# Write EXIF metadata to text file for pelican.photos plugin.
# The original version of this was 100% hard coded script, this version takes arguments to allow you to do more with it as a single install.
# The original is here - https://gist.github.com/Jeffmackinnon/92c747b30a873129a28cddacfc61fbe1

import argparse # The library that will parse the arguments.

import os
from os import listdir
from os.path import isdir,isfile, join

#import PIL
from PIL import Image
from PIL.ExifTags import GPSTAGS
from PIL.ExifTags import TAGS
from fractions import Fraction


# Parser
parser = argparse.ArgumentParser(   prog='exif2txt',
                                    usage='%(prog)s [options] path',
                                    allow_abbrev=False,
                                    description='Write EXIF metadata to text file.',
                                    epilog='it\'s my first public CLI python script, please be kind.',
                                )

parser.add_argument('Path',
                    metavar='path',
                    type=str,
                    help='top level path for with the images'
                    )


#
# Need to add the parser for what information we want to add for each
#           


# Execute parse_args()
args = parser.parse_args()
input_path = args.Path

# Test to make sure that the Path given is valid.
if not os.path.isdir(input_path):
    print('The path specified does not exist')
    sys.exit()

# The first two functions are borrowed from github user @jpstroop
# https://gist.github.com/jpstroop/58a21d02370c8ba34dc8f0fdd4206d70


def _map_key(k):
    try:
        return TAGS[k]
    except KeyError:
        return GPSTAGS.get(k, k)

# Creates a dictionary of image EXIF meta data from an image, borrowed from a github gist
def get_exif(image_path):
    metadata = {}
    with Image.open(image_path) as i:
        info = i._getexif()
    try:
        [ metadata.__setitem__(_map_key(k), v) for k, v in info.items() ]
        return metadata
    except AttributeError:
        return None

# This is from J0el - https://gist.github.com/Jeffmackinnon/92c747b30a873129a28cddacfc61fbe1?permalink_comment_id=4185193#gistcomment-4185193
# A couple of minor tweaks to make it work

def exposure(ExposureTime):
    try:
        time = float(ExposureTime)
        if time > 1:
            return(ExposureTime)
        else:
            return( str(Fraction(time).limit_denominator()))
    except:
        return(ExposureTime)

#Creates a text file with some exif meta data.
def write_exif_file(directory):
    # Open the exif.txt file, create if it doesn't exist, in the current folder.
    txt = open(directory +'/exif.txt', 'w')

    for file in os.listdir(directory):

        # check the files which are end with specific extension
        # Everything that I want to have EXIF information for is a jpg, but you can add others too.
        if file.endswith(".jpg"):
            # Need to iterate through the files in the list and pass each to the 
            image = get_exif(directory +'/'+os.path.join(file))

            txt.write(
                os.path.join(file) + ': ' + 
                str(
                    image.get('Model')) + 
                ' with a ' + str(image.get('LensModel')) + 
                ' - ' + str(exposure(image.get('ExposureTime'))) + 's, ' + # I want to change this to fractions, but it works for now.
                'f/' + str(image.get('FNumber')) + 
                ' at ISO-' +  str(image.get('ISOSpeedRatings')) + 
                '\n'
                )

    # Close the text file now that we are done with it.
    txt.close()
    return None

# This walks through the directories and for each it calls the write exif file function
for root, subdirectories, files in os.walk(input_path):
    for subdirectory in subdirectories:
       print(os.path.join(root, subdirectory))
       write_exif_file(os.path.join(root, subdirectory))