import os
import re
import sys
from typing import List, Optional

from pip._internal.locations import site_packages, user_site
from pip._internal.utils.virtualenv import (
    running_under_virtualenv,
    virtualenv_no_global,
)

__all__ = [
    "egg_link_path_from_sys_path",
    "egg_link_path_from_location",
]


def _egg_link_names(raw_name: str) -> List[str]:
    """
    Convert a Name metadata value to a .egg-link name, by applying
    the same substitution as pkg_resources's safe_name function.
    Note: we cannot use canonicalize_name because it has a different logic.

    We also look for the raw name (without normalization) as setuptools 69 changed
    the way it names .egg-link files (https://github.com/pypa/setuptools/issues/4167).
    """
    return [
        re.sub("[^A-Za-z0-9.]+", "-", raw_name) + ".egg-link",
        f"{raw_name}.egg-link",
    ]


def egg_link_path_from_sys_path(raw_name: str) -> Optional[str]:
    """
    Look for a .egg-link file for project name, by walking sys.path.
    """
    egg_link_names = _egg_link_names(raw_name)
    for path_item in sys.path:
        for egg_link_name in egg_link_names:
            egg_link = os.path.join(path_item, egg_link_name)
            if os.path.isfile(egg_link):
                return egg_link
    return None


def egg_link_path_from_location(raw_name: str) -> Optional[str]:
    """
    Return the path for the .egg-link file if it exists, otherwise, None.

    There's 3 scenarios:
    1) not in a virtualenv
       try to find in site.USER_SITE, then site_packages
    2) in a no-global virtualenv
       try to find in site_packages
    3) in a yes-global virtualenv
       try to find in site_packages, then site.USER_SITE
       (don't look in global location)

    For #1 and #3, there could be odd cases, where there's an egg-link in 2
    locations.

    This method will just return the first one found.
    """
    sites: List[str] = []
    if running_under_virtualenv():
        sites.append(site_packages)
        if not virtualenv_no_global() and user_site:
            sites.append(user_site)
    else:
        if user_site:
            sites.append(user_site)
        sites.append(site_packages)

    egg_link_names = _egg_link_names(raw_name)
    for site in sites:
        for egg_link_name in egg_link_names:
            egglink = os.path.join(site, egg_link_name)
            if os.path.isfile(egglink):
                return egglink
    return None

import os
import string
import urllib.parse
import urllib.request

from .compat import WINDOWS


def path_to_url(path: str) -> str:
    """
    Convert a path to a file: URL.  The path will be made absolute and have
    quoted path parts.
    """
    path = os.path.normpath(os.path.abspath(path))
    url = urllib.parse.urljoin("file:", urllib.request.pathname2url(path))
    return url


def url_to_path(url: str) -> str:
    """
    Convert a file: URL to a path.
    """
    assert url.startswith(
        "file:"
    ), f"You can only turn file: urls into filenames (not {url!r})"

    _, netloc, path, _, _ = urllib.parse.urlsplit(url)

    if not netloc or netloc == "localhost":
        # According to RFC 8089, same as empty authority.
        netloc = ""
    elif WINDOWS:
        # If we have a UNC path, prepend UNC share notation.
        netloc = "\\\\" + netloc
    else:
        raise ValueError(
            f"non-local file URIs are not supported on this platform: {url!r}"
        )

    path = urllib.request.url2pathname(netloc + path)

    # On Windows, urlsplit parses the path as something like "/C:/Users/foo".
    # This creates issues for path-related functions like io.open(), so we try
    # to detect and strip the leading slash.
    if (
        WINDOWS
        and not netloc  # Not UNC.
        and len(path) >= 3
        and path[0] == "/"  # Leading slash to strip.
        and path[1] in string.ascii_letters  # Drive letter.
        and path[2:4] in (":", ":/")  # Colon + end of string, or colon + absolute path.
    ):
        path = path[1:]

    return path