0d6a-4591-a50b-40bbdb798f32'
KV_PATH = 'platform/workloads/keycape/secrets-engine-openbao'
KV_DATA = 'platform/data/workloads/keycape/secrets-engine-openbao'
KV_METADATA = 'platform/metadata/workloads/keycape/secrets-engine-openbao'
FIELD = 'CLIENT_SECRET'
# secrets-engine coordinates (SECRETS-WP-0012, a3897c2); D1-D4 pending founder choice.
CONSUMER_FILE = Path('/home/worsch/.secrets-engine/keycape/secrets-engine-openbao.client-secret')
APPROVERS = ('platform-owner', 'key-cape-owner', 'net-kingdom-owner')
UUID_RE = re.compile(r'^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$')


def require(condition, reason):
    if not condition:
        raise LaneError(reason)


def attended_envelope():
    return (Path.home().parent.name == '.warden-attended-login'
            and not os.environ.get('BAO_TOKEN') and not os.environ.get('VAULT_TOKEN'))


def contract(decision_id):
    require(isinstance(decision_id, str) and UUID_RE.match(decision_id), 'approval_decision_id_required')
    require(decision_id != BOUNDARY_DECISION, 'boundary_decision_does_not_approve_custody_child')
    spec = importlib.util.spec_from_file_location('credential_change', ROOT / 'scripts/credential-change.py')
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    ccr, errors, _ = module.validate_ccr(CCR_PATH)
    require(not errors and ccr['id'] == CCR_ID, 'valid_ccr_required')
    require(ccr['status'] == 'approved', 'approved_ccr_required')
    comments = ccr['review']['comments']
    for role in APPROVERS:
        require(any(c.get('decision') == 'approved' and role in c.get('reviewer', '') for c in comments),
                'all_named_reviews_required')
    require(any(c.get('decision') == 'approved' and decision_id in str(c.get('comment', '')) for c in comments),
            'custody_child_decision_not_recorded_in_ccr')
    openbao = ccr['openbao']
    require(openbao['kv_path'] == KV_PATH and openbao['fields'] == [FIELD]
            and openbao['auth']['bound_claims_confirmed'] is True
            and ccr['custody_child']['script'] == 'scripts/keycape_secrets_engine_openbao_custody.py'
            and ccr['consumer_copy']['file'] == str(CONSUMER_FILE), 'exact_approved_contract_required')
    return hashlib.sha256(CCR_PATH.read_bytes()).hexdigest()


def kv_current_version():
    """Metadata only. None when the path has never been written."""
    result = bao(['read', '-format=json', KV_METADATA], allow_failure=True)
    if result.returncode != 0:
        require(b'404' in result.stderr or b'No value found' in result.stderr, 'absence_not_proven')
        return None
    meta = data(result)['data']
    current = meta['current_version']
    version = meta['versions'][str(current)]
    require(not version.get('destroyed') and not version.get('deletion_time'), 'current_version_not_live')
    return current


def write_kv(value, cas):
    result = data(bao(['write', '-format=json', KV_DATA, '-'],
                      payload={'options': {'cas': cas}, 'data': {FIELD: value}}))
    require(result['data']['version'] == cas + 1, 'unexpected_kv_version')
    return result['data']['version'], result.get('request_id')


def fsync_dir(path):
    fd = os.open(path, os.O_RDONLY | os.O_DIRECTORY)
    try:
        os.fsync(fd)
    finally:
        os.close(fd)


def prepare_parent(target):
    parent = target.parent
    grand = os.lstat(parent.parent)
    require(stat.S_ISDIR(grand.st_mode), 'consumer_grandparent_invalid')
    try:
        info = os.lstat(parent)
    except FileNotFoundError:
        os.mkdir(parent, 0o700)
        fsync_dir(parent.parent)
        info = os.lstat(parent)
    require(stat.S_ISDIR(info.st_mode) and info.st_uid == os.geteuid()
            and stat.S_IMODE(info.st_mode) == 0o700, 'consumer_parent_must_be_owned_0700_directory')
    require(not os.path.lexists(target), 'consumer_file_exists_rotation_needs_separate_approval')


def write_consumer(target, value, receipt):
    parent = target.parent
    temp = parent / ('.' + target.name + '.' + secrets.token_hex(8) + '.tmp')
    fd = os.open(temp, os.O_CREAT | os.O_EXCL | os.O_WRONLY | os.O_NOFOLLOW, 0o600)
    try:
        try:
            os.write(fd, (value + '\n').encode())
            os.fsync(fd)
        finally:
            os.close(fd)
        os.rename(temp, target)
        fsync_dir(parent)
    except BaseException:
        try:
            os.unlink(temp)
            receipt['consumer_temp_removed'] = True
        except FileNotFoundError:
            pass
        raise
    info = os.lstat(target)
    require(stat.S_ISREG(info.st_mode) and stat.S_IMODE(info.st_mode) == 0o600
            and info.st_uid == os.geteuid(), 'consumer_file_readback_failed')


def check_consumer(target, secrets_engine):
    result = command([secrets_engine, 'service-auth', 'check-secret-file', '--path', str(target), '--json'],
                     allow_failure=True)
    try:
        ok = bool(json.loads(result.stdout).get('ok'))
    except (ValueError, AttributeError):
        ok = False
    return result.returncode == 0 and ok


def retry_cas(prior_path, current):
    prior = json.loads(Path(prior_path).read_text())
    require(prior.get('ccr') == CCR_ID and prior.get('status') == 'failed' and prior.get('kv_written')
            and not prior.get('consumer_written'), 'retryable_partial_receipt_required')
    require(current is not None and prior.get('kv_version') == current, 'kv_version_changed_since_prior_receipt')
    return current


def run(args, receipt):
    receipt['approval_decision_id'] = args.approval_decision
    receipt['ccr_sha256'] = contract(args.approval_decision)
    require(attended_envelope(), 'attended_warden_envelope_required')
    os.umask(0o077)
    identity = data(bao(['token', 'lookup', '-format=json']))['data']
    require('platform-admin' in identity['policies'] and 'root' not in identity['policies'],
            'attended_platform_admin_required')
    current = kv_current_version()
    if args.prior_receipt:
        cas = retry_cas(args.prior_receipt, current)
        receipt['retry_of_kv_version'] = cas
    else:
        require(current is None, 'existing_custody_requires_retry_receipt_or_rotation_approval')
        cas = 0
    prepare_parent(CONSUMER_FILE)
    receipt['phase'] = 'kv_write'
    value = secrets.token_urlsafe(48)
    try:
        version, request_id = write_kv(value, cas)
        receipt.update(kv_written=True, kv_version=version, kv_request_id=request_id, kv_cas=cas)
        receipt['phase'] = 'consumer_write'
        write_consumer(CONSUMER_FILE, value, receipt)
        receipt['consumer_written'] = True
    finally:
        value = None
    receipt['phase'] = 'consumer_check'
    receipt['consumer_check_ok'] = check_consumer(CONSUMER_FILE, args.secrets_engine)
    require(receipt['consumer_check_ok'], 'consumer_check_failed')
    receipt['status'] = 'custody_written_pending_issuer_delivery'
    receipt['phase'] = 'done'


def main(argv=None):
    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    parser.add_argument('action', choices=['provision'])
    parser.add_argument('--approval-decision', required=True,
                        help='founder decision id approving this exact custody child')
    parser.add_argument('--receipt', required=True)
    parser.add_argument('--prior-receipt', help='failed receipt with kv_written and no consumer file')
    parser.add_argument('--secrets-engine', default='secrets-engine', help='secrets-engine executable')
    args = parser.parse_args(argv)
    receipt = {'schema': 'platform.keycape-secrets-engine-openbao-custody.v1', 'ccr': CCR_ID,
               'status': 'failed', 'phase': 'preflight',
               'started_at': datetime.now(timezone.utc).isoformat(),
               'credential_values_emitted': False, 'client_side_read_admitted': False,
               'kv_written': False, 'consumer_written': False}
    fd = os.open(args.receipt, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o600)
    try:
        run(args, receipt)
    except Exception as exc:
        receipt['status'] = 'failed'
        receipt['error'] = str(exc) if isinstance(exc, LaneError) else 'contained_operation_failed'
    finally:
        receipt['finished_at'] = datetime.now(timezone.utc).isoformat()
        with os.fdopen(fd, 'w') as out:
            json.dump(receipt, out, indent=2)
            out.write('\n')
    return 0 if receipt['status'] != 'failed' else 1


if __name__ == '__main__':
    raise SystemExit(main())