#!/usr/bin/python
#
# Copyright(c) 2010, Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
#


"""Provides support functions for USE flag settings and analysis"""


__all__ = (
    "get_iuse",
    "get_installed_use",
    "reduce_flag",
    "reduce_flags",
    "defaulted_flags",
    "filter_flags",
    "get_all_cpv_use",
    "get_flags",
)


import portage


def get_iuse(cpv):
    """Gets the current IUSE flags from the tree

    To be used when a gentoolkit package object is not needed
    @type: cpv: string
    @param cpv: cat/pkg-ver
    @rtype list
    @returns [] or the list of IUSE flags
    """
    try:
        # aux_get might return dupes, so run them through set() to remove them
        iuse = set(
            portage.db[portage.root]["porttree"].dbapi.aux_get(cpv, ["IUSE"])[0].split()
        )
        # there could still be dupes due to IUSE defaults
        iuse = [x for x in iuse if "+" + x not in iuse and "-" + x not in iuse]
        return list(iuse)
    except:
        return []


def get_installed_use(cpv, use="USE"):
    """Gets the installed USE flags from the VARDB

    To be used when a gentoolkit package object is not needed
    @type: cpv: string
    @param cpv: cat/pkg-ver
    @type use: string
    @param use: 1 of ["USE", "PKGUSE"]
    @rtype list
    @returns [] or the list of IUSE flags
    """
    return portage.db[portage.root]["vartree"].dbapi.aux_get(cpv, [use])[0].split()


def reduce_flag(flag):
    """Absolute value function for a USE flag

    @type flag: string
    @param flag: the use flag to absolute.
    @rtype: string
    @return absolute USE flag
    """
    if flag[0] in ["+", "-"]:
        return flag[1:]
    else:
        return flag


def reduce_flags(the_list):
    """Absolute value function for a USE flag list

    @type the_list: list
    @param the_list: the use flags to absolute.
    @rtype: list
    @return absolute USE flags
    """
    r = []
    for member in the_list:
        r.append(reduce_flag(member))
    return r


def defaulted_flags(the_list):
    """Absolute value function for a USE flag list

    @type the_list: list
    @param the_list: the use flags to get defaulted ones from.
    @rtype: dict of lists
    @return defaulted USE flags {'+': [...], '-': [...]}
    """
    r = {"+": [], "-": []}
    for member in the_list:
        if member[0] in ["+", "-"]:
            r[member[0]].append(member[1:])
    return r


def filter_flags(use, use_expand_hidden, usemasked, useforced):
    """Filter function to remove hidden or otherwise not normally
    visible USE flags from a list.

    @type use: list
    @param use: the USE flag list to be filtered.
    @type use_expand_hidden: list
    @param  use_expand_hidden: list of flags hidden.
    @type usemasked: list
    @param usemasked: list of masked USE flags.
    @type useforced: list
    @param useforced: the forced USE flags.
    @rtype: list
    @return the filtered USE flags.
    """
    # clean out some environment flags, since they will most probably
    # be confusing for the user
    use = {reduce_flag(flag): flag for flag in use}
    for f in use_expand_hidden:
        f = f.lower() + "_"
        for x in list(use):
            if x.startswith(f):
                del use[x]
    # clean out any arch's
    archlist = portage.settings["PORTAGE_ARCHLIST"].split()
    for a in archlist:
        use.pop(a, None)
    # dbl check if any from usemasked  or useforced are still there
    masked = usemasked + useforced
    for a in masked:
        use.pop(a, None)
    return list(use.values())


def get_all_cpv_use(cpv):
    """Uses portage to determine final USE flags and settings for an emerge

    @type cpv: string
    @param cpv: eg cat/pkg-ver
    @rtype: lists
    @return  use, use_expand_hidden, usemask, useforce
    """
    use = None
    portage.db[portage.root]["porttree"].dbapi.settings.unlock()
    try:
        portage.db[portage.root]["porttree"].dbapi.settings.setcpv(
            cpv, mydb=portage.portdb
        )
        use = portage.settings["PORTAGE_USE"].split()
        use_expand_hidden = portage.settings["USE_EXPAND_HIDDEN"].split()
        usemask = list(portage.db[portage.root]["porttree"].dbapi.settings.usemask)
        useforce = list(portage.db[portage.root]["porttree"].dbapi.settings.useforce)
    except KeyError:
        portage.db[portage.root]["porttree"].dbapi.settings.reset()
        portage.db[portage.root]["porttree"].dbapi.settings.lock()
        return [], [], [], []
    # reset cpv filter
    portage.db[portage.root]["porttree"].dbapi.settings.reset()
    portage.db[portage.root]["porttree"].dbapi.settings.lock()
    return use, use_expand_hidden, usemask, useforce


def get_flags(cpv, final_setting=False, include_forced_masked=False):
    """Retrieves all information needed to filter out hidded, masked, etc.
    USE flags for a given package.

    @type cpv: string
    @param cpv: eg. cat/pkg-ver
    @type final_setting: boolean
    @param final_setting: used to also determine the final
            enviroment USE flag settings and return them as well.
    @type include_forced_masked: boolean
    @param include_forced_masked: used to toggle the inclusion of forced and
            masked USE flags in the returned result.
    @rtype: list
            or list, list
            or list, list, list
            or list, list, list, list
    @return IUSE
            or IUSE, final_flags
            or IUSE, useforced, usemasked
            or IUSE, final_flags, useforced, usemasked
    """
    final_use, use_expand_hidden, usemasked, useforced = get_all_cpv_use(cpv)
    if include_forced_masked:
        iuse_flags = filter_flags(get_iuse(cpv), use_expand_hidden, [], [])
        if final_setting:
            final_flags = filter_flags(final_use, use_expand_hidden, [], [])
            return iuse_flags, final_flags, useforced, usemasked
        return iuse_flags, useforced, usemasked
    else:
        iuse_flags = filter_flags(
            get_iuse(cpv), use_expand_hidden, usemasked, useforced
        )
        if final_setting:
            final_flags = filter_flags(
                final_use, use_expand_hidden, usemasked, useforced
            )
            return iuse_flags, final_flags
        return iuse_flags