import os
import re
from typing import Dict
from urllib.parse import urlparse

from flask import request

from shortener.api_connectors.base_api_connector import BaseApiConnector
from shortener.api_connectors.ovh.ovh_api import OvhApi
from shortener.cache import cache
from shortener.data_structures import UserInput
from shortener.exceptions import BadRequestException, ShortCodeNotFoundException
from shortener.resolver import resolver

SUPPORTED_PROVIDERS: Dict[str, type] = {"ovh": OvhApi}
PROVIDER_NAME = os.environ["PROVIDER"].lower()
PROVIDER_CLASS = SUPPORTED_PROVIDERS[PROVIDER_NAME]
COOLDOWN = "cooldown"


def handle_shorten():
    user_input: UserInput = _validate_user_input()
    cooldown = cache.get(user_input.short_code)
    if cooldown:
        raise BadRequestException(
            message=f"Please wait before submitting again for {user_input.short_code}."
        )
    provider: BaseApiConnector = _get_provider()
    provider.add_record(user_input)
    cache.set(user_input.short_code, COOLDOWN, ex=90)
    return {"status": "ok", "url": user_input.short_url}


def _validate_user_input():
    user_input = request.json
    if not user_input:
        user_input = request.form
    url = user_input.get("url")
    if not url:
        raise BadRequestException(message="`url` is required")
    parsed_url = urlparse(url)
    if not all([parsed_url.scheme, parsed_url.netloc]):
        raise BadRequestException(
            message="`url` doesn't seem well formatted. "
            "Please include at least protocol and domain name. "
            "E.g. 'https://google.com' instead of 'google.com'."
        )

    short_code = user_input.get("short_code")
    if not short_code:
        raise BadRequestException(message="`short_code` is required")
    short_code = str(short_code)
    if len(short_code) < 4:
        raise BadRequestException(
            message="`short_code` must be longer than 4 characters."
        )
    reg = re.compile(r"^[a-zA-Z0-9_-]+$")
    if not reg.match(short_code):
        raise BadRequestException(
            message="`short_code` must only contain non accentuated letters, "
            "digits, dashes (-) and underscores (_)."
        )
    if _short_code_exists(short_code):
        raise BadRequestException(message=f"`{short_code}` is already taken")

    user_input = UserInput(short_code=short_code, url=url)
    return user_input


def _get_provider() -> BaseApiConnector:
    return PROVIDER_CLASS()


def _short_code_exists(short_code):
    try:
        resolver.resolve_shortcode(short_code)
        return True
    except ShortCodeNotFoundException:
        return False