#!/usr/bin/env python3
# -*- python -*-
copyright='''
Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)

This program 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.

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
GNU General Public License for more details.

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

import os
import sys
import threading
from subprocess import Popen, PIPE


PROGRAM_NAME = 'nightshift'
'''
:str  The name of the program
'''

PROGRAM_VERSION = '1.0'
'''
:str  The version of the program
'''


## Set process title
def setproctitle(title):
    '''
    Set process title
    
    @param  title:str  The title of the process
    '''
    import ctypes
    try:
        # Remove path, keep only the file,
        # otherwise we get really bad effects, namely
        # the name title is truncates by the number
        # of slashes in the title. At least that is
        # the observed behaviour when using procps-ng.
        title = title.split('/')[-1]
        # Create strng buffer with title
        title = title.encode(sys.getdefaultencoding(), 'replace')
        title = ctypes.create_string_buffer(title)
        if 'linux' in sys.platform:
            # Set process title on Linux
            libc = ctypes.cdll.LoadLibrary('libc.so.6')
            libc.prctl(15, ctypes.byref(title), 0, 0, 0)
        elif 'bsd' in sys.platform:
            # Set process title on at least FreeBSD
            libc = ctypes.cdll.LoadLibrary('libc.so.7')
            libc.setproctitle(ctypes.create_string_buffer(b'-%s'), title)
    except:
        pass
setproctitle(sys.argv[0])


## Parse options
for arg in sys.argv[1:]:
    if arg in ('-V', '--version'):
        ## Print the version of nightshift and of redshift
        print('%s %s' % (PROGRAM_NAME, PROGRAM_VERSION))
        Popen(['redshift', '-V'], stdout = sys.stdout).wait()
        sys.exit(0)
    elif arg in ('-C', '--copyright'):
        ## Print copyright information
        print(copyright[1 : -1])
        sys.exit(0)
    elif arg in ('-W', '--warranty'):
        ## Print warranty disclaimer
        print(copyright.split('\n\n')[-2])
        sys.exit(0)
    elif arg in ('-h', '--help'):
        ## Display help message
        text = '''USAGE: nightshift [OPTIONS...] [-- REDSHIFT-OPTIONS...]
                  
                  Terminal user interface for redshift, a program for setting the colour
                  temperature of the display according to the time of day.
                  
                    -h --help                       Display this help message
                    -V --version                    Show program version
                    -C --copyright                  Show program copyright information
                    -W --warranty                   Show program warrantly disclaimer
                    
                    -d --daemon                     Start as daemon
                    -x --reset                      Reset mode (remove adjustment from screen)
                    +x --toggle                     Temporarily disable or enable adjustments
                    -s --status                     Print status information
                    
                    -c --config         FILE        Load settings from specified configuration file
                    -b --brightness     DAY:NIGHT   Screen brightness to set at daytime/night
                    -b --brightness     BRIGHTNESS  Screen brightness to apply
                    -t --temperature    DAY:NIGHT   Colour temperature to set at daytime/night
                    -t --temperature    TEMP        Colour temperature to apply
                    -l --location       LAT:LON     Your current location
                    -l --location       PROVIDER    Select provider for automatic location updates
                                                    (Type `list' to see available providers)
                    -m --method         METHOD      Method to use to set colour temperature
                                                    (Type `list' to see available methods)
                    -r --no-transition              Disable temperature transitions
                  
                  Please report bugs to <https://github.com/maandree/nightshift/issues>
               '''
        text = text.split('\n')[:-1]
        indent = min([len(line) - len(line.lstrip()) for line in text if line.rstrip().startswith(' ')])
        print('\n'.join([line[indent:] if line.startswith(' ') else line for line in text]))
        sys.exit(0)
    else:
        ## Unrecognised option
        sys.stderr.write('%s: error: unrecognised option: %s\n' % (sys.argv[0], arg))
        sys.exit(1)


proc = Popen(['redshift', '-v'], stdout = PIPE, stderr = open(os.devnull))
red_brightness, red_period, red_temperature, red_running = 1, 1, 6500, True
red_condition = threading.Condition()

def read_status():
    global red_brightness, red_period, red_temperature, red_running
    while True:
        got = proc.stdout.readline()
        if (got is None) or (len(got) == 0):
            break
        got = got.decode('utf-8', 'replace')[:-1]
        (key, value) = got.split(': ')
        red_condition.acquire()
        try:
            if key == 'Brightness':
                red_brightness = float(value)
            elif key == 'Period':
                if value == 'Night':
                    red_period = 0
                elif value == 'Daytime':
                    red_period = 1
                else:
                    red_period = float(value.split(' ')[1][1 : -1]) / 100
            elif key == 'Color temperature':
                red_temperature = float(value[:-1])
        except:
            pass
        red_condition.notify()
        red_condition.release()
    red_running = False

thread = threading.Thread(target = read_status)
thread.setDaemon(True)
thread.start()


while red_running:
    red_condition.acquire()
    red_condition.wait()
    print('%f: %f, %f' % (red_period, red_temperature, red_brightness))
    red_condition.release()