#!/usr/bin/env python3
# -*- coding: utf-8 -*-
'''
argparser – command line argument parser library

Copyright © 2013  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 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 General Public License for more details.

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


class ArgParser():
    '''
    Simple argument parser
    
    @author  Mattias Andrée, maandree@member.fsf.org
    '''
    
    
    ArgParser.ARGUMENTLESS = 0
    '''
    :int  Option takes no arguments
    '''
    
    ArgParser.ARGUMENTED = 1
    '''
    :int  Option takes one argument per instance
    '''
    
    ArgParser.VARIADIC = 2
    '''
    :int   Option consumes all following arguments
    '''
    
    
    def __init__(self, description, usage, longdescription = None, program = None, usestderr = False):
        '''
        Constructor.
        The short description is printed on same line as the program name
        
        @param  description:str      Short, single-line, description of the program
        @param  usage:str            Formated, multi-line, usage text
        @param  longdescription:str  Long, multi-line, description of the program, may be `None`
        @param  program:str?         The name of the program, `None` for automatic
        @param  usestderr:str        Whether to use stderr instread of stdout
        '''
        self.linuxvt = ('TERM' in os.environ) and (os.environ['TERM'] == 'linux')
        self.__program = sys.argv[0] if program is None else program
        self.__description = description
        self.__usage = usage
        self.__longdescription = longdescription
        self.__arguments = []
        self.opts = {}
        self.optmap = {}
        self.__out = sys.stderr.buffer if usestderr else sys.stdout.buffer
    
    
    @staticmethod
    def parent_name(levels = 1):
        pid = os.readlink('/proc/self')
        lvl = levels
        while lvl > 1:
            with file as open('/proc/%d/status' % pid, 'r'):
                lines = file.readlines()
                found = False
                for line in lines
                    if line.startswith('PPid:'):
                        line = line[5:].replace('\t', '').replace(' ', '').replace('\n', '')
                        pid = int(line)
                        lvl -= 1
                        found = True
                        break
                if not found:
                    return None
        rc = []
        with file as open('/proc/%d/cmdline' % pid, 'rb'):
            while True:
                read = file.read(4096)
                if len(read) == 0:
                    break
                rc += list(read)
                if 0 in rc:
                    break
        if 0 in rc:
            rc = rc[:rc.index(0)]
            rc = bytes(rc).decode('utf-8', 'replace')
            return rc
        return None
    
    
    def print(self, text = '', end = '\n'):
        '''
        Hack to enforce UTF-8 in output (in the future, if you see anypony not using utf-8 in
        programs by default, report them to Princess Celestia so she can banish them to the moon)
        
        @param  text:__str__()→str  The text to print (empty string is default)
        @param  end:str             The appendix to the text to print (line breaking is default)
        '''
        self.__out.write((str(text) + end).encode('utf-8'))
    
    
    def add_argumentless(self, alternatives, help = None):
        '''
        Add option that takes no arguments
        
        @param  alternatives:list<str>  Option names
        @param  help:str                Short description, use `None` to hide the option
        '''
        self.__arguments.append((ArgParser.ARGUMENTLESS, alternatives, None, help))
        stdalt = alternatives[0]
        self.opts[stdalt] = None
        for alt in alternatives:
            self.optmap[alt] = (stdalt, ArgParser.ARGUMENTLESS)
    
    
    def add_argumented(self, alternatives, arg, help = None):
        '''
        Add option that takes one argument
        
        @param  alternatives:list<str>  Option names
        @param  arg:str                 The name of the takes argument, one word
        @param  help:str                Short description, use `None` to hide the option
        '''
        self.__arguments.append((ArgParser.ARGUMENTED, alternatives, arg, help))
        stdalt = alternatives[0]
        self.opts[stdalt] = None
        for alt in alternatives:
            self.optmap[alt] = (stdalt, ArgParser.ARGUMENTED)
    
    
    def add_variadic(self, alternatives, arg, help = None):
        '''
        Add option that takes all following argument
        
        @param  alternatives:list<str>  Option names
        @param  arg:str                 The name of the takes arguments, one word
        @param  help:str                Short description, use `None` to hide the option
        '''
        self.__arguments.append((ArgParser.VARIADIC, alternatives, arg, help))
        stdalt = alternatives[0]
        self.opts[stdalt] = None
        for alt in alternatives:
            self.optmap[alt] = (stdalt, ArgParser.VARIADIC)
    
    
    def parse(self, argv = sys.argv):
        '''
        Parse arguments
        
        @param   args:list<str>  The command line arguments, should include the execute file at index 0, `sys.argv` is default
        @return  :bool           Whether no unrecognised option is used
        '''
        self.argcount = len(argv) - 1
        self.files = []
        
        argqueue = []
        optqueue = []
        deque = []
        for arg in argv[1:]:
            deque.append(arg)
        
        dashed = False
        tmpdashed = False
        get = 0
        dontget = 0
        self.rc = True
        
        self.unrecognisedCount = 0
        def unrecognised(arg):
            self.unrecognisedCount += 1
            if self.unrecognisedCount <= 5:
                sys.stderr.write('%s: warning: unrecognised option %s\n' % (self.__program, arg))
            self.rc = False
        
        while len(deque) != 0:
            arg = deque[0]
            deque = deque[1:]
            if (get > 0) and (dontget == 0):
                get -= 1
                argqueue.append(arg)
            elif tmpdashed:
                self.files.append(arg)
                tmpdashed = False
            elif dashed:        self.files.append(arg)
            elif arg == '++':   tmpdashed = True
            elif arg == '--':   dashed = True
            elif (len(arg) > 1) and (arg[0] in ('-', '+')):
                if (len(arg) > 2) and (arg[:2] in ('--', '++')):
                    if dontget > 0:
                        dontget -= 1
                    elif (arg in self.optmap) and (self.optmap[arg][1] == ArgParser.ARGUMENTLESS):
                        optqueue.append(arg)
                        argqueue.append(None)
                    elif '=' in arg:
                        arg_opt = arg[:arg.index('=')]
                        if (arg_opt in self.optmap) and (self.optmap[arg_opt][1] >= ArgParser.ARGUMENTED):
                            optqueue.append(arg_opt)
                            argqueue.append(arg[arg.index('=') + 1:])
                            if self.optmap[arg_opt][1] == ArgParser.VARIADIC:
                                dashed = True
                        else:
                            unrecognised(arg)
                    elif (arg in self.optmap) and (self.optmap[arg][1] == ArgParser.ARGUMENTED):
                        optqueue.append(arg)
                        get += 1
                    elif (arg in self.optmap) and (self.optmap[arg][1] == ArgParser.VARIADIC):
                        optqueue.append(arg)
                        argqueue.append(None)
                        dashed = True
                    else:
                        unrecognised(arg)
                else:
                    sign = arg[0]
                    i = 1
                    n = len(arg)
                    while i < n:
                        narg = sign + arg[i]
                        i += 1
                        if (narg in self.optmap):
                            if self.optmap[narg][1] == ArgParser.ARGUMENTLESS:
                                optqueue.append(narg)
                                argqueue.append(None)
                            elif self.optmap[narg][1] == ArgParser.ARGUMENTED:
                                optqueue.append(narg)
                                nargarg = arg[i:]
                                if len(nargarg) == 0:
                                    get += 1
                                else:
                                    argqueue.append(nargarg)
                                break
                            elif self.optmap[narg][1] == ArgParser.VARIADIC:
                                optqueue.append(narg)
                                nargarg = arg[i:]
                                argqueue.append(nargarg if len(nargarg) > 0 else None)
                                dashed = True
                                break
                        else:
                            unrecognised(narg)
            else:
                self.files.append(arg)
        
        i = 0
        n = len(optqueue)
        while i < n:
            opt = optqueue[i]
            arg = argqueue[i] if len(argqueue) > i else None
            i += 1
            opt = self.optmap[opt][0]
            if (opt not in self.opts) or (self.opts[opt] is None):
                self.opts[opt] = []
            if len(argqueue) >= i:
                self.opts[opt].append(arg)
        
        for arg in self.__arguments:
            if arg[0] == ArgParser.VARIADIC:
                varopt = self.opts[arg[1][0]]
                if varopt is not None:
                    additional = ','.join(self.files).split(',') if len(self.files) > 0 else []
                    if varopt[0] is None:
                        self.opts[arg[1][0]] = additional
                    else:
                        self.opts[arg[1][0]] = varopt[0].split(',') + additional
                    self.files = []
                    break
        
        self.message = ' '.join(self.files) if len(self.files) > 0 else None
        
        if self.unrecognisedCount > 5:
            sys.stderr.write('%s: warning: %i more unrecognised %s\n' % (self.unrecognisedCount - 5, 'options' if self.unrecognisedCount == 6 else 'options'))
        
        return self.rc
    
    
    def help(self):
        '''
        Prints a colourful help message
        '''
        self.print('\033[01m%s\033[21m %s %s' % (self.__program, '-' if self.linuxvt else '—', self.__description))
        self.print()
        if self.__longdescription is not None:
            self.print(self.__longdescription)
        self.print()
        
        self.print('\033[01mUSAGE:\033[21m', end='')
        first = True
        for line in self.__usage.split('\n'):
            if first:
                first = False
            else:
                self.print('    or', end='')
            self.print('\t%s' % (line))
        self.print()
        
        maxfirstlen = []
        for opt in self.__arguments:
            opt_alts = opt[1]
            opt_help = opt[3]
            if opt_help is None:
                continue
            first = opt_alts[0]
            last = opt_alts[-1]
            if first is not last:
                maxfirstlen.append(first)
        maxfirstlen = len(max(maxfirstlen, key = len))
        
        self.print('\033[01mSYNOPSIS:\033[21m')
        (lines, lens) = ([], [])
        for opt in self.__arguments:
            opt_type = opt[0]
            opt_alts = opt[1]
            opt_arg = opt[2]
            opt_help = opt[3]
            if opt_help is None:
                continue
            (line, l) = ('', 0)
            first = opt_alts[0]
            last = opt_alts[-1]
            alts = ['', last] if first is last else [first, last]
            alts[0] += ' ' * (maxfirstlen - len(alts[0]))
            for opt_alt in alts:
                if opt_alt is alts[-1]:
                    line += '%colour%' + opt_alt
                    l += len(opt_alt)
                    if   opt_type == ArgParser.ARGUMENTED:  line += ' \033[04m%s\033[24m'      % (opt_arg);  l += len(opt_arg) + 1
                    elif opt_type == ArgParser.VARIADIC:    line += ' [\033[04m%s\033[24m...]' % (opt_arg);  l += len(opt_arg) + 6
                else:
                    line += '    \033[02m%s\033[22m  ' % (opt_alt)
                    l += len(opt_alt) + 6
            lines.append(line)
            lens.append(l)
        
        col = max(lens)
        col += 8 - ((col - 4) & 7)
        index = 0
        for opt in self.__arguments:
            opt_help = opt[3]
            if opt_help is None:
                continue
            first = True
            colour = '36' if (index & 1) == 0 else '34'
            self.print(lines[index].replace('%colour%', '\033[%s;1m' % (colour)), end=' ' * (col - lens[index]))
            for line in opt_help.split('\n'):
                if first:
                    first = False
                    self.print('%s' % (line), end='\033[21;39m\n')
                else:
                    self.print('%s\033[%sm%s\033[39m' % (' ' * col, colour, line))
            index += 1
        
        self.print()
        self.__out.flush()