import re
from time import strftime, gmtime
from string import ascii_letters

HTTP_STATUS_CODES = {
    100: "Continue",
    101: "Switching Protocols",
    102: "Processing",
    200: "OK",
    201: "Created",
    202: "Accepted",
    203: "Non Authoritative Information",
    204: "No Content",
    205: "Reset Content",
    206: "Partial Content",
    207: "Multi Status",
    226: "IM Used",  # see RFC 3229
    300: "Multiple Choices",
    301: "Moved Permanently",
    302: "Found",
    303: "See Other",
    304: "Not Modified",
    305: "Use Proxy",
    307: "Temporary Redirect",
    308: "Permanent Redirect",
    400: "Bad Request",
    401: "Unauthorized",
    402: "Payment Required",  # unused
    403: "Forbidden",
    404: "Not Found",
    405: "Method Not Allowed",
    406: "Not Acceptable",
    407: "Proxy Authentication Required",
    408: "Request Timeout",
    409: "Conflict",
    410: "Gone",
    411: "Length Required",
    412: "Precondition Failed",
    413: "Request Entity Too Large",
    414: "Request URI Too Long",
    415: "Unsupported Media Type",
    416: "Requested Range Not Satisfiable",
    417: "Expectation Failed",
    418: "I'm a teapot",  # see RFC 2324
    421: "Misdirected Request",  # see RFC 7540
    422: "Unprocessable Entity",
    423: "Locked",
    424: "Failed Dependency",
    426: "Upgrade Required",
    428: "Precondition Required",  # see RFC 6585
    429: "Too Many Requests",
    431: "Request Header Fields Too Large",
    449: "Retry With",  # proprietary MS extension
    451: "Unavailable For Legal Reasons",
    500: "Internal Server Error",
    501: "Not Implemented",
    502: "Bad Gateway",
    503: "Service Unavailable",
    504: "Gateway Timeout",
    505: "HTTP Version Not Supported",
    507: "Insufficient Storage",
    510: "Not Extended",
}

HTTP_VERSION = 'HTTP/1.1'
HTTP_METHODS = ['GET', 'POST', 'OPTIONS', 'HEAD', 'PUT', 'PATCH', 'DELETE', 'TRACE', 'CONNECT']

URL_REGEX_PATTERN = re.compile(r'/((.*?/?)+)?')
FIRST_LINE_PATTERN = re.compile(rf'{"(" + "|".join(HTTP_METHODS) + ")"} {URL_REGEX_PATTERN.pattern} HTTP/1\.[01]')


def get_status_code(code):
    return f'{HTTP_VERSION} {code} {HTTP_STATUS_CODES[code]}'


SUCCESS = get_status_code(200)
BAD_REQUEST = get_status_code(400)
NOT_FOUND = get_status_code(404)
METHOD_NOT_ALLOWED = get_status_code(405)


def add_text_headers(status, html: str):
    """
    Добавляет заголовки к ответной html-странице
    """

    return '\r\n'.join([
        status,
        f'Date: {strftime("%a, %d %b %Y %H:%M:%S GMT", gmtime())}',
        'Server: BrandNewServer',
        'Content-Type: text/html; charset=utf-8',
        'Connection: keep-alive',
        '', html
    ])


def validate_url(url):
    return bool(URL_REGEX_PATTERN.fullmatch(url))


def validate_first_line(line):
    return bool(FIRST_LINE_PATTERN.fullmatch(line))


def parse_cookies(cookies_line: str):
    cookies_line = cookies_line.strip().strip(';')
    pairs = cookies_line.split(';')
    d = {}
    for pair in pairs:
        try:
            key, value = pair.split('=', maxsplit=1)
            d[key] = value
        except ValueError:
            raise ValueError('Wrong format of cookies')
    return d


def format_cookies(cookies: dict):
    """
    Формирование cookie-строки из переданного словаря.
    """

    pairs = []
    for key, value in cookies:
        pairs.append(f'{key}={value}')

    return ';'.join(pairs)


def parse_headers(request_line: str):
    request = request_line.split('\r\n')

    first_line = request.pop(0)
    if validate_first_line(first_line):
        method, url, http_ver = first_line.split()
    else:
        # Я не знаю зачем в условии необходимо завершать работу сервера, если пришел не-HTTP запрос,
        # поэтому оставлю эту строку здесь.
        # raise ValueError('Wrong format of HTTP request')
        raise ConnectionError('Wrong format of HTTP request')

    headers = {}
    for line in request:

        try:
            field, value = line.split(': ', maxsplit=1)
        except ValueError:
            # raise ValueError('Wrong format of HTTP header')
            raise ConnectionError('Wrong format of HTTP request')

        headers[field] = value

    return method, url, http_ver, headers


def parse_query(query_line: str):
    pairs = query_line.strip().split('&')
    d = {}
    for pair in pairs:
        try:
            key, value = pair.split('=', maxsplit=1)
            d[url_decoder(key)] = url_decoder(value)
        except ValueError:
            # raise ValueError('Wrong format of query')
            raise ConnectionError('Wrong format of query')

    return d


def url_decoder(url_line: str):
    url_line = url_line.replace('+', ' ')
    encoded = b''
    i = 0
    while i < len(url_line):
        if url_line[i] == '%':
            hex_value = url_line[i + 1: i + 3]
            encoded += bytes([int(hex_value, 16)])

            i += 3
            continue
        else:
            encoded += bytes([ord(url_line[i])])
            i += 1

    return encoded.decode()


def url_encoder(line: str):
    s = ''
    for char in line:
        if char == ' ':
            s += '+'
        elif char not in ascii_letters:
            for byte in char.encode():
                s += '%' + hex(byte)[2:].upper()
        else:
            s += char

    return s