#!/usr/bin/env python3


from subprocess import Popen, PIPE
from datetime import datetime
import json
from os.path import isfile


def extractor(input_files, start, end):
    if not isinstance(input_files, type(list())):
        raise ValueError("Input files must be a list.")
    exif_dict_list = []
    usefull_exif = [
        "Image.Model",
        "Photo.LensModel",
        "Photo.FocalLength",
        "Photo.ApertureValue",
        "Photo.ExposureTime",
        "Photo.ISOSpeedRatings",
        "Photo.PixelXDimension",
        "Photo.PixelYDimension",
        "Image.ImageWidth",
        "Image.ImageLength",
        "Photo.DateTimeOriginal"
    ]
    for input_file in input_files:
        exif_dict = {}
        if not isfile(input_file):
            raise ValueError("{} doesn't exist here.".format(input_file))
        exif_dict.update({'file': input_file})
        for extracted in usefull_exif:
            cmd = ["exiv2", "-g", extracted, "-Pt", input_file]
            with Popen(cmd, stdout=PIPE) as extracted_data:
                extracted_data = extracted_data.stdout.read().decode()
                if extracted_data:
                    extracted_data = extracted_data.splitlines()[0]
                    exif_dict.update({extracted.split(".")[1]: extracted_data})
                else:
                    exif_dict.update({extracted.split(".")[1]: None})
        if exif_dict['FocalLength']:
            exif_dict['FocalLength'] = float(
                exif_dict['FocalLength'].replace(" mm", ""))
        if exif_dict['ApertureValue']:
            exif_dict['ApertureValue'] = float(
                exif_dict['ApertureValue'].replace("F", ""))
        if exif_dict['PixelXDimension'] and exif_dict['PixelYDimension']:
            exif_dict['PixelXDimension'] = int(exif_dict['PixelXDimension'])
            exif_dict['PixelYDimension'] = int(exif_dict['PixelYDimension'])
            pixels = exif_dict['PixelXDimension'] * \
                exif_dict['PixelYDimension']
        elif exif_dict['ImageLength'] and exif_dict['ImageWidth']:
            exif_dict['PixelXDimension'] = int(exif_dict['ImageLength'])
            exif_dict['PixelYDimension'] = int(exif_dict['ImageWidth'])
            pixels = exif_dict['PixelXDimension'] * \
                exif_dict['PixelYDimension']
        else:
            pixels = None
        if exif_dict['DateTimeOriginal']:
            exif_dict['DateTimeOriginal'] = datetime.strptime(
                exif_dict['DateTimeOriginal'], "%Y:%m:%d %H:%M:%S")
        if exif_dict['ExposureTime']:
            try:
                exif_dict['ExposureTime'] = float(
                    exif_dict['ExposureTime'].split(" ")[0])
            except ValueError:
                exposure = exif_dict['ExposureTime'].split(" ")[0]
                exif_dict['ExposureTime'] = float(
                    1/(float(exposure.split("/")[1])))
        if pixels:
            exif_dict.update({'Dimension': round((pixels/10**6), 1)})
        else:
            exif_dict.update({'Dimension': None})
        exif_dict_list.append(exif_dict)
    cameras, lenses, focals, apertures, exposures = {}, {}, {}, {}, {}
    isos, dimensions, cameras_lenses, dates = {}, {}, {}, {}
    cameras_list, lenses_list, focals_list, apertures_list, exposures_list = [], [], [], [], []
    isos_list, dimensions_list, cameras_lenses_list, dates_list = [], [], [], []
    for data in exif_dict_list:
        if start <= data['DateTimeOriginal'] <= end:
            cameras_list.append(data['Model'])
            lenses_list.append(data['LensModel'])
            focals_list.append(data['FocalLength'])
            apertures_list.append(data['ApertureValue'])
            exposures_list.append(data['ExposureTime'])
            isos_list.append(data['ISOSpeedRatings'])
            dimensions_list.append(data['Dimension'])
            if data['LensModel']:
                cameras_lenses_list.append(
                    "{} + {}".format(data['Model'], data['LensModel']))
            dates_list.append(data['DateTimeOriginal'].strftime("%Y%m%d"))
    for camera in list(set(cameras_list)):
        if camera:
            cameras.update({camera: cameras_list.count(camera)})
    for lens in list(set(lenses_list)):
        if lens:
            lenses.update({lens: lenses_list.count(lens)})
    for camera_lens in list(set(cameras_lenses_list)):
        if camera_lens:
            cameras_lenses.update(
                {camera_lens: cameras_lenses_list.count(camera_lens)})
    for focal in list(set(focals_list)):
        if focal:
            focals.update({focal: focals_list.count(focal)})
    for aperture in list(set(apertures_list)):
        if aperture:
            apertures.update({aperture: apertures_list.count(aperture)})
    for exposure in list(set(exposures_list)):
        if exposure:
            exposures.update(
                {float(exposure*1000): exposures_list.count(exposure)})
    for iso in list(set(isos_list)):
        if iso:
            isos.update({iso: isos_list.count(iso)})
    for dimension in list(set(dimensions_list)):
        if dimension:
            dimensions.update({dimension: dimensions_list.count(dimension)})
    for date in list(set(dates_list)):
        if date:
            dates.update({date: dates_list.count(date)})
    return {
        "total": len(dimensions_list),
        "date": dates,
        "cameras": cameras,
        "lenses": lenses,
        "cameras+lenses": cameras_lenses,
        "focals": focals,
        "apertures": apertures,
        "shutter_speeds": exposures,
        "isos": isos,
        "dimensions": dimensions
    }


if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "infile", help="input file (EXV, JPG, CR2, ...). Can be more than one.", nargs='+')
    parser.add_argument("-s", "--start-date", help="start date as YYYYMMDD. If omitted, begin of the collection.", const=None)
    parser.add_argument("-e", "--end-date", help="end date as YYYYMMDD. If omitted, today", const=None)
    args = parser.parse_args()
    if not args.start_date:
        args.start_date = "18250101" # Ok, that's the year of the 1st photography by Nicéphore Niépce. Shoul'd be enough for a start date.
    if not args.end_date:
        args.end_date = datetime.strftime(datetime.now(), "%Y%m%d")
    try:
        datetime.strptime(args.start_date, "%Y%m%d")
        datetime.strptime(args.end_date, "%Y%m%d")
    except ValueError:
        print("Date must be YYYYMMDD.")
        exit()
    print(json.dumps(extractor(args.infile, datetime.strptime(args.start_date, "%Y%m%d"), datetime.strptime(args.end_date, "%Y%m%d")), indent=4, sort_keys=True))