"""Support for mixed digit/string type Issue field

Class for handling the odd permutations of an 'issue number' that the
comics industry throws at us.
e.g.: "12", "12.1", "0", "-1", "5AU", "100-2"
"""

# Copyright 2012-2014 Anthony Beville

from typing import Optional


class IssueString:
    """Class to handle various types of comic issue numbers."""

    def __init__(self, text: str) -> None:

        # break up the issue number string into 2 parts: the numeric and suffix string.
        # (assumes that the numeric portion is always first)

        self.num: Optional[float] = None
        self.suffix: str = ""

        if text is None:
            return

        # TODO: Once type hinting is finished for the project this check can be removed
        if isinstance(text, int) or isinstance(text, float):
            text = str(text)

        if len(text) == 0:
            return

        # skip the minus sign if it's first
        start: int = 1 if text[0] == "-" else 0
        # if it's still not numeric at start skip it
        if text[start].isdigit() or text[start] == ".":
            idx = self.find_splitpoint(text, start)
            idx = self.move_trailing_numeric_decimal_to_suffix(idx, text)
            idx = self.determine_if_number_after_minus_sign(idx, start)

            part1 = text[0:idx]
            part2 = text[idx : len(text)]

            if part1 != "":
                self.num = float(part1)
            self.suffix = part2
        else:
            self.suffix = text

    def move_trailing_numeric_decimal_to_suffix(self, idx: int, text: str) -> int:
        # move trailing numeric decimal to suffix (only if there is other junk after )
        if text[idx - 1] == "." and len(text) != idx:
            idx -= 1
        return idx

    def determine_if_number_after_minus_sign(self, idx: int, start: int) -> int:
        # if there is no numeric after the minus, make the minus part of
        # the suffix
        if idx == 1 and start == 1:
            return 0
        else:
            return idx

    def find_splitpoint(self, text: str, start: int) -> int:
        # walk through the string, look for split point (the first non-numeric)
        decimal_count: int = 0
        for idx in range(start, len(text)):
            if text[idx] not in "0123456789.":
                break
            # special case: also split on second "."
            if text[idx] == ".":
                decimal_count += 1
                if decimal_count > 1:
                    break
        else:
            idx = len(text)

        return idx

    def as_string(self, pad: int = 0) -> str:
        """Returns a string with left-side zero padding"""
        # return the float, left side zero-padded, with suffix attached
        if self.num is None:
            return self.suffix

        negative: bool = self.num < 0

        num_f: float = abs(self.num)

        num_int = int(num_f)
        num_s = str(num_int)
        if float(num_int) != num_f:
            num_s = str(num_f)

        num_s += self.suffix

        # create padding
        padding: str = ""
        length = len(str(num_int))
        if length < pad:
            padding = "0" * (pad - length)

        num_s = padding + num_s
        if negative:
            num_s = "-" + num_s

        return num_s

    def as_float(self) -> Optional[float]:
        """Return a float with no suffix

        example: "1½" is returned as "1.5"
        """
        if self.suffix == "½":
            if self.num is not None:
                return self.num + 0.5
            else:
                return 0.5
        return self.num

    def as_int(self) -> Optional[int]:
        """Returns the integer version of the float"""
        if self.num is None:
            return None
        return int(self.num)
