#!/usr/bin/python3

import sys
import piexif as x
import datetime as dt

offset = '+02:00'
print('Override offset with', offset)

if len(sys.argv) <= 1:
    print(sys.argv[0], 'img1.jpg img2.jpg')
    quit()

def codesOfLabelsContaining(value: str):
    codes = []
    for (k, v) in x.TAGS['Exif'].items():
        if value in v['name']:
            codes.append(k)
    return codes

timeCodes = codesOfLabelsContaining('Time')
offsetCodes = codesOfLabelsContaining('OffsetTime')

filenames = sys.argv[1:]


def describeExif(exif):
    for k in timeCodes:
        if k in exif.keys():
            print('Exif[', k, ']=', exif[k], '->', x.TAGS['Exif'][k]['name'])
        else:
            print('Exif[', k, ']=', '?', '->', x.TAGS['Exif'][k]['name'])


def overrideOffset(exifDict):
    e = exifDict['Exif']
    offsetBytes = offset.encode()
    for k in offsetCodes:
        print('Exif[', k, ']=', e[k], '->', offsetBytes, ':', x.TAGS['Exif'][k]['name'])
        e[k] = offsetBytes

    return exifDict


for filename in filenames:
    print(filename)
    exifDict = x.load(filename)
    describeExif(exifDict['Exif'])
    exifDict = overrideOffset(exifDict)
    describeExif(exifDict['Exif'])
    exifBytes = x.dump(exifDict)
    x.insert(exifBytes, filename)
    print()