#!/usr/bin/python
"""
Author: Vertigo Designs, Ryan Summers

Description: Provides an API for controlling Booster NGFW over MQTT.
"""
import argparse
import asyncio

from . import BoosterApi, Action


# A dictionary of all the available commands, their number of arguments, argument type, and help
# information about the command.
CMDS = {
    'save': {
        'nargs': 0,
        'help': 'Save channel configuration',
    },
    'tune': {
        'nargs': 1,
        'type': float,
        'help': 'Tune the channel RF drain current to the specified amps',
    },
}

def parse_command(entry):
    """ Parse a command string into a command and arguments. """
    try:
        pieces = entry.split('=')
        assert 1 <= len(pieces) <= 2, 'Invalid command format'

        cmd = pieces[0]
        tail = pieces[1] if len(pieces) > 1 else None
        args = tail.split(',') if tail else []

        assert cmd in CMDS, f'Unknown command specified: {cmd}'
        assert CMDS[cmd]['nargs'] == len(args), \
            f'Invalid args specified. Expected {CMDS[cmd]["nargs"]}, but found {len(args)}'
        return (cmd, [CMDS[cmd]['type'](x) for x in args])

    except Exception as exception:
        raise Exception(f'Failed to parse command "{entry}": {exception}')


def main():
    """ Main program entry point. """
    parser = argparse.ArgumentParser(
        formatter_class=argparse.RawTextHelpFormatter,
        description='Modify booster RF channel configuration')
    parser.add_argument('--prefix', type=str, help='The prefix of the booster to configure')
    parser.add_argument('--channel', required=True, type=int, choices=range(8),
                        help='The RF channel index to control')
    parser.add_argument('--broker', default='mqtt', type=str, help='The MQTT broker address')

    command_help = 'Individual commands. Options:\n'
    for cmd, info in CMDS.items():
        line = f'{cmd}'
        if info['nargs'] == 1:
            line += '=x'
        if info['nargs'] == 2:
            line += '=x,y'

        command_help += f'{line:<30} | {info["help"]}\n'

    parser.add_argument('commands', nargs='+', help=command_help)

    async def channel_configuration(args):
        """ Configure an RF channel. """

        # Establish a communication interface with Booster.
        interface = await BoosterApi.create(args.prefix, args.broker)

        for command in args.commands:
            command, cmd_args = parse_command(command)
            if command == 'save':
                await interface.perform_action(Action.Save, args.channel)
                print(f'Channel {args.channel} configuration saved')
            elif command == 'tune':
                vgs, ids = await interface.tune_bias(args.channel, cmd_args[0])
                print(f'Channel {args.channel}: Vgs = {vgs:.3f} V, Ids = {ids * 1000:.2f} mA')

    loop = asyncio.get_event_loop()
    loop.run_until_complete(channel_configuration(parser.parse_args()))


if __name__ == '__main__':
    main()