#!/usr/bin/env python

import os
import sys
from encodings import aliases
try:
    set
except NameError:
    from sets import Set as set
    
def usage():
    print """Usage: %s inencoding outencoding [filein|-] [fileout|-]
List of supported encodings:
 http://docs.python.org/lib/standard-encodings.html

Usage2: %s [list|listencondings]

Examples:
 echo abcd |  pyrecode ascii base64 - -
 pyrecode latin1 utf8 myscript.py out.py
 """ % (
        os.path.basename(sys.argv[0]),
        os.path.basename(sys.argv[0])
        )

def error(exc, mystr):
    print exc
    part=mystr[max(exc.start-10, 0):min(exc.end+10, len(mystr))]
    print "Error in part: start: %s end: %s len(): %s %r" % (
        exc.start, exc.end, len(mystr), part)
    
def main():
    if len(sys.argv)==2 and sys.argv[1].startswith("list"):
        encs=list(set(aliases.aliases.values()))
        encs.sort()
        print ' '.join(encs)
        sys.exit(0)
    if not len(sys.argv)==5:
        usage()
        sys.exit(2)
    inenc, outenc, filein, fileout = sys.argv[1:]
    if filein=="-":
        fd=sys.stdin
    else:
        fd=open(filein, "rb")
    bytesin=fd.read()
    fd.close()
    try:
        unistr=bytesin.decode(inenc)
    except UnicodeDecodeError, exc:
        print "Error while decoding (%s to unicode)" % inenc
        error(exc, bytesin)
        sys.exit(1)
    try:
        outstr=unistr.encode(outenc)
    except UnicodeEncodeError, exc:
        print "Error while encoding (unicode to %s)" % outenc
        error(exc, unistr)
        sys.exit(1)
    if fileout=="-":
        fd=sys.stdout
    else:
        fd=open(fileout, "wb")
    fd.write(outstr)
    fd.close()
    
if __name__=="__main__":
    main()