#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
#  gameshell.py
#  
#  Copyright 2018 chees <chees@DESKTOP-0CA7MCF>
#  
#  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 2 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, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#  
#  Ver. 0.1.0017


import types as _types
import traceback as _tb

class Shell(object):
    
    def __init__(self):
        self.__commands = {'exit': self.exitShell}
        self.__aliases = {}
        self.ps1 = '> '
        self.ps2 = '> '
        self.__exit = False
        
    def run(self):
        """The main game/shell loop"""
        while not self.__exit:
            print(self.ps1, end = '')
            command = self.scanInput()
            # we have to handle shell built-ins first (when we get some)
            if len(command) == 0:
                continue
            if command[0] in self.__commands:
                try:
                    self.__commands[command[0]](command[1:])
                except Exception as e:
                    _tb.print_exc()
                    print(e)
            else:
                self.handleUnknownCommand(command)
            self.update()
            
    def man(self, args):
        help(self.__commands[args[0]])
                
    def registerCommand(self, commandName: str, command: _types.FunctionType):
        """command must be a function that takes one argument: a list of strings,
conventionally called args or argv"""
        self.__commands[commandName] = command
        
    def registerAlias(self, a: str, original: list):
        """makes 'a' an alias for original.
'a' must be one token, but original can be multiple."""
        self.__aliases[a] = original
        
    def getAlias(self, a: str):
        if a in self.__aliases:
            return self.__aliases[a]
        else:
            return None
        
    def exitShell(self, args):
        """The default exit command."""
        self.__exit = True
        
    # Beyond this point are functions that are called within the main loop.
    def scanInput(self):
        """Parses input. Override this for custom input parsing, or input source."""
        ret = input()
        if ret == '':
            return []
        ret = ret.split()
        a = self.getAlias(ret[0])
        if a:
            ret = a[:] + ret[1:]
        return ret
        
    def handleUnknownCommand(self, command):
        """Handle commands that aren't registered. Override this if you want to do
something with those commands."""
        print("Bad command.")
        
    def update(self):
        """Runs at the end of each loop. Does nothing by default. Override this if
there is something you want the shell to do between every command."""
        pass

def main(args):
    return 0

if __name__ == '__main__':
    import sys
    sys.exit(main(sys.argv))