#!/usr/bin/env python3
"""Patch or verify non-secret KeyCape live config requirements.

The script reads a Kubernetes Secret JSON object from stdin. It never prints the
decoded KeyCape config or private key; stdout is either a JSON merge patch for
kubectl, or a short non-secret verification message.
"""

from __future__ import annotations

import argparse
import base64
import json
import copy
import re
import subprocess
import sys
from datetime import datetime, timezone
from typing import Any

try:
    import yaml
except ImportError as exc:  # pragma: no cover - operator environment guard
    raise SystemExit("PyYAML is required: install python3-yaml or run in the NetKingdom tool environment") from exc


OPENBAO_CLIENT = {
    "clientId": "openbao-admin",
    "displayName": "Railiance OpenBao Admin",
    "redirectUris": [
        "http://localhost:8250/oidc/callback",
        "http://127.0.0.1:8250/oidc/callback",
        "http://127.0.0.1:18200/ui/vault/auth/netkingdom/oidc/callback",
        "https://bao.coulomb.social/ui/vault/auth/netkingdom/oidc/callback",
        "https://bao.coulomb.social/ui/vault/auth/keycape/oidc/callback",
    ],
    "allowedScopes": ["openid", "profile", "email", "groups"],
    "grantTypes": ["authorization_code"],
    "clientType": "public",
}

RAPP_QONTO_CLIENT = {
    "clientId": "rapp-qonto-client",
    "displayName": "rapp-qonto workload",
    "allowedScopes": ["qonto:read"],
    "grantTypes": ["client_credentials"],
    "clientType": "confidential",
    "secretRef": "env:KEYCAPE_RAPP_QONTO_CLIENT_SECRET",
    "serviceSubject": "rapp-qonto",
    "tenant": "tenant:friendly:binky",
    "roles": ["qonto-reader"],
}

LLDAP_REQUIRED = {
    "userOU": "ou=people",
    "groupOU": "ou=groups",
}

# Verified against an actual signed upstream token on 2026-09-08 (KEY-WP-0013).
VERIFIED_UPSTREAM_ISSUER = "https://auth.coulomb.social"


class IssuerPinError(Exception):
    """Only fixed, non-secret reason codes may leave the contained operation."""


class UniqueLoader(yaml.SafeLoader):
    pass


def unique_mapping(loader: Any, node: Any) -> dict[str, Any]:
    result = {}
    for key_node, value_node in node.value:
        key = loader.construct_object(key_node, deep=True)
        if not isinstance(key, str) or key in result:
            raise IssuerPinError("ambiguous_yaml_mapping")
        result[key] = loader.construct_object(value_node, deep=True)
    return result


UniqueLoader.add_constructor(yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG, unique_mapping)


def issuer_document(secret: dict[str, Any]) -> tuple[str, dict[str, Any], Any]:
    """Parse privately; never include a parser exception or document in output."""
    raw = base64.b64decode(secret['data']['config.yaml'], validate=True).decode('utf-8')
    if any(isinstance(t, (yaml.tokens.AnchorToken, yaml.tokens.AliasToken)) for t in yaml.scan(raw)):
        raise IssuerPinError("yaml_alias_or_anchor")
    config = yaml.load(raw, Loader=UniqueLoader)
    if not isinstance(config, dict) or not isinstance(config.get('authelia'), dict):
        raise IssuerPinError("unexpected_configuration_shape")
    node = yaml.compose(raw)
    authelia = next(v for k, v in node.value if k.value == 'authelia')
    if authelia.flow_style or not authelia.value:
        raise IssuerPinError("unsupported_authelia_mapping")
    return raw, config, authelia


def issuer_replacement(secret: dict[str, Any]) -> tuple[str, bool, str]:
    raw, config, authelia = issuer_document(secret)
    old = config['authelia'].get('issuer')
    prior = 'absent' if 'issuer' not in config['authelia'] else 'matching' if old == VERIFIED_UPSTREAM_ISSUER else 'different'
    if old == VERIFIED_UPSTREAM_ISSUER:
        return secret['data']['config.yaml'], False, prior
    field = next((v for k, v in authelia.value if k.value == 'issuer'), None)
    if field is not None:
        if not isinstance(field, yaml.nodes.ScalarNode):
            raise IssuerPinError("unsupported_issuer_value")
        updated = raw[:field.start_mark.index] + json.dumps(VERIFIED_UPSTREAM_ISSUER) + raw[field.end_mark.index:]
    else:
        index = authelia.start_mark.index - authelia.start_mark.column
        indent = ' ' * authelia.start_mark.column
        updated = raw[:index] + indent + 'issuer: ' + json.dumps(VERIFIED_UPSTREAM_ISSUER) + '\n' + raw[index:]
    expected = copy.deepcopy(config)
    expected['authelia']['issuer'] = VERIFIED_UPSTREAM_ISSUER
    if yaml.load(updated, Loader=UniqueLoader) != expected:
        raise IssuerPinError("unexpected_configuration_change")
    return base64.b64encode(updated.encode()).decode('ascii'), True, prior


def contained_kube(args: list[str], payload: Any = None) -> Any:
    # Secret JSON and patch bodies stay in process memory and child stdin.
    # In particular, never use -p <patch>, a shell pipeline, or inherited stderr.
    result = subprocess.run(
        ['kubectl', '--request-timeout=20s', '-n', 'sso', *args],
        input=None if payload is None else json.dumps(payload),
        capture_output=True, text=True, timeout=30, check=False,
    )
    if result.returncode:
        raise IssuerPinError("kubernetes_operation_failed")
    return json.loads(result.stdout)


def safe_metadata(obj: dict[str, Any]) -> dict[str, str]:
    metadata = obj['metadata']
    uid, revision = metadata['uid'], metadata['resourceVersion']
    if not re.fullmatch(r'[0-9a-f-]{36}', uid) or not re.fullmatch(r'[0-9]+', revision):
        raise IssuerPinError("unexpected_metadata_shape")
    return {'uid': uid, 'resource_version': revision}


def issuer_live(mode: str, expected_uid: str | None = None, expected_revision: str | None = None) -> dict[str, Any]:
    if mode == 'issuer-pin-live' and (not expected_uid or not expected_revision):
        raise IssuerPinError("pin_requires_observed_uid_and_revision")
    before = contained_kube(['get', 'secret', 'keycape-config', '-o', 'json'])
    if before.get('kind') != 'Secret' or before['metadata'].get('name') != 'keycape-config' or before['metadata'].get('namespace') != 'sso':
        raise IssuerPinError("unexpected_target")
    metadata = safe_metadata(before)
    if mode == 'issuer-pin-live' and metadata != {'uid': expected_uid, 'resource_version': expected_revision}:
        raise IssuerPinError("observed_revision_changed")
    replacement, changed, prior = issuer_replacement(before)
    receipt = {'schema': 'netkingdom.keycape-issuer-pin.v1', 'mode': mode,
               'observed_at': datetime.now(timezone.utc).isoformat(),
               'target': 'sso/keycape-config', 'verified_issuer': VERIFIED_UPSTREAM_ISSUER,
               'before': metadata, 'prior_pin_state': prior,
               'issuer_matches': not changed, 'config_changed': False,
               'secret_values_emitted': False, 'deployment_changed': False}
    if mode == 'issuer-check-live':
        return receipt
    if changed:
        patch = [
            {'op': 'test', 'path': '/metadata/uid', 'value': expected_uid},
            {'op': 'test', 'path': '/metadata/resourceVersion', 'value': expected_revision},
            {'op': 'replace', 'path': '/data/config.yaml', 'value': replacement},
        ]
        contained_kube(['patch', 'secret', 'keycape-config', '--type=json', '--patch-file=/dev/stdin', '-o', 'json'], patch)
    after = contained_kube(['get', 'secret', 'keycape-config', '-o', 'json'])
    expected_data = dict(before['data'], **{'config.yaml': replacement})
    if after['metadata']['uid'] != metadata['uid'] or after['data'] != expected_data:
        raise IssuerPinError("readback_mismatch_stop_without_replaying_stale_config")
    receipt.update({'after': safe_metadata(after), 'issuer_matches': True,
                    'config_changed': changed, 'other_secret_data_unchanged': True,
                    'unrelated_config_bytes_preserved': True})
    return receipt


def issuer_main(args: Any) -> int:
    try:
        receipt = issuer_live(args.mode, args.expected_uid, args.expected_resource_version)
    except IssuerPinError as exc:
        receipt = {'schema': 'netkingdom.keycape-issuer-pin.v1', 'status': 'failed', 'reason': str(exc)}
    except Exception:
        # Kubernetes/YAML exceptions may contain entire response/config fragments.
        receipt = {'schema': 'netkingdom.keycape-issuer-pin.v1', 'status': 'failed', 'reason': 'contained_operation_failed'}
    print(json.dumps(receipt, sort_keys=True))
    return 1 if receipt.get('status') == 'failed' else 0


def load_config() -> dict[str, Any]:
    secret = json.load(sys.stdin)
    encoded_config = (secret.get("data") or {}).get("config.yaml")
    if not encoded_config:
        raise SystemExit("keycape-config Secret does not contain data.config.yaml")
    try:
        config_text = base64.b64decode(encoded_config).decode("utf-8")
    except Exception as exc:  # noqa: BLE001 - concise operator error
        raise SystemExit(f"could not decode data.config.yaml: {exc}") from exc
    config = yaml.safe_load(config_text) or {}
    if not isinstance(config, dict):
        raise SystemExit("KeyCape config.yaml must decode to a YAML mapping")
    return config


def client_errors(config: dict[str, Any], required: dict[str, Any]) -> list[str]:
    clients = config.get("clients")
    if not isinstance(clients, list):
        return ["clients must be a list"]
    target = next(
        (client for client in clients if isinstance(client, dict) and client.get("clientId") == required["clientId"]),
        None,
    )
    if target is None:
        return [f"missing {required['clientId']} client"]

    errors: list[str] = []
    for key, expected in required.items():
        if key in ("redirectUris", "allowedScopes", "grantTypes", "roles"):
            missing = sorted(set(expected) - set(target.get(key) or []))
            if missing:
                errors.append(f"{required['clientId']}.{key} missing: {', '.join(missing)}")
        elif target.get(key) != expected:
            errors.append(f"{required['clientId']}.{key} should be {expected!r}")
    return errors


def upsert_client(config: dict[str, Any], required: dict[str, Any]) -> dict[str, Any]:
    clients = config.get("clients")
    if not isinstance(clients, list):
        clients = []
        config["clients"] = clients
    for index, client in enumerate(clients):
        if isinstance(client, dict) and client.get("clientId") == required["clientId"]:
            clients[index] = dict(required)
            return config
    clients.append(dict(required))
    return config


def lldap_errors(config: dict[str, Any]) -> list[str]:
    lldap = config.get("lldap")
    if not isinstance(lldap, dict):
        return ["lldap must be a mapping"]
    return [
        f"lldap.{key} should be {expected!r}"
        for key, expected in LLDAP_REQUIRED.items()
        if lldap.get(key) != expected
    ]


def enforce_lldap_defaults(config: dict[str, Any]) -> dict[str, Any]:
    lldap = config.get("lldap")
    if not isinstance(lldap, dict):
        lldap = {}
        config["lldap"] = lldap
    lldap.update(LLDAP_REQUIRED)
    return config


def render_patch(config: dict[str, Any]) -> None:
    updated = enforce_lldap_defaults(upsert_client(upsert_client(config, OPENBAO_CLIENT), RAPP_QONTO_CLIENT))
    config_text = yaml.safe_dump(updated, sort_keys=False)
    encoded = base64.b64encode(config_text.encode("utf-8")).decode("ascii")
    json.dump({"data": {"config.yaml": encoded}}, sys.stdout, separators=(",", ":"))
    sys.stdout.write("\n")


def verify(config: dict[str, Any]) -> None:
    errors = client_errors(config, OPENBAO_CLIENT) + client_errors(config, RAPP_QONTO_CLIENT) + lldap_errors(config)
    if errors:
        for error in errors:
            print(f"[FAIL] {error}")
        raise SystemExit(1)
    print("[PASS] openbao-admin and rapp-qonto clients and LLDAP OU lookup settings are present")


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("mode", choices=("patch", "verify", "issuer-check-live", "issuer-pin-live"))
    parser.add_argument("--expected-uid")
    parser.add_argument("--expected-resource-version")
    args = parser.parse_args()
    if args.mode.startswith('issuer-'):
        raise SystemExit(issuer_main(args))
    config = load_config()
    if args.mode == "patch":
        render_patch(config)
    else:
        verify(config)


if __name__ == "__main__":
    main()