#!/usr/bin/env python3
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 Affero 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 Affero General Public License for more details.

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

from argparser import *


PROGRAM_NAME = 'blueshift'
PROGRAM_VERSION = '1.0'


## Set global variables
global DATADIR, i_size, o_size, r_curve, g_curve, b_curve, clip_result, reset, panicgate
global periodically, wait_period, fadein_time, fadeout_time, fadein_steps, fadeout_steps
global monitor_controller, running, continuous_run, panic
global signal_SIGTERM


from solar import *
from curve import *
from colour import *
from monitor import *


config_file = None


periodically = None
'''
:(int, int, int, int, int, int, int, float?)?→void  Place holder for periodically invoked function

Invoked periodically

If you want to control at what to invoke this function next time
you can set the value of the global variable `wait_period` to the
number of seconds to wait before invoking this function again.
The value does not need to be an integer.

@param   year:int     The year
@param   month:int    The month, 1 = January, 12 = December
@param   day:int      The day, minimum value is 1, probable maximum value is 31 (*)
@param   hour:int     The hour, minimum value is 0, maximum value is 23
@param   minute:int   The minute, minimum value is 0, maximum value is 59
@param   second:int   The second, minimum value is 0, probable maximum value is 60 (**)
@param   weekday:int  The weekday, 1 = Monday, 7 = Sunday
@param   fade:float?  Blueshift can use this function to fade into a state when it start
                      or exits. `fade` can either be negative, zero or positive or `None`,
                      but the magnitude of value cannot exceed 1. When Blueshift starts,
                      the this function will be invoked multiple with the time parameters
                      of the time it is invoked and each time `fade` will increase towards
                      1, starting at 0, when the value is 1, the settings should be applied
                      to 100 %. After this this function will be invoked once again with
                     `fade` being `None`. When Blueshift exits the same behaviour is used
                      except, `fade` decrease towards -1 but start slightly below 0, when
                      -1 is reached all settings should be normal. Then Blueshift will NOT
                      invoke this function with `fade` being `None`, instead it will by
                      itself revert all settings and quit.

(*)  Can be exceeded if the calendar system is changed, like in 1712-(02)Feb-30
(**) See https://en.wikipedia.org/wiki/Leap_second
'''

wait_period = 60
'''
:float  The number of seconds to wait before invoking `periodically` again
'''

monitor_controller = lambda : randr()
'''
:()→void  Function used by Blueshift on exit to apply reset colour curves, if using preimplemented `reset`
'''

fadein_time = 2
'''
:float?  The number of seconds used to fade in on start, `None` for no fading
'''

fadeout_time = 2
'''
:float?  The number of seconds used to fade out on exit, `None` for no fading
'''

fadein_steps = 40
'''
:int  The number of steps in the fade in phase, if any
'''

fadeout_steps = 40
'''
:int  The number of steps in the fade out phase, if any
'''

panicgate = False
'''
:bool  `True` if translition into initial state should be skipped
'''

running = True
'''
:bool  `True` while to program has not received a terminate signal
'''

panic = False
'''
:bool  `True` if the program has received two terminate signals
'''

conf_opts = None
'''
:list<str>  This list will never be `None` and it will always have at least
            one element. This list is filled with options passed to the
            configurations, with the first element being the configuration file
'''

def reset():
    '''
    Invoked to reset the displays
    '''
    start_over()
    monitor_controller()



def signal_SIGTERM(signum, frame):
    '''
    Signal handler for SIGTERM
    
    @param  signum  The signal number, 0 if called from the program itself
    @param  frame   Ignore, it will probably be `None`
    '''
    global running, panic
    if not running:
        panic = True
    running = False


def continuous_run():
    '''
    Invoked to run continuously if `periodically` is not `None`
    '''
    global running, wait_period, fadein_time, fadeout_time, fadein_steps, fadeout_steps
    def p(t, fade = None):
        try:
            wd = t.isocalendar()[2]
            periodically(t.year, t.month, t.day, t.hour, t.minute, t.second, wd, fade)
        except:
            signal_SIGTERM(0, None)
    def sleep(seconds):
        try:
            time.sleep(seconds)
        except KeyboardInterrupt:
            signal_SIGTERM(0, None)
    
    ## Catch signals
    signal.signal(signal.SIGTERM, signal_SIGTERM)
    
    ## Fade in
    early_exit = False
    ftime = 0
    if (fadein_time is not None) and not panicgate:
        dtime = fadein_time / fadein_steps
        df = 1 / fadein_steps
        while running:
            ftime += df
            if ftime > 1:
                break
            p(datetime.datetime.now(), ftime)
            sleep(dtime)
        if ftime <= 1:
            early_exit = True
    
    ## Run periodically
    if not early_exit:
        while running:
            p(datetime.datetime.now(), None)
            if running:
                sleep(wait_period)
    
    ## Fade out
    if fadeout_time is not None:
        dtime = fadeout_time / fadeout_steps
        df = 1 / fadeout_steps
        if not early_exit:
            ftime = 1
        while not panic:
            ftime -= df
            if ftime <= 0:
                break
            p(datetime.datetime.now(), -ftime)
            sleep(dtime)
    
    ## Reset
    reset()


## Read command line arguments
parser =  ArgParser('Colour temputare controller',
                    sys.argv[0] + ' [options] [-- configuration-options]',
                    'Blueshift adjusts the colour temperature of your\n'
                    'monitor according to brightness outside to reduce\n'
                    'eye strain and make it easier to fall asleep when\n'
                    'going to bed. IT can also be used to increase the\n'
                    'colour temperature and make the monitor bluer,\n'
                    'this helps you focus on your work.',
                    None, True, ArgParser.standard_abbreviations())

dn = '\nUse twice or daytime and nighttime respectively'
parser.add_argumented(['-c', '--configurations'], 0, 'FILE', 'Select configuration file')
parser.add_argumentless(['-p', '--panic-gate', '--panicgate'], 0, 'Skip transition into initial settings')
parser.add_argumented(['-g', '--gamma'], 0, 'RGB|R:G:B', 'Set gamma correction' + dn)
parser.add_argumented(['-b', '--brightness'], 0, 'RGB|R:G:B', 'Set brightness using sRGB' + dn)
parser.add_argumented(['+b', '++brightness'], 0, 'Y', 'Set brightness using CIE xyY' + dn)
parser.add_argumented(['-t', '--temperature'], 0, 'TEMP', 'Set colour temperature' + dn)
parser.add_argumented(['-l', '--location'], 0, 'LAT:LON', 'Select your GPS location\n'
                                                          'Measured in degrees, negative for south or west')
parser.add_argumentless(['-r', '--reset'], 0, 'Reset to default settings')
parser.add_argumented(['-o', '--output', '--crtc'], 0, 'CRTCS',
                      'Select CRTC to apply changes to\nComma separated or multiple options\n'
                      'It is best to start one instance per monitor with colour calibration')
parser.add_argumentless(['-h', '-?', '--help'], 0, 'Print this help information')
parser.add_argumentless(['-C', '--copying', '--copyright'], 0, 'Print copyright information')
parser.add_argumentless(['-W', '--warranty'], 0, 'Print warranty information')
parser.add_argumentless(['-v', '--version'], 0, 'Print program name and version')

parser.parse()
parser.support_alternatives()

if parser.opts['--help'] is not None:
    parser.help()
    sys.exit(0)
elif parser.opts['--copyright'] is not None:
    print(copyright[1 : -1])
    sys.exit(0)
elif parser.opts['--warranty'] is not None:
    print('This program is distributed in the hope that it will be useful,')
    print('but WITHOUT ANY WARRANTY; without even the implied warranty of')
    print('MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the')
    print('GNU Affero General Public License for more details.')
    sys.exit(0)
elif parser.opts['--version'] is not None:
    print('%s %s' % (PROGRAM_NAME, PROGRAM_VERSION))
    sys.exit(0)

a = lambda opt : opt[0] if opt is not None else None
config_file = a(parser.opts['--configurations'])
panicgate = parser.opts['--panicgate'] is not None
doreset = parser.opts['--reset'] is not None
location = a(parser.opts['--location'])
gammas = parser.opts['--gamma']
rgb_brightnesses = parser.opts['--brightness']
cie_brightnesses = parser.opts['++brightness']
temperatures = parser.opts['--temperature']
output = parser.opts['--output']
if output is None:
    output = []


settings = [gammas, rgb_brightnesses, cie_brightnesses, temperatures]
if (config_file is None) and any([doreset, location] + settings):
    ## Use one time configurations
    d = lambda a, default : [default, default] if a is None else (a * 2 if len(a) == 1 else a)
    continuous = any(map(lambda a : (a is not None) and (len(a) == 2), settings))
    continuous = continuous or (location is not None)
    gammas = d(gammas, "1:1:1")
    rgb_brightnesses = d(rgb_brightnesses, "1")
    cie_brightnesses = d(cie_brightnesses, "1")
    if temperatures is None:
        temperatures = ['3700', '6500']
    elif len(temperatures) == 1:
        temperatures *= 2
    settings = [gammas, rgb_brightnesses, cie_brightnesses, temperatures, [location]]
    settings = [None if c is None else [[float(y) for y in x.split(':')] for x in c] for c in settings]
    [gammas, rgb_brightnesses, cie_brightnesses, temperatures, location] = settings
    location = None if location is None else location[0]
    alpha = lambda : 1
    if continuous:
        if location is not None:
            alpha = lambda : sun(*location)
        else:
            def alpha_():
                now = datetime.datetime.now()
                hh, mm = now.hour, now.minute + now.second / 60
                if 12 <= hh <= 22:
                    return 1 - (hh - 12) / (22 - 12) - mm / 60
                if hh <= 12:
                    hh += 22 - 12
                return (hh - 22) / 14 + m / 60
            alpha = alpha_
    def reduce(f, items):
        if len(items) < 2:
            return items
        rc = items[0]
        for i in range(1, len(items)):
            rc = f(rc, items[i])
        return rc
    output = reduce(lambda x, y : x + y, [a.split(',') for a in output])
    monitor_controller = lambda : randr(*output)
    def apply(dayness, pureness):
        start_over()
        interpol_ = lambda d, p, a, r : d * r + (p[0] * a + p[1] * (1 - a)) * (1 - r)
        interpol = lambda d, p : [interpol_(d, [p[0][i], p[1][i]], dayness, pureness) for i in range(len(p[0]))]
        temperature(*interpol(6500, temperatures), algorithm = lambda t : divide_by_maximum(cmf_10deg(t)))
        rgb_brightness(*interpol(1, rgb_brightnesses))
        cie_brightness(*interpol(1, cie_brightnesses))
        clip()
        gamma(*interpol(1, gammas))
        clip()
        monitor_controller()
    if continuous and not doreset:
        def periodically(year, month, day, hour, minute, second, weekday, fade):
            apply(alpha(), 0 if fade is None else 1 - abs(fade))
    else:
        if not panicgate:
            signal.signal(signal.SIGTERM, signal_SIGTERM)
            trans = 0
            while running:
                apply(alpha(), trans if doreset else 1 - trans)
                trans += 0.05
                time.sleep(0.1)
                if trans >= 1:
                    break
        apply(alpha(), 1 if doreset else 0)
else:
    ## Load extension and configurations via blueshiftrc
    if config_file is None:
        for file in ('$XDG_CONFIG_HOME/%/%rc', '$HOME/.config/%/%rc', '$HOME/.%rc', '/etc/%rc'):
            file = file.replace('%', 'blueshift')
            for arg in ('XDG_CONFIG_HOME', 'HOME'):
                if '$' + arg in file:
                    if arg in os.environ:
                        file = file.replace('$' + arg, os.environ[arg].replace('$', '\0'))
                    else:
                        file = None
                        break
            if file is not None:
                file = file.replace('\0', '$')
                if os.path.exists(file):
                    config_file = file
                    break
    conf_opts = [config_file] + parser.files
    if config_file is not None:
        code = None
        with open(file, 'rb') as script:
            code = script.read()
        code = code.decode('utf8', 'error') + '\n'
        code = compile(code, file, 'exec')
        g, l = globals(), dict(locals())
        for key in l:
            g[key] = l[key]
        exec(code, g)
    else:
        print('No configuration file found')
        sys.exit(1)


## Run periodically if configured to
if periodically is not None:
    continuous_run()

close_c_bindings()