#!/usr/bin/env python3

import argparse
import json
import logging
from os.path import expanduser
import subprocess

import dialog


class NoMatchingProfile(ValueError):
    pass


class LogLevel:
    def __init__(self, value: str) -> None:
        try:
            self.numerical_level = logging.getLevelNamesMapping()[value.upper()]
        except KeyError:
            raise ValueError("invalid value")


class MonitorMenu():
    def __init__(self, config_file='~/.config/monitor-profiles.json'):
        with open(expanduser(config_file)) as fh:
            self.profiles = json.load(fh)
        self.d = dialog.Dialog(autowidgetsize=True)

    def run(self, profile_idx=None):
        choices = []

        if profile_idx is None:
            i = 0
            for p in self.profiles:
                choices.append((str(i), p['name']))
                i += 1

            code, profile_idx = self.d.menu(
                    'Select the profile you want to use.',
                    choices=choices)

            if code in (self.d.ESC, self.d.CANCEL):
                return

        try:
            profile = self.profiles[int(profile_idx)]
        except IndexError:
            raise NoMatchingProfile from None

        # We build the command line starting from just "xrandr" and adding
        # arguments.
        xrandr_cmd = ['xrandr']
        feh_cmd = ['feh', '--bg-fill']

        try:
            xrandr_cmd += profile['xrandr-opts']
        except KeyError:
            pass

        for monitor in profile['monitors']:
            xrandr_cmd.extend(monitor['xrandr-opts'])

            if monitor.get('background') is not None:
                feh_cmd.append(monitor['background'])

        logging.debug("Executing: %s", xrandr_cmd)
        subprocess.run(xrandr_cmd, check=False)
        logging.debug("Executing: %s", feh_cmd)
        subprocess.run(feh_cmd, check=False)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--log-level", "--loglevel", type=LogLevel, default="info")
    parser.add_argument("--index", type=int, required=False)
    args = parser.parse_args()
    logging.basicConfig(level=args.log_level.numerical_level)

    menu = MonitorMenu()

    if args.index is not None:
        menu.run(profile_idx=args.index)
    else:
        menu.run()


if __name__ == '__main__':
    main()