# coding=utf-8
"""Support for ANSI escape sequences which are used for things like applying style to text"""
import functools
import re
from typing import Any

import colorama
from colorama import Fore, Back, Style
from wcwidth import wcswidth

# Regular expression to match ANSI escape sequences
ANSI_ESCAPE_RE = re.compile(r'\x1b[^m]*m')

# Foreground color presets
FG_COLORS = {
    'black': Fore.BLACK,
    'red': Fore.RED,
    'green': Fore.GREEN,
    'yellow': Fore.YELLOW,
    'blue': Fore.BLUE,
    'magenta': Fore.MAGENTA,
    'cyan': Fore.CYAN,
    'white': Fore.WHITE,
    'gray': Fore.LIGHTBLACK_EX,
    'lightred': Fore.LIGHTRED_EX,
    'lightblue': Fore.LIGHTBLUE_EX,
    'lightgreen': Fore.LIGHTGREEN_EX,
    'lightyellow': Fore.LIGHTYELLOW_EX,
    'lightmagenta': Fore.LIGHTMAGENTA_EX,
    'lightcyan': Fore.LIGHTCYAN_EX,
    'lightwhite': Fore.LIGHTWHITE_EX,
    'reset': Fore.RESET,
}

# Background color presets
BG_COLORS = {
    'black': Back.BLACK,
    'red': Back.RED,
    'green': Back.GREEN,
    'yellow': Back.YELLOW,
    'blue': Back.BLUE,
    'magenta': Back.MAGENTA,
    'cyan': Back.CYAN,
    'white': Back.WHITE,
    'gray': Back.LIGHTBLACK_EX,
    'lightred': Back.LIGHTRED_EX,
    'lightblue': Back.LIGHTBLUE_EX,
    'lightgreen': Back.LIGHTGREEN_EX,
    'lightyellow': Back.LIGHTYELLOW_EX,
    'lightmagenta': Back.LIGHTMAGENTA_EX,
    'lightcyan': Back.LIGHTCYAN_EX,
    'lightwhite': Back.LIGHTWHITE_EX,
    'reset': Back.RESET,
}


def strip_ansi(text: str) -> str:
    """Strip ANSI escape sequences from a string.

    :param text: string which may contain ANSI escape sequences
    :return: the same string with any ANSI escape sequences removed
    """
    return ANSI_ESCAPE_RE.sub('', text)


def ansi_safe_wcswidth(text: str) -> int:
    """
    Wraps wcswidth to make it compatible with colored strings

    :param text: the string being measured
    """
    # Strip ANSI escape sequences since they cause wcswidth to return -1
    return wcswidth(strip_ansi(text))


# ANSI escape sequences not provided by colorama
UNDERLINE_ENABLE = colorama.ansi.code_to_chars(4)
UNDERLINE_DISABLE = colorama.ansi.code_to_chars(24)


def style(text: Any, *, fg: str = '', bg: str = '', bold: bool = False, underline: bool = False) -> str:
    """
    Applies styles to text

    :param text: Any object compatible with str.format()
    :param fg: foreground color. Expects color names in FG_COLORS (e.g. 'lightred'). Defaults to no color.
    :param bg: background color. Expects color names in BG_COLORS (e.g. 'black'). Defaults to no color.
    :param bold: apply the bold style if True. Defaults to False.
    :param underline: apply the underline style if True. Defaults to False.

    :return: the stylized string
    """
    # List of strings that add style
    additions = []

    # List of strings that remove style
    removals = []

    # Convert the text object into a string if it isn't already one
    text = "{}".format(text)

    # Process the style settings
    if fg:
        try:
            additions.append(FG_COLORS[fg.lower()])
            removals.append(FG_COLORS['reset'])
        except KeyError:
            raise ValueError('Color {} does not exist.'.format(fg))

    if bg:
        try:
            additions.append(BG_COLORS[bg.lower()])
            removals.append(BG_COLORS['reset'])
        except KeyError:
            raise ValueError('Color {} does not exist.'.format(bg))

    if bold:
        additions.append(Style.BRIGHT)
        removals.append(Style.NORMAL)

    if underline:
        additions.append(UNDERLINE_ENABLE)
        removals.append(UNDERLINE_DISABLE)

    # Combine the ANSI escape sequences with the text
    return "".join(additions) + text + "".join(removals)


# Default styles for printing strings of various types.
# These can be altered to suit an application's needs and only need to be a
# function with the following structure: func(str) -> str
style_success = functools.partial(style, fg='green', bold=True)
style_warning = functools.partial(style, fg='lightyellow')
style_error = functools.partial(style, fg='lightred')