# This file is part of the pycalver project
# https://github.com/mbarkhau/pycalver
#
# Copyright (c) 2018 Manuel Barkhau (@mbarkhau) - MIT License
# SPDX-License-Identifier: MIT
"""Parse PyCalVer strings.

>>> version_info = PYCALVER_RE.match("v201712.0123-alpha").groupdict()
>>> assert version_info == {
...     "version" : "v201712.0123-alpha",
...     "calver"  : "v201712",
...     "year"    : "2017",
...     "month"   : "12",
...     "build"   : ".0123",
...     "release" : "-alpha",
... }
>>>
>>> version_info = PYCALVER_RE.match("v201712.0033").groupdict()
>>> assert version_info == {
...     "version" : "v201712.0033",
...     "calver"  : "v201712",
...     "year"    : "2017",
...     "month"   : "12",
...     "build"   : ".0033",
...     "release" : None,
... }
"""

import re
import logging
import typing as typ
import pkg_resources


log = logging.getLogger("pycalver.parse")


VALID_RELESE_VALUES = ("alpha", "beta", "dev", "rc", "post")


# https://regex101.com/r/fnj60p/10
PYCALVER_PATTERN = r"""
\b
(?P<version>
    (?P<calver>
       v                        # "v" version prefix
       (?P<year>\d{4})
       (?P<month>\d{2})
    )
    (?P<build>
        \.                      # "." build nr prefix
        \d{4,}
    )
    (?P<release>
        \-                      # "-" release prefix
        (?:alpha|beta|dev|rc|post)
    )?
)(?:\s|$)
"""

PYCALVER_RE: typ.Pattern[str] = re.compile(PYCALVER_PATTERN, flags=re.VERBOSE)

PATTERN_ESCAPES = [
    ("\u005c", "\u005c\u005c"),
    ("-"     , "\u005c-"),
    ("."     , "\u005c."),
    ("+"     , "\u005c+"),
    ("*"     , "\u005c*"),
    ("["     , "\u005c["),
    ("("     , "\u005c("),
]

# NOTE (mb 2018-09-03): These are matchers for parts, which are
#   used in the patterns, they're not for validation. This means
#   that they may find strings, which are not valid pycalver
#   strings, when parsed in their full context. For such cases,
#   the patterns should be expanded.


RE_PATTERN_PARTS = {
    'pep440_version': r"\d{6}\.[1-9]\d*(a|b|dev|rc|post)?\d*",
    'version'       : r"v\d{6}\.\d{4,}(\-(alpha|beta|dev|rc|post))?",
    'calver'        : r"v\d{6}",
    'build'         : r"\.\d{4,}",
    'release'       : r"(\-(alpha|beta|dev|rc|post))?",
}


class VersionInfo(typ.NamedTuple):
    """Container for parsed version string."""

    version: str
    calver : str
    year   : str
    month  : str
    build  : str
    release: typ.Optional[str]

    @property
    def pep440_version(self) -> str:
        """Generate pep440 compliant version string.

        >>> vnfo = VersionInfo.parse("v201712.0033-beta")
        >>> vnfo.pep440_version
        '201712.33b0'
        """
        return str(pkg_resources.parse_version(self.version))

    @staticmethod
    def parse(version: str) -> 'VersionInfo':
        """Parse a PyCalVer string.

        >>> vnfo = VersionInfo.parse("v201712.0033-beta")
        >>> assert vnfo == VersionInfo(
        ...     version="v201712.0033-beta",
        ...     calver="v201712",
        ...     year="2017",
        ...     month="12",
        ...     build=".0033",
        ...     release="-beta",
        ... )
        """
        match = PYCALVER_RE.match(version)
        if match is None:
            raise ValueError(f"Invalid pycalver: {version}")

        return VersionInfo(**match.groupdict())


class PatternMatch(typ.NamedTuple):
    """Container to mark a version string in a file."""

    lineno : int  # zero based
    line   : str
    pattern: str
    span   : typ.Tuple[int, int]
    match  : str

    @staticmethod
    def _iter_for_pattern(lines: typ.List[str], pattern: str) -> typ.Iterable['PatternMatch']:
        # The pattern is escaped, so that everything besides the format
        # string variables is treated literally.

        pattern_tmpl = pattern

        for char, escaped in PATTERN_ESCAPES:
            pattern_tmpl = pattern_tmpl.replace(char, escaped)

        pattern_str = pattern_tmpl.format(**RE_PATTERN_PARTS)
        pattern_re  = re.compile(pattern_str)
        for lineno, line in enumerate(lines):
            match = pattern_re.search(line)
            if match:
                yield PatternMatch(lineno, line, pattern, match.span(), match.group(0))

    @staticmethod
    def iter_matches(lines: typ.List[str], patterns: typ.List[str]) -> typ.Iterable['PatternMatch']:
        """Iterate over all matches of any pattern on any line.

        >>> lines = ["__version__ = 'v201712.0002-alpha'"]
        >>> patterns = ["{version}", "{pep440_version}"]
        >>> matches = list(PatternMatch.iter_matches(lines, patterns))
        >>> assert matches[0] == PatternMatch(
        ...     lineno = 0,
        ...     line   = "__version__ = 'v201712.0002-alpha'",
        ...     pattern= "{version}",
        ...     span   = (15, 33),
        ...     match  = "v201712.0002-alpha",
        ... )
        """
        for pattern in patterns:
            for match in PatternMatch._iter_for_pattern(lines, pattern):
                yield match