# rcutil.py - utilities about config paths, special config sections etc.

#

#  Copyright Mercurial Contributors

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import os

from . import (

    encoding,

    pycompat,

    util,

)

from .utils import resourceutil

if pycompat.iswindows:

    from . import scmwindows as scmplatform

else:

    from . import scmposix as scmplatform

fallbackpager = scmplatform.fallbackpager

systemrcpath = scmplatform.systemrcpath

userrcpath = scmplatform.userrcpath

def _expandrcpath(path):

    '''path could be a file or a directory. return a list of file paths'''

    p = util.expandpath(path)

    if os.path.isdir(p):

        join = os.path.join

        return sorted(

            join(p, f) for f, k in util.listdir(p) if f.endswith(b'.rc')

        )

    return [p]

def envrcitems(env=None):

    """Return [(section, name, value, source)] config items.

    The config items are extracted from environment variables specified by env,

    used to override systemrc, but not userrc.

    If env is not provided, encoding.environ will be used.

    """

    if env is None:

        env = encoding.environ

    checklist = [

        (b'EDITOR', b'ui', b'editor'),

        (b'VISUAL', b'ui', b'editor'),

        (b'PAGER', b'pager', b'pager'),

    ]

    result = []

    for envname, section, configname in checklist:

        if envname not in env:

            continue

        result.append((section, configname, env[envname], b'$%s' % envname))

    return result

def default_rc_resources():

    """return rc resource IDs in defaultrc"""

    rsrcs = resourceutil.contents(b'mercurial.defaultrc')

    return [

        (b'mercurial.defaultrc', r)

        for r in sorted(rsrcs)

        if resourceutil.is_resource(b'mercurial.defaultrc', r)

        and r.endswith(b'.rc')

    ]

def rccomponents():

    """return an ordered [(type, obj)] about where to load configs.

    respect $HGRCPATH. if $HGRCPATH is empty, only .hg/hgrc of current repo is

    used. if $HGRCPATH is not set, the platform default will be used.

    if a directory is provided, *.rc files under it will be used.

    type could be either 'path', 'items' or 'resource'. If type is 'path',

    obj is a string, and is the config file path. if type is 'items', obj is a

    list of (section, name, value, source) that should fill the config directly.

    If type is 'resource', obj is a tuple of (package name, resource name).

    """

    envrc = (b'items', envrcitems())

    if b'HGRCPATH' in encoding.environ:

        # assume HGRCPATH is all about user configs so environments can be

        # overridden.

        _rccomponents = [envrc]

        for p in encoding.environ[b'HGRCPATH'].split(pycompat.ospathsep):

            if not p:

                continue

            _rccomponents.extend((b'path', p) for p in _expandrcpath(p))

    else:

        _rccomponents = [(b'resource', r) for r in default_rc_resources()]

        normpaths = lambda paths: [

            (b'path', os.path.normpath(p)) for p in paths

        ]

        _rccomponents.extend(normpaths(systemrcpath()))

        _rccomponents.append(envrc)

        _rccomponents.extend(normpaths(userrcpath()))

    return _rccomponents

def defaultpagerenv():

    """return a dict of default environment variables and their values,

    intended to be set before starting a pager.

    """

    return {b'LESS': b'FRX', b'LV': b'-c'}

def use_repo_hgrc():

    """True if repositories `.hg/hgrc` config should be read"""

    return b'HGRCSKIPREPO' not in encoding.environ