import logging
from base64 import b64encode as b64enc
from calendar import timegm
from contextlib import asynccontextmanager
from datetime import datetime, timedelta, UTC
from hashlib import sha256
from json import loads as json_loads, dumps as json_dumps
from os import getenv as env
from os.path import join, dirname
from uuid import uuid4

from dateutil.relativedelta import relativedelta
from dotenv import load_dotenv
from fastapi import FastAPI
from fastapi.requests import Request
from fastapi.responses import Response, RedirectResponse, StreamingResponse
from jose import jws, jwk, jwt, JWTError
from jose.constants import ALGORITHMS
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from starlette.middleware.cors import CORSMiddleware

from orm import Origin, Lease, init as db_init, migrate
from util import CASetup, PrivateKey, Cert, ProductMapping, load_file

# Load variables
load_dotenv('../version.env')

# Get current timezone
TZ = datetime.now().astimezone().tzinfo

# Load basic variables
VERSION, COMMIT, DEBUG = env('VERSION', 'unknown'), env('COMMIT', 'unknown'), bool(env('DEBUG', False))

# Database connection
db = create_engine(str(env('DATABASE', 'sqlite:///db.sqlite')))
db_init(db), migrate(db)

# Load DLS variables (all prefixed with "INSTANCE_*" is used as "SERVICE_INSTANCE_*" or "SI_*" in official dls service)
DLS_URL = str(env('DLS_URL', 'localhost'))
DLS_PORT = int(env('DLS_PORT', '443'))
SITE_KEY_XID = str(env('SITE_KEY_XID', '00000000-0000-0000-0000-000000000000'))
INSTANCE_REF = str(env('INSTANCE_REF', '10000000-0000-0000-0000-000000000001'))
ALLOTMENT_REF = str(env('ALLOTMENT_REF', '20000000-0000-0000-0000-000000000001'))
TOKEN_EXPIRE_DELTA = relativedelta(days=int(env('TOKEN_EXPIRE_DAYS', 1)), hours=int(env('TOKEN_EXPIRE_HOURS', 0)))
LEASE_EXPIRE_DELTA = relativedelta(days=int(env('LEASE_EXPIRE_DAYS', 90)), hours=int(env('LEASE_EXPIRE_HOURS', 0)))
LEASE_RENEWAL_PERIOD = float(env('LEASE_RENEWAL_PERIOD', 0.15))
LEASE_RENEWAL_DELTA = timedelta(days=int(env('LEASE_EXPIRE_DAYS', 90)), hours=int(env('LEASE_EXPIRE_HOURS', 0)))
CLIENT_TOKEN_EXPIRE_DELTA = relativedelta(years=12)
CORS_ORIGINS = str(env('CORS_ORIGINS', '')).split(',') if (env('CORS_ORIGINS')) else [f'https://{DLS_URL}']
DT_FORMAT = '%Y-%m-%dT%H:%M:%S.%fZ'
PRODUCT_MAPPING = ProductMapping(filename=join(dirname(__file__), 'static/product_mapping.json'))

# Create certificate chain and signing keys
ca_setup = CASetup(service_instance_ref=INSTANCE_REF)
my_root_certificate = Cert.from_file(ca_setup.root_certificate_filename)
my_ca_certificate = Cert.from_file(ca_setup.ca_certificate_filename)
my_si_certificate = Cert.from_file(ca_setup.si_certificate_filename)
my_si_private_key = PrivateKey.from_file(ca_setup.si_private_key_filename)
my_si_public_key = my_si_private_key.public_key()

jwt_encode_key = jwk.construct(my_si_private_key.pem(), algorithm=ALGORITHMS.RS256)
jwt_decode_key = jwk.construct(my_si_private_key.public_key().pem(), algorithm=ALGORITHMS.RS256)

# Logging
LOG_LEVEL = logging.DEBUG if DEBUG else logging.INFO
logging.basicConfig(format='[{levelname:^7}] [{module:^15}] {message}', style='{')
logger = logging.getLogger(__name__)
logger.setLevel(LOG_LEVEL)
logging.getLogger('util').setLevel(LOG_LEVEL)
logging.getLogger('NV').setLevel(LOG_LEVEL)


# FastAPI
@asynccontextmanager
async def lifespan(_: FastAPI):
    # on startup
    logger.info(f'''
    
    Using timezone: {str(TZ)}. Make sure this is correct and match your clients!
    
    Your clients renew their license every {str(Lease.calculate_renewal(LEASE_RENEWAL_PERIOD, LEASE_RENEWAL_DELTA))}.
    If the renewal fails, the license is {str(LEASE_RENEWAL_DELTA)} valid.
    
    Your client-token file (.tok) is valid for {str(CLIENT_TOKEN_EXPIRE_DELTA)}.
    ''')

    logger.info(f'Debug is {"enabled" if DEBUG else "disabled"}.')

    yield

    # on shutdown
    logger.info(f'Shutting down ...')


config = dict(openapi_url=None, docs_url=None, redoc_url=None)  # dict(openapi_url='/-/openapi.json', docs_url='/-/docs', redoc_url='/-/redoc')
app = FastAPI(title='FastAPI-DLS', description='Minimal Delegated License Service (DLS).', version=VERSION, lifespan=lifespan, **config)

app.debug = DEBUG
app.add_middleware(
    CORSMiddleware,
    allow_origins=CORS_ORIGINS,
    allow_credentials=True,
    allow_methods=['*'],
    allow_headers=['*'],
)


# Helper
def __get_token(request: Request) -> dict:
    authorization_header = request.headers.get('authorization')
    token = authorization_header.split(' ')[1]
    return jwt.decode(token=token, key=jwt_decode_key, algorithms=ALGORITHMS.RS256, options={'verify_aud': False})


# Endpoints

@app.get('/', summary='Index')
async def index():
    return RedirectResponse('/-/readme')


@app.get('/-/', summary='* Index')
async def _index():
    return RedirectResponse('/-/readme')


@app.get('/-/health', summary='* Health')
async def _health():
    return Response(content=json_dumps({'status': 'up'}), media_type='application/json', status_code=200)


@app.get('/-/config', summary='* Config', description='returns environment variables.')
async def _config():
    response = {
        'VERSION': str(VERSION),
        'COMMIT': str(COMMIT),
        'DEBUG': str(DEBUG),
        'DLS_URL': str(DLS_URL),
        'DLS_PORT': str(DLS_PORT),
        'SITE_KEY_XID': str(SITE_KEY_XID),
        'INSTANCE_REF': str(INSTANCE_REF),
        'ALLOTMENT_REF': [str(ALLOTMENT_REF)],
        'TOKEN_EXPIRE_DELTA': str(TOKEN_EXPIRE_DELTA),
        'LEASE_EXPIRE_DELTA': str(LEASE_EXPIRE_DELTA),
        'LEASE_RENEWAL_PERIOD': str(LEASE_RENEWAL_PERIOD),
        'CORS_ORIGINS': str(CORS_ORIGINS),
        'TZ': str(TZ),
    }

    return Response(content=json_dumps(response), media_type='application/json', status_code=200)



@app.get('/-/config/root-ca', summary='* Root CA', description='returns Root-CA needed for patching nvidia-gridd')
async def _config():
    return Response(content=my_root_certificate.pem().decode('utf-8'), media_type='text/plain')


@app.get('/-/readme', summary='* Readme')
async def _readme():
    from markdown import markdown
    content = load_file(join(dirname(__file__), '../README.md')).decode('utf-8')
    response = markdown(text=content, extensions=['tables', 'fenced_code', 'md_in_html', 'nl2br', 'toc'])
    return Response(response, media_type='text/html', status_code=200)


@app.get('/-/manage', summary='* Management UI')
async def _manage(request: Request):
    response = '''
    <!DOCTYPE html>
    <html>
        <head>
            <title>FastAPI-DLS Management</title>
        </head>
        <body>
            <button onclick="deleteOrigins()">delete ALL origins and their leases</button>
            <button onclick="deleteLease()">delete specific lease</button>
            
            <script>
                function deleteOrigins() {
                    const response = confirm('Are you sure you want to delete all origins and their leases?');

                    if (response) {
                        var xhr = new XMLHttpRequest();
                        xhr.open("DELETE", '/-/origins', true);
                        xhr.send();
                    }
                }
                function deleteLease(lease_ref) {
                    if(lease_ref === undefined)
                        lease_ref = window.prompt("Please enter 'lease_ref' which should be deleted");
                    if(lease_ref === null || lease_ref === "")
                        return
                    var xhr = new XMLHttpRequest();
                    xhr.open("DELETE", `/-/lease/${lease_ref}`, true);
                    xhr.send();
                }
            </script>
        </body>
    </html>
    '''
    return Response(response, media_type='text/html', status_code=200)


@app.get('/-/origins', summary='* Origins')
async def _origins(request: Request, leases: bool = False):
    session = sessionmaker(bind=db)()
    response = []
    for origin in session.query(Origin).all():
        x = origin.serialize()
        if leases:
            serialize = dict(renewal_period=LEASE_RENEWAL_PERIOD, renewal_delta=LEASE_RENEWAL_DELTA)
            x['leases'] = list(map(lambda _: _.serialize(**serialize), Lease.find_by_origin_ref(db, origin.origin_ref)))
        response.append(x)
    session.close()
    return Response(content=json_dumps(response), media_type='application/json', status_code=200)


@app.delete('/-/origins', summary='* Origins')
async def _origins_delete(request: Request):
    Origin.delete(db)
    return Response(status_code=201)


@app.get('/-/leases', summary='* Leases')
async def _leases(request: Request, origin: bool = False):
    session = sessionmaker(bind=db)()
    response = []
    for lease in session.query(Lease).all():
        serialize = dict(renewal_period=LEASE_RENEWAL_PERIOD, renewal_delta=LEASE_RENEWAL_DELTA)
        x = lease.serialize(**serialize)
        if origin:
            lease_origin = session.query(Origin).filter(Origin.origin_ref == lease.origin_ref).first()
            if lease_origin is not None:
                x['origin'] = lease_origin.serialize()
        response.append(x)
    session.close()
    return Response(content=json_dumps(response), media_type='application/json', status_code=200)


@app.delete('/-/leases/expired', summary='* Leases')
async def _lease_delete_expired(request: Request):
    Lease.delete_expired(db)
    return Response(status_code=201)


@app.delete('/-/lease/{lease_ref}', summary='* Lease')
async def _lease_delete(request: Request, lease_ref: str):
    if Lease.delete(db, lease_ref) == 1:
        return Response(status_code=201)
    response = {'status': 404, 'detail': 'lease not found'}
    return Response(content=json_dumps(response), media_type='application/json', status_code=404)


# venv/lib/python3.9/site-packages/nls_core_service_instance/service_instance_token_manager.py
@app.get('/-/client-token', summary='* Client-Token', description='creates a new messenger token for this service instance')
async def _client_token():
    cur_time = datetime.now(UTC)
    exp_time = cur_time + CLIENT_TOKEN_EXPIRE_DELTA

    payload = {
        "jti": str(uuid4()),
        "iss": "NLS Service Instance",
        "aud": "NLS Licensed Client",
        "iat": timegm(cur_time.timetuple()),
        "nbf": timegm(cur_time.timetuple()),
        "exp": timegm(exp_time.timetuple()),
        "protocol_version": "2.0",
        "update_mode": "ABSOLUTE",
        "scope_ref_list": [ALLOTMENT_REF],
        "fulfillment_class_ref_list": [],
        "service_instance_configuration": {
            "nls_service_instance_ref": INSTANCE_REF,
            "svc_port_set_list": [
                {
                    "idx": 0,
                    "d_name": "DLS",
                    # todo: {"service": "quick_release", "port": 80} - see "shutdown for windows"
                    "svc_port_map": [{"service": "auth", "port": DLS_PORT}, {"service": "lease", "port": DLS_PORT}]
                }
            ],
            "node_url_list": [{"idx": 0, "url": DLS_URL, "url_qr": DLS_URL, "svc_port_set_idx": 0}]
        },
        "service_instance_public_key_configuration": {
            "service_instance_public_key_me": {
                "mod": my_si_public_key.mod(),
                "exp": my_si_public_key.exp(),
            },
            "service_instance_public_key_pem": my_si_private_key.public_key().pem().decode('utf-8'),
            "key_retention_mode": "LATEST_ONLY"
        },
    }

    content = jws.sign(payload, key=jwt_encode_key, headers=None, algorithm=ALGORITHMS.RS256)

    response = StreamingResponse(iter([content]), media_type="text/plain")
    filename = f'client_configuration_token_{datetime.now().strftime("%d-%m-%y-%H-%M-%S")}.tok'
    response.headers["Content-Disposition"] = f'attachment; filename={filename}'

    return response


# venv/lib/python3.9/site-packages/nls_services_auth/test/test_origins_controller.py
@app.post('/auth/v1/origin', description='find or create an origin')
async def auth_v1_origin(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    origin_ref = j.get('candidate_origin_ref')
    logger.info(f'> [  origin  ]: {origin_ref}: {j}')

    data = Origin(
        origin_ref=origin_ref,
        hostname=j.get('environment').get('hostname'),
        guest_driver_version=j.get('environment').get('guest_driver_version'),
        os_platform=j.get('environment').get('os_platform'), os_version=j.get('environment').get('os_version'),
    )

    Origin.create_or_update(db, data)

    environment = {
        'raw_env': j.get('environment')
    }
    environment.update(j.get('environment'))

    response = {
        "origin_ref": origin_ref,
        "environment": environment,
        "svc_port_set_list": None,
        "node_url_list": None,
        "node_query_order": None,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT)
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_auth/test/test_origins_controller.py
@app.post('/auth/v1/origin/update', description='update an origin evidence')
async def auth_v1_origin_update(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    origin_ref = j.get('origin_ref')
    logger.info(f'> [  update  ]: {origin_ref}: {j}')

    data = Origin(
        origin_ref=origin_ref,
        hostname=j.get('environment').get('hostname'),
        guest_driver_version=j.get('environment').get('guest_driver_version'),
        os_platform=j.get('environment').get('os_platform'), os_version=j.get('environment').get('os_version'),
    )

    Origin.create_or_update(db, data)

    response = {
        "environment": j.get('environment'),
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT)
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_auth/test/test_auth_controller.py
# venv/lib/python3.9/site-packages/nls_core_auth/auth.py - CodeResponse
@app.post('/auth/v1/code', description='get an authorization code')
async def auth_v1_code(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    origin_ref = j.get('origin_ref')
    logger.info(f'> [   code   ]: {origin_ref}: {j}')

    delta = relativedelta(minutes=15)
    expires = cur_time + delta

    payload = {
        'iat': timegm(cur_time.timetuple()),
        'exp': timegm(expires.timetuple()),
        'challenge': j.get('code_challenge'),
        'origin_ref': j.get('origin_ref'),
        'key_ref': SITE_KEY_XID,
        'kid': SITE_KEY_XID
    }

    auth_code = jws.sign(payload, key=jwt_encode_key, headers={'kid': payload.get('kid')}, algorithm=ALGORITHMS.RS256)

    response = {
        "auth_code": auth_code,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_auth/test/test_auth_controller.py
# venv/lib/python3.9/site-packages/nls_core_auth/auth.py - TokenResponse
@app.post('/auth/v1/token', description='exchange auth code and verifier for token')
async def auth_v1_token(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    try:
        payload = jwt.decode(token=j.get('auth_code'), key=jwt_decode_key, algorithms=ALGORITHMS.RS256)
    except JWTError as e:
        response = {'status': 400, 'title': 'invalid token', 'detail': str(e)}
        return Response(content=json_dumps(response), media_type='application/json', status_code=400)

    origin_ref = payload.get('origin_ref')
    logger.info(f'> [   auth   ]: {origin_ref}: {j}')

    # validate the code challenge
    challenge = b64enc(sha256(j.get('code_verifier').encode('utf-8')).digest()).rstrip(b'=').decode('utf-8')
    if payload.get('challenge') != challenge:
        response = {'status': 401, 'detail': 'expected challenge did not match verifier'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=401)

    access_expires_on = cur_time + TOKEN_EXPIRE_DELTA

    new_payload = {
        'iat': timegm(cur_time.timetuple()),
        'nbf': timegm(cur_time.timetuple()),
        'iss': 'https://cls.nvidia.org',
        'aud': 'https://cls.nvidia.org',
        'exp': timegm(access_expires_on.timetuple()),
        'key_ref': SITE_KEY_XID,
        'kid': SITE_KEY_XID,
        'origin_ref': origin_ref,
    }

    auth_token = jwt.encode(new_payload, key=jwt_encode_key, headers={'kid': payload.get('kid')}, algorithm=ALGORITHMS.RS256)

    response = {
        "auth_token": auth_token,
        "expires": access_expires_on.strftime(DT_FORMAT),
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# NLS 3.4.0 - venv/lib/python3.12/site-packages/nls_services_lease/test/test_lease_single_controller.py
@app.post('/leasing/v1/config-token', description='request to get config token for lease operations')
async def leasing_v1_config_token(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    cur_time = datetime.now(UTC)
    exp_time = cur_time + CLIENT_TOKEN_EXPIRE_DELTA

    payload = {
        "iss": "NLS Service Instance",
        "aud": "NLS Licensed Client",
        "iat": timegm(cur_time.timetuple()),
        "nbf": timegm(cur_time.timetuple()),
        "exp": timegm(exp_time.timetuple()),
        "protocol_version": "2.0",
        "d_name": "DLS",
        "service_instance_ref": j.get('service_instance_ref'),
        "service_instance_public_key_configuration": {
            "service_instance_public_key_me": {
                "mod": my_si_public_key.mod(),
                "exp": my_si_public_key.exp(),
            },
            # 64 chars per line (pem default)
            "service_instance_public_key_pem": my_si_private_key.public_key().pem().decode('utf-8').strip(),
            "key_retention_mode": "LATEST_ONLY"
        },
    }

    my_jwt_encode_key = jwk.construct(my_si_private_key.pem().decode('utf-8'), algorithm=ALGORITHMS.RS256)
    config_token = jws.sign(payload, key=my_jwt_encode_key, headers=None, algorithm=ALGORITHMS.RS256)

    response_ca_chain = my_ca_certificate.pem().decode('utf-8')
    response_si_certificate = my_si_certificate.pem().decode('utf-8')

    response = {
        "certificateConfiguration": {
            # 76 chars per line
            "caChain": [response_ca_chain],
            # 76 chars per line
            "publicCert": response_si_certificate,
            "publicKey": {
                "exp": int(my_si_certificate.raw().public_key().public_numbers().e),
                "mod": [hex(my_si_certificate.raw().public_key().public_numbers().n)[2:]],
            },
        },
        "configToken": config_token,
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_lease/test/test_lease_multi_controller.py
@app.post('/leasing/v1/lessor', description='request multiple leases (borrow) for current origin')
async def leasing_v1_lessor(request: Request):
    j, token, cur_time = json_loads((await request.body()).decode('utf-8')), __get_token(request), datetime.now(UTC)

    try:
        token = __get_token(request)
    except JWTError:
        response = {'status': 401, 'detail': 'token is not valid'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=401)

    origin_ref = token.get('origin_ref')
    scope_ref_list = j.get('scope_ref_list')
    lease_proposal_list = j.get('lease_proposal_list')
    logger.info(f'> [  create  ]: {origin_ref}: create leases for scope_ref_list {scope_ref_list}')

    for scope_ref in scope_ref_list:
        # if scope_ref not in [ALLOTMENT_REF]:
        #     response = {'status': 400, 'detail': f'service instances not found for scopes: ["{scope_ref}"]')}
        #     return Response(content=json_dumps(response), media_type='application/json', status_code=400)
        pass

    lease_result_list = []
    for lease_proposal in lease_proposal_list:
        lease_ref = str(uuid4())
        expires = cur_time + LEASE_EXPIRE_DELTA

        product_name = lease_proposal.get('product').get('name')
        feature_name = PRODUCT_MAPPING.get_feature_name(product_name=product_name)

        lease_result_list.append({
            "error": None,
            "lease": {
                "created": cur_time.strftime(DT_FORMAT),
                "expires": expires.strftime(DT_FORMAT),  # todo: lease_proposal.get('duration') => "P0Y0M0DT12H0M0S
                "feature_name": feature_name,
                "lease_intent_id": None,
                "license_type": "CONCURRENT_COUNTED_SINGLE",
                "metadata": None,
                "offline_lease": False,  # todo
                "product_name": product_name,
                "recommended_lease_renewal": LEASE_RENEWAL_PERIOD,
                "ref": lease_ref,
            },
            "ordinal": None,
        })

        data = Lease(origin_ref=origin_ref, lease_ref=lease_ref, lease_created=cur_time, lease_expires=expires)
        Lease.create_or_update(db, data)

    response = {
        "client_challenge": j.get('client_challenge'),
        "lease_result_list": lease_result_list,
        "prompts": None,
        "result_code": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    content = json_dumps(response, separators=(',', ':'))
    content = f'{content}\n'.encode('ascii')
    signature = my_si_private_key.generate_signature(content)

    headers = {
        'Content-Type': 'application/json',
        'access-control-expose-headers': 'X-NLS-Signature',
        'X-NLS-Signature': f'{signature.hex().encode()}'
    }

    return Response(content=content, media_type='application/json', headers=headers)


# venv/lib/python3.9/site-packages/nls_services_lease/test/test_lease_multi_controller.py
# venv/lib/python3.9/site-packages/nls_dal_service_instance_dls/schema/service_instance/V1_0_21__product_mapping.sql
@app.get('/leasing/v1/lessor/leases', description='get active leases for current origin')
async def leasing_v1_lessor_lease(request: Request):
    token, cur_time = __get_token(request), datetime.now(UTC)

    origin_ref = token.get('origin_ref')

    active_lease_list = list(map(lambda x: x.lease_ref, Lease.find_by_origin_ref(db, origin_ref)))
    logger.info(f'> [  leases  ]: {origin_ref}: found {len(active_lease_list)} active leases')

    response = {
        "active_lease_list": active_lease_list,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_lease/test/test_lease_single_controller.py
# venv/lib/python3.9/site-packages/nls_core_lease/lease_single.py
@app.put('/leasing/v1/lease/{lease_ref}', description='renew a lease')
async def leasing_v1_lease_renew(request: Request, lease_ref: str):
    j, token, cur_time = json_loads((await request.body()).decode('utf-8')), __get_token(request), datetime.now(UTC)

    origin_ref = token.get('origin_ref')
    logger.info(f'> [  renew   ]: {origin_ref}: renew {lease_ref}')

    entity = Lease.find_by_origin_ref_and_lease_ref(db, origin_ref, lease_ref)
    if entity is None:
        response = {'status': 404, 'detail': 'requested lease not available'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=404)

    expires = cur_time + LEASE_EXPIRE_DELTA
    response = {
        "client_challenge": j.get('client_challenge'),
        "expires": expires.strftime('%Y-%m-%dT%H:%M:%S.%f'),  # DT_FORMAT => "trailing 'Z' missing in this response
        "feature_expired": False,
        "lease_ref": lease_ref,
        "metadata": None,
        "offline_lease": False,  # todo
        "prompts": None,
        "recommended_lease_renewal": LEASE_RENEWAL_PERIOD,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    Lease.renew(db, entity, expires, cur_time)

    content = json_dumps(response, separators=(',', ':'))
    content = f'{content}\n'.encode('ascii')
    signature = my_si_private_key.generate_signature(content)

    headers = {
        'Content-Type': 'application/json',
        'access-control-expose-headers': 'X-NLS-Signature',
        'X-NLS-Signature': f'{signature.hex().encode()}'
    }

    return Response(content=content, media_type='application/json', headers=headers)



# venv/lib/python3.9/site-packages/nls_services_lease/test/test_lease_single_controller.py
@app.delete('/leasing/v1/lease/{lease_ref}', description='release (return) a lease')
async def leasing_v1_lease_delete(request: Request, lease_ref: str):
    token, cur_time = __get_token(request), datetime.now(UTC)

    origin_ref = token.get('origin_ref')
    logger.info(f'> [  return  ]: {origin_ref}: return {lease_ref}')

    entity = Lease.find_by_lease_ref(db, lease_ref)
    if entity.origin_ref != origin_ref:
        response = {'status': 403, 'detail': 'access or operation forbidden'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=403)
    if entity is None:
        response = {'status': 404, 'detail': 'requested lease not available'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=404)

    if Lease.delete(db, lease_ref) == 0:
        response = {'status': 404, 'detail': 'lease not found'}
        return Response(content=json_dumps(response), media_type='application/json', status_code=404)

    response = {
        "client_challenge": None,
        "lease_ref": lease_ref,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


# venv/lib/python3.9/site-packages/nls_services_lease/test/test_lease_multi_controller.py
@app.delete('/leasing/v1/lessor/leases', description='release all leases')
async def leasing_v1_lessor_lease_remove(request: Request):
    token, cur_time = __get_token(request), datetime.now(UTC)

    origin_ref = token.get('origin_ref')

    released_lease_list = list(map(lambda x: x.lease_ref, Lease.find_by_origin_ref(db, origin_ref)))
    deletions = Lease.cleanup(db, origin_ref)
    logger.info(f'> [  remove  ]: {origin_ref}: removed {deletions} leases')

    response = {
        "released_lease_list": released_lease_list,
        "release_failure_list": None,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


@app.post('/leasing/v1/lessor/shutdown', description='shutdown all leases')
async def leasing_v1_lessor_shutdown(request: Request):
    j, cur_time = json_loads((await request.body()).decode('utf-8')), datetime.now(UTC)

    token = j.get('token')
    token = jwt.decode(token=token, key=jwt_decode_key, algorithms=ALGORITHMS.RS256, options={'verify_aud': False})
    origin_ref = token.get('origin_ref')

    released_lease_list = list(map(lambda x: x.lease_ref, Lease.find_by_origin_ref(db, origin_ref)))
    deletions = Lease.cleanup(db, origin_ref)
    logger.info(f'> [ shutdown ]: {origin_ref}: removed {deletions} leases')

    response = {
        "released_lease_list": released_lease_list,
        "release_failure_list": None,
        "prompts": None,
        "sync_timestamp": cur_time.strftime(DT_FORMAT),
    }

    return Response(content=json_dumps(response, separators=(',', ':')), media_type='application/json', status_code=200)


if __name__ == '__main__':
    import uvicorn

    ###
    #
    # Running `python app/main.py` assumes that the user created a keypair, e.g. with openssl.
    #
    # openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout app/cert/webserver.key -out app/cert/webserver.crt
    #
    ###

    logger.info(f'> Starting dev-server ...')

    ssl_keyfile = join(dirname(__file__), 'cert/webserver.key')
    ssl_certfile = join(dirname(__file__), 'cert/webserver.crt')

    uvicorn.run('main:app', host='0.0.0.0', port=443, ssl_keyfile=ssl_keyfile, ssl_certfile=ssl_certfile, reload=True)