import itertools
import logging
import os
import posixpath
import urllib.parse
from dataclasses import dataclass
from typing import List

from pip._vendor.packaging.utils import canonicalize_name

from pip._internal.models.index import PyPI
from pip._internal.utils.compat import has_tls
from pip._internal.utils.misc import normalize_path, redact_auth_from_url

logger = logging.getLogger(__name__)


@dataclass(frozen=True)
class SearchScope:
    """
    Encapsulates the locations that pip is configured to search.
    """

    __slots__ = ["find_links", "index_urls", "no_index"]

    find_links: List[str]
    index_urls: List[str]
    no_index: bool

    @classmethod
    def create(
        cls,
        find_links: List[str],
        index_urls: List[str],
        no_index: bool,
    ) -> "SearchScope":
        """
        Create a SearchScope object after normalizing the `find_links`.
        """
        # Build find_links. If an argument starts with ~, it may be
        # a local file relative to a home directory. So try normalizing
        # it and if it exists, use the normalized version.
        # This is deliberately conservative - it might be fine just to
        # blindly normalize anything starting with a ~...
        built_find_links: List[str] = []
        for link in find_links:
            if link.startswith("~"):
                new_link = normalize_path(link)
                if os.path.exists(new_link):
                    link = new_link
            built_find_links.append(link)

        # If we don't have TLS enabled, then WARN if anyplace we're looking
        # relies on TLS.
        if not has_tls():
            for link in itertools.chain(index_urls, built_find_links):
                parsed = urllib.parse.urlparse(link)
                if parsed.scheme == "https":
                    logger.warning(
                        "pip is configured with locations that require "
                        "TLS/SSL, however the ssl module in Python is not "
                        "available."
                    )
                    break

        return cls(
            find_links=built_find_links,
            index_urls=index_urls,
            no_index=no_index,
        )

    def get_formatted_locations(self) -> str:
        lines = []
        redacted_index_urls = []
        if self.index_urls and self.index_urls != [PyPI.simple_url]:
            for url in self.index_urls:
                redacted_index_url = redact_auth_from_url(url)

                # Parse the URL
                purl = urllib.parse.urlsplit(redacted_index_url)

                # URL is generally invalid if scheme and netloc is missing
                # there are issues with Python and URL parsing, so this test
                # is a bit crude. See bpo-20271, bpo-23505. Python doesn't
                # always parse invalid URLs correctly - it should raise
                # exceptions for malformed URLs
                if not purl.scheme and not purl.netloc:
                    logger.warning(
                        'The index url "%s" seems invalid, please provide a scheme.',
                        redacted_index_url,
                    )

                redacted_index_urls.append(redacted_index_url)

            lines.append(
                "Looking in indexes: {}".format(", ".join(redacted_index_urls))
            )

        if self.find_links:
            lines.append(
                "Looking in links: {}".format(
                    ", ".join(redact_auth_from_url(url) for url in self.find_links)
                )
            )
        return "\n".join(lines)

    def get_index_urls_locations(self, project_name: str) -> List[str]:
        """Returns the locations found via self.index_urls

        Checks the url_name on the main (first in the list) index and
        use this url_name to produce all locations
        """

        def mkurl_pypi_url(url: str) -> str:
            loc = posixpath.join(
                url, urllib.parse.quote(canonicalize_name(project_name))
            )
            # For maximum compatibility with easy_install, ensure the path
            # ends in a trailing slash.  Although this isn't in the spec
            # (and PyPI can handle it without the slash) some other index
            # implementations might break if they relied on easy_install's
            # behavior.
            if not loc.endswith("/"):
                loc = loc + "/"
            return loc

        return [mkurl_pypi_url(url) for url in self.index_urls]

from __future__ import annotations

import contextlib
import re
from dataclasses import dataclass
from typing import Iterator, NoReturn

from .specifiers import Specifier


@dataclass
class Token:
    name: str
    text: str
    position: int


class ParserSyntaxError(Exception):
    """The provided source text could not be parsed correctly."""

    def __init__(
        self,
        message: str,
        *,
        source: str,
        span: tuple[int, int],
    ) -> None:
        self.span = span
        self.message = message
        self.source = source

        super().__init__()

    def __str__(self) -> str:
        marker = " " * self.span[0] + "~" * (self.span[1] - self.span[0]) + "^"
        return "\n    ".join([self.message, self.source, marker])


DEFAULT_RULES: dict[str, str | re.Pattern[str]] = {
    "LEFT_PARENTHESIS": r"\(",
    "RIGHT_PARENTHESIS": r"\)",
    "LEFT_BRACKET": r"\[",
    "RIGHT_BRACKET": r"\]",
    "SEMICOLON": r";",
    "COMMA": r",",
    "QUOTED_STRING": re.compile(
        r"""
            (
                ('[^']*')
                |
                ("[^"]*")
            )
        """,
        re.VERBOSE,
    ),
    "OP": r"(===|==|~=|!=|<=|>=|<|>)",
    "BOOLOP": r"\b(or|and)\b",
    "IN": r"\bin\b",
    "NOT": r"\bnot\b",
    "VARIABLE": re.compile(
        r"""
            \b(
                python_version
                |python_full_version
                |os[._]name
                |sys[._]platform
                |platform_(release|system)
                |platform[._](version|machine|python_implementation)
                |python_implementation
                |implementation_(name|version)
                |extra
            )\b
        """,
        re.VERBOSE,
    ),
    "SPECIFIER": re.compile(
        Specifier._operator_regex_str + Specifier._version_regex_str,
        re.VERBOSE | re.IGNORECASE,
    ),
    "AT": r"\@",
    "URL": r"[^ \t]+",
    "IDENTIFIER": r"\b[a-zA-Z0-9][a-zA-Z0-9._-]*\b",
    "VERSION_PREFIX_TRAIL": r"\.\*",
    "VERSION_LOCAL_LABEL_TRAIL": r"\+[a-z0-9]+(?:[-_\.][a-z0-9]+)*",
    "WS": r"[ \t]+",
    "END": r"$",
}


class Tokenizer:
    """Context-sensitive token parsing.

    Provides methods to examine the input stream to check whether the next token
    matches.
    """

    def __init__(
        self,
        source: str,
        *,
        rules: dict[str, str | re.Pattern[str]],
    ) -> None:
        self.source = source
        self.rules: dict[str, re.Pattern[str]] = {
            name: re.compile(pattern) for name, pattern in rules.items()
        }
        self.next_token: Token | None = None
        self.position = 0

    def consume(self, name: str) -> None:
        """Move beyond provided token name, if at current position."""
        if self.check(name):
            self.read()

    def check(self, name: str, *, peek: bool = False) -> bool:
        """Check whether the next token has the provided name.

        By default, if the check succeeds, the token *must* be read before
        another check. If `peek` is set to `True`, the token is not loaded and
        would need to be checked again.
        """
        assert (
            self.next_token is None
        ), f"Cannot check for {name!r}, already have {self.next_token!r}"
        assert name in self.rules, f"Unknown token name: {name!r}"

        expression = self.rules[name]

        match = expression.match(self.source, self.position)
        if match is None:
            return False
        if not peek:
            self.next_token = Token(name, match[0], self.position)
        return True

    def expect(self, name: str, *, expected: str) -> Token:
        """Expect a certain token name next, failing with a syntax error otherwise.

        The token is *not* read.
        """
        if not self.check(name):
            raise self.raise_syntax_error(f"Expected {expected}")
        return self.read()

    def read(self) -> Token:
        """Consume the next token and return it."""
        token = self.next_token
        assert token is not None

        self.position += len(token.text)
        self.next_token = None

        return token

    def raise_syntax_error(
        self,
        message: str,
        *,
        span_start: int | None = None,
        span_end: int | None = None,
    ) -> NoReturn:
        """Raise ParserSyntaxError at the given position."""
        span = (
            self.position if span_start is None else span_start,
            self.position if span_end is None else span_end,
        )
        raise ParserSyntaxError(
            message,
            source=self.source,
            span=span,
        )

    @contextlib.contextmanager
    def enclosing_tokens(
        self, open_token: str, close_token: str, *, around: str
    ) -> Iterator[None]:
        if self.check(open_token):
            open_position = self.position
            self.read()
        else:
            open_position = None

        yield

        if open_position is None:
            return

        if not self.check(close_token):
            self.raise_syntax_error(
                f"Expected matching {close_token} for {open_token}, after {around}",
                span_start=open_position,
            )

        self.read()