"""Simple script which adds matching rainbow colors to data read on stdin."""

import io
from typing import Literal
from dataclasses import dataclass


@dataclass
class Stackpointer():
    """A "fancy" integer which implements pre-and post decrement."""

    depth: int = 0

    def __call__(self, c: int):
        """
        Update and return current state.

        :param c:
            An integer.
            Positive integers increment the value after returning it,
            negative integers decrement the value before returning it,
            0 returns the value as is.
        """
        ret: int
        if c > 0:
            ret = self.depth
            self.depth += 1
        elif c < 0:
            self.depth -= 1
            ret = self.depth
        else:
            ret = self.depth
        return ret


@dataclass
class Colored:
    """
    Tag an item with a color "depth".

    Depth is an arbitarary (positive) integer, from 0 and
    incrementing by up. Each distinct value should correspond to a
    color. The colors may repeat.
    """

    depth: int
    item: str


def color(depth: int, c: str) -> Colored:
    """Write a highlighted string."""
    return Colored(depth, c)


def colorize(strm: io.TextIOBase) -> list[str | Colored]:
    """
    Colorize a given string.

    :param strm:
        Text stream to get contents from.

        Use ``io.StringIO`` if you want to pass a string.
    :returns:
        A list where each item is either a plain string, or a
        ``Colored`` object.
    """
    in_string: Literal[False] | Literal['"'] | Literal["'"] = False

    paren = 0
    brace = 0
    brack = 0

    depth = Stackpointer()

    out: list[str | Colored] = []
    while c := strm.read(1):
        match c:
            case '(':
                out.append(color(depth(1), c))
                paren += 1
            case ')':
                out.append(color(depth(-1), c))
                paren -= 1
            case '[':
                out.append(color(depth(1), c))
                brack += 1
            case ']':
                out.append(color(depth(-1), c))
                brack -= 1
            case '{':
                out.append(color(depth(1), c))
                brace += 1
            case '}':
                out.append(color(depth(-1), c))
                brace -= 1
            case "'":
                if in_string == "'":
                    in_string = False
                else:
                    in_string = "'"
                out.append(c)
            case '"':
                if in_string == '"':
                    in_string = False
                else:
                    in_string = '"'
                out.append(c)
            case '\\':
                out.append(strm.read(1))
            case c:
                out.append(c)
    return out