# Copyright 2020 Huawei Technologies Co., Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============================================================================
import argparse

import glob

import os

import os.path as osp

import sys

from multiprocessing import Pool





def encode_video(frame_dir_item):

    """Encode frames to video using ffmpeg.



    Args:

        frame_dir_item (list): Rawframe item containing raw frame directory

            full path, rawframe directory (short) path, rawframe directory id.



    Returns:

        bool: Whether synthesize video successfully.

    """

    full_path, frame_dir_path, frame_dir_id = frame_dir_item

    out_full_path = args.out_dir



    img_name_tmpl = args.filename_tmpl + '.' + args.in_format

    img_path = osp.join(full_path, img_name_tmpl)



    out_vid_name = frame_dir_path + '.' + args.ext

    out_vid_path = osp.join(out_full_path, out_vid_name)



    cmd = osp.join(

        f"ffmpeg -start_number {args.start_idx} -r {args.fps} -i '{img_path}' "

        f"-vcodec {args.vcodec} '{out_vid_path}'")

    os.system(cmd)



    print(f'{frame_dir_id} {frame_dir_path} done')

    sys.stdout.flush()

    return True





def parse_args():

    parser = argparse.ArgumentParser(description='synthesize videos')

    parser.add_argument('src_dir', type=str, help='source rawframe directory')

    parser.add_argument('out_dir', type=str, help='output video directory')

    parser.add_argument(

        '--fps', type=int, default=30, help='fps of videos to be synthesized')

    parser.add_argument(

        '--level',

        type=int,

        choices=[1, 2],

        default=2,

        help='directory level of data')

    parser.add_argument(

        '--num-worker',

        type=int,

        default=8,

        help='number of workers to build videos')

    parser.add_argument(

        '--in-format',

        type=str,

        default='jpg',

        choices=['jpg', 'png'],

        help='input format')

    parser.add_argument(

        '--start-idx', type=int, default=0, help='starting index of rawframes')

    parser.add_argument(

        '--filename-tmpl',

        type=str,

        default='img_%05d',

        help='filename template of rawframes')

    parser.add_argument(

        '--vcodec', type=str, default='mpeg4', help='coding method of videos')

    parser.add_argument(

        '--ext',

        type=str,

        default='mp4',

        choices=['mp4', 'avi'],

        help='video file extensions')

    parser.add_argument('--num-gpu', type=int, default=8, help='number of GPU')

    parser.add_argument(

        '--resume',

        action='store_true',

        default=False,

        help='resume optical flow extraction instead of overwriting')

    args = parser.parse_args()



    return args





if __name__ == '__main__':

    args = parse_args()



    if not osp.isdir(args.out_dir):

        print(f'Creating folder: {args.out_dir}')

        os.makedirs(args.out_dir)



    if args.level == 2:

        classes = os.listdir(args.src_dir)

        for classname in classes:

            new_dir = osp.join(args.out_dir, classname)

            if not osp.isdir(new_dir):

                print(f'Creating folder: {new_dir}')

                os.makedirs(new_dir)



    print('Reading rgb frames from folder: ', args.src_dir)

    print('Input format of rgb frames: ', args.in_format)

    fullpath_list = glob.glob(args.src_dir + '/*' * args.level)

    done_fullpath_list = glob.glob(args.src_dir + '/*' * args.level + '.' +

                                   args.ext)

    print('Total number of rgb frame folders found: ', len(fullpath_list))



    if args.resume:

        fullpath_list = set(fullpath_list).difference(set(done_fullpath_list))

        fullpath_list = list(fullpath_list)

        print('Resuming. number of videos to be synthesized: ',

              len(fullpath_list))



    if args.level == 2:

        frame_dir_list = list(

            map(

                lambda p: osp.join(

                    osp.basename(osp.dirname(p)), osp.basename(p)),

                fullpath_list))

    elif args.level == 1:

        frame_dir_list = list(map(osp.basename, fullpath_list))



    pool = Pool(args.num_worker)

    pool.map(encode_video,

             zip(fullpath_list, frame_dir_list, range(len(frame_dir_list))))