#!/usr/bin/env python
'''
Usage: splitpea MODE [OPTIONS] FILE

Modes:
  -s, --split            Splits the file specifed by FILE, naming each
                         piece FILE.001, FILE.002, ...
  -j, --join             Joins pieces named FILE.001, FILE.002, ... into
                         a single file named FILE.

Split Mode Options:
  -b SIZE, --bytes=SIZE  Outputs pieces of SIZE bytes, default is 1m.

SIZE may have a multiplier suffix: b for 512 bytes, k for kilobytes, m for
megabytes.

General Options:
  -?, -h, --help         Show this help.
  --version              Show the program version.
  -v, --verbose          Displays more information while running
'''

__title__ = 'splitpea'
__author__ = 'Gordon Tyler'
__version__ = '1.0'

import sys
import os.path
import getopt
import string

def printVersion():
    print '%s version %s' % (__title__, __version__)

def printHeader():
    printVersion()
    print 'Copyright (C) 1999, %s' % __author__
    print 'This may be free distributed under the terms of the GNU GPL.'
    print

def printUsage(errorMessage = ''):
    printHeader()

    if errorMessage != '':
        print 'Error: %s' % errorMessage

    print __doc__
    return

def printError(errorMessage):
    print '%s: %s' % (__title__, message)

def main(args):
    try:
        options, args = getopt.getopt(args, '?hsjb:v', ['help', 'split', 'join', 'bytes=', 'version', 'verbose'])
    except getopt.error, detail:
        printError(detail)
        return

    splitSize =  1048576 
    mode = ''
    verbose =  0 

    for option in options:
        if option[ 0 ] == '-?' or option[ 0 ] == '-h' or option[ 0 ] == '--help':
            printUsage()
            return
        elif option[ 0 ] == '--version':
            printVersion()
        elif option[ 0 ] == '-s' or option[ 0 ] == '--split':
            mode = 'split'
        elif option[ 0 ] == '-j' or option[ 0 ] == '--join':
            mode = 'join'
        elif option[ 0 ] == '-b' or option[ 0 ] == '--bytes':
            suffix = option[ 1 ][- 1 :]
            if string.count('bkm', suffix) >  0 :
                splitSize = int(option[ 1 ][:- 1 ])
                if suffix == 'b':
                    splitSize = splitSize *  512 
                elif suffix == 'k':
                    splitSize = splitSize *  1024 
                elif suffix == 'm':
                    splitSize = splitSize *  1048576 
                else:
                    printUsage('Unrecognised size suffix.')
                    return
            else:
                splitSize = int(option[ 1 ])
        elif option[ 0 ] == '-v' or option[ 0 ] == '--verbose':
            verbose =  1 
            
    if mode == '':
        printUsage('Must specify a mode')
        return
    
    if mode == 'split':
        if len(args) ==  0 :
            printUsage('Must specify a file to split')
            return

        if not os.path.exists(args[ 0 ]):
            printError('%s: No such file' % args[ 0 ])
            return
        
        inputFilename = args[ 0 ]
        
        try:
            input = open(inputFilename, 'rb')
        except IOError, detail:
            printError(detail)
            return

        outputCount =  1 

        try:
            data = input.read(splitSize)
            while (len(data) >  0 ):
                outputFilename = inputFilename + '.%03d' % outputCount

                if verbose >  0 :
                    print 'Writing piece: %s... ' % outputFilename,

                output = open(outputFilename, 'wb')
                output.write(data)
                output.close()
                outputCount = outputCount +  1 
                data = input.read(splitSize)

                if verbose >  0 :
                    print 'done.'
        except IOError, detail:
            printError(detail)

        input.close()
    elif mode == 'join':
        if len(args) ==  0 :
            printUsage('Must specify the original split filename')
            return

        prefix = args[ 0 ]

        try:
            output = open(prefix, 'wb')
        except IOError, detail:
            printError(detail)
            return

        done =  0 
        inputCount =  1 

        while (not done):
            inputFilename = prefix + '.%03d' % inputCount
            if os.path.exists(inputFilename):
                try:
                    if verbose >  0 :
                        print 'Reading piece: %s... ' % inputFilename,
                        
                    input = open(inputFilename, 'rb')
                    data = input.read()
                    output.write(data)
                    input.close()

                    if verbose >  0 :
                        print 'done.'
                except IOError, detail:
                    printError(detail)
                    return

                inputCount = inputCount +  1 
            else:
                done =  1 

        output.close()
        
    return

if __name__ == '__main__':
    main(sys.argv[ 1 :])