robosats/api/views.py

import hashlib
from datetime import datetime, timedelta
from math import log2
from pathlib import Path

from decouple import config
from django.conf import settings
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth.models import User
from django.db.models import Q, Sum
from django.utils import timezone
from drf_spectacular.utils import extend_schema
from rest_framework import status, viewsets
from rest_framework.authentication import (
    SessionAuthentication,  # DEPRECATE session authentication
)
from rest_framework.authentication import TokenAuthentication
from rest_framework.generics import CreateAPIView, ListAPIView, UpdateAPIView
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.views import APIView
from robohash import Robohash
from scipy.stats import entropy

from api.logics import Logics
from api.models import Currency, LNPayment, MarketTick, OnchainPayment, Order
from api.notifications import Telegram
from api.oas_schemas import (
    BookViewSchema,
    HistoricalViewSchema,
    InfoViewSchema,
    LimitViewSchema,
    MakerViewSchema,
    OrderViewSchema,
    PriceViewSchema,
    RewardViewSchema,
    RobotViewSchema,
    StealthViewSchema,
    TickViewSchema,
    UserViewSchema,
)
from api.serializers import (
    ClaimRewardSerializer,
    InfoSerializer,
    ListOrderSerializer,
    MakeOrderSerializer,
    OrderPublicSerializer,
    PriceSerializer,
    StealthSerializer,
    TickSerializer,
    UpdateOrderSerializer,
    UserGenSerializer,
)
from api.utils import (
    compute_avg_premium,
    compute_premium_percentile,
    get_lnd_version,
    get_robosats_commit,
    validate_pgp_keys,
)
from chat.models import Message
from control.models import AccountingDay, BalanceLog

from .nick_generator.nick_generator import NickGenerator

EXP_MAKER_BOND_INVOICE = int(config("EXP_MAKER_BOND_INVOICE"))
RETRY_TIME = int(config("RETRY_TIME"))
PUBLIC_DURATION = 60 * 60 * int(config("DEFAULT_PUBLIC_ORDER_DURATION")) - 1
ESCROW_DURATION = 60 * int(config("INVOICE_AND_ESCROW_DURATION"))
BOND_SIZE = int(config("DEFAULT_BOND_SIZE"))

avatar_path = Path(settings.AVATAR_ROOT)
avatar_path.mkdir(parents=True, exist_ok=True)

# Create your views here.


class MakerView(CreateAPIView):
    serializer_class = MakeOrderSerializer
    authentication_classes = [TokenAuthentication, SessionAuthentication]
    permission_classes = [IsAuthenticated]

    @extend_schema(**MakerViewSchema.post)
    def post(self, request):

        serializer = self.serializer_class(data=request.data)

        if not request.user.is_authenticated:
            return Response(
                {"bad_request": "Woops! It seems you do not have a robot avatar"},
                status.HTTP_400_BAD_REQUEST,
            )

        if not serializer.is_valid():
            return Response(status=status.HTTP_400_BAD_REQUEST)

        # In case it gets overwhelming. Limit the number of public orders.
        if Order.objects.filter(status=Order.Status.PUB).count() >= int(
            config("MAX_PUBLIC_ORDERS")
        ):
            return Response(
                {
                    "bad_request": "Woah! RoboSats' book is at full capacity! Try again later"
                },
                status.HTTP_400_BAD_REQUEST,
            )
        # Only allow users who are not already engaged in an order
        valid, context, _ = Logics.validate_already_maker_or_taker(request.user)
        if not valid:
            return Response(context, status.HTTP_409_CONFLICT)

        type = serializer.data.get("type")
        currency = serializer.data.get("currency")
        amount = serializer.data.get("amount")
        has_range = serializer.data.get("has_range")
        min_amount = serializer.data.get("min_amount")
        max_amount = serializer.data.get("max_amount")
        payment_method = serializer.data.get("payment_method")
        premium = serializer.data.get("premium")
        satoshis = serializer.data.get("satoshis")
        is_explicit = serializer.data.get("is_explicit")
        public_duration = serializer.data.get("public_duration")
        escrow_duration = serializer.data.get("escrow_duration")
        bond_size = serializer.data.get("bond_size")

        # Optional params
        if public_duration is None:
            public_duration = PUBLIC_DURATION
        if escrow_duration is None:
            escrow_duration = ESCROW_DURATION
        if bond_size is None:
            bond_size = BOND_SIZE
        if has_range is None:
            has_range = False

        # TODO add a check - if `is_explicit` is true then `satoshis` need to be specified

        # An order can either have an amount or a range (min_amount and max_amount)
        if has_range:
            amount = None
        else:
            min_amount = None
            max_amount = None

        # Either amount or min_max has to be specified.
        if has_range and (min_amount is None or max_amount is None):
            return Response(
                {
                    "bad_request": "You must specify min_amount and max_amount for a range order"
                },
                status.HTTP_400_BAD_REQUEST,
            )
        elif not has_range and amount is None:
            return Response(
                {"bad_request": "You must specify an order amount"},
                status.HTTP_400_BAD_REQUEST,
            )

        # Creates a new order
        order = Order(
            type=type,
            currency=Currency.objects.get(id=currency),
            amount=amount,
            has_range=has_range,
            min_amount=min_amount,
            max_amount=max_amount,
            payment_method=payment_method,
            premium=premium,
            satoshis=satoshis,
            is_explicit=is_explicit,
            expires_at=timezone.now() + timedelta(seconds=EXP_MAKER_BOND_INVOICE),
            maker=request.user,
            public_duration=public_duration,
            escrow_duration=escrow_duration,
            bond_size=bond_size,
        )

        order.last_satoshis = order.t0_satoshis = Logics.satoshis_now(order)

        valid, context = Logics.validate_order_size(order)
        if not valid:
            return Response(context, status.HTTP_400_BAD_REQUEST)

        order.save()
        return Response(ListOrderSerializer(order).data, status=status.HTTP_201_CREATED)


class OrderView(viewsets.ViewSet):
    authentication_classes = [TokenAuthentication, SessionAuthentication]
    permission_classes = [IsAuthenticated]
    serializer_class = UpdateOrderSerializer
    lookup_url_kwarg = "order_id"

    @extend_schema(**OrderViewSchema.get)
    def get(self, request, format=None):
        """
        Full trade pipeline takes place while looking/refreshing the order page.
        """
        order_id = request.GET.get(self.lookup_url_kwarg)

        if not request.user.is_authenticated:
            return Response(
                {
                    "bad_request": "You must have a robot avatar to see the order details"
                },
                status=status.HTTP_400_BAD_REQUEST,
            )

        if order_id is None:
            return Response(
                {"bad_request": "Order ID parameter not found in request"},
                status=status.HTTP_400_BAD_REQUEST,
            )

        order = Order.objects.filter(id=order_id)

        # check if exactly one order is found in the db
        if len(order) != 1:
            return Response(
                {"bad_request": "Invalid Order Id"}, status.HTTP_404_NOT_FOUND
            )

        # This is our order.
        order = order[0]

        # 2) If order has been cancelled
        if order.status == Order.Status.UCA:
            return Response(
                {"bad_request": "This order has been cancelled by the maker"},
                status.HTTP_400_BAD_REQUEST,
            )
        if order.status == Order.Status.CCA:
            return Response(
                {"bad_request": "This order has been cancelled collaborativelly"},
                status.HTTP_400_BAD_REQUEST,
            )

        data = ListOrderSerializer(order).data
        data["total_secs_exp"] = order.t_to_expire(order.status)

        # if user is under a limit (penalty), inform him.
        is_penalized, time_out = Logics.is_penalized(request.user)
        if is_penalized:
            data["penalty"] = request.user.robot.penalty_expiration

        # Add booleans if user is maker, taker, partipant, buyer or seller
        data["is_maker"] = order.maker == request.user
        data["is_taker"] = order.taker == request.user
        data["is_participant"] = data["is_maker"] or data["is_taker"]

        # 3.a) If not a participant and order is not public, forbid.
        if not data["is_participant"] and order.status != Order.Status.PUB:
            return Response(
                {"bad_request": "This order is not available"},
                status.HTTP_403_FORBIDDEN,
            )

        # WRITE Update last_seen for maker and taker.
        # Note down that the taker/maker was here recently, so counterpart knows if the user is paying attention.
        data["maker_nick"] = str(order.maker)
        if order.maker == request.user:
            order.maker_last_seen = timezone.now()
            order.save()
        if order.taker == request.user:
            order.taker_last_seen = timezone.now()
            order.save()

        # Add activity status of participants based on last_seen
        if order.taker_last_seen is not None:
            data["taker_status"] = Logics.user_activity_status(order.taker_last_seen)
        if order.maker_last_seen is not None:
            data["maker_status"] = Logics.user_activity_status(order.maker_last_seen)

        # 3.b) Non participants can view details (but only if PUB)
        if not data["is_participant"] and order.status == Order.Status.PUB:
            data["price_now"], data["premium_now"] = Logics.price_and_premium_now(order)
            data["satoshis_now"] = Logics.satoshis_now(order)
            return Response(data, status=status.HTTP_200_OK)

        # 4) If order is between public and WF2
        if order.status >= Order.Status.PUB and order.status < Order.Status.WF2:
            data["price_now"], data["premium_now"] = Logics.price_and_premium_now(order)
            data["satoshis_now"] = Logics.satoshis_now(order)

            # 4. a) If maker and Public/Paused, add premium percentile
            # num similar orders, and maker information to enable telegram notifications.
            if data["is_maker"] and order.status in [
                Order.Status.PUB,
                Order.Status.PAU,
            ]:
                data["premium_percentile"] = compute_premium_percentile(order)
                data["num_similar_orders"] = len(
                    Order.objects.filter(
                        currency=order.currency, status=Order.Status.PUB
                    )
                )

        # For participants add positions, nicks and status as a message and hold invoices status
        data["is_buyer"] = Logics.is_buyer(order, request.user)
        data["is_seller"] = Logics.is_seller(order, request.user)
        data["taker_nick"] = str(order.taker)
        data["status_message"] = Order.Status(order.status).label
        data["is_fiat_sent"] = order.is_fiat_sent
        data["is_disputed"] = order.is_disputed
        data["ur_nick"] = request.user.username
        data["satoshis_now"] = order.last_satoshis

        # Add whether hold invoices are LOCKED (ACCEPTED)
        # Is there a maker bond? If so, True if locked, False otherwise
        if order.maker_bond:
            data["maker_locked"] = order.maker_bond.status == LNPayment.Status.LOCKED
        else:
            data["maker_locked"] = False

        # Is there a taker bond? If so, True if locked, False otherwise
        if order.taker_bond:
            data["taker_locked"] = order.taker_bond.status == LNPayment.Status.LOCKED
        else:
            data["taker_locked"] = False

        # Is there an escrow? If so, True if locked, False otherwise
        if order.trade_escrow:
            data["escrow_locked"] = order.trade_escrow.status == LNPayment.Status.LOCKED
        else:
            data["escrow_locked"] = False

        # If both bonds are locked, participants can see the final trade amount in sats.
        if order.taker_bond:
            if (
                order.maker_bond.status
                == order.taker_bond.status
                == LNPayment.Status.LOCKED
            ):
                # Seller sees the amount he sends
                if data["is_seller"]:
                    data["trade_satoshis"] = Logics.escrow_amount(order, request.user)[
                        1
                    ]["escrow_amount"]
                # Buyer sees the amount he receives
                elif data["is_buyer"]:
                    data["trade_satoshis"] = Logics.payout_amount(order, request.user)[
                        1
                    ]["invoice_amount"]

        # 5) If status is 'waiting for maker bond' and user is MAKER, reply with a MAKER hold invoice.
        if order.status == Order.Status.WFB and data["is_maker"]:
            valid, context = Logics.gen_maker_hold_invoice(order, request.user)
            if valid:
                data = {**data, **context}
            else:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 6)  If status is 'waiting for taker bond' and user is TAKER, reply with a TAKER hold invoice.
        elif order.status == Order.Status.TAK and data["is_taker"]:
            valid, context = Logics.gen_taker_hold_invoice(order, request.user)
            if valid:
                data = {**data, **context}
            else:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 7 a. ) If seller and status is 'WF2' or 'WFE'
        elif data["is_seller"] and (
            order.status == Order.Status.WF2 or order.status == Order.Status.WFE
        ):
            # If the two bonds are locked, reply with an ESCROW hold invoice.
            if (
                order.maker_bond.status
                == order.taker_bond.status
                == LNPayment.Status.LOCKED
            ):
                valid, context = Logics.gen_escrow_hold_invoice(order, request.user)
                if valid:
                    data = {**data, **context}
                else:
                    return Response(context, status.HTTP_400_BAD_REQUEST)

        # 7.b) If user is Buyer and status is 'WF2' or 'WFI'
        elif data["is_buyer"] and (
            order.status == Order.Status.WF2 or order.status == Order.Status.WFI
        ):

            # If the two bonds are locked, reply with an AMOUNT and onchain swap cost so he can send the buyer invoice/address.
            if (
                order.maker_bond.status
                == order.taker_bond.status
                == LNPayment.Status.LOCKED
            ):
                valid, context = Logics.payout_amount(order, request.user)
                if valid:
                    data = {**data, **context}
                else:
                    return Response(context, status.HTTP_400_BAD_REQUEST)

        # 8) If status is 'CHA' or 'FSE' and all HTLCS are in LOCKED
        elif order.status in [Order.Status.WFI, Order.Status.CHA, Order.Status.FSE]:
            # If all bonds are locked.
            if (
                order.maker_bond.status
                == order.taker_bond.status
                == order.trade_escrow.status
                == LNPayment.Status.LOCKED
            ):
                # add whether a collaborative cancel is pending or has been asked
                if (data["is_maker"] and order.taker_asked_cancel) or (
                    data["is_taker"] and order.maker_asked_cancel
                ):
                    data["pending_cancel"] = True
                elif (data["is_maker"] and order.maker_asked_cancel) or (
                    data["is_taker"] and order.taker_asked_cancel
                ):
                    data["asked_for_cancel"] = True
                else:
                    data["asked_for_cancel"] = False

            # Add index of last chat message. To be used by client on Chat endpoint to fetch latest messages
            messages = Message.objects.filter(order=order)
            if len(messages) == 0:
                data["chat_last_index"] = 0
            else:
                data["chat_last_index"] = messages.latest().index

        # 9) If status is 'DIS' and all HTLCS are in LOCKED
        elif order.status == Order.Status.DIS:

            # add whether the dispute statement has been received
            if data["is_maker"]:
                data["statement_submitted"] = (
                    order.maker_statement is not None and order.maker_statement != ""
                )
            elif data["is_taker"]:
                data["statement_submitted"] = (
                    order.taker_statement is not None and order.taker_statement != ""
                )

        # 9) If status is 'Failed routing', reply with retry amounts, time of next retry and ask for invoice at third.
        elif (
            order.status == Order.Status.FAI and order.payout.receiver == request.user
        ):  # might not be the buyer if after a dispute where winner wins
            data["retries"] = order.payout.routing_attempts
            data["next_retry_time"] = order.payout.last_routing_time + timedelta(
                minutes=RETRY_TIME
            )
            if order.payout.failure_reason:
                data["failure_reason"] = LNPayment.FailureReason(
                    order.payout.failure_reason
                ).label

            if order.payout.status == LNPayment.Status.EXPIRE:
                data["invoice_expired"] = True
                # Add invoice amount once again if invoice was expired.
                data["trade_satoshis"] = Logics.payout_amount(order, request.user)[1][
                    "invoice_amount"
                ]

        # 10) If status is 'Expired', "Sending", "Finished" or "failed routing", add info for renewal:
        elif order.status in [
            Order.Status.EXP,
            Order.Status.SUC,
            Order.Status.PAY,
            Order.Status.FAI,
        ]:
            data["public_duration"] = order.public_duration
            data["bond_size"] = order.bond_size

            # Adds trade summary
            if order.status in [Order.Status.SUC, Order.Status.PAY, Order.Status.FAI]:
                valid, context = Logics.summarize_trade(order, request.user)
                if valid:
                    data = {**data, **context}

            # If status is 'Expired' add expiry reason
            if order.status == Order.Status.EXP:
                data["expiry_reason"] = order.expiry_reason
                data["expiry_message"] = Order.ExpiryReasons(order.expiry_reason).label

            # If status is 'Succes' add final stats and txid if it is a swap
            if order.status == Order.Status.SUC:
                # If buyer and is a swap, add TXID
                if Logics.is_buyer(order, request.user):
                    if order.is_swap:
                        data["num_satoshis"] = order.payout_tx.num_satoshis
                        data["sent_satoshis"] = order.payout_tx.sent_satoshis
                        data["network"] = str(config("NETWORK"))
                        if order.payout_tx.status in [
                            OnchainPayment.Status.MEMPO,
                            OnchainPayment.Status.CONFI,
                        ]:
                            data["txid"] = order.payout_tx.txid
                        elif order.payout_tx.status == OnchainPayment.Status.QUEUE:
                            data["tx_queued"] = True
                            data["address"] = order.payout_tx.address

        return Response(data, status.HTTP_200_OK)

    @extend_schema(**OrderViewSchema.take_update_confirm_dispute_cancel)
    def take_update_confirm_dispute_cancel(self, request, format=None):
        """
        Here takes place all of the updates to the order object.
        That is: take, confim, cancel, dispute, update_invoice or rate.
        """
        order_id = request.GET.get(self.lookup_url_kwarg)

        serializer = UpdateOrderSerializer(data=request.data)
        if not serializer.is_valid():
            return Response(status=status.HTTP_400_BAD_REQUEST)

        order = Order.objects.get(id=order_id)

        # action is either 1)'take', 2)'confirm', 2.b)'undo_confirm', 3)'cancel', 4)'dispute' , 5)'update_invoice'
        # 5.b)'update_address' 6)'submit_statement' (in dispute), 7)'rate_user' , 8)'rate_platform'
        action = serializer.data.get("action")
        invoice = serializer.data.get("invoice")
        routing_budget_ppm = serializer.data.get("routing_budget_ppm", 0)
        address = serializer.data.get("address")
        mining_fee_rate = serializer.data.get("mining_fee_rate")
        statement = serializer.data.get("statement")
        rating = serializer.data.get("rating")

        # 1) If action is take, it is a taker request!
        if action == "take":
            if order.status == Order.Status.PUB:
                valid, context, _ = Logics.validate_already_maker_or_taker(request.user)
                if not valid:
                    return Response(context, status=status.HTTP_409_CONFLICT)

                # For order with amount range, set the amount now.
                if order.has_range:
                    amount = float(serializer.data.get("amount"))
                    valid, context = Logics.validate_amount_within_range(order, amount)
                    if not valid:
                        return Response(context, status=status.HTTP_400_BAD_REQUEST)

                    valid, context = Logics.take(order, request.user, amount)
                else:
                    valid, context = Logics.take(order, request.user)
                if not valid:
                    return Response(context, status=status.HTTP_403_FORBIDDEN)

                return self.get(request)

            else:
                Response(
                    {"bad_request": "This order is not public anymore."},
                    status.HTTP_400_BAD_REQUEST,
                )

        # Any other action is only allowed if the user is a participant
        if not (order.maker == request.user or order.taker == request.user):
            return Response(
                {"bad_request": "You are not a participant in this order"},
                status.HTTP_403_FORBIDDEN,
            )

        # 2) If action is 'update invoice'
        elif action == "update_invoice":
            valid, context = Logics.update_invoice(
                order, request.user, invoice, routing_budget_ppm
            )
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 2.b) If action is 'update address'
        elif action == "update_address":
            valid, context = Logics.update_address(
                order, request.user, address, mining_fee_rate
            )
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 3) If action is cancel
        elif action == "cancel":
            valid, context = Logics.cancel_order(order, request.user)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 4) If action is confirm
        elif action == "confirm":
            valid, context = Logics.confirm_fiat(order, request.user)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 4.b) If action is confirm
        elif action == "undo_confirm":
            valid, context = Logics.undo_confirm_fiat_sent(order, request.user)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 5) If action is dispute
        elif action == "dispute":
            valid, context = Logics.open_dispute(order, request.user)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        elif action == "submit_statement":
            valid, context = Logics.dispute_statement(order, request.user, statement)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 6) If action is rate
        elif action == "rate_user" and rating:
            """No user rating"""
            pass

        # 7) If action is rate_platform
        elif action == "rate_platform" and rating:
            valid, context = Logics.rate_platform(request.user, rating)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # 8) If action is rate_platform
        elif action == "pause":
            valid, context = Logics.pause_unpause_public_order(order, request.user)
            if not valid:
                return Response(context, status.HTTP_400_BAD_REQUEST)

        # If nothing of the above... something else is going on. Probably not allowed!
        else:
            return Response(
                {
                    "bad_request": "The Robotic Satoshis working in the warehouse did not understand you. "
                    + "Please, fill a Bug Issue in Github https://github.com/reckless-satoshi/robosats/issues"
                },
                status.HTTP_501_NOT_IMPLEMENTED,
            )

        return self.get(request)


class RobotView(APIView):
    authentication_classes = [TokenAuthentication, SessionAuthentication]
    permission_classes = [IsAuthenticated]

    @extend_schema(**RobotViewSchema.get)
    def get(self, request, format=None):
        """
        Respond with Nickname, pubKey, privKey.
        """
        user = request.user
        context = {}
        context["nickname"] = user.username
        context["public_key"] = user.robot.public_key
        context["encrypted_private_key"] = user.robot.encrypted_private_key
        context["earned_rewards"] = user.robot.earned_rewards
        context["wants_stealth"] = user.robot.wants_stealth
        context["last_login"] = user.last_login

        # Adds/generate telegram token and whether it is enabled
        context = {**context, **Telegram.get_context(user)}

        # return active order or last made order if any
        has_no_active_order, _, order = Logics.validate_already_maker_or_taker(
            request.user
        )
        if not has_no_active_order:
            context["active_order_id"] = order.id
        else:
            last_order = Order.objects.filter(
                Q(maker=request.user) | Q(taker=request.user)
            ).last()
            if last_order:
                context["last_order_id"] = last_order.id

        # Robot was found, only if created +5 mins ago
        if user.date_joined < (timezone.now() - timedelta(minutes=5)):
            context["found"] = True

        return Response(context, status=status.HTTP_200_OK)


class UserView(APIView):
    """
    Deprecated. UserView will be completely replaced by the smaller RobotView in
    combination with the RobotTokenSHA256 middleware (on-the-fly robot generation)
    """

    NickGen = NickGenerator(
        lang="English", use_adv=False, use_adj=True, use_noun=True, max_num=999
    )

    serializer_class = UserGenSerializer

    @extend_schema(**UserViewSchema.post)
    def post(self, request, format=None):
        """
        Get a new user derived from a high entropy token

        - Request has a hash of a high-entropy token
        - Request includes pubKey and encrypted privKey
        - Generates new nickname and avatar.
        - Creates login credentials (new User object)

        Response with Avatar, Nickname, pubKey, privKey.
        """
        context = {}
        serializer = self.serializer_class(data=request.data)

        # Return bad request if serializer is not valid
        if not serializer.is_valid():
            context = {"bad_request": "Invalid serializer"}
            return Response(context, status=status.HTTP_400_BAD_REQUEST)

        # The new way. The token is never sent. Only its SHA256
        token_sha256 = serializer.data.get("token_sha256")
        public_key = serializer.data.get("public_key")
        encrypted_private_key = serializer.data.get("encrypted_private_key")

        # Now the server only receives a hash of the token. So server trusts the client
        # with computing length, counts and unique_values to confirm the high entropy of the token
        # In any case, it is up to the client if they want to create a bad high entropy token.

        # Submitting the three params needed to compute token entropy is not mandatory
        # If not submitted, avatars can be created with garbage entropy token. Frontend will always submit them.
        try:
            unique_values = serializer.data.get("unique_values")
            counts = serializer.data.get("counts")
            length = serializer.data.get("length")

            shannon_entropy = entropy(counts, base=62)
            bits_entropy = log2(unique_values**length)

            # Payload
            context = {
                "token_shannon_entropy": shannon_entropy,
                "token_bits_entropy": bits_entropy,
            }

            # Deny user gen if entropy below 128 bits or 0.7 shannon heterogeneity
            if bits_entropy < 128 or shannon_entropy < 0.7:
                context["bad_request"] = "The token does not have enough entropy"
                return Response(context, status=status.HTTP_400_BAD_REQUEST)
        except Exception:
            pass

        # Hash the token_sha256, only 1 iteration. (this is the second SHA256 of the user token, aka RoboSats ID)
        hash = hashlib.sha256(token_sha256.encode("utf-8")).hexdigest()

        # Generate nickname deterministically
        nickname = self.NickGen.short_from_SHA256(hash, max_length=18)[0]
        context["nickname"] = nickname

        # Generate avatar
        rh = Robohash(hash)
        rh.assemble(roboset="set1", bgset="any")  # for backgrounds ON

        # Does not replace image if existing (avoid re-avatar in case of nick collusion)
        # Deprecate "png" and keep "webp" only after v0.4.4
        image_path = avatar_path.joinpath(nickname + ".webp")
        if not image_path.exists():
            with open(image_path, "wb") as f:
                rh.img.save(f, format="WEBP", quality=80)

            image_small_path = avatar_path.joinpath(nickname + ".small.webp")
            with open(image_small_path, "wb") as f:
                resized_img = rh.img.resize((80, 80))
                resized_img.save(f, format="WEBP", quality=80)

            png_path = avatar_path.joinpath(nickname + ".png")
            with open(png_path, "wb") as f:
                rh.img.save(f, format="png", optimize=True)

        # Create new credentials and login if nickname is new
        if len(User.objects.filter(username=nickname)) == 0:
            if not public_key or not encrypted_private_key:
                context[
                    "bad_request"
                ] = "Must provide valid 'pub' and 'enc_priv' PGP keys"
                return Response(context, status.HTTP_400_BAD_REQUEST)
            (
                valid,
                bad_keys_context,
                public_key,
                encrypted_private_key,
            ) = validate_pgp_keys(public_key, encrypted_private_key)
            if not valid:
                return Response(bad_keys_context, status.HTTP_400_BAD_REQUEST)

            User.objects.create_user(
                username=nickname, password=token_sha256, is_staff=False
            )
            user = authenticate(request, username=nickname, password=token_sha256)
            login(request, user)

            user.robot.avatar = "static/assets/avatars/" + nickname + ".webp"

            # Noticed some PGP keys replaced at re-login. Should not happen.
            # Let's implement this sanity check "If robot has not keys..."
            if not user.robot.public_key:
                user.robot.public_key = public_key
            if not user.robot.encrypted_private_key:
                user.robot.encrypted_private_key = encrypted_private_key

            user.robot.save()

            context = {**context, **Telegram.get_context(user)}
            context["public_key"] = user.robot.public_key
            context["encrypted_private_key"] = user.robot.encrypted_private_key
            context["wants_stealth"] = user.robot.wants_stealth
            return Response(context, status=status.HTTP_201_CREATED)

        # log in user and return pub/priv keys if existing
        else:
            user = authenticate(request, username=nickname, password=token_sha256)
            if user is not None:
                login(request, user)
                context["public_key"] = user.robot.public_key
                context["encrypted_private_key"] = user.robot.encrypted_private_key
                context["earned_rewards"] = user.robot.earned_rewards
                context["wants_stealth"] = user.robot.wants_stealth

                # Adds/generate telegram token and whether it is enabled
                context = {**context, **Telegram.get_context(user)}

                # return active order or last made order if any
                has_no_active_order, _, order = Logics.validate_already_maker_or_taker(
                    request.user
                )
                if not has_no_active_order:
                    context["active_order_id"] = order.id
                else:
                    last_order = Order.objects.filter(
                        Q(maker=request.user) | Q(taker=request.user)
                    ).last()
                    if last_order:
                        context["last_order_id"] = last_order.id

                # Sends the welcome back message.
                context["found"] = "We found your Robot avatar. Welcome back!"
                return Response(context, status=status.HTTP_202_ACCEPTED)
            else:
                # It is unlikely, but maybe the nickname is taken (1 in 20 Billion chance)
                context["found"] = "Bad luck, this nickname is taken"
                context["bad_request"] = "Enter a different token"
                return Response(context, status.HTTP_403_FORBIDDEN)

    @extend_schema(**UserViewSchema.delete)
    def delete(self, request):
        """Pressing "give me another" deletes the logged in user"""
        user = request.user
        if not user.is_authenticated:
            return Response(status.HTTP_403_FORBIDDEN)

        # Only delete if user life is shorter than 30 minutes. Helps to avoid deleting users by mistake
        if user.date_joined < (timezone.now() - timedelta(minutes=30)):
            return Response(status.HTTP_400_BAD_REQUEST)

        # Check if it is not a maker or taker!
        not_participant, _, _ = Logics.validate_already_maker_or_taker(user)
        if not not_participant:
            return Response(
                {
                    "bad_request": "Maybe a mistake? User cannot be deleted while he is part of an order"
                },
                status.HTTP_400_BAD_REQUEST,
            )
        # Check if has already a robot with
        if user.robot.total_contracts > 0:
            return Response(
                {
                    "bad_request": "Maybe a mistake? User cannot be deleted as it has completed trades"
                },
                status.HTTP_400_BAD_REQUEST,
            )

        logout(request)
        user.delete()
        return Response(
            {"user_deleted": "User deleted permanently"},
            status.HTTP_301_MOVED_PERMANENTLY,
        )


class BookView(ListAPIView):
    serializer_class = OrderPublicSerializer
    queryset = Order.objects.filter(status=Order.Status.PUB)

    @extend_schema(**BookViewSchema.get)
    def get(self, request, format=None):
        currency = request.GET.get("currency", 0)
        type = request.GET.get("type", 2)

        queryset = Order.objects.filter(status=Order.Status.PUB)

        # Currency 0 and type 2 are special cases treated as "ANY". (These are not really possible choices)
        if int(currency) == 0 and int(type) != 2:
            queryset = Order.objects.filter(type=type, status=Order.Status.PUB)
        elif int(type) == 2 and int(currency) != 0:
            queryset = Order.objects.filter(currency=currency, status=Order.Status.PUB)
        elif not (int(currency) == 0 and int(type) == 2):
            queryset = Order.objects.filter(
                currency=currency, type=type, status=Order.Status.PUB
            )

        if len(queryset) == 0:
            return Response(
                {"not_found": "No orders found, be the first to make one"},
                status=status.HTTP_404_NOT_FOUND,
            )

        book_data = []
        for order in queryset:
            data = ListOrderSerializer(order).data
            data["maker_nick"] = str(order.maker)

            data["satoshis_now"] = Logics.satoshis_now(order)
            # Compute current premium for those orders that are explicitly priced.
            data["price"], data["premium"] = Logics.price_and_premium_now(order)
            data["maker_status"] = Logics.user_activity_status(order.maker_last_seen)
            for key in (
                "status",
                "taker",
            ):  # Non participants should not see the status or who is the taker
                del data[key]

            book_data.append(data)

        return Response(book_data, status=status.HTTP_200_OK)


class InfoView(ListAPIView):

    serializer_class = InfoSerializer

    @extend_schema(**InfoViewSchema.get)
    def get(self, request):
        context = {}

        context["num_public_buy_orders"] = len(
            Order.objects.filter(type=Order.Types.BUY, status=Order.Status.PUB)
        )
        context["num_public_sell_orders"] = len(
            Order.objects.filter(type=Order.Types.SELL, status=Order.Status.PUB)
        )
        context["book_liquidity"] = Order.objects.filter(
            status=Order.Status.PUB
        ).aggregate(Sum("last_satoshis"))["last_satoshis__sum"]
        context["book_liquidity"] = (
            0 if context["book_liquidity"] is None else context["book_liquidity"]
        )

        # Number of active users (logged in in last 30 minutes)
        today = datetime.today()
        context["active_robots_today"] = len(
            User.objects.filter(last_login__day=today.day)
        )

        # Compute average premium and volume of today
        last_day = timezone.now() - timedelta(days=1)
        queryset = MarketTick.objects.filter(timestamp__gt=last_day)
        if not len(queryset) == 0:
            avg_premium, total_volume = compute_avg_premium(queryset)
        # If no contracts, fallback to lifetime avg premium
        else:
            queryset = MarketTick.objects.all()
            avg_premium, _ = compute_avg_premium(queryset)
            total_volume = 0

        queryset = MarketTick.objects.all()
        if not len(queryset) == 0:
            volume_contracted = []
            for tick in queryset:
                volume_contracted.append(tick.volume)
            lifetime_volume = sum(volume_contracted)
        else:
            lifetime_volume = 0

        context["last_day_nonkyc_btc_premium"] = round(avg_premium, 2)
        context["last_day_volume"] = round(total_volume, 8)
        context["lifetime_volume"] = round(lifetime_volume, 8)
        context["lnd_version"] = get_lnd_version()
        context["robosats_running_commit_hash"] = get_robosats_commit()
        context["version"] = settings.VERSION
        context["alternative_site"] = config("ALTERNATIVE_SITE")
        context["alternative_name"] = config("ALTERNATIVE_NAME")
        context["node_alias"] = config("NODE_ALIAS")
        context["node_id"] = config("NODE_ID")
        context["network"] = config("NETWORK")
        context["maker_fee"] = float(config("FEE")) * float(config("MAKER_FEE_SPLIT"))
        context["taker_fee"] = float(config("FEE")) * (
            1 - float(config("MAKER_FEE_SPLIT"))
        )
        context["bond_size"] = float(config("DEFAULT_BOND_SIZE"))

        try:
            context["current_swap_fee_rate"] = Logics.compute_swap_fee_rate(
                BalanceLog.objects.latest("time")
            )
        except BalanceLog.DoesNotExist:
            context["current_swap_fee_rate"] = 0

        return Response(context, status.HTTP_200_OK)


class RewardView(CreateAPIView):
    authentication_classes = [TokenAuthentication, SessionAuthentication]
    permission_classes = [IsAuthenticated]

    serializer_class = ClaimRewardSerializer

    @extend_schema(**RewardViewSchema.post)
    def post(self, request):
        serializer = self.serializer_class(data=request.data)

        if not serializer.is_valid():
            return Response(status=status.HTTP_400_BAD_REQUEST)

        invoice = serializer.data.get("invoice")

        valid, context = Logics.withdraw_rewards(request.user, invoice)

        if not valid:
            context["successful_withdrawal"] = False
            return Response(context, status.HTTP_400_BAD_REQUEST)

        return Response({"successful_withdrawal": True}, status.HTTP_200_OK)


class PriceView(ListAPIView):

    serializer_class = PriceSerializer

    @extend_schema(**PriceViewSchema.get)
    def get(self, request):

        payload = {}
        queryset = Currency.objects.all().order_by("currency")

        for currency in queryset:
            code = Currency.currency_dict[str(currency.currency)]
            try:
                last_tick = MarketTick.objects.filter(currency=currency).latest(
                    "timestamp"
                )
                payload[code] = {
                    "price": last_tick.price,
                    "volume": last_tick.volume,
                    "premium": last_tick.premium,
                    "timestamp": last_tick.timestamp,
                }
            except Exception:
                payload[code] = None

        return Response(payload, status.HTTP_200_OK)


class TickView(ListAPIView):

    queryset = MarketTick.objects.all()
    serializer_class = TickSerializer

    @extend_schema(**TickViewSchema.get)
    def get(self, request):
        data = self.serializer_class(
            self.queryset.all(), many=True, read_only=True
        ).data
        return Response(data, status=status.HTTP_200_OK)


class LimitView(ListAPIView):
    @extend_schema(**LimitViewSchema.get)
    def get(self, request):

        # Trade limits as BTC
        min_trade = float(config("MIN_TRADE")) / 100_000_000
        max_trade = float(config("MAX_TRADE")) / 100_000_000

        payload = {}
        queryset = Currency.objects.all().order_by("currency")

        for currency in queryset:
            code = Currency.currency_dict[str(currency.currency)]
            exchange_rate = float(currency.exchange_rate)
            payload[currency.currency] = {
                "code": code,
                "price": exchange_rate,
                "min_amount": min_trade * exchange_rate,
                "max_amount": max_trade * exchange_rate,
            }

        return Response(payload, status.HTTP_200_OK)


class HistoricalView(ListAPIView):
    @extend_schema(**HistoricalViewSchema.get)
    def get(self, request):
        payload = {}
        queryset = AccountingDay.objects.all().order_by("day")

        for accounting_day in queryset:
            payload[str(accounting_day.day)] = {
                "volume": accounting_day.contracted,
                "num_contracts": accounting_day.num_contracts,
            }

        return Response(payload, status.HTTP_200_OK)


class StealthView(UpdateAPIView):
    authentication_classes = [TokenAuthentication, SessionAuthentication]
    permission_classes = [IsAuthenticated]

    serializer_class = StealthSerializer

    @extend_schema(**StealthViewSchema.put)
    def put(self, request):
        serializer = self.serializer_class(data=request.data)

        if not serializer.is_valid():
            return Response(status=status.HTTP_400_BAD_REQUEST)

        stealth = serializer.data.get("wantsStealth")

        request.user.robot.wants_stealth = stealth
        request.user.robot.save()

        return Response({"wantsStealth": stealth})