# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
import argparse
import numpy as np
import os
from itertools import chain
import cv2
from PIL import Image

from fsdet.config import get_cfg
from fsdet.data import DatasetCatalog, MetadataCatalog, build_detection_train_loader
from fsdet.data import detection_utils as utils
from fsdet.utils.logger import setup_logger
from fsdet.utils.visualizer import Visualizer

from fsdet.data.dataset_mapper import AlbumentationMapper

def setup(args):
    cfg = get_cfg()
    if args.config_file:
        cfg.merge_from_file(args.config_file)
    cfg.merge_from_list(args.opts)
    cfg.freeze()
    return cfg


def parse_args(in_args=None):
    parser = argparse.ArgumentParser(description="Visualize ground-truth data")
    parser.add_argument(
        "--source",
        choices=["annotation", "dataloader"],
        required=True,
        help="visualize the annotations or the data loader (with pre-processing)",
    )
    parser.add_argument("--config-file", default="", metavar="FILE", help="path to config file")
    parser.add_argument("--output-dir", default="./", help="path to output directory")
    parser.add_argument("--show", action="store_true", help="show output in a window")
    parser.add_argument(
        "opts",
        help="Modify config options using the command-line",
        default=None,
        nargs=argparse.REMAINDER,
    )
    return parser.parse_args(in_args)


if __name__ == "__main__":
    args = parse_args()
    logger = setup_logger()
    logger.info("Arguments: " + str(args))
    cfg = setup(args)

    dirname = args.output_dir
    os.makedirs(dirname, exist_ok=True)
    metadata = MetadataCatalog.get(cfg.DATASETS.TRAIN[0])

    def output(vis, fname):
        if args.show:
            print(fname)
            cv2.imshow("window", vis.get_image()[:, :, ::-1])
            cv2.waitKey()
        else:
            filepath = os.path.join(dirname, fname)
            # adds a random name for duplicated image name, 发现 fsdet use horizontal flip and scale(有待考证)
            if os.path.exists(filepath):
                filepath = filepath[:-4] + '_dup_' + str(np.random.randint(0, 1000)) + '.jpg'
            print("Saving to {} ...".format(filepath))
            vis.save(filepath)

    scale = 2.0 if args.show else 1.0
    if args.source == "dataloader":
        mapper = None
        if cfg.INPUT.USE_ALBUMENTATIONS:
            mapper = AlbumentationMapper(cfg, is_train=True)
        train_data_loader = build_detection_train_loader(cfg, mapper=mapper)
        for batch in train_data_loader:
            for per_image in batch:
                # type(per_image), per_images.keys()
                # <class 'dict'>, dict_keys(['file_name', 'image_id', 'height', 'width', 'image', 'instances'])

                # Pytorch tensor is in (C, H, W) format
                img = per_image["image"].permute(1, 2, 0)
                if cfg.INPUT.FORMAT == "BGR":
                    img = img[:, :, [2, 1, 0]]
                else:
                    img = np.asarray(Image.fromarray(img, mode=cfg.INPUT.FORMAT).convert("RGB"))

                visualizer = Visualizer(img, metadata=metadata, scale=scale)
                # target_fields.keys() => dict_keys(['gt_boxes', 'gt_classes'])
                target_fields = per_image["instances"].get_fields()
                labels = [metadata.thing_classes[i] for i in target_fields["gt_classes"]]
                vis = visualizer.overlay_instances(
                    labels=labels,
                    boxes=target_fields.get("gt_boxes", None),
                )

                # modified: voc I=1 in any case
                num_instances = len(per_image['instances'])
                output(vis, "I{}_".format(num_instances) + str(per_image["image_id"]) + ".jpg")
    else:
        dicts = list(chain.from_iterable([DatasetCatalog.get(k) for k in cfg.DATASETS.TRAIN]))
        for dic in dicts:
            img = utils.read_image(dic["file_name"], "RGB")
            visualizer = Visualizer(img, metadata=metadata, scale=scale)
            vis = visualizer.draw_dataset_dict(dic)
            output(vis, os.path.basename(dic["file_name"]))
