# Copyright 2018-2022 Streamlit Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import re
import urllib
from typing import Optional

# Regular expression for process_gitblob_url
_GITBLOB_RE = re.compile(
    r"(?P<base>https:\/\/?(gist.)?github.com\/)"
    r"(?P<account>([\w\.]+\/){1,2})"
    r"(?P<blob_or_raw>(blob|raw))?"
    r"(?P<suffix>(.+)?)"
)


def process_gitblob_url(url: str) -> str:
    """Check url to see if it describes a GitHub Gist "blob" URL.

    If so, returns a new URL to get the "raw" script.
    If not, returns URL unchanged.
    """
    # Matches github.com and gist.github.com.  Will not match githubusercontent.com.
    # See this regex with explainer and sample text here: https://regexr.com/4odk3
    match = _GITBLOB_RE.match(url)
    if match:
        mdict = match.groupdict()
        # If it has "blob" in the url, replace this with "raw" and we're done.
        if mdict["blob_or_raw"] == "blob":
            return "{base}{account}raw{suffix}".format(**mdict)

        # If it is a "raw" url already, return untouched.
        if mdict["blob_or_raw"] == "raw":
            return url

        # It's a gist. Just tack "raw" on the end.
        return url + "/raw"

    return url


def get_hostname(url: str) -> Optional[str]:
    """Return the hostname of a URL (with or without protocol)."""
    # Just so urllib can parse the URL, make sure there's a protocol.
    # (The actual protocol doesn't matter to us)
    if "://" not in url:
        url = "http://%s" % url

    parsed = urllib.parse.urlparse(url)
    return parsed.hostname


def print_url(title, url):
    """Pretty-print a URL on the terminal."""
    import click

    click.secho("  %s: " % title, nl=False, fg="blue")
    click.secho(url, bold=True)