import os

VersionNum = 'ALPHA'


def GetDirectorySize(directory):
    """
    Returns interger / float
    Returns the size (in btyes) of a given directory or file.
    """

    tmpTotalBytez = 0 #Variable to store culumative size of directory.

    #check if directory is in fact a directory (and not a file).
    if os.path.isdir(directory):

        #walk through directory and each sub directory and add size of each file.
        for root, dirs, files in os.walk(directory):
            for file in files:
                try:
                    tmpTotalBytez += os.path.getsize(root + '\\' + file)
                except:
                    pass #Probably because of access denied: TODO: implement a way to track these.

    #check is directory is a file.
    elif os.path.isfile(directory):
        tmpTotalBytez = os.path.getsize(directory)

    return tmpTotalBytez

def ClearScreen():
    """
    Clears the whole console screen
    """

    if os.name == "posix":
        # Unix/Linux/MacOS/BSD/etc
        os.system('clear')
    elif os.name in ("nt", "dos", "ce"):
        # DOS/Windows
        os.system('CLS')
    else:
        # Fallback for other operating systems.
        print ('\n' * 100)



def UpOneLevel(directory):
    """
    Retians a string
    Removes the last folder from a string containing a path (nt only)
    """

    tail = ''
    while tail == '': #moves last directory
        directory, tail = os.path.split(directory)
        if directory.endswith(':\\'): break #if this is the root of Windows drive break loop

    if directory.endswith('\\') == False: #ensures '\\' is added incase it is not
        directory = directory + '\\'
    return directory
def GetDirectorySizes(directory, Verbose = False):
    """
    Returns a list.
    list contains a list of the name and size (in bytes) of each object in the directory.
    [[objectName,objectSize]].
    Pass Verbose = True to enable some console prints of progress.
    """

    # create a fresh list to store name and size of each folder and file
    FolderSizeList = []
    TotalRootSize = 0

    CurrentFile = 0

    # grab objects in current directory
    if Verbose == True:
        tmpNumOfDirs = len(os.listdir(directory))
        tmpCurrentDir = 1

    for RootDirs in os.listdir(directory):

        if Verbose == True:
            ClearScreen()
            print('Currently calculating ' + RootDirs + ' (' + str(tmpCurrentDir) + '/' + str(tmpNumOfDirs) + ')' )
            tmpCurrentDir += 1

        tmp = GetDirectorySize(directory + '\\' + RootDirs)
        FolderSizeList.append([RootDirs, tmp])



    return FolderSizeList

def MainMenu(directory):

    """
    This will present a main screen
    show directories of /path
    Continues presenting directory until user states a directory to use.
    """

    OldDirectory = directory #back up incase moving into a directory fails (due to access denied or something)
    while True:



        #Main Menu
        ClearScreen()
        print ('Welcome to DirectorySizes')
        print ('Version: ' + VersionNum)
        print ()
        print ('Current Directory: ' + directory)

        Indices = 0 # used to present options
        OptionList = [] #create a blank list to store options

        #stops runtime error on access denied.
        try:
            SubDirList = os.listdir(directory)
        except:
            input('Access Denied (5): Returning to previous directory, Press any key')
            directory = OldDirectory
            SubDirList = os.listdir(directory)
            print ('Welcome to DirectorySizes')
            print ('Version: ' + VersionNum)
            print ()
            print ('Current Directory: ' + directory)


        for Directory in SubDirList:
            if os.path.isdir(directory + Directory):
                printline = '{0:4}' + (' ' * 2) + '{1:24}'
                print(printline.format(str(Indices) + ')', Directory)) #Prints each folder in the current directory
                Indices += 1
                OptionList.append(Directory)
        #Option for going up one level
        OptionList.append('Up one level')
        printline = '{0:4}' + (' ' * 2) + '{1:24}'
        print(printline.format(str(Indices) + ')','Up one level'))
        Indices += 1

        #Option Use Current
        OptionList.append('Use current directory')
        printline = '{0:4}' + (' ' * 2) + '{1:24}'
        print(printline.format(str(Indices) + ')','Use current directory'))
        print

        #grab user input

        SelectedOption = int(input('Select an option; '))

        #return a value

        if OptionList[SelectedOption] == 'Up one level':
            OldDirectory = directory
            directory = UpOneLevel(directory)
            #loop code


        elif OptionList[SelectedOption] == 'Use current directory':
            #Complete = True
            return directory


        else:
            OldDirectory = directory
            directory = directory + OptionList[SelectedOption] + '\\'
            #loop code

def ConvertByteSize(SizeInBytes, form = 'Standard' ):
    """
    Converts an amount of bytes, given as an interger, into KB, MB etc...
    returns a list [value(int/float), format(string)]
    Will convert based on algorythm or to a format given as form.
    Options for form are:
    Standard,
    B,
    KB,
    MB,
    GB.
    """
    tmpTotalBytez = [0,'']
    tmpTotalBytez[0] = SizeInBytes

    #Based on 'form' paramater, select a format to give back the data
    if form == 'GB':
        tmpTotalBytez[0] = tmpTotalBytez[0]/1024/1024/1024 # convert to GB
        tmpTotalBytez[1] = 'GB'
        return tmpTotalBytez

    elif form == 'MB':
        tmpTotalBytez[0] = tmpTotalBytez[0]/1024/1024 # convert to MB
        tmpTotalBytez[1] = 'MB'
        return tmpTotalBytez

    elif form == 'KB':
        tmpTotalBytez[0] = tmpTotalBytez[0]/1024 # convert to KB
        tmpTotalBytez[1] = 'KB'
        return tmpTotalBytez

    elif form == 'B':
        tmpTotalBytez[1] = 'B'
        return tmpTotalBytez

    else:

        if tmpTotalBytez[0] > 1024*1024*1024*1.3:
            tmpTotalBytez[0] = tmpTotalBytez[0]/1024/1024/1024 # convert to GB
            tmpTotalBytez[1] = 'GB'
            return tmpTotalBytez

        elif tmpTotalBytez[0] > 1024*1024*1.3:
            tmpTotalBytez[0] = tmpTotalBytez[0]/1024/1024 # convert to MB
            tmpTotalBytez[1] = 'MB'
            return tmpTotalBytez

        elif tmpTotalBytez[0] > 1024*1.3:
            tmpTotalBytez[0] = tmpTotalBytez[0]/1024 # convert to KB
            tmpTotalBytez[1] = 'KB'
            return tmpTotalBytez

        else:
            tmpTotalBytez[1] = 'B'
            return tmpTotalBytez