#!/usr/bin/python

import os,sys
import math,shutil,re

VERSION="0.1"

def setup_options():
    ''' Setup the command line options '''
    from argparse import ArgumentParser

    parser=ArgumentParser(description="Splits files to subfolders equally.")
    
    parser.add_argument("--order",'-o',type=str,action='store', dest='order',default="sequence",
                      help="Splitting method:  sequence, sparse, regexp")
    parser.add_argument("-m",action='store_true', dest='move',default=False,
                      help="Move entries instead of hardlink.")
    parser.add_argument("-f",action='store_true', dest='files',default=False,
                      help="Split files only, skipping folders")
    parser.add_argument("-r",'--regexp',type=str,action='store', dest='regexp',default="",
                      help="Regular expression for splitting. When set, order regexp used, -n not used.")
    parser.add_argument("-n",'-N',type=int,action='store', dest='n',
                      help="Number of subfolders to split into.")                      
    parser.add_argument("path",type=str,action="store",default=".",nargs="?",
                      help="Folder to split.")
    options=parser.parse_args()
    if options.n==None and options.regexp=="":
        parser.print_help()
        parser.error("Either -n or -r must be passed")
    if options.regexp!="":
        options.order="regexp"
    return options

def linktree(src, dst):
    """Recursively link a directory tree using os.link.
       Modified from shutil.copytree 
    """
    names = os.listdir(src)
    os.makedirs(dst)
    errors = []
    for name in names:
        srcname = os.path.join(src, name)
        dstname = os.path.join(dst, name)
        try:
            if os.path.isdir(srcname):
                linktree(srcname, dstname)
            else:
                # Will raise a SpecialFileError for unsupported file types
                os.link(srcname, dstname)
        except Error, err:
            errors.extend(err.args[0])
        except EnvironmentError, why:
            errors.append((srcname, dstname, str(why)))

    if errors:
        raise Error, errors

def copyfileorfolder(basename,source,target,move):
    ''' Copies a file or folder structure under target folder '''
    if move:
        shutil.move(os.path.join(source,basename),os.path.join(target,basename))
        return
    if os.path.isfile(os.path.join(source,basename)):
        os.link(os.path.join(source,basename),os.path.join(target,basename))
        return
    if os.path.isdir(os.path.join(source,basename)):
        linktree(os.path.join(source,basename),os.path.join(target,basename))
        return
    raise RuntimeError(source+' was neither file nor folder.')

def portorder(inFiles,inFolder,outFolders,N,link):
    ''' Copy files in port order (sparse) '''
    outidx=0
    for row in inFiles:
        copyfileorfolder(row,inFolder,outFolders[outidx],link)
        outidx+=1
        if outidx+1>N:
            outidx=0

def fileorder(inFiles,inFolder,outFolders,N,link):
    ''' Copy files in input file order (sequnce)  '''

    bins=[int(math.floor(float(len(inFiles))/float(N)))]*int(N)
    binidx=0
    while sum(bins)<len(inFiles):
        bins[binidx]+=1
        binidx+=1
    offsets=list(offset(bins))
    offsets.insert(0,0)

    for outidx in range(N):
        for f in range(offsets[outidx], offsets[outidx]+bins[outidx]):
            copyfileorfolder(inFiles[f],inFolder,outFolders[outidx],link)

def regexorder(inFiles,inFolder,outFolders,matcher,uniqlabel,link):
    ''' Copy files by regex match '''
    
    for f in inFiles:
        m=matcher.search(f)
        if m:
            outidx=uniqlabel.index(m.group(1))
            copyfileorfolder(f,inFolder,outFolders[outidx],link)

def regexmatches(inFiles, opts):
    matcher=re.compile(opts.regexp)
    matches=[]
    skipped=0
    for f in inFiles:
        m=matcher.search(f)
        if m:
            matches.append(m.group(1))
        else:
            skipped+=1
    uniqlabel=sorted(set(matches))
    print("Unique matches",uniqlabel)
    print("Not matching %d files."% skipped)
    for x in uniqlabel:
        outFolders.append(os.path.join(opts.path,x))
    return (outFolders, uniqlabel, matcher)

def offset(it):
    total = 0
    for x in it:
        total += x
        yield total

def report(outFolders):
    for x in outFolders:
        n=len(os.listdir(x))
        print( os.path.basename( x )+":"+str(n) )

''' Splits a folder input in N outputs '''
options=setup_options()
outFolders=[]
method = options.order.lower().strip()
if method not in ('sparse','sequence','regexp'):
    print("Writing order: \""+method+"\" not recognized.")
    sys.exit(1)
# list files, and remove hidden  (.files)
inFiles=sorted(filter(lambda x: not x.startswith('.'), os.listdir(options.path)))
if options.files:
    inFiles=[ f for f in inFiles if os.path.isfile( os.path.join( options.path, f ) ) ]

if method=='regexp':
    (outFolders, uniqlabel, matcher)=regexmatches(inFiles, options)
    raw_input("correct?")
else:
    for x in range(options.n):
        outFolders.append(os.path.join(options.path,'folder'+str(x+1)))

for x in outFolders:
    if not os.path.isdir(x):
        os.mkdir(x)

if method=='regexp':
    regexorder(inFiles,options.path,outFolders,matcher,uniqlabel,options.move)
if method=='sparse':
    portorder(inFiles,options.path,outFolders,options.n,options.move)
if method=='sequence':
    fileorder(inFiles,options.path,outFolders,options.n,options.move)

report(outFolders)