import datetime
import re
import secrets
import socket
from typing import Dict, Tuple

# thanks jess!
IRCV3_FORMAT_STRFTIME = "%Y-%m-%dT%H:%M:%S.%f%z"


def ircv3_timestamp_to_unixtime(timestamp: str) -> float:
    return datetime.datetime.strptime(timestamp, IRCV3_FORMAT_STRFTIME).timestamp()


def random_name(base: str) -> str:
    return base + "-" + secrets.token_hex(8)


def find_hostname_and_port() -> Tuple[str, int]:
    """Find available hostname/port to listen on."""
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(("", 0))
    (hostname, port) = s.getsockname()
    s.close()
    return (hostname, port)


"""
Stolen from supybot:
"""


class MultipleReplacer:
    """Return a callable that replaces all dict keys by the associated
    value. More efficient than multiple .replace()."""

    # We use an object instead of a lambda function because it avoids the
    # need for using the staticmethod() on the lambda function if assigning
    # it to a class in Python 3.
    def __init__(self, dict_: Dict[str, str]):
        self._dict = dict_
        dict_ = dict([(re.escape(key), val) for key, val in dict_.items()])
        self._matcher = re.compile("|".join(dict_.keys()))

    def __call__(self, s: str) -> str:
        return self._matcher.sub(lambda m: self._dict[m.group(0)], s)