# -*- coding: utf-8 -*-
#
# Copyright (C) 2012-2017 The Python Software Foundation.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
"""
Implementation of a flexible versioning scheme providing support for PEP-440,
setuptools-compatible and semantic versioning.
"""

import logging
import re

from .compat import string_types
from .util import parse_requirement

__all__ = ['NormalizedVersion', 'NormalizedMatcher',
           'LegacyVersion', 'LegacyMatcher',
           'SemanticVersion', 'SemanticMatcher',
           'UnsupportedVersionError', 'get_scheme']

logger = logging.getLogger(__name__)


class UnsupportedVersionError(ValueError):
    """This is an unsupported version."""
    pass


class Version(object):
    def __init__(self, s):
        self._string = s = s.strip()
        self._parts = parts = self.parse(s)
        assert isinstance(parts, tuple)
        assert len(parts) > 0

    def parse(self, s):
        raise NotImplementedError('please implement in a subclass')

    def _check_compatible(self, other):
        if type(self) != type(other):
            raise TypeError('cannot compare %r and %r' % (self, other))

    def __eq__(self, other):
        self._check_compatible(other)
        return self._parts == other._parts

    def __ne__(self, other):
        return not self.__eq__(other)

    def __lt__(self, other):
        self._check_compatible(other)
        return self._parts < other._parts

    def __gt__(self, other):
        return not (self.__lt__(other) or self.__eq__(other))

    def __le__(self, other):
        return self.__lt__(other) or self.__eq__(other)

    def __ge__(self, other):
        return self.__gt__(other) or self.__eq__(other)

    # See http://docs.python.org/reference/datamodel#object.__hash__
    def __hash__(self):
        return hash(self._parts)

    def __repr__(self):
        return "%s('%s')" % (self.__class__.__name__, self._string)

    def __str__(self):
        return self._string

    @property
    def is_prerelease(self):
        raise NotImplementedError('Please implement in subclasses.')


class Matcher(object):
    version_class = None

    # value is either a callable or the name of a method
    _operators = {
        '<': lambda v, c, p: v < c,
        '>': lambda v, c, p: v > c,
        '<=': lambda v, c, p: v == c or v < c,
        '>=': lambda v, c, p: v == c or v > c,
        '==': lambda v, c, p: v == c,
        '===': lambda v, c, p: v == c,
        # by default, compatible => >=.
        '~=': lambda v, c, p: v == c or v > c,
        '!=': lambda v, c, p: v != c,
    }

    # this is a method only to support alternative implementations
    # via overriding
    def parse_requirement(self, s):
        return parse_requirement(s)

    def __init__(self, s):
        if self.version_class is None:
            raise ValueError('Please specify a version class')
        self._string = s = s.strip()
        r = self.parse_requirement(s)
        if not r:
            raise ValueError('Not valid: %r' % s)
        self.name = r.name
        self.key = self.name.lower()    # for case-insensitive comparisons
        clist = []
        if r.constraints:
            # import pdb; pdb.set_trace()
            for op, s in r.constraints:
                if s.endswith('.*'):
                    if op not in ('==', '!='):
                        raise ValueError('\'.*\' not allowed for '
                                         '%r constraints' % op)
                    # Could be a partial version (e.g. for '2.*') which
                    # won't parse as a version, so keep it as a string
                    vn, prefix = s[:-2], True
                    # Just to check that vn is a valid version
                    self.version_class(vn)
                else:
                    # Should parse as a version, so we can create an
                    # instance for the comparison
                    vn, prefix = self.version_class(s), False
                clist.append((op, vn, prefix))
        self._parts = tuple(clist)

    def match(self, version):
        """
        Check if the provided version matches the constraints.

        :param version: The version to match against this instance.
        :type version: String or :class:`Version` instance.
        """
        if isinstance(version, string_types):
            version = self.version_class(version)
        for operator, constraint, prefix in self._parts:
            f = self._operators.get(operator)
            if isinstance(f, string_types):
                f = getattr(self, f)
            if not f:
                msg = ('%r not implemented '
                       'for %s' % (operator, self.__class__.__name__))
                raise NotImplementedError(msg)
            if not f(version, constraint, prefix):
                return False
        return True

    @property
    def exact_version(self):
        result = None
        if len(self._parts) == 1 and self._parts[0][0] in ('==', '==='):
            result = self._parts[0][1]
        return result

    def _check_compatible(self, other):
        if type(self) != type(other) or self.name != other.name:
            raise TypeError('cannot compare %s and %s' % (self, other))

    def __eq__(self, other):
        self._check_compatible(other)
        return self.key == other.key and self._parts == other._parts

    def __ne__(self, other):
        return not self.__eq__(other)

    # See http://docs.python.org/reference/datamodel#object.__hash__
    def __hash__(self):
        return hash(self.key) + hash(self._parts)

    def __repr__(self):
        return "%s(%r)" % (self.__class__.__name__, self._string)

    def __str__(self):
        return self._string


PEP440_VERSION_RE = re.compile(r'^v?(\d+!)?(\d+(\.\d+)*)((a|b|c|rc)(\d+))?'
                               r'(\.(post)(\d+))?(\.(dev)(\d+))?'
                               r'(\+([a-zA-Z\d]+(\.[a-zA-Z\d]+)?))?$')


def _pep_440_key(s):
    s = s.strip()
    m = PEP440_VERSION_RE.match(s)
    if not m:
        raise UnsupportedVersionError('Not a valid version: %s' % s)
    groups = m.groups()
    nums = tuple(int(v) for v in groups[1].split('.'))
    while len(nums) > 1 and nums[-1] == 0:
        nums = nums[:-1]

    if not groups[0]:
        epoch = 0
    else:
        epoch = int(groups[0])
    pre = groups[4:6]
    post = groups[7:9]
    dev = groups[10:12]
    local = groups[13]
    if pre == (None, None):
        pre = ()
    else:
        pre = pre[0], int(pre[1])
    if post == (None, None):
        post = ()
    else:
        post = post[0], int(post[1])
    if dev == (None, None):
        dev = ()
    else:
        dev = dev[0], int(dev[1])
    if local is None:
        local = ()
    else:
        parts = []
        for part in local.split('.'):
            # to ensure that numeric compares as > lexicographic, avoid
            # comparing them directly, but encode a tuple which ensures
            # correct sorting
            if part.isdigit():
                part = (1, int(part))
            else:
                part = (0, part)
            parts.append(part)
        local = tuple(parts)
    if not pre:
        # either before pre-release, or final release and after
        if not post and dev:
            # before pre-release
            pre = ('a', -1)     # to sort before a0
        else:
            pre = ('z',)        # to sort after all pre-releases
    # now look at the state of post and dev.
    if not post:
        post = ('_',)   # sort before 'a'
    if not dev:
        dev = ('final',)

    #print('%s -> %s' % (s, m.groups()))
    return epoch, nums, pre, post, dev, local


_normalized_key = _pep_440_key


class NormalizedVersion(Version):
    """A rational version.

    Good:
        1.2         # equivalent to "1.2.0"
        1.2.0
        1.2a1
        1.2.3a2
        1.2.3b1
        1.2.3c1
        1.2.3.4
        TODO: fill this out

    Bad:
        1           # minimum two numbers
        1.2a        # release level must have a release serial
        1.2.3b
    """
    def parse(self, s):
        result = _normalized_key(s)
        # _normalized_key loses trailing zeroes in the release
        # clause, since that's needed to ensure that X.Y == X.Y.0 == X.Y.0.0
        # However, PEP 440 prefix matching needs it: for example,
        # (~= 1.4.5.0) matches differently to (~= 1.4.5.0.0).
        m = PEP440_VERSION_RE.match(s)      # must succeed
        groups = m.groups()
        self._release_clause = tuple(int(v) for v in groups[1].split('.'))
        return result

    PREREL_TAGS = set(['a', 'b', 'c', 'rc', 'dev'])

    @property
    def is_prerelease(self):
        return any(t[0] in self.PREREL_TAGS for t in self._parts if t)


def _match_prefix(x, y):
    x = str(x)
    y = str(y)
    if x == y:
        return True
    if not x.startswith(y):
        return False
    n = len(y)
    return x[n] == '.'


class NormalizedMatcher(Matcher):
    version_class = NormalizedVersion

    # value is either a callable or the name of a method
    _operators = {
        '~=': '_match_compatible',
        '<': '_match_lt',
        '>': '_match_gt',
        '<=': '_match_le',
        '>=': '_match_ge',
        '==': '_match_eq',
        '===': '_match_arbitrary',
        '!=': '_match_ne',
    }

    def _adjust_local(self, version, constraint, prefix):
        if prefix:
            strip_local = '+' not in constraint and version._parts[-1]
        else:
            # both constraint and version are
            # NormalizedVersion instances.
            # If constraint does not have a local component,
            # ensure the version doesn't, either.
            strip_local = not constraint._parts[-1] and version._parts[-1]
        if strip_local:
            s = version._string.split('+', 1)[0]
            version = self.version_class(s)
        return version, constraint

    def _match_lt(self, version, constraint, prefix):
        version, constraint = self._adjust_local(version, constraint, prefix)
        if version >= constraint:
            return False
        release_clause = constraint._release_clause
        pfx = '.'.join([str(i) for i in release_clause])
        return not _match_prefix(version, pfx)

    def _match_gt(self, version, constraint, prefix):
        version, constraint = self._adjust_local(version, constraint, prefix)
        if version <= constraint:
            return False
        release_clause = constraint._release_clause
        pfx = '.'.join([str(i) for i in release_clause])
        return not _match_prefix(version, pfx)

    def _match_le(self, version, constraint, prefix):
        version, constraint = self._adjust_local(version, constraint, prefix)
        return version <= constraint

    def _match_ge(self, version, constraint, prefix):
        version, constraint = self._adjust_local(version, constraint, prefix)