# Portions Copyright (c) Facebook, Inc. and its affiliates.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2.

# 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 errno
import os

from . import config, encoding, mdiff, pycompat, util


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 [join(p, f) for f, k in util.listdir(p) if f.endswith(".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 = [
        ("EDITOR", "ui", "editor"),
        ("VISUAL", "ui", "editor"),
        ("PAGER", "pager", "pager"),
    ]
    result = []
    for envname, section, configname in checklist:
        if envname not in env:
            continue
        result.append((section, configname, env[envname], "$%s" % envname))
    return result


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' or 'items', 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.
    """
    envrc = ("items", envrcitems())

    if "HGRCPATH" in encoding.environ:
        # assume HGRCPATH is all about user configs so environments can be
        # overridden.
        _rccomponents = [envrc]
        for p in encoding.environ["HGRCPATH"].split(pycompat.ospathsep):
            if not p:
                continue
            _rccomponents.extend(("path", p) for p in _expandrcpath(p))
    else:
        normpaths = lambda paths: [("path", os.path.normpath(p)) for p in paths]
        _rccomponents = 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 {"LESS": "FRX", "LV": "-c"}


def editconfig(path, section, name, value):
    """Append a config item to the given config path.

    Try to edit the config in-place without breaking config file syntax for
    simple cases. Fallback to just append the new config.
    """
    path = os.path.realpath(path)
    content = ""
    try:
        content = util.readfile(path)
    except IOError as ex:
        if ex.errno != errno.ENOENT:
            raise
    cfg = config.config()
    cfg.parse("", content, include=lambda *args, **kwargs: None)
    source = cfg.source(section, name)
    edited = False

    # in-place edit if possible
    if source.startswith(":"):
        # line index
        index = int(source[1:]) - 1
        lines = mdiff.splitnewlines(content)
        # for simple case, we can edit the line in-place
        if (  # config line should still exist
            index < len(lines)
            # the line should start with "NAME ="
            and lines[index].split("=")[0].rstrip() == name
            # the next line should not be indented (a multi-line value)
            and (index + 1 >= len(lines) or not lines[index + 1][:1].isspace())
        ):
            edited = True
            # edit the line
            content = "".join(
                lines[:index] + ["%s = %s\n" % (name, value)] + lines[index + 1 :]
            )
    if not edited:
        # append as new config
        if content:
            content += "\n"
        content += "[%s]\n%s = %s\n" % (section, name, value)
    with util.atomictempfile(path) as f:
        f.write(content)