'''
Importer for OTP Bank CSV transaction history.
'''
__copyright__ = 'Copyright (c) 2020  Kristóf Marussy <kristof@marussy.com>'
__license__ = 'GNU GPLv2'

import csv
import datetime as dt
from decimal import Decimal
import logging
from typing import Callable, Dict, Iterable, List, NamedTuple, Optional
import re
from os import path

import beancount.core.amount as am
from beancount.core.amount import Amount
from beancount.core import data
from beancount.core.number import ZERO
from beancount.ingest.cache import _FileMemo as FileMemo
from beancount.ingest.importer import ImporterProtocol

from beancount_extras_kris7t.importers import utils
from beancount_extras_kris7t.importers.utils import COMMENT_META, InvalidEntry, PAYEE_META, \
        Posting
from beancount_extras_kris7t.plugins.transfer_accounts import TRANSFER_ACCOUNT_META, \
        TRANSFER_DATE_META

OTP_BANK = 'OTP Bank'
BOOKING_DATE_META = 'booking-date'
ENTRY_TYPE_META = 'otpbank-entry-type'
OTPBANK_CSV_TAG = 'otpbank-csv'
PAYPASS_TAG = 'paypass'
SIMPLE_TAG = 'processor-simple'
CARD_REGEX = re.compile(
    r'^(?P<date>\d{4}\.\d{2}\.\d{2})\s+(?P<card_number>\d+)')
PAYPASS_REGEX = re.compile(r'-ÉRINT(Ő|\?)|PPASS$', re.IGNORECASE)
SIMPLE_REGEX = re.compile(r'-SIMPLE$', re.IGNORECASE)
SMS_REGEX = re.compile(
    r'^(?P<date>\d{4}\.\d{2}\.\d{2})\s+\((?P<count>\d+) DB SMS\)',
    re.IGNORECASE)


def _parse_date(date_str: str) -> dt.date:
    return utils.parse_date(date_str, '%Y%m%d')


def _parse_card_date(date_str: str) -> dt.date:
    return utils.parse_date(date_str, '%Y.%m.%d')


def _parse_number(amount_str: str) -> Decimal:
    cleaned_str = amount_str.replace('.', '').replace(',', '.')
    return utils.parse_number(cleaned_str)


def _validate_cd(amount: Amount, cd: str) -> None:
    if cd == 'T':
        if amount.number >= ZERO:
            raise InvalidEntry(f'Invalid debit amount: {amount}')
    elif cd == 'J':
        if amount.number <= ZERO:
            raise InvalidEntry(f'Invalid credit amount: {amount}')
    else:
        raise InvalidEntry(f'Invalid credit/debit type: {cd}')


class Conversion(NamedTuple):
    foreign_amount: Amount
    foreign_rate: Amount
    conversion_fee: Optional[Posting]


class Card(NamedTuple):
    card_account: str
    card_date: dt.date


class Row(utils.Row):
    account_name: str
    cd: str
    native_amount: Amount
    booking_date: dt.date
    value_date: dt.date
    _raw_payee: Optional[str]
    _raw_comment: str
    _conversion: Optional[Conversion]
    _card: Optional[Card]

    def __init__(self, file_name: str, index: int, row: List[str], accounts: Dict[str, str]):
        account_number, cd, amount_str, currency, booking_date_str, \
            value_date_str, _, _, payee, comment1, comment2, comment3, entry_type, _, _ = row
        comment = f'{comment1}{comment2}{comment3}'.strip()
        super().__init__(file_name, index, entry_type, payee, comment)
        if account_name := accounts.get(account_number, None):
            self.account_name = account_name
        else:
            raise InvalidEntry(f'Unknown account number {account_number}')
        self.cd = cd
        self.native_amount = Amount(_parse_number(amount_str), currency)
        _validate_cd(self.native_amount, self.cd)
        self.booking_date = _parse_date(booking_date_str)
        self.value_date = _parse_date(value_date_str)
        self.tags.add(OTPBANK_CSV_TAG)
        self._raw_payee = payee
        self._raw_comment = comment
        self._conversion = None
        self._card = None

    @property
    def conversion(self) -> Optional[Conversion]:
        return self._conversion

    @conversion.setter
    def conversion(self, conversion: Optional[Conversion]) -> None:
        if self._conversion:
            raise InvalidEntry(
                f'Conversion {self._conversion} was already set for row ' +
                f' when trying to set it to {conversion}')
        self._conversion = conversion

    @property
    def card(self) -> Optional[Card]:
        return self._card

    @card.setter
    def card(self, card: Optional[Card]) -> None:
        if self._card:
            raise InvalidEntry(
                f'Card {self._card} was already set for row ' +
                f' when trying to set it to {card}')
        self._card = card

    @property
    def transacted_amount(self) -> Amount:
        if self.conversion:
            return self.conversion.foreign_amount
        return self.native_amount

    @property
    def _extended_meta(self) -> data.Meta:
        meta = dict(self.meta)
        if self.entry_type:
            meta[ENTRY_TYPE_META] = self.entry_type
        if self.booking_date != self.value_date:
            meta[BOOKING_DATE_META] = self.booking_date
        if self._raw_payee:
            meta[PAYEE_META] = self._raw_payee
        if self._raw_comment:
            meta[COMMENT_META] = self._raw_comment
        return meta

    @property
    def _card_meta(self) -> Optional[data.Meta]:
        if self._card:
            card_meta: data.Meta = {
                TRANSFER_ACCOUNT_META: self._card.card_account
            }
            if self._card.card_date != self.value_date:
                card_meta[TRANSFER_DATE_META] = self._card.card_date
            return card_meta
        else:
            return None

    def _to_transaction(self) -> data.Transaction:
        if not self.postings:
            raise InvalidEntry('No postings were extracted from this entry')
        if self.payee == '':
            payee = None
        else:
            payee = self.payee
        if self.comment == '' or self.comment == self.payee:
            if payee:
                desc = ''
            else:
                desc = self.entry_type or ''
        else:
            desc = self.comment
        if self._conversion:
            foreign_rate = self._conversion.foreign_rate
            conversion_fee = self._conversion.conversion_fee
        else:
            foreign_rate = None
            conversion_fee = None
        meta = self._extended_meta
        card_meta = self._card_meta
        postings = [
            data.Posting(self.account_name, self.native_amount, None, None, None, None)
        ]
        if len(self.postings) == 1 and not foreign_rate:
            account, amount = self.postings[0]
            postings.append(
                data.Posting(account, utils.MISSING_AMOUNT, None, None, None, card_meta))
        else:
            for account, amount in self.postings:
                postings.append(
                    data.Posting(account, -amount, None, foreign_rate, None, card_meta))
        if conversion_fee and conversion_fee.amount.number != ZERO:
            account, amount = conversion_fee
            postings.append(
                data.Posting(account, amount, None, None, None, None))
        return data.Transaction(
            meta, self.value_date, self.flag, payee, desc, self.tags, self.links, postings)


Extractor = Callable[[Row], None]


def extract_foreign_currencies(
        currencies: Iterable[str], conversion_fees_account: str) -> Extractor:
    currencies_joined = '|'.join(currencies)
    currency_regex = re.compile(
        r'(?P<amount>\d+(,\d+)?)(?P<currency>' + currencies_joined
        + r')\s+(?P<rate>\d+(,\d+)?)$', re.IGNORECASE)

    def do_extract(row: Row) -> None:
        if currency_match := currency_regex.search(row.comment):
            foreign_amount_d = _parse_number(currency_match.group('amount'))
            if row.cd == 'T':
                foreign_amount_d *= -1
            foreign_currency = currency_match.group('currency')
            foreign_amount = Amount(
                foreign_amount_d, foreign_currency.upper())
            foreign_rate_d = _parse_number(currency_match.group('rate'))
            foreign_rate = Amount(
                foreign_rate_d, row.native_amount.currency)
            converted_amount = am.mul(foreign_rate, foreign_amount_d)
            conversion_fee_amount = am.sub(
                converted_amount, row.native_amount)
            conversion_fee = Posting(
                conversion_fees_account, conversion_fee_amount)
            row.conversion = Conversion(
                foreign_amount, foreign_rate, conversion_fee)
            row.comment = row.comment[:currency_match.start()].strip()
    return do_extract


def extract_cards(card_accounts: Dict[str, str]) -> Extractor:
    def do_extract(row: Row) -> None:
        if row.entry_type.lower() not in [
                'vásárlás kártyával',
                'bankkártyával kapcs. díj',
        ]:
            return
        if card_match := CARD_REGEX.search(row.comment):
            card_number = card_match.group('card_number')
            if card_number not in card_accounts:
                raise InvalidEntry(f'No account for card {card_number}')
            card_account = card_accounts[card_number]
            card_date = _parse_card_date(card_match.group('date'))
            row.card = Card(card_account, card_date)
            row.comment = row.comment[card_match.end():].strip()
        else:
            raise InvalidEntry(
                f'Cannot extract card information from: {row.comment}')
        if paypass_match := PAYPASS_REGEX.search(row.comment):
            row.comment = row.comment[:paypass_match.start()].strip()
            row.tags.add(PAYPASS_TAG)
        elif simple_match := PAYPASS_REGEX.search(row.comment):
            row.comment = row.comment[:simple_match.start()].strip()
            row.tags.add(SIMPLE_TAG)
    return do_extract


def extract_sms(sms: str, sms_liability: str, sms_expense: str) -> Extractor:
    def do_extract(row: Row) -> None:
        if row.entry_type != 'OTPdirekt  ÜZENETDÍJ':
            return
        if sms_match := SMS_REGEX.search(row.comment):
            card_account = sms_liability
            card_date = _parse_card_date(sms_match.group('date'))
            row.card = Card(card_account, card_date)
            sms_amount_d = _parse_number(sms_match.group('count'))
            foreign_amount = -Amount(sms_amount_d, sms)
            foreign_rate = am.div(-row.native_amount, sms_amount_d)
            row.conversion = Conversion(
                foreign_amount, foreign_rate, None)
            row.comment = 'SMS díj'
            row.payee = OTP_BANK
            row.assign_to_account(sms_expense)
        else:
            raise InvalidEntry(
                f'Cannot parse SMS transaction: {row.comment}')
    return do_extract


class Importer(ImporterProtocol):
    '''
    Importer for OTP Bank CSV transaction history.
    '''

    _log: logging.Logger
    _accounts: Dict[str, str]
    _extracts: List[Extractor]

    def __init__(self,
                 accounts: Dict[str, str],
                 extractors: List[Extractor]):
        self._log = logging.getLogger(type(self).__qualname__)
        self._accounts = {number.replace('-', ''): name for number, name in accounts.items()}
        self._extractors = extractors

    def identify(self, file: FileMemo) -> bool:
        _, extension = path.splitext(file.name)
        if extension.lower() != '.csv':
            return False
        return self._find_account(file) is not None

    def _find_account(self, file: FileMemo) -> Optional[str]:
        head = file.head().strip().split('\n')[0]
        if head.count(';') != 14:
            return None
        for account_number, account_name in self._accounts.items():
            if head.startswith(f'"{account_number}"'):
                return account_name
        return None

    def file_name(self, file: FileMemo) -> str:
        return 'otpbank.csv'

    def file_account(self, file: FileMemo) -> str:
        account_name = self._find_account(file)
        if not account_name:
            raise RuntimeError(f'Invalid account number in {file.name}')
        return account_name

    def file_date(self, file: FileMemo) -> Optional[dt.date]:
        '''
        Files account statements according to the booking date of the last
        transaction.
        '''
        date = None
        with open(file.name, 'r') as csv_file:
            for row in csv.reader(csv_file, delimiter=';'):
                date_str = row[4]
                try:
                    date = _parse_date(date_str)
                except InvalidEntry as exc:
                    self._log.error(
                        'Invalid entry in %s when looking for filing date',
                        file.name, exc_info=exc)
                    return None
        return date

    def extract(self, file: FileMemo) -> data.Entries:
        file_name = file.name
        entries: data.Entries = []
        with open(file_name, 'r') as csv_file:
            last_date: Optional[dt.date] = None
            last_date_str = ""
            count_within_date = 1
            for index, row_str in enumerate(csv.reader(csv_file, delimiter=';')):
                try:
                    row = Row(file_name, index, row_str, self._accounts)
                    if last_date != row.booking_date:
                        last_date = row.booking_date
                        last_date_str = last_date.strftime('%Y-%m-%d')
                        count_within_date = 1
                    else:
                        count_within_date += 1
                    row.links.add(f'otpbank_{last_date_str}_{count_within_date:03}')
                    self._run_row_extractors(row)
                    entries.append(row._to_transaction())
                except InvalidEntry as exc:
                    self._log.warning(
                        'Skipping invalid entry %d of %s',
                        index, file_name, exc_info=exc)
        return entries

    def _run_row_extractors(self, row: Row):
        utils.run_row_extractors(row, self._extractors)