## Converts Grayscale 16-bit TIFs to 8-bit TIFs
## Python 2.7.12
## James Fleming 10/02/2018

from PIL import Image
import numpy
import sys
import os

def convert(filepath, scale=True):
    ## Loads Image As Array
    image = Image.open(filepath)
    image_array = numpy.array(image)

    ## Validate Requirement For Conversion
    if image_array.dtype != 'uint16':
        return image

    ## Scale If Required Or Clip
    if numpy.amax(image_array) > 255:
        if scale:
            scale_factor = numpy.amax(image_array)
            image_array *= (255 / scale_factor)
            print (filepath + ' scaled!')
        else:
            image_array[image_array > 255] = 255
            print (filepath + ' clipped!')

    ## Convert To Uint8 Image
    converted_array = image_array.astype('uint8')
    converted_image = Image.fromarray(converted_array)

    return converted_image

## Command Line Utility
if __name__ == "__main__":

    ## Check Arguements
    if len(sys.argv) == 3:
        inpath = sys.argv[1]
        outpath = sys.argv[2]
    else:
        print 'Incorrect Arguments Given!'

    ## Check If Input Exists
    if os.path.exists(inpath):
        ## Check If Single File Or Directory
        if os.path.isfile(inpath):
            convert(inpath).save(outpath)
        else:
            ## Create Ouput Folder If Required
            if not os.path.exists(outpath):
                os.mkdir(outpath)

            ## Find All Valid Files
            for root, dirs, files in os.walk(inpath):
                for file in files:
                    if file.endswith(".tif"):
                        filepath = os.path.join(root, file)
                        convertedpath = os.path.join(outpath, file)

                        ## Do Indivdual Conversion
                        convert(filepath).save(convertedpath)
                        print 'Converted ' + filepath

    ## Input Non-Existent
    else:
        print 'Given input does not exist!'