from datetime import timedelta
from hashlib import sha256

from django.conf import settings
from django.utils import timezone
from orjson import dumps

from core.clients.aggregator import AggregatorClient
from core.clients.base import BaseClient
from core.util import logs

log = logs.get_logger("nordigen")


class NordigenClient(BaseClient, AggregatorClient):
    url = "https://ob.nordigen.com/api/v2"

    async def connect(self):
        now = timezone.now()
        # Check if access token expires later than now
        if self.instance.access_token_expires is not None:
            if self.instance.access_token_expires > now:
                self.token = self.instance.access_token
                return
        await self.get_access_token()

    def method_filter(self, method):
        new_method = method.replace("/", "_")
        return new_method

    async def get_access_token(self):
        """
        Get the access token for the Nordigen API.
        """
        log.debug(f"Getting new access token for {self.instance}")
        data = {
            "secret_id": self.instance.secret_id,
            "secret_key": self.instance.secret_key,
        }

        response = await self.call("token/new", http_method="post", data=data)
        access = response["access"]
        access_expires = response["access_expires"]
        now = timezone.now()
        # Offset now by access_expires seconds
        access_expires = now + timedelta(seconds=access_expires)
        self.instance.access_token = access
        self.instance.access_token_expires = access_expires
        self.instance.save()

        self.token = access

    async def get_requisitions(self):
        """
        Get a list of active accounts.
        """
        response = await self.call("requisitions")
        return response["results"]

    async def get_countries(self):
        """
        Get a list of countries.
        """
        # This function is a stub.

        return ["GB", "SE", "BG"]

    async def get_banks(self, country):
        """
        Get a list of supported banks for a country.
        :param country: country to query
        :return: list of institutions
        :rtype: list
        """
        if not len(country) == 2:
            return False
        path = f"institutions/?country={country}"
        response = await self.call(path, schema="Institutions", append_slash=False)

        return response

    async def build_link(self, institution_id, redirect=None):
        """Create a link to access an institution.
        :param institution_id: ID of the institution
        """

        data = {
            "institution_id": institution_id,
            "redirect": settings.URL,
        }
        if redirect:
            data["redirect"] = redirect
        response = await self.call(
            "requisitions", schema="RequisitionsPost", http_method="post", data=data
        )
        if "link" in response:
            return response["link"]
        return False

    async def delete_requisition(self, requisition_id):
        """
        Delete a requisision ID.
        """
        path = f"requisitions/{requisition_id}"

        response = await self.call(
            path, schema="RequisitionDelete", http_method="delete"
        )
        return response

    async def get_requisition(self, requisition):
        """
        Get a list of accounts for a requisition.
        :param requisition: requisition ID"""
        path = f"requisitions/{requisition}"
        response = await self.call(path, schema="Requisition")

        return response

    # def get_ownernames(self):
    #     """
    #     Get list of supplementary owner names.
    #     """
    #     ownernames = loads(settings.Nordigen.OwnerNames)
    #     return ownernames

    async def get_account(self, account_id):
        """
        Get details of an account.
        :param account_id: account ID"""

        path = f"accounts/{account_id}/details"
        response = await self.call(path, schema="AccountDetails")
        if "account" not in response:
            return False
        parsed = response["account"]
        if "iban" in parsed and parsed["currency"] == "GBP":
            if parsed["iban"]:
                sort_code = parsed["iban"][-14:-8]
                account_number = parsed["iban"][-8:]
                del parsed["iban"]
                # if "iban" in parsed:
                #     del parsed["iban"]
                sort_code = "-".join(list(map("".join, zip(*[iter(sort_code)] * 2))))
                parsed["sort_code"] = sort_code
                parsed["number"] = account_number
                parsed["recipient"] = "TODO"
        # Let's add the account ID so we can reference it later
        parsed["account_id"] = account_id
        parsed["aggregator_id"] = str(self.instance.id)
        return parsed

    async def get_all_account_info(self, requisition=None, store=False):
        to_return = {}
        if not requisition:
            requisitions = await self.get_requisitions()
        else:
            requisitions = [await self.get_requisition(requisition)]

        for req in requisitions:
            accounts = req["accounts"]
            for account_id in accounts:
                account_info = await self.get_account(account_id)
                if not account_info:
                    continue
                if req["institution_id"] in to_return:
                    to_return[req["institution_id"]].append(account_info)
                else:
                    to_return[req["institution_id"]] = [account_info]

        if store:
            if requisition is not None:
                raise Exception("Cannot store partial data")
            self.store_account_info(to_return)
        return to_return

    async def get_balance(self, account_id):
        """
        Get the balance and currency of an account.
        :param account_id: the account ID
        :return: tuple of (currency, amount)
        :rtype: tuple
        """

        path = f"accounts/{account_id}/balances"
        response = await self.call(path, schema="AccountBalances")

        total = 0
        currency = None
        if "balances" not in response:
            return (False, False)
        for entry in response["balances"]:
            if currency:
                if not currency == entry["balanceAmount"]["currency"]:
                    return (False, False)
                if not entry["balanceType"] == "interimAvailable":
                    continue
            total += float(entry["balanceAmount"]["amount"])
            currency = entry["balanceAmount"]["currency"]
        return (currency, total)

    async def get_all_balances(self):
        """
        Get all balances.
        Keyed by bank.
        """
        if self.instance.account_info is None:
            await self.get_all_account_info(store=True)

        account_balances = {}
        for bank, accounts in self.instance.account_info.items():
            if bank not in account_balances:
                account_balances[bank] = []
            for account in accounts:
                account_id = account["account_id"]
                currency, amount = await self.get_balance(account_id)
                account_balances[bank].append(
                    {
                        "currency": currency,
                        "balance": amount,
                        "account_id": account_id,
                    }
                )
        return account_balances

    async def get_total_map(self):
        """
        Return a dictionary keyed by currencies with the amounts as values.
        :return: dict keyed by currency, values are amounts
        :rtype: dict
        """
        if self.instance.account_info is None:
            await self.get_all_account_info(store=True)

        totals = {}
        for bank, accounts in self.instance.account_info.items():
            for account in accounts:
                account_id = account["account_id"]
                currency, amount = await self.get_balance(account_id)
                if not amount:
                    continue
                if not currency:
                    continue
                if currency in totals:
                    totals[currency] += amount
                else:
                    totals[currency] = amount
        return totals

    def normalise_transactions(self, transactions):
        for transaction in transactions:
            # Rename ID
            if "transactionId" in transaction:
                transaction["transaction_id"] = transaction["transactionId"]
                del transaction["transactionId"]
            elif "internalTransactionId" in transaction:
                transaction["transaction_id"] = transaction["internalTransactionId"]
                del transaction["internalTransactionId"]
            else:
                # No transaction ID. This is a problem for our implementation

                tx_hash = sha256(
                    dumps(transaction, sort_keys=True).encode("utf8")
                ).hexdigest()
                transaction["transaction_id"] = tx_hash

            # Rename timestamp

            if "bookingDateTime" in transaction:
                transaction["ts"] = transaction["bookingDateTime"]
                del transaction["bookingDateTime"]
            elif "bookingDate" in transaction:
                transaction["ts"] = transaction["bookingDate"]
                del transaction["bookingDate"]

            transaction["amount"] = float(transaction["transactionAmount"]["amount"])
            transaction["currency"] = transaction["transactionAmount"]["currency"]
            del transaction["transactionAmount"]

            if transaction["remittanceInformationUnstructuredArray"]:
                ref_list = transaction["remittanceInformationUnstructuredArray"]
                reference = "|".join(ref_list)
                transaction["reference"] = reference
                del transaction["remittanceInformationUnstructuredArray"]
            elif transaction["remittanceInformationUnstructured"]:
                reference = transaction["remittanceInformationUnstructured"]
                transaction["reference"] = reference
                del transaction["remittanceInformationUnstructured"]
            else:
                raise Exception(f"No way to get reference: {transaction}")

    async def get_transactions(self, account_id, process=False):
        """
        Get all transactions for an account.
        :param account_id: account to fetch transactions for
        :return: list of transactions
        :rtype: dict
        """
        path = f"accounts/{account_id}/transactions"
        response = await self.call(path, schema="Transactions")

        parsed = response["booked"]
        self.normalise_transactions(parsed)
        if process:
            await self.process_transactions(parsed)
        return parsed