#!/usr/bin/env python3
# pylint: disable=missing-docstring,invalid-name

#import argparse
from collections import namedtuple
import datetime
import re
from typing import List, BinaryIO
import PyPDF3

Rate = namedtuple('Rate', ['abbr', 'full_name', 'ask', 'bid'])

class CurrencyResult():
    def __init__(self):
        self.rates = list()
        self.card_type = str()
        self.date = None

def _select_date():
    date = datetime.date.today()-datetime.timedelta(1)
    if datetime.date().isoweekday() in [6, 0]:
        date = datetime.date.today()

def _parse_rate(text: str) -> float or None:
    if re.match('Keine Kursdaten vorhanden', text):
        _r = None
    else:
        text = text.strip(' ').replace(',', '.')
        try:
            _r = float(text)
        except ValueError:
            _r = None
    return _r

def _parse_card_type(text: str) -> str:
    text = text.split(':')[1]
    text = text.strip('" ')
    return text

def _parse_date(text: str) -> datetime.date:
    text = text.split(': ')[1].rstrip()
    return datetime.datetime.strptime(text, '%d.%m.%Y').date()

def _array_remove_empty(obj: list) -> List[str]:
    try:
        while True:
            obj.remove('')
    except ValueError:
        return obj
    return obj

def _parse_line(line: str) -> Rate or None:
    arr = line.split("   ") # 3 spaces = minimum separation in PDF
    arr = _array_remove_empty(arr)
    # process currency name
    names = arr[0].split(" ", 1)
    rate = Rate(
        abbr=names[0],
        full_name=names[1].strip("()"),
        ask=_parse_rate(arr[1]),
        bid=_parse_rate(arr[2])
        )
    return rate


def get_results_from_text(text: str, currency: str = None) -> CurrencyResult:
    rates = {}
    result = CurrencyResult()
    lines = text.splitlines()
    # skip intro lines
    lines = lines[2:]
    # card type
    result.card_type = _parse_card_type(lines.pop(0))
    # get date
    result.date = _parse_date(lines.pop(0))
    # skip more lines
    lines = lines[4:]
    # now the rates begin
    if currency is None:
        for line in lines:
            line_result = _parse_line(line)
            rates[line_result.abbr] = line_result
    else:
        pattern = re.compile("^"+currency)
        for line in lines:
            if pattern.match(line):
                line_result = _parse_line(line)
                rates[line_result.abbr] = line_result
    result.rates = rates
    return result

def get_results_from_pdf(buf: BinaryIO or str, currency: str = None) -> CurrencyResult:
    reader = PyPDF3.PdfFileReader(buf)
    text = str()
    pages = []
    for num in range(0, reader.getNumPages()-1):
        pages.append(reader.getPage(num))
    for page in pages:
        text += page.extractText()
    return get_results_from_text(text, currency=currency)