#!/usr/bin/python3
# Toggle the brightness on the given randr output

import subprocess
import os
import os.path
import re
import random
import sys
import tempfile

class Display:
    index           = None
    name            = None
    offset          = None
    size            = None

    wall_filename   = None

    def __cmp__(self, other):
        if self.offset[1] != other.offset[1]:
            return cmp(self.offset[1], other.offset[1])
        return cmp(self.offset[0], other.offset[0])

def parse_outputs():
    outputs = {}

    p = subprocess.run(['xrandr', '--verbose'], check = True, capture_output = True,
                       encoding = 'utf-8')
    cur_output = None
    for line in p.stdout.splitlines():
        m = re.match(r'(\S*) connected.*', line)
        if m:
            cur_output = m.group(1)
            continue

        if 'Brightness:' in line:
            _, val = line.strip().split()
            outputs[cur_output] = float(val)
            cur_output = None

    return outputs

if len(sys.argv) < 2:
    sys.stderr.write('Usage: %s <output name>\n'%(sys.argv[0]))
    sys.exit(1)

output  = sys.argv[1]
outputs = parse_outputs()

if not output in outputs:
    sys.stderr.write('No such output: %s\n' % output)
    sys.exit(1)

val = 0.0 if outputs[output] == 1.0 else 1.0
subprocess.run(['xrandr', '--output', output, '--brightness', str(val)],
               check = True)