# Copyright (c) Alibaba, Inc. and its affiliates.
import os

import numpy as np

from easycv.datasets.registry import DATASOURCES
from easycv.file import io
from easycv.utils.bbox_util import batched_cxcywh2xyxy_with_shape
from .voc import DetSourceVOC

img_formats = ['.bmp', '.jpg', '.jpeg', '.png', '.tif', '.tiff', '.dng']
label_formats = ['.txt']


@DATASOURCES.register_module
class DetSourceRaw(DetSourceVOC):
    """
    data dir is as follows:
    ```
    |- data_dir
        |-images
            |-1.jpg
            |-...
        |-labels
            |-1.txt
            |-...

    ```
    Label txt file is as follows:
    The first column is the label id, and columns 2 to 5 are
    coordinates relative to the image width and height [x_center, y_center, bbox_w, bbox_h].
    ```
    15 0.519398 0.544087 0.476359 0.572061
    2 0.501859 0.820726 0.996281 0.332178
    ...
    ```
    Example:
        data_source = DetSourceRaw(
            img_root_path='/your/data_dir/images',
            label_root_path='/your/data_dir/labels',
        )
    """

    def __init__(self,
                 img_root_path,
                 label_root_path,
                 cache_at_init=False,
                 cache_on_the_fly=False,
                 delimeter=' ',
                 **kwargs):
        """
        Args:
            img_root_path: images dir path
            label_root_path: labels dir path
            cache_at_init: if set True, will cache in memory in __init__ for faster training
            cache_on_the_fly: if set True, will cache in memroy during training
        """
        self.cache_on_the_fly = cache_on_the_fly
        self.cache_at_init = cache_at_init
        self.delimeter = delimeter

        self.img_root_path = img_root_path
        self.label_root_path = label_root_path

        self.img_files = [
            os.path.join(self.img_root_path, i)
            for i in io.listdir(self.img_root_path, recursive=True)
        ]
        self.img_files = sorted([
            i for i in self.img_files
            if os.path.splitext(i)[-1].lower() in img_formats
        ])
        assert len(
            self.img_files) > 0, 'No images found in %s' % self.img_root_path

        self.label_files = [
            os.path.join(self.label_root_path, i)
            for i in io.listdir(self.label_root_path, recursive=True)
        ]
        self.label_files = sorted([
            i for i in self.label_files
            if os.path.splitext(i)[-1].lower() in label_formats
        ])
        assert len(self.label_files
                   ) > 0, 'No labels found in %s.' % self.label_root_path

        # TODO: filter bad sample
        self.samples_list = self.build_samples(
            list(zip(self.img_files, self.label_files)))

    def get_source_info(self, img_and_label):
        img_path = img_and_label[0]
        label_path = img_and_label[1]

        source_info = {'filename': img_path}

        with io.open(label_path, 'r') as f:
            labels_and_boxes = np.array(
                [line.split(self.delimeter) for line in f.read().splitlines()])

        if not len(labels_and_boxes):
            return {}

        labels = labels_and_boxes[:, 0]
        bboxes = labels_and_boxes[:, 1:]

        source_info.update({
            'gt_bboxes': np.array(bboxes, dtype=np.float32),
            'gt_labels': labels.astype(np.int64)
        })

        return source_info

    def _build_sample_from_source_info(self, source_info):
        if 'filename' not in source_info:
            return {}

        result_dict = source_info

        img_info = self.load_image(source_info['filename'])
        result_dict.update(img_info)

        result_dict.update({
            'img_fields': ['img'],
            'bbox_fields': ['gt_bboxes']
        })
        # shape: h, w
        result_dict['gt_bboxes'] = batched_cxcywh2xyxy_with_shape(
            result_dict['gt_bboxes'], shape=img_info['img_shape'][:2])

        return result_dict