# Copyright 2022 The KerasCV Authors
#
# 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
#
#     https://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 tensorflow as tf

from keras_cv.api_export import keras_cv_export
from keras_cv.backend import keras
from keras_cv.backend import random

POINT_CLOUDS = "point_clouds"
BOUNDING_BOXES = "bounding_boxes"
OBJECT_POINT_CLOUDS = "object_point_clouds"
OBJECT_BOUNDING_BOXES = "object_bounding_boxes"
ADDITIONAL_POINT_CLOUDS = "additional_point_clouds"
ADDITIONAL_BOUNDING_BOXES = "additional_bounding_boxes"
BOX_LABEL_INDEX = 7
POINTCLOUD_LABEL_INDEX = 3
POINTCLOUD_FEATURE_INDEX = 4


@keras_cv_export("keras_cv.layers.BaseAugmentationLayer3D")
class BaseAugmentationLayer3D(keras.layers.Layer):
    """Abstract base layer for data augmentation for 3D perception.

    This layer contains base functionalities for preprocessing layers which
    augment 3D perception related data, e.g. point_clouds and in the future,
    images. The subclasses could avoid making certain mistakes and reduce code
    duplications.

    This layer requires you to implement one method: `augment_point_clouds()`,
    which augments one or a sequence of point clouds during the training. There
    are a few additional methods that you can implement for added functionality
    on the layer:

    `augment_bounding_boxes()`, which handles the bounding box augmentation, if
    the layer supports that.

    `get_random_transformation()`, which should produce a random transformation
    setting. The transformation object, which could be any type, will be passed
    to `augment_point_clouds` and `augment_bounding_boxes`, to coordinate the
    randomness behavior, eg, in the RotateZ layer, the point_clouds and
    bounding_boxes should be changed in the same way.

    The `call()` method support two formats of inputs:
    1. A dict of tensors with stable keys. The supported keys are:
      `"point_clouds"` and `"bounding_boxes"` at the moment. We might add
      more keys in future when we support more types of augmentation.

    The output of the `call()` will be in two formats, which will be the same
    structure as the inputs.

    The `call()` will handle the logic detecting the training/inference mode,
    unpack the inputs, forward to the correct function, and pack the output back
    to the same structure as the inputs.

    By default, the `call()` method leverages the `tf.vectorized_map()`
    function. Auto-vectorization can be disabled by setting
    `self.auto_vectorize = False` in your `__init__()` method. When disabled,
    `call()` instead relies on `tf.map_fn()`. For example:

    ```python
    class SubclassLayer(keras_cv.BaseImageAugmentationLayer):
      def __init__(self):
        super().__init__()
        self.auto_vectorize = False
    ```

    Example:

    ```python
    class RandomRotateZ(keras_cv.BaseImageAugmentationLayer):

      def __init__(self, max_rotation, **kwargs):
        super().__init__(**kwargs)
        self._max_rotation = max_rotation

      def augment_pointclouds(self, point_clouds, transformation):
        pose = transformation['pos']
        # Rotate points.
        pointcloud_xyz = geometry.CoordinateTransform(pointcloud[..., :3], pose)
        pointcloud = tf.concat([pointcloud_xyz, pointcloud[..., 3:]], axis=-1)
        return pointcloud, boxes
    ```
    """

    def __init__(self, seed=None, **kwargs):
        super().__init__(**kwargs)
        self.auto_vectorize = False
        self.seed = seed
        self._random_generator = random.SeedGenerator(seed=self.seed)

    @property
    def auto_vectorize(self):
        """Control whether automatic vectorization occurs.

        By default, the `call()` method leverages the `tf.vectorized_map()`
        function. Auto-vectorization can be disabled by setting
        `self.auto_vectorize = False` in your `__init__()` method. When
        disabled, `call()` instead relies on `tf.map_fn()`. For example:

        ```python
        class SubclassLayer(BaseImageAugmentationLayer):
          def __init__(self):
            super().__init__()
            self.auto_vectorize = False
        ```
        """
        return getattr(self, "_auto_vectorize", True)

    @auto_vectorize.setter
    def auto_vectorize(self, auto_vectorize):
        self._auto_vectorize = auto_vectorize

    @property
    def _map_fn(self):
        if self.auto_vectorize:
            return tf.vectorized_map
        else:
            return tf.map_fn

    def augment_point_clouds_bounding_boxes(
        self, point_clouds, bounding_boxes, transformation, **kwargs
    ):
        """Augment a single point cloud frame during training.

        Args:
          point_clouds: 3D point cloud input tensor to the layer. Forwarded from
            `layer.call()`.
          bounding_boxes: 3D bounding boxes to the layer. Forwarded from
            `call()`.
          transformation: The transformation object produced by
            `get_random_transformation`. Used to coordinate the randomness
            between point clouds, bounding boxs.

        Returns:
          output 3D tensor, which will be forward to `layer.call()`.
        """
        raise NotImplementedError()

    def get_random_transformation(self, point_clouds=None, bounding_boxes=None):
        """Produce random transformation config for one single input.

        This is used to produce same randomness between
        image/label/bounding_box.

        Args:
          point_clouds: 3D point clouds tensor from inputs.
          bounding_boxes: 3D bounding boxes tensor from inputs.

        Returns:
          Any type of object, which will be forwarded to `augment_point_clouds`,
          and `augment_bounding_box` as the `transformation` parameter.
        """
        return None

    def call(self, inputs):
        if "3d_boxes" in inputs.keys():
            # TODO(ianstenbit): Consider using the better format internally
            # (in the KPL implementations) instead of wrapping it at call time.
            point_clouds, bounding_boxes = convert_from_model_format(inputs)
            inputs = {
                POINT_CLOUDS: point_clouds,
                BOUNDING_BOXES: bounding_boxes,
            }
            use_model_format = True
        else:
            point_clouds = inputs[POINT_CLOUDS]
            bounding_boxes = inputs[BOUNDING_BOXES]
            use_model_format = False
        if point_clouds.shape.rank == 3 and bounding_boxes.shape.rank == 3:
            outputs = self._augment(inputs)
        elif point_clouds.shape.rank == 4 and bounding_boxes.shape.rank == 4:
            outputs = self._batch_augment(inputs)
        else:
            raise ValueError(
                "Point clouds augmentation layers are expecting inputs "
                "point clouds and bounding boxes to be rank 3D (Frame, Point, "
                "Feature) or 4D (Batch, Frame, Point, Feature) tensors. Got "
                "shape: {} and {}".format(
                    point_clouds.shape, bounding_boxes.shape
                )
            )
        if use_model_format:
            return convert_to_model_format(outputs)
        else:
            return outputs

    def _augment(self, inputs):
        point_clouds = inputs.get(POINT_CLOUDS, None)
        bounding_boxes = inputs.get(BOUNDING_BOXES, None)
        transformation = self.get_random_transformation(
            point_clouds=point_clouds,
            bounding_boxes=bounding_boxes,
        )
        point_clouds, bounding_boxes = self.augment_point_clouds_bounding_boxes(
            point_clouds,
            bounding_boxes=bounding_boxes,
            transformation=transformation,
        )

        result = {POINT_CLOUDS: point_clouds, BOUNDING_BOXES: bounding_boxes}

        # preserve any additional inputs unmodified by this layer.
        for key in inputs.keys() - result.keys():
            result[key] = inputs[key]
        return result

    def _batch_augment(self, inputs):
        return self._map_fn(self._augment, inputs)


def convert_to_model_format(inputs):
    point_clouds = {
        "point_xyz": inputs["point_clouds"][..., :3],
        "point_feature": inputs["point_clouds"][..., 3:-1],
        "point_mask": tf.cast(inputs["point_clouds"][..., -1], tf.bool),
    }
    boxes = {
        "boxes": inputs["bounding_boxes"][..., :7],
        "classes": inputs["bounding_boxes"][..., 7],
        "mask": tf.cast(inputs["bounding_boxes"][..., 8], tf.bool),
    }

    # Special case for when we have a difficulty field
    if inputs["bounding_boxes"].shape[-1] > 8:
        boxes["difficulty"] = inputs["bounding_boxes"][..., -1]

    return {
        "point_clouds": point_clouds,
        "3d_boxes": boxes,
    }


def convert_from_model_format(inputs):
    point_clouds = tf.concat(
        [
            inputs["point_clouds"]["point_xyz"],
            inputs["point_clouds"]["point_feature"],
            tf.expand_dims(
                tf.cast(
                    inputs["point_clouds"]["point_mask"],
                    inputs["point_clouds"]["point_xyz"].dtype,
                ),
                axis=-1,
            ),
        ],
        axis=-1,
    )

    box_tensors = [
        inputs["3d_boxes"]["boxes"],
        tf.expand_dims(
            tf.cast(
                inputs["3d_boxes"]["classes"], inputs["3d_boxes"]["boxes"].dtype
            ),
            axis=-1,
        ),
        tf.expand_dims(
            tf.cast(
                inputs["3d_boxes"]["mask"], inputs["3d_boxes"]["boxes"].dtype
            ),
            axis=-1,
        ),
    ]

    # Special case for when we have a difficulty field
    if "difficulty" in inputs["3d_boxes"].keys():
        box_tensors.append(
            tf.expand_dims(
                tf.cast(
                    inputs["3d_boxes"]["difficulty"],
                    inputs["3d_boxes"]["boxes"].dtype,
                ),
                axis=-1,
            )
        )

    boxes = tf.concat(box_tensors, axis=-1)

    return point_clouds, boxes
