##############################################################################
# Copyright (c) 2013-2018, Lawrence Livermore National Security, LLC.
# Produced at the Lawrence Livermore National Laboratory.
#
# This file is part of Spack.
# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
# LLNL-CODE-647188
#
# For details, see https://github.com/spack/spack
# Please also see the NOTICE and LICENSE files for our notice and the LGPL.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License (as
# published by the Free Software Foundation) version 2.1, February 1999.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
# conditions of the GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##############################################################################
"""
This module implements Version and version-ish objects.  These are:

Version
  A single version of a package.
VersionRange
  A range of versions of a package.
VersionList
  A list of Versions and VersionRanges.

All of these types support the following operations, which can
be called on any of the types::

  __eq__, __ne__, __lt__, __gt__, __ge__, __le__, __hash__
  __contains__
  satisfies
  overlaps
  union
  intersection
  concrete
"""
import re
import numbers
from bisect import bisect_left
from functools import wraps
from six import string_types

from spack.util.spack_yaml import syaml_dict


__all__ = ['Version', 'VersionRange', 'VersionList', 'ver']

# Valid version characters
VALID_VERSION = r'[A-Za-z0-9_.-]'


def int_if_int(string):
    """Convert a string to int if possible.  Otherwise, return a string."""
    try:
        return int(string)
    except ValueError:
        return string


def coerce_versions(a, b):
    """
    Convert both a and b to the 'greatest' type between them, in this order:
           Version < VersionRange < VersionList
    This is used to simplify comparison operations below so that we're always
    comparing things that are of the same type.
    """
    order = (Version, VersionRange, VersionList)
    ta, tb = type(a), type(b)

    def check_type(t):
        if t not in order:
            raise TypeError("coerce_versions cannot be called on %s" % t)
    check_type(ta)
    check_type(tb)

    if ta == tb:
        return (a, b)
    elif order.index(ta) > order.index(tb):
        if ta == VersionRange:
            return (a, VersionRange(b, b))
        else:
            return (a, VersionList([b]))
    else:
        if tb == VersionRange:
            return (VersionRange(a, a), b)
        else:
            return (VersionList([a]), b)


def coerced(method):
    """Decorator that ensures that argument types of a method are coerced."""
    @wraps(method)
    def coercing_method(a, b, *args, **kwargs):
        if type(a) == type(b) or a is None or b is None:
            return method(a, b, *args, **kwargs)
        else:
            ca, cb = coerce_versions(a, b)
            return getattr(ca, method.__name__)(cb, *args, **kwargs)
    return coercing_method


class Version(object):
    """Class to represent versions"""

    def __init__(self, string):
        string = str(string)

        if not re.match(VALID_VERSION, string):
            raise ValueError("Bad characters in version string: %s" % string)

        # preserve the original string, but trimmed.
        string = string.strip()
        self.string = string

        # Split version into alphabetical and numeric segments
        segment_regex = r'[a-zA-Z]+|[0-9]+'
        segments = re.findall(segment_regex, string)
        self.version = tuple(int_if_int(seg) for seg in segments)

        # Store the separators from the original version string as well.
        self.separators = tuple(re.split(segment_regex, string)[1:])

    @property
    def dotted(self):
        """The dotted representation of the version.

        Example:
        >>> version = Version('1-2-3b')
        >>> version.dotted
        Version('1.2.3b')

        Returns:
            Version: The version with separator characters replaced by dots
        """
        return Version(self.string.replace('-', '.').replace('_', '.'))

    @property
    def underscored(self):
        """The underscored representation of the version.

        Example:
        >>> version = Version('1.2.3b')
        >>> version.underscored
        Version('1_2_3b')

        Returns:
            Version: The version with separator characters replaced by
                underscores
        """
        return Version(self.string.replace('.', '_').replace('-', '_'))

    @property
    def dashed(self):
        """The dashed representation of the version.

        Example:
        >>> version = Version('1.2.3b')
        >>> version.dashed
        Version('1-2-3b')

        Returns:
            Version: The version with separator characters replaced by dashes
        """
        return Version(self.string.replace('.', '-').replace('_', '-'))

    @property
    def joined(self):
        """The joined representation of the version.

        Example:
        >>> version = Version('1.2.3b')
        >>> version.joined
        Version('123b')

        Returns:
            Version: The version with separator characters removed
        """
        return Version(
            self.string.replace('.', '').replace('-', '').replace('_', ''))

    def up_to(self, index):
        """The version up to the specified component.

        Examples:
        >>> version = Version('1.23-4b')
        >>> version.up_to(1)
        Version('1')
        >>> version.up_to(2)
        Version('1.23')
        >>> version.up_to(3)
        Version('1.23-4')
        >>> version.up_to(4)
        Version('1.23-4b')
        >>> version.up_to(-1)
        Version('1.23-4')
        >>> version.up_to(-2)
        Version('1.23')
        >>> version.up_to(-3)
        Version('1')

        Returns:
            Version: The first index components of the version
        """
        return self[:index]

    def lowest(self):
        return self

    def highest(self):
        return self

    def isnumeric(self):
        """Tells if this version is numeric (vs. a non-numeric version).  A
        version will be numeric as long as the first section of it is,
        even if it contains non-numerica portions.

        Some numeric versions:
            1
            1.1
            1.1a
            1.a.1b
        Some non-numeric versions:
            develop
            system
            myfavoritebranch
        """
        return isinstance(self.version[0], numbers.Integral)

    def isdevelop(self):
        """Triggers on the special case of the `@develop` version."""
        return self.string == 'develop'

    @coerced
    def satisfies(self, other):
        """A Version 'satisfies' another if it is at least as specific and has
        a common prefix.  e.g., we want gcc@4.7.3 to satisfy a request for
        gcc@4.7 so that when a user asks to build with gcc@4.7, we can find
        a suitable compiler.
        """

        nself = len(self.version)
        nother = len(other.version)
        return nother <= nself and self.version[:nother] == other.version

    def __iter__(self):
        return iter(self.version)

    def __len__(self):
        return len(self.version)

    def __getitem__(self, idx):
        cls = type(self)

        if isinstance(idx, numbers.Integral):
            return self.version[idx]

        elif isinstance(idx, slice):
            string_arg = []

            pairs = zip(self.version[idx], self.separators[idx])
            for token, sep in pairs:
                string_arg.append(str(token))
                string_arg.append(str(sep))

            string_arg.pop()  # We don't need the last separator
            string_arg = ''.join(string_arg)
            return cls(string_arg)

        message = '{cls.__name__} indices must be integers'
        raise TypeError(message.format(cls=cls))

    def __repr__(self):
        return 'Version(' + repr(self.string) + ')'

    def __str__(self):
        return self.string

    def __format__(self, format_spec):
        return self.string.format(format_spec)

    @property
    def concrete(self):
        return self

    def _numeric_lt(self, other):
        """Compares two versions, knowing they're both numeric"""
        # Standard comparison of two numeric versions
        for a, b in zip(self.version, other.version):
            if a == b:
                continue
            else:
                # Numbers are always "newer" than letters.
                # This is for consistency with RPM.  See patch
                # #60884 (and details) from bugzilla #50977 in
                # the RPM project at rpm.org.  Or look at
                # rpmvercmp.c if you want to see how this is
                # implemented there.
                if type(a) != type(b):
                    return type(b) == int
                else:
                    return a < b
        # If the common prefix is equal, the one
        # with more segments is bigger.
        return len(self.version) < len(other.version)

    @coerced
    def __lt__(self, other):
        """Version comparison is designed for consistency with the way RPM
           does things.  If you need more complicated versions in installed
           packages, you should override your package's version string to
           express it more sensibly.
        """
        if other is None:
            return False

        # Coerce if other is not a Version
        # simple equality test first.
        if self.version == other.version:
            return False

        # First priority: anything < develop
        sdev = self.isdevelop()
        if sdev:
            return False    # source = develop, it can't be < anything

        # Now we know !sdev
        odev = other.isdevelop()
        if odev:
            return True    # src < dst

        # now we know neither self nor other isdevelop().

        # Principle: Non-numeric is less than numeric
        # (so numeric will always be preferred by default)
        if self.isnumeric():
            if other.isnumeric():
                return self._numeric_lt(other)
            else:    # self = numeric; other = non-numeric
                # Numeric > Non-numeric (always)
                return False
        else:
            if other.isnumeric():  # self = non-numeric, other = numeric
                # non-numeric < numeric (always)
                return True
            else:  # Both non-numeric
                # Maybe consider other ways to compare here...
                return self.string < other.string

    @coerced
    def __eq__(self, other):
        return (other is not None and
                type(other) == Version and self.version == other.version)

    @coerced
    def __ne__(self, other):
        return not (self == other)

    @coerced
    def __le__(self, other):
        return self == other or self < other

    @coerced
    def __ge__(self, other):
        return not (self < other)

    @coerced
    def __gt__(self, other):
        return not (self == other) and not (self < other)

    def __hash__(self):
        return hash(self.version)

    @coerced
    def __contains__(self, other):
        if other is None:
            return False
        return other.version[:len(self.version)] == self.version

    def is_predecessor(self, other):
        """True if the other version is the immediate predecessor of this one.
           That is, NO versions v exist such that:
           (self < v < other and v not in self).
        """
        if len(self.version) != len(other.version):
            return False

        sl = self.version[-1]
        ol = other.version[-1]
        return type(sl) == int and type(ol) == int and (ol - sl == 1)

    def is_successor(self, other):
        return other.is_predecessor(self)

    @coerced
    def overlaps(self, other):
        return self in other or other in self

    @coerced
    def union(self, other):
        if self == other or other in self:
            return self
        elif self in other:
            return other
        else:
            return VersionList([self, other])

    @coerced
    def intersection(self, other):
        if self == other:
            return self
        else:
            return VersionList()


class VersionRange(object):

    def __init__(self, start, end):
        if isinstance(start, string_types):
            start = Version(start)
        if isinstance(end, string_types):
            end = Version(end)

        self.start = start
        self.end = end
        if start and end and end < start:
            raise ValueError("Invalid Version range: %s" % self)

    def lowest(self):
        return self.start

    def highest(self):
        return self.end

    @coerced
    def __lt__(self, other):
        """Sort VersionRanges lexicographically so that they are ordered first
           by start and then by end.  None denotes an open range, so None in
           the start position is less than everything except None, and None in
           the end position is greater than everything but None.
        """
        if other is None:
            return False

        s, o = self, other
        if s.start != o.start:
            return s.start is None or (
                o.start is not None and s.start < o.start)
        return (s.end != o.end and
                o.end is None or (s.end is not None and s.end < o.end))

    @coerced
    def __eq__(self, other):
        return (other is not None and
                type(other) == VersionRange and
                self.start == other.start and self.end == other.end)

    @coerced
    def __ne__(self, other):
        return not (self == other)

    @coerced
    def __le__(self, other):
        return self == other or self < other

    @coerced
    def __ge__(self, other):
        return not (self < other)

    @coerced
    def __gt__(self, other):
        return not (self == other) and not (self < other)

    @property
    def concrete(self):
        return self.start if self.start == self.end else None

    @coerced
    def __contains__(self, other):
        if other is None:
            return False

        in_lower = (self.start == other.start or
                    self.start is None or
                    (other.start is not None and (
                        self.start < other.start or
                        other.start in self.start)))
        if not in_lower:
            return False

        in_upper = (self.end == other.end or
                    self.end is None or
                    (other.end is not None and (
                        self.end > other.end or
                        other.end in self.end)))
        return in_upper

    @coerced
    def satisfies(self, other):
        """A VersionRange satisfies another if some version in this range
        would satisfy some version in the other range.  To do this it must
        either:

        a) Overlap with the other range
        b) The start of this range satisfies the end of the other range.

        This is essentially the same as overlaps(), but overlaps assumes
        that its arguments are specific.  That is, 4.7 is interpreted as
        4.7.0.0.0.0... .  This funciton assumes that 4.7 woudl be satisfied
        by 4.7.3.5, etc.

        Rationale:

        If a user asks for gcc@4.5:4.7, and a package is only compatible with
        gcc@4.7.3:4.8, then that package should be able to build under the
        constraints.  Just using overlaps() would not work here.

        Note that we don't need to check whether the end of this range
        would satisfy the start of the other range, because overlaps()
        already covers that case.

        Note further that overlaps() is a symmetric operation, while
        satisfies() is not.
        """
        return (self.overlaps(other) or
                # if either self.start or other.end are None, then this can't
                # satisfy, or overlaps() would've taken care of it.
                self.start and other.end and self.start.satisfies(other.end))

    @coerced
    def overlaps(self, other):
        return ((self.start is None or other.end is None or
                 self.start <= other.end or
                 other.end in self.start or self.start in other.end) and
                (other.start is None or self.end is None or
                 other.start <= self.end or
                 other.start in self.end or self.end in other.start))

    @coerced
    def union(self, other):
        if not self.overlaps(other):
            if (self.end is not None and other.start is not None and
                    self.end.is_predecessor(other.start)):
                return VersionRange(self.start, other.end)

            if (other.end is not None and self.start is not None and
                    other.end.is_predecessor(self.start)):
                return VersionRange(other.start, self.end)

            return VersionList([self, other])

        # if we're here, then we know the ranges overlap.
        if self.start is None or other.start is None:
            start = None
        else:
            start = self.start
            # TODO: See note in intersection() about < and in discrepancy.
            if self.start in other.start or other.start < self.start:
                start = other.start

        if self.end is None or other.end is None:
            end = None
        else:
            end = self.end
            # TODO: See note in intersection() about < and in discrepancy.
            if other.end not in self.end:
                if end in other.end or other.end > self.end:
                    end = other.end

        return VersionRange(start, end)

    @coerced
    def intersection(self, other):
        if self.overlaps(other):
            if self.start is None:
                start = other.start
            else:
                start = self.start
                if other.start is not None:
                    if other.start > start or other.start in start:
                        start = other.start

            if self.end is None:
                end = other.end
            else:
                end = self.end
                # TODO: does this make sense?
                # This is tricky:
                #     1.6.5 in 1.6 = True  (1.6.5 is more specific)
                #     1.6 < 1.6.5  = True  (lexicographic)
                # Should 1.6 NOT be less than 1.6.5?  Hm.
                # Here we test (not end in other.end) first to avoid paradox.
                if other.end is not None and end not in other.end:
                    if other.end < end or other.end in end:
                        end = other.end

            return VersionRange(start, end)

        else:
            return VersionList()

    def __hash__(self):
        return hash((self.start, self.end))

    def __repr__(self):
        return self.__str__()

    def __str__(self):
        out = ""
        if self.start:
            out += str(self.start)
        out += ":"
        if self.end:
            out += str(self.end)
        return out


class VersionList(object):
    """Sorted, non-redundant list of Versions and VersionRanges."""

    def __init__(self, vlist=None):
        self.versions = []
        if vlist is not None:
            if isinstance(vlist, string_types):
                vlist = _string_to_version(vlist)
                if type(vlist) == VersionList:
                    self.versions = vlist.versions
                else:
                    self.versions = [vlist]
            else:
                vlist = list(vlist)
                for v in vlist:
                    self.add(ver(v))

    def add(self, version):
        if type(version) in (Version, VersionRange):
            # This normalizes single-value version ranges.
            if version.concrete:
                version = version.concrete

            i = bisect_left(self, version)

            while i - 1 >= 0 and version.overlaps(self[i - 1]):
                version = version.union(self[i - 1])
                del self.versions[i - 1]
                i -= 1

            while i < len(self) and version.overlaps(self[i]):
                version = version.union(self[i])
                del self.versions[i]

            self.versions.insert(i, version)

        elif type(version) == VersionList:
            for v in version:
                self.add(v)

        else:
            raise TypeError("Can't add %s to VersionList" % type(version))

    @property
    def concrete(self):
        if len(self) == 1:
            return self[0].concrete
        else:
            return None

    def copy(self):
        return VersionList(self)

    def lowest(self):
        """Get the lowest version in the list."""
        if not self:
            return None
        else:
            return self[0].lowest()

    def highest(self):
        """Get the highest version in the list."""
        if not self:
            return None
        else:
            return self[-1].highest()

    @coerced
    def overlaps(self, other):
        if not other or not self:
            return False

        s = o = 0
        while s < len(self) and o < len(other):
            if self[s].overlaps(other[o]):
                return True
            elif self[s] < other[o]:
                s += 1
            else:
                o += 1
        return False

    def to_dict(self):
        """Generate human-readable dict for YAML."""
        if self.concrete:
            return syaml_dict([
                ('version', str(self[0]))
            ])
        else:
            return syaml_dict([
                ('versions', [str(v) for v in self])
            ])

    @staticmethod
    def from_dict(dictionary):
        """Parse dict from to_dict."""
        if 'versions' in dictionary:
            return VersionList(dictionary['versions'])
        elif 'version' in dictionary:
            return VersionList([dictionary['version']])
        else:
            raise ValueError("Dict must have 'version' or 'versions' in it.")

    @coerced
    def satisfies(self, other, strict=False):
        """A VersionList satisfies another if some version in the list
           would satisfy some version in the other list.  This uses
           essentially the same algorithm as overlaps() does for
           VersionList, but it calls satisfies() on member Versions
           and VersionRanges.

           If strict is specified, this version list must lie entirely
           *within* the other in order to satisfy it.
        """
        if not other or not self:
            return False

        if strict:
            return self in other

        s = o = 0
        while s < len(self) and o < len(other):
            if self[s].satisfies(other[o]):
                return True
            elif self[s] < other[o]:
                s += 1
            else:
                o += 1
        return False

    @coerced
    def update(self, other):
        for v in other.versions:
            self.add(v)

    @coerced
    def union(self, other):
        result = self.copy()
        result.update(other)
        return result

    @coerced
    def intersection(self, other):
        # TODO: make this faster.  This is O(n^2).
        result = VersionList()
        for s in self:
            for o in other:
                result.add(s.intersection(o))
        return result

    @coerced
    def intersect(self, other):
        """Intersect this spec's list with other.

        Return True if the spec changed as a result; False otherwise
        """
        isection = self.intersection(other)
        changed = (isection.versions != self.versions)
        self.versions = isection.versions
        return changed

    @coerced
    def __contains__(self, other):
        if len(self) == 0:
            return False

        for version in other:
            i = bisect_left(self, other)
            if i == 0:
                if version not in self[0]:
                    return False
            elif all(version not in v for v in self[i - 1:]):
                return False

        return True

    def __getitem__(self, index):
        return self.versions[index]

    def __iter__(self):
        return iter(self.versions)

    def __reversed__(self):
        return reversed(self.versions)

    def __len__(self):
        return len(self.versions)

    @coerced
    def __eq__(self, other):
        return other is not None and self.versions == other.versions

    @coerced
    def __ne__(self, other):
        return not (self == other)

    @coerced
    def __lt__(self, other):
        return other is not None and self.versions < other.versions

    @coerced
    def __le__(self, other):
        return self == other or self < other

    @coerced
    def __ge__(self, other):
        return not (self < other)

    @coerced
    def __gt__(self, other):
        return not (self == other) and not (self < other)

    def __hash__(self):
        return hash(tuple(self.versions))

    def __str__(self):
        return ",".join(str(v) for v in self.versions)

    def __repr__(self):
        return str(self.versions)


def _string_to_version(string):
    """Converts a string to a Version, VersionList, or VersionRange.
       This is private.  Client code should use ver().
    """
    string = string.replace(' ', '')

    if ',' in string:
        return VersionList(string.split(','))

    elif ':' in string:
        s, e = string.split(':')
        start = Version(s) if s else None
        end = Version(e) if e else None
        return VersionRange(start, end)

    else:
        return Version(string)


def ver(obj):
    """Parses a Version, VersionRange, or VersionList from a string
       or list of strings.
    """
    if isinstance(obj, (list, tuple)):
        return VersionList(obj)
    elif isinstance(obj, string_types):
        return _string_to_version(obj)
    elif isinstance(obj, (int, float)):
        return _string_to_version(str(obj))
    elif type(obj) in (Version, VersionRange, VersionList):
        return obj
    else:
        raise TypeError("ver() can't convert %s to version!" % type(obj))
