import os.path as osp
import pickle

import mmcv
import numpy as np
import pycocotools.mask as maskUtils
from mmcv import track_iter_progress
from pycocotools.coco import COCO

import mmdet3d.core.bbox.box_np_ops as box_np_ops
from mmdet3d.datasets import build_dataset
from mmdet.core.evaluation.bbox_overlaps import bbox_overlaps
from mmdet.ops import roi_align


def _poly2mask(mask_ann, img_h, img_w):
    if isinstance(mask_ann, list):
        # polygon -- a single object might consist of multiple parts
        # we merge all parts into one mask rle code
        rles = maskUtils.frPyObjects(mask_ann, img_h, img_w)
        rle = maskUtils.merge(rles)
    elif isinstance(mask_ann['counts'], list):
        # uncompressed RLE
        rle = maskUtils.frPyObjects(mask_ann, img_h, img_w)
    else:
        # rle
        rle = mask_ann
    mask = maskUtils.decode(rle)
    return mask


def _parse_coco_ann_info(ann_info):
    gt_bboxes = []
    gt_labels = []
    gt_bboxes_ignore = []
    gt_masks_ann = []

    for i, ann in enumerate(ann_info):
        if ann.get('ignore', False):
            continue
        x1, y1, w, h = ann['bbox']
        if ann['area'] <= 0:
            continue
        bbox = [x1, y1, x1 + w, y1 + h]
        if ann.get('iscrowd', False):
            gt_bboxes_ignore.append(bbox)
        else:
            gt_bboxes.append(bbox)
            gt_masks_ann.append(ann['segmentation'])

    if gt_bboxes:
        gt_bboxes = np.array(gt_bboxes, dtype=np.float32)
        gt_labels = np.array(gt_labels, dtype=np.int64)
    else:
        gt_bboxes = np.zeros((0, 4), dtype=np.float32)
        gt_labels = np.array([], dtype=np.int64)

    if gt_bboxes_ignore:
        gt_bboxes_ignore = np.array(gt_bboxes_ignore, dtype=np.float32)
    else:
        gt_bboxes_ignore = np.zeros((0, 4), dtype=np.float32)

    ann = dict(
        bboxes=gt_bboxes, bboxes_ignore=gt_bboxes_ignore, masks=gt_masks_ann)

    return ann


def crop_image_patch_v2(pos_proposals, pos_assigned_gt_inds, gt_masks):
    import torch
    from torch.nn.modules.utils import _pair
    device = pos_proposals.device
    num_pos = pos_proposals.size(0)
    fake_inds = (
        torch.arange(num_pos,
                     device=device).to(dtype=pos_proposals.dtype)[:, None])
    rois = torch.cat([fake_inds, pos_proposals], dim=1)  # Nx5
    mask_size = _pair(28)
    rois = rois.to(device=device)
    gt_masks_th = (
        torch.from_numpy(gt_masks).to(device).index_select(
            0, pos_assigned_gt_inds).to(dtype=rois.dtype))
    # Use RoIAlign could apparently accelerate the training (~0.1s/iter)
    targets = (
        roi_align(gt_masks_th, rois, mask_size[::-1], 1.0, 0, True).squeeze(1))
    return targets


def crop_image_patch(pos_proposals, gt_masks, pos_assigned_gt_inds, org_img):
    num_pos = pos_proposals.shape[0]
    masks = []
    img_patches = []
    for i in range(num_pos):
        gt_mask = gt_masks[pos_assigned_gt_inds[i]]
        bbox = pos_proposals[i, :].astype(np.int32)
        x1, y1, x2, y2 = bbox
        w = np.maximum(x2 - x1 + 1, 1)
        h = np.maximum(y2 - y1 + 1, 1)

        mask_patch = gt_mask[y1:y1 + h, x1:x1 + w]
        masked_img = gt_mask[..., None] * org_img
        img_patch = masked_img[y1:y1 + h, x1:x1 + w]

        img_patches.append(img_patch)
        masks.append(mask_patch)
    return img_patches, masks


def create_groundtruth_database(dataset_class_name,
                                data_path,
                                info_prefix,
                                info_path=None,
                                mask_anno_path=None,
                                used_classes=None,
                                database_save_path=None,
                                db_info_save_path=None,
                                relative_path=True,
                                add_rgb=False,
                                lidar_only=False,
                                bev_only=False,
                                coors_range=None,
                                with_mask=False):
    """Given the raw data, generate the ground truth database.

    Args:
        dataset_class_name （str): Name of the input dataset.
        data_path (str): Path of the data.
        info_prefix (str): Prefix of the info file.
        info_path (str): Path of the info file.
            Default: None.
        mask_anno_path (str): Path of the mask_anno.
            Default: None.
        used_classes (list[str]): Classes have been used.
            Default: None.
        database_save_path (str): Path to save database.
            Default: None.
        db_info_save_path (str): Path to save db_info.
            Default: None.
        relative_path (bool): Whether to use relative path.
            Default: True.
        with_mask (bool): Whether to use mask.
            Default: False.
    """
    print(f'Create GT Database of {dataset_class_name}')
    dataset_cfg = dict(
        type=dataset_class_name,
        root_path=data_path,
        ann_file=info_path,
    )
    if dataset_class_name == 'KittiDataset':
        dataset_cfg.update(
            training=True,
            split='training',
            modality=dict(
                use_lidar=True,
                use_depth=False,
                use_lidar_intensity=True,
                use_camera=with_mask,
            ))
    dataset = build_dataset(dataset_cfg)

    if database_save_path is None:
        database_save_path = osp.join(data_path,
                                      '{}_gt_database'.format(info_prefix))
    if db_info_save_path is None:
        db_info_save_path = osp.join(
            data_path, '{}_dbinfos_train.pkl'.format(info_prefix))
    mmcv.mkdir_or_exist(database_save_path)
    all_db_infos = dict()

    if with_mask:
        coco = COCO(osp.join(data_path, mask_anno_path))
        imgIds = coco.getImgIds()
        file2id = dict()
        for i in imgIds:
            info = coco.loadImgs([i])[0]
            file2id.update({info['file_name']: i})

    group_counter = 0
    for j in track_iter_progress(list(range(len(dataset)))):
        image_idx = j
        annos = dataset.get_sensor_data(j)
        image_idx = annos['sample_idx']
        points = annos['points']
        gt_boxes_3d = annos['gt_bboxes_3d']
        names = annos['gt_names']
        group_dict = dict()
        group_ids = np.full([gt_boxes_3d.shape[0]], -1, dtype=np.int64)
        if 'group_ids' in annos:
            group_ids = annos['group_ids']
        else:
            group_ids = np.arange(gt_boxes_3d.shape[0], dtype=np.int64)
        difficulty = np.zeros(gt_boxes_3d.shape[0], dtype=np.int32)
        if 'difficulty' in annos:
            difficulty = annos['difficulty']

        num_obj = gt_boxes_3d.shape[0]
        point_indices = box_np_ops.points_in_rbbox(points, gt_boxes_3d)

        if with_mask:
            # prepare masks
            gt_boxes = annos['gt_bboxes']
            img_path = annos['filename'].split('/')[-1]
            if img_path not in file2id.keys():
                print('skip image {} for empty mask'.format(img_path))
                continue
            img_id = file2id[img_path]
            kins_annIds = coco.getAnnIds(imgIds=img_id)
            kins_raw_info = coco.loadAnns(kins_annIds)
            kins_ann_info = _parse_coco_ann_info(kins_raw_info)
            h, w = annos['img_shape'][:2]
            gt_masks = [
                _poly2mask(mask, h, w) for mask in kins_ann_info['masks']
            ]
            # get mask inds based on iou mapping
            bbox_iou = bbox_overlaps(kins_ann_info['bboxes'], gt_boxes)
            mask_inds = bbox_iou.argmax(axis=0)
            valid_inds = (bbox_iou.max(axis=0) > 0.5)

            # mask the image
            # use more precise crop when it is ready
            # object_img_patches = np.ascontiguousarray(
            #     np.stack(object_img_patches, axis=0).transpose(0, 3, 1, 2))
            # crop image patches using roi_align
            # object_img_patches = crop_image_patch_v2(
            #     torch.Tensor(gt_boxes),
            #     torch.Tensor(mask_inds).long(), object_img_patches)
            object_img_patches, object_masks = crop_image_patch(
                gt_boxes, gt_masks, mask_inds, annos['img'])

        for i in range(num_obj):
            filename = f'{image_idx}_{names[i]}_{i}.bin'
            filepath = osp.join(database_save_path, filename)

            # save point clouds and image patches for each object
            gt_points = points[point_indices[:, i]]
            gt_points[:, :3] -= gt_boxes_3d[i, :3]

            if with_mask:
                if object_masks[i].sum() == 0 or not valid_inds[i]:
                    # Skip object for empty or invalid mask
                    continue
                img_patch_path = filepath + '.png'
                mask_patch_path = filepath + '.mask.png'
                mmcv.imwrite(object_img_patches[i], img_patch_path)
                mmcv.imwrite(object_masks[i], mask_patch_path)

            with open(filepath, 'w') as f:
                gt_points.tofile(f)

            if (used_classes is None) or names[i] in used_classes:
                if relative_path:
                    db_path = osp.join(data_path, filename)
                else:
                    db_path = filepath
                db_info = {
                    'name': names[i],
                    'path': db_path,
                    'image_idx': image_idx,
                    'gt_idx': i,
                    'box3d_lidar': gt_boxes_3d[i],
                    'num_points_in_gt': gt_points.shape[0],
                    'difficulty': difficulty[i],
                }
                local_group_id = group_ids[i]
                # if local_group_id >= 0:
                if local_group_id not in group_dict:
                    group_dict[local_group_id] = group_counter
                    group_counter += 1
                db_info['group_id'] = group_dict[local_group_id]
                if 'score' in annos:
                    db_info['score'] = annos['score'][i]
                if with_mask:
                    db_info.update({'box2d_camera': gt_boxes[i]})
                if names[i] in all_db_infos:
                    all_db_infos[names[i]].append(db_info)
                else:
                    all_db_infos[names[i]] = [db_info]

    for k, v in all_db_infos.items():
        print(f'load {len(v)} {k} database infos')

    with open(db_info_save_path, 'wb') as f:
        pickle.dump(all_db_infos, f)
