"""
Classify photos by EXIF attributes.

Before classified:

    DCIM
    ├── 100ANDRO
    │   ├── DSC_2828.JPG
    │   └── DSC_2830.JPG
    ├── 99ANDRO
    │   ├── DSC_2822.JPG
    │   └── DSC_2827.JPG
    ├── Camera
    │   ├── C1
    │   │   ├── P_20180124_165745.jpg
    │   │   └── P_20180124_165756.jpg
    │   ├── C2
    │   │   ├── P_20180124_172141.jpg
    │   │   └── P_20180124_172720.jpg
    │   └── P_20180124_165611.jpg
    └── DSC_2833.JPG

After classified:

    DCIM
    ├── 100ANDRO
    ├── 99ANDRO
    ├── Camera
    │   ├── C1
    │   └── C2
    └── Classified
        ├── 2015-11
        │   ├── 29-062447-Sony-D5503.jpg
        │   ├── 29-063154-Sony-D5503.jpg
        │   ├── 29-063503-Sony-D5503.jpg
        │   ├── 29-063617-Sony-D5503.jpg
        │   └── 29-063810-Sony-D5503.jpg
        └── 2018-01
            ├── 24-165610-ASUS-Z00UD.jpg
            ├── 24-165745-ASUS-Z00UD.jpg
            ├── 24-165755-ASUS-Z00UD.jpg
            ├── 24-172141-ASUS-Z00UD.jpg
            └── 24-172719-ASUS-Z00UD.jpg
"""

import piexif
import json
import re
import os
import shutil
import time
from datetime import datetime

class ExifReader:

    def __init__(self, photo):
        self.ifds = piexif.load(photo)

    def read_attribute(self, tag, ifd='0th'):
        if ifd in self.ifds:
            if tag in self.ifds[ifd]:
                if isinstance(self.ifds[ifd][tag], bytes):
                    return self.ifds[ifd][tag].decode('ascii')
                else:
                    return self.ifds[ifd][tag]
        return None

def rearrange(photo_src, base_dest = 'rearranged'):
    # See: http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf p.79
    exr = ExifReader(photo_src)
    brand = exr.read_attribute(271)
    model = exr.read_attribute(272)
    mtime = exr.read_attribute(306)

    m = re.match(r'(\d{4}):(\d{2}):(\d{2}) (\d{2}):(\d{2}):(\d{2})', mtime)
    if m is None:
        exit()

    if model.lower().startswith(brand.lower()):
        camera = model
    else:
        camera = (brand + '-' + model)

    camera = camera.replace('_', '-')

    photo_dir = '{}/{}-{}'.format(base_dest, m[1], m[2])
    photo_dest = '{}/{}-{}{}{}-{}.jpg'.format(photo_dir, m[3], m[4], m[5], m[6], camera)

    if not os.path.isdir(photo_dir):
        os.makedirs(photo_dir)

    shutil.copy2(photo_src, photo_dest)
    ts_mtime = time.mktime(time.strptime(mtime, '%Y:%m:%d %H:%M:%S'))

    st = os.stat(photo_dest)
    os.chmod(photo_dest, 0o644)
    os.utime(photo_dest, (ts_mtime, ts_mtime))
    os.remove(photo_src)

def main():
    source_dir = 'DCIM'
    target_dir = 'DCIM/Classified'
    for base, directories, files in os.walk(source_dir):
        if base == target_dir:
            continue
        for f in files:
            if re.match(r'.+\.jpg', f, re.I):
                photo_src = '{}/{}'.format(base, f)
                rearrange(photo_src, target_dir)

if __name__ == '__main__':
    main()