EDMarketConnector/companion.py

"""
Handle use of Frontier's Companion API (CAPI) service.

Deals with initiating authentication for, and use of, CAPI.
Some associated code is in protocol.py which creates and handles the edmc://
protocol used for the callback.
"""

import base64
import collections
import csv
import hashlib
import json
import numbers
import os
import random
import time
import urllib.parse
import webbrowser
from builtins import object, range, str
from email.utils import parsedate
# TODO: see https://github.com/EDCD/EDMarketConnector/issues/569
from http.cookiejar import LWPCookieJar  # noqa: F401 - No longer needed but retained in case plugins use it
from os.path import join
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union

import requests

from config import appname, appversion, config
from edmc_data import companion_category_map as category_map
from EDMCLogging import get_main_logger
from monitor import monitor
from protocol import protocolhandler

logger = get_main_logger()

if TYPE_CHECKING:
    def _(x): return x

    UserDict = collections.UserDict[str, Any]  # indicate to our type checkers what this generic class holds normally
else:
    UserDict = collections.UserDict  # type: ignore # Otherwise simply use the actual class


# Define custom type for the dicts that hold CAPI data
# CAPIData = NewType('CAPIData', Dict)

holdoff = 60  # be nice
timeout = 10  # requests timeout
auth_timeout = 30  # timeout for initial auth

# Currently the "Elite Dangerous Market Connector (EDCD/Athanasius)" one in
# Athanasius' Frontier account
# Obtain from https://auth.frontierstore.net/client/signup
CLIENT_ID = os.getenv('CLIENT_ID') or 'fb88d428-9110-475f-a3d2-dc151c2b9c7a'
SERVER_AUTH = 'https://auth.frontierstore.net'
URL_AUTH = '/auth'
URL_TOKEN = '/token'
URL_DECODE = '/decode'

USER_AGENT = f'EDCD-{appname}-{appversion()}'

SERVER_LIVE = 'https://companion.orerve.net'
SERVER_BETA = 'https://pts-companion.orerve.net'
URL_QUERY = '/profile'
URL_MARKET = '/market'
URL_SHIPYARD = '/shipyard'

commodity_map: Dict = {}


class CAPIData(UserDict):
    """CAPI Response."""

    def __init__(self, data: Union[str, Dict[str, Any], 'CAPIData', None] = None, source_endpoint: str = None) -> None:
        if data is None:
            super().__init__()
        elif isinstance(data, str):
            super().__init__(json.loads(data))
        else:
            super().__init__(data)

        self.original_data = self.data.copy()  # Just in case

        self.source_endpoint = source_endpoint

        if source_endpoint is None:
            return

        if source_endpoint == URL_SHIPYARD and self.data.get('lastStarport'):
            # All the other endpoints may or may not have a lastStarport, but definitely wont have valid data
            # for this check, which means it'll just make noise for no reason while we're working on other things
            self.check_modules_ships()

    def check_modules_ships(self) -> None:
        """
        Sanity check our `data` for modules and ships being as expected.

        This has side-effects of fixing `data` to be as expected in terms of
        types of those elements.
        """
        modules: Dict[str, Any] = self.data['lastStarport'].get('modules')
        if modules is None or not isinstance(modules, dict):
            if modules is None:
                logger.debug('modules was None.  FC or Damaged Station?')

            elif isinstance(modules, list):
                if len(modules) == 0:
                    logger.debug('modules is empty list. Damaged Station?')

                else:
                    logger.error(f'modules is non-empty list: {modules!r}')

            else:
                logger.error(f'modules was not None, a list, or a dict! type: {type(modules)}, content: {modules}')

            # Set a safe value
            self.data['lastStarport']['modules'] = modules = {}

        ships: Dict[str, Any] = self.data['lastStarport'].get('ships')
        if ships is None or not isinstance(ships, dict):
            if ships is None:
                logger.debug('ships was None')

            else:
                logger.error(f'ships was neither None nor a Dict! type: {type(ships)}, content: {ships}')

            # Set a safe value
            self.data['lastStarport']['ships'] = {'shipyard_list': {}, 'unavailable_list': []}


def listify(thing: Union[List, Dict]) -> List:
    """
    Convert actual JSON array or int-indexed dict into a Python list.

    Companion API sometimes returns an array as a json array, sometimes as
    a json object indexed by "int".  This seems to depend on whether the
    there are 'gaps' in the Cmdr's data - i.e. whether the array is sparse.
    In practice these arrays aren't very sparse so just convert them to
    lists with any 'gaps' holding None.
    """
    if thing is None:
        return []  # data is not present

    elif isinstance(thing, list):
        return list(thing)  # array is not sparse

    elif isinstance(thing, dict):
        retval: List[Any] = []
        for k, v in thing.items():
            idx = int(k)

            if idx >= len(retval):
                retval.extend([None] * (idx - len(retval)))
                retval.append(v)
            else:
                retval[idx] = v

        return retval

    else:
        raise ValueError(f"expected an array or sparse array, got {thing!r}")


class ServerError(Exception):
    """Exception Class for CAPI ServerErrors."""

    def __init__(self, *args) -> None:
        # Raised when cannot contact the Companion API server
        self.args = args
        if not args:
            self.args = (_('Error: Frontier server is down'),)


class ServerLagging(Exception):
    """Exception Class for CAPI Server lagging.

    Raised when Companion API server is returning old data, e.g. when the
    servers are too busy.
    """

    def __init__(self, *args) -> None:
        self.args = args
        if not args:
            self.args = (_('Error: Frontier server is lagging'),)


class SKUError(Exception):
    """Exception Class for CAPI SKU error.

    Raised when the Companion API server thinks that the user has not
    purchased E:D i.e. doesn't have the correct 'SKU'.
    """

    def __init__(self, *args) -> None:
        self.args = args
        if not args:
            self.args = (_('Error: Frontier server SKU problem'),)


class CredentialsError(Exception):
    """Exception Class for CAPI Credentials error."""

    def __init__(self, *args) -> None:
        self.args = args
        if not args:
            self.args = (_('Error: Invalid Credentials'),)


class CmdrError(Exception):
    """Exception Class for CAPI Commander error.

    Raised when the user has multiple accounts and the username/password
    setting is not for the account they're currently playing OR the user has
    reset their Cmdr and the Companion API server is still returning data
    for the old Cmdr.
    """

    def __init__(self, *args) -> None:
        self.args = args
        if not args:
            self.args = (_('Error: Wrong Cmdr'),)


class Auth(object):
    """Handles authentication with the Frontier CAPI service via oAuth2."""

    def __init__(self, cmdr: str) -> None:
        self.cmdr: str = cmdr
        self.session = requests.Session()
        self.session.headers['User-Agent'] = USER_AGENT
        self.verifier: Union[bytes, None] = None
        self.state: Union[str, None] = None

    def __del__(self) -> None:
        """Ensure our Session is closed if we're being deleted."""
        if self.session:
            self.session.close()

    def refresh(self) -> Optional[str]:
        """
        Attempt use of Refresh Token to get a valid Access Token.

        If the Refresh Token doesn't work, make a new authorization request.

        :return: Access Token if retrieved, else None.
        """
        logger.debug(f'Trying for "{self.cmdr}"')

        self.verifier = None
        cmdrs = config.get_list('cmdrs', default=[])
        logger.debug(f'Cmdrs: {cmdrs}')

        idx = cmdrs.index(self.cmdr)
        logger.debug(f'idx = {idx}')

        tokens = config.get_list('fdev_apikeys', default=[])
        tokens = tokens + [''] * (len(cmdrs) - len(tokens))
        if tokens[idx]:
            logger.debug('We have a refresh token for that idx')
            data = {
                'grant_type':   'refresh_token',
                'client_id':     CLIENT_ID,
                'refresh_token': tokens[idx],
            }

            logger.debug('Attempting refresh with Frontier...')
            try:
                r = self.session.post(SERVER_AUTH + URL_TOKEN, data=data, timeout=auth_timeout)
                if r.status_code == requests.codes.ok:
                    data = r.json()
                    tokens[idx] = data.get('refresh_token', '')
                    config.set('fdev_apikeys', tokens)
                    config.save()  # Save settings now for use by command-line app

                    return data.get('access_token')

                else:
                    logger.error(f"Frontier CAPI Auth: Can't refresh token for \"{self.cmdr}\"")
                    self.dump(r)

            except (ValueError, requests.RequestException, ):
                logger.exception(f"Frontier CAPI Auth: Can't refresh token for \"{self.cmdr}\"")
                self.dump(r)

        else:
            logger.error(f"Frontier CAPI Auth: No token for \"{self.cmdr}\"")

        # New request
        logger.info('Frontier CAPI Auth: New authorization request')
        v = random.SystemRandom().getrandbits(8 * 32)
        self.verifier = self.base64_url_encode(v.to_bytes(32, byteorder='big')).encode('utf-8')
        s = random.SystemRandom().getrandbits(8 * 32)
        self.state = self.base64_url_encode(s.to_bytes(32, byteorder='big'))
        # Won't work under IE: https://blogs.msdn.microsoft.com/ieinternals/2011/07/13/understanding-protocols/
        logger.info(f'Trying auth from scratch for Commander "{self.cmdr}"')
        challenge = self.base64_url_encode(hashlib.sha256(self.verifier).digest())
        webbrowser.open(
            f'{SERVER_AUTH}{URL_AUTH}?response_type=code'
            f'&audience=frontier,steam,epic'
            f'&scope=auth capi'
            f'&client_id={CLIENT_ID}'
            f'&code_challenge={challenge}'
            f'&code_challenge_method=S256'
            f'&state={self.state}'
            f'&redirect_uri={protocolhandler.redirect}'
        )

        return None

    def authorize(self, payload: str) -> str:  # noqa: CCR001
        """Handle oAuth authorization callback.

        :return: access token if successful, otherwise raises CredentialsError.
        """
        logger.debug('Checking oAuth authorization callback')
        if '?' not in payload:
            logger.error(f'Frontier CAPI Auth: Malformed response (no "?" in payload)\n{payload}\n')
            raise CredentialsError('malformed payload')  # Not well formed

        data = urllib.parse.parse_qs(payload[(payload.index('?') + 1):])
        if not self.state or not data.get('state') or data['state'][0] != self.state:
            logger.error(f'Frontier CAPI Auth: Unexpected response\n{payload}\n')
            raise CredentialsError(f'Unexpected response from authorization {payload!r}')

        if not data.get('code'):
            logger.error(f'Frontier CAPI Auth: Negative response (no "code" in returned data)\n{payload}\n')
            error = next(
                (data[k] for k in ('error_description', 'error', 'message') if k in data),
                '<unknown error>'
            )
            raise CredentialsError(f'{_("Error")}: {error!r}')

        r = None
        try:
            logger.debug('Got code, posting it back...')
            request_data = {
                'grant_type': 'authorization_code',
                'client_id': CLIENT_ID,
                'code_verifier': self.verifier,
                'code': data['code'][0],
                'redirect_uri': protocolhandler.redirect,
            }

            # import http.client as http_client
            # http_client.HTTPConnection.debuglevel = 1
            # import logging
            # requests_log = logging.getLogger("requests.packages.urllib3")
            # requests_log.setLevel(logging.DEBUG)
            # requests_log.propagate = True

            r = self.session.post(SERVER_AUTH + URL_TOKEN, data=request_data, timeout=auth_timeout)
            data_token = r.json()
            if r.status_code == requests.codes.ok:
                # Now we need to /decode the token to check the customer_id against FID
                r = self.session.get(
                    SERVER_AUTH + URL_DECODE,
                    headers={
                        'Authorization': f'Bearer {data_token.get("access_token", "")}',
                        'Content-Type': 'application/json',
                    },
                    timeout=auth_timeout
                )
                data_decode = r.json()
                if r.status_code != requests.codes.ok:
                    r.raise_for_status()

                if (usr := data_decode.get('usr')) is None:
                    logger.error('No "usr" in /decode data')
                    raise CredentialsError(_("Error: Couldn't check token customer_id"))

                if (customer_id := usr.get('customer_id')) is None:
                    logger.error('No "usr"->"customer_id" in /decode data')
                    raise CredentialsError(_("Error: Couldn't check token customer_id"))

                # All 'FID' seen in Journals so far have been 'F<id>'
                # Frontier, Steam and Epic
                if f'F{customer_id}' != monitor.state.get('FID'):
                    raise CredentialsError(_("Error: customer_id doesn't match!"))

                logger.info(f'Frontier CAPI Auth: New token for \"{self.cmdr}\"')
                cmdrs = config.get_list('cmdrs', default=[])
                idx = cmdrs.index(self.cmdr)
                tokens = config.get_list('fdev_apikeys', default=[])
                tokens = tokens + [''] * (len(cmdrs) - len(tokens))
                tokens[idx] = data_token.get('refresh_token', '')
                config.set('fdev_apikeys', tokens)
                config.save()  # Save settings now for use by command-line app

                return str(data_token.get('access_token'))

        except CredentialsError:
            raise

        except Exception as e:
            logger.exception(f"Frontier CAPI Auth: Can't get token for \"{self.cmdr}\"")
            if r:
                self.dump(r)

            raise CredentialsError(_('Error: unable to get token')) from e

        logger.error(f"Frontier CAPI Auth: Can't get token for \"{self.cmdr}\"")
        self.dump(r)
        error = next(
            (data[k] for k in ('error_description', 'error', 'message') if k in data),
            '<unknown error>'
        )
        raise CredentialsError(f'{_("Error")}: {error!r}')

    @staticmethod
    def invalidate(cmdr: str) -> None:
        """Invalidate Refresh Token for specified Commander."""
        logger.info(f'Frontier CAPI Auth: Invalidated token for "{cmdr}"')
        cmdrs = config.get_list('cmdrs', default=[])
        idx = cmdrs.index(cmdr)
        tokens = config.get_list('fdev_apikeys', default=[])
        tokens = tokens + [''] * (len(cmdrs) - len(tokens))
        tokens[idx] = ''
        config.set('fdev_apikeys', tokens)
        config.save()  # Save settings now for use by command-line app

    # noinspection PyMethodMayBeStatic
    def dump(self, r: requests.Response) -> None:
        """Dump details of HTTP failure from oAuth attempt."""
        if r:
            logger.debug(f'Frontier CAPI Auth: {r.url} {r.status_code} {r.reason if r.reason else "None"} {r.text}')

        else:
            logger.debug(f'Frontier CAPI Auth: failed with `r` False: {r!r}')

    # noinspection PyMethodMayBeStatic
    def base64_url_encode(self, text: bytes) -> str:
        """Base64 encode text for URL."""
        return base64.urlsafe_b64encode(text).decode().replace('=', '')


class Session(object):
    """Methods for handling an oAuth2 session."""

    STATE_INIT, STATE_AUTH, STATE_OK = list(range(3))

    def __init__(self) -> None:
        self.state = Session.STATE_INIT
        self.server: Optional[str] = None
        self.credentials: Optional[Dict[str, Any]] = None
        self.session: Optional[requests.Session] = None
        self.auth: Optional[Auth] = None
        self.retrying = False  # Avoid infinite loop when successful auth / unsuccessful query

    def login(self, cmdr: str = None, is_beta: Union[None, bool] = None) -> bool:
        """
        Attempt oAuth2 login.

        :return: True if login succeeded, False if re-authorization initiated.
        """
        if not CLIENT_ID:
            logger.error('CLIENT_ID is None')
            raise CredentialsError('cannot login without a valid Client ID')

        # TODO: WTF is the intent behind this logic ?
        if not cmdr or is_beta is None:
            # Use existing credentials
            if not self.credentials:
                logger.error('self.credentials is None')
                raise CredentialsError('Missing credentials')  # Shouldn't happen

            elif self.state == Session.STATE_OK:
                logger.debug('already logged in (state == STATE_OK)')
                return True  # already logged in

        else:
            credentials = {'cmdr': cmdr, 'beta': is_beta}
            if self.credentials == credentials and self.state == Session.STATE_OK:
                logger.debug(f'already logged in (is_beta = {is_beta})')
                return True  # already logged in

            else:
                logger.debug('changed account or retrying login during auth')
                self.close()
                self.credentials = credentials

        self.server = self.credentials['beta'] and SERVER_BETA or SERVER_LIVE
        self.state = Session.STATE_INIT
        self.auth = Auth(self.credentials['cmdr'])

        access_token = self.auth.refresh()
        if access_token:
            logger.debug('We have an access_token')
            self.auth = None
            self.start(access_token)
            return True

        else:
            logger.debug('We do NOT have an access_token')
            self.state = Session.STATE_AUTH
            return False
            # Wait for callback

    # Callback from protocol handler
    def auth_callback(self) -> None:
        """Handle callback from edmc:// or localhost:/auth handler."""
        logger.debug('Handling auth callback')
        if self.state != Session.STATE_AUTH:
            # Shouldn't be getting a callback
            logger.debug('Got an auth callback while not doing auth')
            raise CredentialsError('Got an auth callback while not doing auth')

        try:
            logger.debug('Trying authorize with payload from handler')
            self.start(self.auth.authorize(protocolhandler.lastpayload))  # type: ignore
            self.auth = None

        except Exception:
            logger.exception('Failed, will try again next login or query')
            self.state = Session.STATE_INIT  # Will try to authorize again on next login or query
            self.auth = None
            raise  # Bad thing happened

    def start(self, access_token: str) -> None:
        """Start an oAuth2 session."""
        logger.debug('Starting session')
        self.session = requests.Session()
        self.session.headers['Authorization'] = f'Bearer {access_token}'
        self.session.headers['User-Agent'] = USER_AGENT
        self.state = Session.STATE_OK

    def query(self, endpoint: str) -> CAPIData:
        """Perform a query against the specified CAPI endpoint."""
        logger.trace(f'Performing query for endpoint "{endpoint}"')
        if self.state == Session.STATE_INIT:
            if self.login():
                return self.query(endpoint)

        elif self.state == Session.STATE_AUTH:
            logger.error('cannot make a query when unauthorized')
            raise CredentialsError('cannot make a query when unauthorized')

        try:
            logger.trace('Trying...')
            r = self.session.get(self.server + endpoint, timeout=timeout)  # type: ignore

        except Exception as e:
            logger.debug('Attempting GET', exc_info=e)
            raise ServerError(f'unable to get endpoint {endpoint}') from e

        if r.url.startswith(SERVER_AUTH):
            logger.info('Redirected back to Auth Server')
            # Redirected back to Auth server - force full re-authentication
            self.dump(r)
            self.invalidate()
            self.retrying = False
            self.login()
            raise CredentialsError()

        elif 500 <= r.status_code < 600:
            # Server error. Typically 500 "Internal Server Error" if server is down
            logger.debug('500 status back from CAPI')
            self.dump(r)
            raise ServerError(f'Received error {r.status_code} from server')

        try:
            r.raise_for_status()  # Typically 403 "Forbidden" on token expiry
            data = CAPIData(r.json(), endpoint)  # May also fail here if token expired since response is empty

        except (requests.HTTPError, ValueError) as e:
            logger.exception('Frontier CAPI Auth: GET ')
            self.dump(r)
            self.close()

            if self.retrying:		# Refresh just succeeded but this query failed! Force full re-authentication
                logger.error('Frontier CAPI Auth: query failed after refresh')
                self.invalidate()
                self.retrying = False
                self.login()
                raise CredentialsError('query failed after refresh') from e

            elif self.login():		# Maybe our token expired. Re-authorize in any case
                logger.debug('Maybe our token expired.')
                self.retrying = True
                return self.query(endpoint)

            else:
                self.retrying = False
                logger.error('Frontier CAPI Auth: HTTP error or invalid JSON')
                raise CredentialsError('HTTP error or invalid JSON') from e

        self.retrying = False
        if 'timestamp' not in data:
            # logger.trace('timestamp not in data, adding from response headers')
            data['timestamp'] = time.strftime('%Y-%m-%dT%H:%M:%SZ', parsedate(r.headers['Date']))  # type: ignore

        # Update Odyssey Suit data
        if endpoint == URL_QUERY:
            self.suit_update(data)

        return data

    def profile(self) -> CAPIData:
        """Perform general CAPI /profile endpoint query."""
        data = self.query(URL_QUERY)
        if 'commander' not in data:
            logger.error('No commander in returned data')

        return data

    def station(self) -> CAPIData:
        """Perform CAPI /profile endpoint query for station data."""
        data = self.query(URL_QUERY)
        if 'commander' not in data:
            logger.error('No commander in returned data')
            return data

        if not data['commander'].get('docked') and not monitor.state['OnFoot']:
            return data

        services = data['lastStarport'].get('services', {})

        last_starport_name = data['lastStarport']['name']
        last_starport_id = int(data['lastStarport']['id'])

        if services.get('commodities'):
            marketdata = self.query(URL_MARKET)
            if last_starport_name != marketdata['name'] or last_starport_id != int(marketdata['id']):
                raise ServerLagging()

            else:
                data['lastStarport'].update(marketdata)

        if services.get('outfitting') or services.get('shipyard'):
            shipdata = self.query(URL_SHIPYARD)
            if last_starport_name != shipdata['name'] or last_starport_id != int(shipdata['id']):
                raise ServerLagging()

            else:
                data['lastStarport'].update(shipdata)

        return data

    def suit_update(self, data: CAPIData) -> None:
        """
        Update monitor.state suit data.

        :param data: CAPI data to extra suit data from.
        """
        if (current_suit := data.get('suit')) is None:
            # Probably no Odyssey on the account, so point attempting more.
            return

        monitor.state['SuitCurrent'] = current_suit
        monitor.state['Suits'] = data.get('suits')

        if (suit_loadouts := data.get('loadouts')) is None:
            logger.warning('CAPI data had "suit" but no (suit) "loadouts"')

        monitor.state['SuitLoadoutCurrent'] = data.get('loadout')
        monitor.state['SuitLoadouts'] = suit_loadouts

    def close(self) -> None:
        """Close CAPI authorization session."""
        self.state = Session.STATE_INIT
        if self.session:
            try:
                self.session.close()

            except Exception as e:
                logger.debug('Frontier CAPI Auth: closing', exc_info=e)

        self.session = None

    def invalidate(self) -> None:
        """Invalidate oAuth2 credentials."""
        logger.debug('Forcing a full re-authentication')
        # Force a full re-authentication
        self.close()
        Auth.invalidate(self.credentials['cmdr'])  # type: ignore

    # noinspection PyMethodMayBeStatic
    def dump(self, r: requests.Response) -> None:
        """Log, as error, status of requests.Response from CAPI request."""
        logger.error(f'Frontier CAPI Auth: {r.url} {r.status_code} {r.reason and r.reason or "None"} {r.text}')


def fixup(data: CAPIData) -> CAPIData:  # noqa: C901, CCR001 # Can't be usefully simplified
    """
    Fix up commodity names to English & miscellaneous anomalies fixes.

    :return: a shallow copy of the received data suitable for export to
             older tools.
    """
    if not commodity_map:
        # Lazily populate
        for f in ('commodity.csv', 'rare_commodity.csv'):
            with open(join(config.respath_path, f), 'r') as csvfile:
                reader = csv.DictReader(csvfile)

                for row in reader:
                    commodity_map[row['symbol']] = (row['category'], row['name'])

    commodities = []
    for commodity in data['lastStarport'].get('commodities') or []:

        # Check all required numeric fields are present and are numeric
        # Catches "demandBracket": "" for some phantom commodites in
        # ED 1.3 - https://github.com/Marginal/EDMarketConnector/issues/2
        #
        # But also see https://github.com/Marginal/EDMarketConnector/issues/32
        for thing in ('buyPrice', 'sellPrice', 'demand', 'demandBracket', 'stock', 'stockBracket'):
            if not isinstance(commodity.get(thing), numbers.Number):
                logger.debug(f'Invalid {thing}:{commodity.get(thing)} ({type(commodity.get(thing))}) for {commodity.get("name", "")}')  # noqa: E501
                break

        else:
            # Check not marketable i.e. Limpets
            if not category_map.get(commodity['categoryname'], True):
                pass

            # Check not normally stocked e.g. Salvage
            elif commodity['demandBracket'] == 0 and commodity['stockBracket'] == 0:
                pass
            elif commodity.get('legality'):  # Check not prohibited
                pass

            elif not commodity.get('categoryname'):
                logger.debug(f'Missing "categoryname" for {commodity.get("name", "")}')

            elif not commodity.get('name'):
                logger.debug(f'Missing "name" for a commodity in {commodity.get("categoryname", "")}')

            elif not commodity['demandBracket'] in range(4):
                logger.debug(f'Invalid "demandBracket":{commodity["demandBracket"]} for {commodity["name"]}')

            elif not commodity['stockBracket'] in range(4):
                logger.debug(f'Invalid "stockBracket":{commodity["stockBracket"]} for {commodity["name"]}')

            else:
                # Rewrite text fields
                new = dict(commodity)  # shallow copy
                if commodity['name'] in commodity_map:
                    (new['categoryname'], new['name']) = commodity_map[commodity['name']]
                elif commodity['categoryname'] in category_map:
                    new['categoryname'] = category_map[commodity['categoryname']]

                # Force demand and stock to zero if their corresponding bracket is zero
                # Fixes spurious "demand": 1 in ED 1.3
                if not commodity['demandBracket']:
                    new['demand'] = 0
                if not commodity['stockBracket']:
                    new['stock'] = 0

                # We're good
                commodities.append(new)

    # return a shallow copy
    datacopy = data.copy()
    datacopy['lastStarport'] = data['lastStarport'].copy()
    datacopy['lastStarport']['commodities'] = commodities
    return datacopy


def ship(data: CAPIData) -> CAPIData:
    """Construct a subset of the received data describing the current ship."""
    def filter_ship(d: CAPIData) -> CAPIData:
        """Filter provided ship data."""
        filtered = CAPIData()
        for k, v in d.items():
            if not v:
                pass  # just skip empty fields for brevity

            elif k in ('alive', 'cargo', 'cockpitBreached', 'health', 'oxygenRemaining',
                       'rebuilds', 'starsystem', 'station'):
                pass  # noisy

            elif k in ('locDescription', 'locName') or k.endswith('LocDescription') or k.endswith('LocName'):
                pass  # also noisy, and redundant

            elif k in ('dir', 'LessIsGood'):
                pass  # dir is not ASCII - remove to simplify handling

            elif hasattr(v, 'items'):
                filtered[k] = filter_ship(v)

            else:
                filtered[k] = v

        return filtered

    # subset of "ship" that's not noisy
    return filter_ship(data['ship'])


# singleton
session = Session()