import argparse
import glob
import os.path as osp
from functools import partial

import cv2
import mmcv
import numpy as np
import scipy.io as scio
from shapely.geometry import Polygon

from mmocr.utils import convert_annotations, drop_orientation, is_not_png


def collect_files(img_dir, gt_dir, split):
    """Collect all images and their corresponding groundtruth files.

    Args:
        img_dir(str): The image directory
        gt_dir(str): The groundtruth directory
        split(str): The split of dataset. Namely: training or test

    Returns:
        files(list): The list of tuples (img_file, groundtruth_file)
    """
    assert isinstance(img_dir, str)
    assert img_dir
    assert isinstance(gt_dir, str)
    assert gt_dir

    # note that we handle png and jpg only. Pls convert others such as gif to
    # jpg or png offline
    suffixes = ['.png', '.PNG', '.jpg', '.JPG', '.jpeg', '.JPEG']
    # suffixes = ['.png']

    imgs_list = []
    for suffix in suffixes:
        imgs_list.extend(glob.glob(osp.join(img_dir, '*' + suffix)))

    imgs_list = [
        drop_orientation(f) if is_not_png(f) else f for f in imgs_list
    ]

    files = []
    if split == 'training':
        for img_file in imgs_list:
            gt_file = osp.join(
                gt_dir,
                'poly_gt_' + osp.splitext(osp.basename(img_file))[0] + '.mat')
            files.append((img_file, gt_file))
        assert len(files), f'No images found in {img_dir}'
        print(f'Loaded {len(files)} images from {img_dir}')
    elif split == 'test':
        for img_file in imgs_list:
            gt_file = osp.join(
                gt_dir,
                'poly_gt_' + osp.splitext(osp.basename(img_file))[0] + '.mat')
            files.append((img_file, gt_file))
        assert len(files), f'No images found in {img_dir}'
        print(f'Loaded {len(files)} images from {img_dir}')

    return files


def collect_annotations(files, split, nproc=1):
    """Collect the annotation information.

    Args:
        files(list): The list of tuples (image_file, groundtruth_file)
        split(str): The split of dataset. Namely: training or test
        nproc(int): The number of process to collect annotations

    Returns:
        images(list): The list of image information dicts
    """
    assert isinstance(files, list)
    assert isinstance(split, str)
    assert isinstance(nproc, int)

    load_img_info_with_split = partial(load_img_info, split=split)
    if nproc > 1:
        images = mmcv.track_parallel_progress(
            load_img_info_with_split, files, nproc=nproc)
    else:
        images = mmcv.track_progress(load_img_info_with_split, files)

    return images


def get_contours(gt_path, split):
    """Get the contours and words for each ground_truth file.

    Args:
        gt_path(str): The relative path of the ground_truth mat file
        split(str): The split of dataset: training or test

    Returns:
        contours(list[lists]): A list of lists of contours
        for the text instances
        words(list[list]): A list of lists of words (string)
        for the text instances
    """
    assert isinstance(gt_path, str)
    assert isinstance(split, str)

    contours = []
    words = []
    data = scio.loadmat(gt_path)
    if split == 'training':
        data_polygt = data['polygt']
    elif split == 'test':
        data_polygt = data['polygt']

    for i, lines in enumerate(data_polygt):
        X = np.array(lines[1])
        Y = np.array(lines[3])

        point_num = len(X[0])
        word = lines[4]
        if len(word) == 0:
            word = '???'
        else:
            word = word[0]

        if word == '#':
            word = '###'
            continue

        words.append(word)

        arr = np.concatenate([X, Y]).T
        contour = []
        for i in range(point_num):
            contour.append(arr[i][0])
            contour.append(arr[i][1])
        contours.append(np.asarray(contour))

    return contours, words


def load_mat_info(img_info, gt_file, split):
    """Load the information of one ground truth in .mat format.

    Args:
        img_info(dict): The dict of only the image information
        gt_file(str): The relative path of the ground_truth mat
        file for one image
        split(str): The split of dataset: training or test

    Returns:
        img_info(dict): The dict of the img and annotation information
    """
    assert isinstance(img_info, dict)
    assert isinstance(gt_file, str)
    assert isinstance(split, str)

    contours, words = get_contours(gt_file, split)
    anno_info = []
    for contour in contours:
        if contour.shape[0] == 2:
            continue
        category_id = 1
        coordinates = np.array(contour).reshape(-1, 2)
        polygon = Polygon(coordinates)
        iscrowd = 0

        area = polygon.area
        # convert to COCO style XYWH format
        min_x, min_y, max_x, max_y = polygon.bounds
        bbox = [min_x, min_y, max_x - min_x, max_y - min_y]

        anno = dict(
            iscrowd=iscrowd,
            category_id=category_id,
            bbox=bbox,
            area=area,
            segmentation=[contour])
        anno_info.append(anno)

    img_info.update(anno_info=anno_info)

    return img_info


def load_png_info(gt_file, img_info):
    """Load the information of one ground truth in .png format.

    Args:
        gt_file(str): The relative path of the ground_truth file for one image
        img_info(dict): The dict of only the image information

    Returns:
        img_info(dict): The dict of the img and annotation information
    """
    assert isinstance(gt_file, str)
    assert isinstance(img_info, dict)
    gt_img = cv2.imread(gt_file, 0)
    contours, _ = cv2.findContours(gt_img, cv2.RETR_EXTERNAL,
                                   cv2.CHAIN_APPROX_SIMPLE)

    anno_info = []
    for contour in contours:
        if contour.shape[0] == 2:
            continue
        category_id = 1
        xy = np.array(contour).flatten().tolist()

        coordinates = np.array(contour).reshape(-1, 2)
        polygon = Polygon(coordinates)
        iscrowd = 0

        area = polygon.area
        # convert to COCO style XYWH format
        min_x, min_y, max_x, max_y = polygon.bounds
        bbox = [min_x, min_y, max_x - min_x, max_y - min_y]

        anno = dict(
            iscrowd=iscrowd,
            category_id=category_id,
            bbox=bbox,
            area=area,
            segmentation=[xy])
        anno_info.append(anno)

    img_info.update(anno_info=anno_info)

    return img_info


def load_img_info(files, split):
    """Load the information of one image.

    Args:
        files(tuple): The tuple of (img_file, groundtruth_file)
        split(str): The split of dataset: training or test

    Returns:
        img_info(dict): The dict of the img and annotation information
    """
    assert isinstance(files, tuple)
    assert isinstance(split, str)

    img_file, gt_file = files
    # read imgs with ignoring orientations
    img = mmcv.imread(img_file, 'unchanged')
    # read imgs with orientations as dataloader does when training and testing
    img_color = mmcv.imread(img_file, 'color')
    # make sure imgs have no orientation info, or annotation gt is wrong.
    assert img.shape[0:2] == img_color.shape[0:2]

    split_name = osp.basename(osp.dirname(img_file))
    img_info = dict(
        # remove img_prefix for filename
        file_name=osp.join(split_name, osp.basename(img_file)),
        height=img.shape[0],
        width=img.shape[1],
        # anno_info=anno_info,
        segm_file=osp.join(split_name, osp.basename(gt_file)))

    if split == 'training':
        img_info = load_mat_info(img_info, gt_file, split)
    elif split == 'test':
        img_info = load_mat_info(img_info, gt_file, split)
    else:
        raise NotImplementedError

    return img_info


def parse_args():
    parser = argparse.ArgumentParser(
        description='Convert totaltext annotations to COCO format')
    parser.add_argument('root_path', help='totaltext root path')
    parser.add_argument('-o', '--out-dir', help='output path')
    parser.add_argument(
        '--split-list',
        nargs='+',
        help='a list of splits. e.g., "--split_list training test"')

    parser.add_argument(
        '--nproc', default=1, type=int, help='number of process')
    args = parser.parse_args()
    return args


def main():
    args = parse_args()
    root_path = args.root_path
    out_dir = args.out_dir if args.out_dir else root_path
    mmcv.mkdir_or_exist(out_dir)

    img_dir = osp.join(root_path, 'imgs')
    gt_dir = osp.join(root_path, 'annotations')

    set_name = {}
    for split in args.split_list:
        set_name.update({split: 'instances_' + split + '.json'})
        assert osp.exists(osp.join(img_dir, split))

    for split, json_name in set_name.items():
        print(f'Converting {split} into {json_name}')
        with mmcv.Timer(
                print_tmpl='It takes {}s to convert totaltext annotation'):
            files = collect_files(
                osp.join(img_dir, split), osp.join(gt_dir, split), split)
            image_infos = collect_annotations(files, split, nproc=args.nproc)
            convert_annotations(image_infos, osp.join(out_dir, json_name))


if __name__ == '__main__':
    main()