# utils.py -- utility functions source
# This file is part of Redshift.

# Redshift is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# Redshift 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
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with Redshift.  If not, see <http://www.gnu.org/licenses/>.

# Copyright (c) 2010  Francesco Marella <francesco.marella@gmail.com>
# Copyright (c) 2011  Jon Lund Steffensen <jonlst@gmail.com>

import ctypes
import os
import sys

try:
    from xdg import BaseDirectory
    from xdg import DesktopEntry
    has_xdg = True
except ImportError:
    has_xdg = False


REDSHIFT_DESKTOP = 'redshift-gtk.desktop'

# Keys to set when enabling/disabling autostart.
# Only first one is checked on "get".
AUTOSTART_KEYS = (('Hidden', ('true', 'false')),
                  ('X-GNOME-Autostart-enabled', ('false', 'true')))


def open_autostart_file():
    autostart_dir = BaseDirectory.save_config_path("autostart")
    autostart_file = os.path.join(autostart_dir, REDSHIFT_DESKTOP)

    if not os.path.exists(autostart_file):
        desktop_files = list(
            BaseDirectory.load_data_paths(
                "applications", REDSHIFT_DESKTOP))

        if not desktop_files:
            raise IOError("Installed redshift desktop file not found!")

        desktop_file_path = desktop_files[0]

        # Read installed file
        dfile = DesktopEntry.DesktopEntry(desktop_file_path)
        for key, values in AUTOSTART_KEYS:
            dfile.set(key, values[False])
        dfile.write(filename=autostart_file)
    else:
        dfile = DesktopEntry.DesktopEntry(autostart_file)

    return dfile, autostart_file


def supports_autostart():
    return has_xdg


def get_autostart():
    if not has_xdg:
        return False

    dfile, path = open_autostart_file()
    check_key, check_values = AUTOSTART_KEYS[0]
    return dfile.get(check_key) == check_values[True]


def set_autostart(active):
    if not has_xdg:
        return

    dfile, path = open_autostart_file()
    for key, values in AUTOSTART_KEYS:
        dfile.set(key, values[active])
    dfile.write(filename=path)


def setproctitle(title):
    """Set process title."""
    title_bytes = title.encode(sys.getdefaultencoding(), 'replace')
    buf = ctypes.create_string_buffer(title_bytes)
    if 'linux' in sys.platform:
        try:
            libc = ctypes.cdll.LoadLibrary("libc.so.6")
        except OSError:
            return
        try:
            libc.prctl(15, buf, 0, 0, 0)
        except AttributeError:
            return  # Strange libc, just skip this
    elif 'bsd' in sys.platform:
        try:
            libc = ctypes.cdll.LoadLibrary("libc.so.7")
        except OSError:
            return
        try:
            libc.setproctitle(ctypes.create_string_buffer(b"-%s"), buf)
        except AttributeError:
            return