import tensorflow as tf
from ._dimenet_conv import DimNetInteractionPPBlock, DimNetOutputBlock, EmbeddingDimeBlock, SphericalBasisLayer
from kgcnn.layers.gather import GatherNodes
from kgcnn.layers.geom import NodeDistanceEuclidean, EdgeAngle, BesselBasisLayer, NodePosition, ShiftPeriodicLattice
from kgcnn.layers.modules import Dense, LazyConcatenate, LazyAdd, LazySubtract
from kgcnn.layers.pooling import PoolingNodes
from kgcnn.model.utils import update_model_kwargs
from kgcnn.layers.mlp import MLP

ks = tf.keras

# Keep track of model version from commit date in literature.
# To be updated if model is changed in a significant way.
__model_version__ = "2022.11.25"

# Implementation of DimeNet++ in `tf.keras` from paper:
# Fast and Uncertainty-Aware Directional Message Passing for Non-Equilibrium Molecules
# Johannes Klicpera, Shankari Giri, Johannes T. Margraf, Stephan Günnemann
# https://arxiv.org/abs/2011.14115
# Original code: https://github.com/gasteigerjo/dimenet

model_default = {
    "name": "DimeNetPP",
    "inputs": [{"shape": [None], "name": "node_attributes", "dtype": "float32", "ragged": True},
               {"shape": [None, 3], "name": "node_coordinates", "dtype": "float32", "ragged": True},
               {"shape": [None, 2], "name": "edge_indices", "dtype": "int64", "ragged": True},
               {"shape": [None, 2], "name": "angle_indices", "dtype": "int64", "ragged": True}],
    "input_embedding": {"node": {"input_dim": 95, "output_dim": 128,
                                 "embeddings_initializer": {"class_name": "RandomUniform",
                                                            "config": {"minval": -1.7320508075688772,
                                                                       "maxval": 1.7320508075688772}}}},
    "emb_size": 128, "out_emb_size": 256, "int_emb_size": 64, "basis_emb_size": 8,
    "num_blocks": 4, "num_spherical": 7, "num_radial": 6,
    "cutoff": 5.0, "envelope_exponent": 5,
    "num_before_skip": 1, "num_after_skip": 2, "num_dense_output": 3,
    "num_targets": 64, "extensive": True, "output_init": "zeros",
    "activation": "swish", "verbose": 10,
    "output_embedding": "graph",
    "use_output_mlp": True,
    "output_mlp": {"use_bias": [True, False],
                   "units": [64, 12], "activation": ["swish", "linear"]}
}


@update_model_kwargs(model_default)
def make_model(inputs: list = None,
               input_embedding: dict = None,
               emb_size: int = None,
               out_emb_size: int = None,
               int_emb_size: int = None,
               basis_emb_size: int = None,
               num_blocks: int = None,
               num_spherical: int = None,
               num_radial: int = None,
               cutoff: float = None,
               envelope_exponent: int = None,
               num_before_skip: int = None,
               num_after_skip: int = None,
               num_dense_output: int = None,
               num_targets: int = None,
               activation: str = None,
               extensive: bool = None,
               output_init: str = None,
               verbose: int = None,
               name: str = None,
               output_embedding: str = None,
               use_output_mlp: bool = None,
               output_mlp: dict = None
               ):
    """Make `DimeNetPP <https://arxiv.org/abs/2011.14115>`_ graph network via functional API.
    Default parameters can be found in :obj:`kgcnn.literature.DimeNetPP.model_default`.

    .. note::
        DimeNetPP does require a large amount of memory for this implementation, which increase quickly with
        the number of connections in a batch.

    Inputs:
        list: `[node_attributes, node_coordinates, bond_indices, angle_indices]`

            - node_attributes (tf.RaggedTensor): Node attributes of shape `(batch, None, F)` or `(batch, None)`
              using an embedding layer.
            - node_coordinates (tf.RaggedTensor): Atomic coordinates of shape `(batch, None, 3)`.
            - bond_indices (tf.RaggedTensor): Index list for edges or bonds of shape `(batch, None, 2)`.
            - angle_indices (tf.RaggedTensor): Index list of angles referring to bonds of shape `(batch, None, 2)`.

    Outputs:
        tf.Tensor: Graph embeddings of shape `(batch, L)` if :obj:`output_embedding="graph"`.


    Args:
        inputs (list): List of dictionaries unpacked in :obj:`tf.keras.layers.Input`. Order must match model definition.
        input_embedding (dict): Dictionary of embedding arguments for nodes etc. unpacked in :obj:`Embedding` layers.
        emb_size (int): Overall embedding size used for the messages.
        out_emb_size (int): Embedding size for output of :obj:`DimNetOutputBlock`.
        int_emb_size (int): Embedding size used for interaction triplets.
        basis_emb_size (int): Embedding size used inside the basis transformation.
        num_blocks (int): Number of graph embedding blocks or depth of the network.
        num_spherical (int): Number of spherical components in :obj:`SphericalBasisLayer`.
        num_radial (int): Number of radial components in basis layer.
        cutoff (float): Distance cutoff for basis layer.
        envelope_exponent (int): Exponent in envelope function for basis layer.
        num_before_skip (int): Number of residual layers in interaction block before skip connection
        num_after_skip (int): Number of residual layers in interaction block after skip connection
        num_dense_output (int): Number of dense units in output :obj:`DimNetOutputBlock`.
        num_targets (int): Number of targets or output embedding dimension of the model.
        activation (str, dict): Activation to use.
        extensive (bool): Graph output for extensive target to apply sum for pooling or mean otherwise.
        output_init (str, dict): Output initializer for kernel.
        verbose (int): Level of verbosity.
        name (str): Name of the model.
        output_embedding (str): Main embedding task for graph network. Either "node", "edge" or "graph".
        use_output_mlp (bool): Whether to use the final output MLP. Possibility to skip final :obj:`MLP`.
        output_mlp (dict): Dictionary of layer arguments unpacked in the final classification :obj:`MLP` layer block.
            Defines number of model outputs and activation. Note that DimeNetPP originally defines the output dimension
            via `num_targets`. But this can be set to `out_emb_size` and the `output_mlp` be used for more
            specific control.

    Returns:
        :obj:`tf.keras.models.Model`
    """
    # Make input
    node_input = ks.layers.Input(**inputs[0])
    xyz_input = ks.layers.Input(**inputs[1])
    bond_index_input = ks.layers.Input(**inputs[2])
    angle_index_input = ks.layers.Input(**inputs[3])

    # Atom embedding
    # n = generate_node_embedding(node_input, input_node_shape, input_embedding["nodes"])
    if len(inputs[0]["shape"]) == 1:
        n = EmbeddingDimeBlock(**input_embedding["node"])(node_input)
    else:
        n = node_input

    x = xyz_input
    edi = bond_index_input
    adi = angle_index_input

    # Calculate distances
    pos1, pos2 = NodePosition()([x, edi])
    d = NodeDistanceEuclidean()([pos1, pos2])
    rbf = BesselBasisLayer(num_radial=num_radial, cutoff=cutoff, envelope_exponent=envelope_exponent)(d)

    # Calculate angles
    v12 = LazySubtract()([pos1, pos2])
    a = EdgeAngle()([v12, adi])
    sbf = SphericalBasisLayer(num_spherical=num_spherical, num_radial=num_radial, cutoff=cutoff,
                              envelope_exponent=envelope_exponent)([d, a, adi])

    # Embedding block
    rbf_emb = Dense(emb_size, use_bias=True, activation=activation,
                    kernel_initializer="kgcnn>glorot_orthogonal")(rbf)
    n_pairs = GatherNodes()([n, edi])
    x = LazyConcatenate(axis=-1)([n_pairs, rbf_emb])
    x = Dense(emb_size, use_bias=True, activation=activation, kernel_initializer="kgcnn>glorot_orthogonal")(x)
    ps = DimNetOutputBlock(emb_size, out_emb_size, num_dense_output, num_targets=num_targets,
                           output_kernel_initializer=output_init)([n, x, rbf, edi])

    # Interaction blocks
    add_xp = LazyAdd()
    for i in range(num_blocks):
        x = DimNetInteractionPPBlock(emb_size, int_emb_size, basis_emb_size, num_before_skip, num_after_skip)(
            [x, rbf, sbf, adi])
        p_update = DimNetOutputBlock(emb_size, out_emb_size, num_dense_output, num_targets=num_targets,
                                     output_kernel_initializer=output_init)([n, x, rbf, edi])
        ps = add_xp([ps, p_update])

    if extensive:
        out = PoolingNodes(pooling_method="sum")(ps)
    else:
        out = PoolingNodes(pooling_method="mean")(ps)

    if use_output_mlp:
        out = MLP(**output_mlp)(out)

    if output_embedding != "graph":
        raise ValueError("Unsupported output embedding for mode `DimeNetPP`.")

    model = ks.models.Model(inputs=[node_input, xyz_input, bond_index_input, angle_index_input],
                            outputs=out)

    model.__kgcnn_model_version__ = __model_version__
    return model


model_crystal_default = {
    "name": "DimeNetPP",
    "inputs": [{"shape": [None], "name": "node_attributes", "dtype": "float32", "ragged": True},
               {"shape": [None, 3], "name": "node_coordinates", "dtype": "float32", "ragged": True},
               {"shape": [None, 2], "name": "edge_indices", "dtype": "int64", "ragged": True},
               {"shape": [None, 2], "name": "angle_indices", "dtype": "int64", "ragged": True},
               {'shape': (None, 3), 'name': "edge_image", 'dtype': 'int64', 'ragged': True},
               {'shape': (3, 3), 'name': "graph_lattice", 'dtype': 'float32', 'ragged': False}
               ],
    "input_embedding": {"node": {"input_dim": 95, "output_dim": 128,
                                 "embeddings_initializer": {"class_name": "RandomUniform",
                                                            "config": {"minval": -1.7320508075688772,
                                                                       "maxval": 1.7320508075688772}}}},
    "emb_size": 128, "out_emb_size": 256, "int_emb_size": 64, "basis_emb_size": 8,
    "num_blocks": 4, "num_spherical": 7, "num_radial": 6,
    "cutoff": 5.0, "envelope_exponent": 5,
    "num_before_skip": 1, "num_after_skip": 2, "num_dense_output": 3,
    "num_targets": 64, "extensive": True, "output_init": "zeros",
    "activation": "swish", "verbose": 10,
    "output_embedding": "graph",
    "use_output_mlp": True,
    "output_mlp": {"use_bias": [True, False],
                   "units": [64, 12], "activation": ["swish", "linear"]}
}


@update_model_kwargs(model_crystal_default)
def make_crystal_model(inputs: list = None,
                       input_embedding: dict = None,
                       emb_size: int = None,
                       out_emb_size: int = None,
                       int_emb_size: int = None,
                       basis_emb_size: int = None,
                       num_blocks: int = None,
                       num_spherical: int = None,
                       num_radial: int = None,
                       cutoff: float = None,
                       envelope_exponent: int = None,
                       num_before_skip: int = None,
                       num_after_skip: int = None,
                       num_dense_output: int = None,
                       num_targets: int = None,
                       activation: str = None,
                       extensive: bool = None,
                       output_init: str = None,
                       verbose: int = None,
                       name: str = None,
                       output_embedding: str = None,
                       use_output_mlp: bool = None,
                       output_mlp: dict = None
                       ):
    """Make `DimeNetPP <https://arxiv.org/abs/2011.14115>`_ graph network via functional API.
    Default parameters can be found in :obj:`kgcnn.literature.DimeNetPP.model_crystal_default`.

    .. note::
        DimeNetPP does require a large amount of memory for this implementation, which increase quickly with
        the number of connections in a batch.

    Inputs:
        list: `[node_attributes, node_coordinates, bond_indices, angle_indices, edge_image, lattice]`

            - node_attributes (tf.RaggedTensor): Node attributes of shape `(batch, None, F)` or `(batch, None)`
              using an embedding layer.
            - node_coordinates (tf.RaggedTensor): Atomic coordinates of shape `(batch, None, 3)`.
            - bond_indices (tf.RaggedTensor): Index list for edges or bonds of shape `(batch, None, 2)`.
            - angle_indices (tf.RaggedTensor): Index list of angles referring to bonds of shape `(batch, None, 2)`.
            - lattice (tf.Tensor): Lattice matrix of the periodic structure of shape `(batch, 3, 3)`.
            - edge_image (tf.RaggedTensor): Indices of the periodic image the sending node is located. The indices
                of and edge are :math:`(i, j)` with :math:`j` being the sending node.

    Outputs:
        tf.Tensor: Graph embeddings of shape `(batch, L)` if :obj:`output_embedding="graph"`.


    Args:
        inputs (list): List of dictionaries unpacked in :obj:`tf.keras.layers.Input`. Order must match model definition.
        input_embedding (dict): Dictionary of embedding arguments for nodes etc. unpacked in :obj:`Embedding` layers.
        emb_size (int): Overall embedding size used for the messages.
        out_emb_size (int): Embedding size for output of :obj:`DimNetOutputBlock`.
        int_emb_size (int): Embedding size used for interaction triplets.
        basis_emb_size (int): Embedding size used inside the basis transformation.
        num_blocks (int): Number of graph embedding blocks or depth of the network.
        num_spherical (int): Number of spherical components in :obj:`SphericalBasisLayer`.
        num_radial (int): Number of radial components in basis layer.
        cutoff (float): Distance cutoff for basis layer.
        envelope_exponent (int): Exponent in envelope function for basis layer.
        num_before_skip (int): Number of residual layers in interaction block before skip connection
        num_after_skip (int): Number of residual layers in interaction block after skip connection
        num_dense_output (int): Number of dense units in output :obj:`DimNetOutputBlock`.
        num_targets (int): Number of targets or output embedding dimension of the model.
        activation (str, dict): Activation to use.
        extensive (bool): Graph output for extensive target to apply sum for pooling or mean otherwise.
        output_init (str, dict): Output initializer for kernel.
        verbose (int): Level of verbosity.
        name (str): Name of the model.
        output_embedding (str): Main embedding task for graph network. Either "node", "edge" or "graph".
        use_output_mlp (bool): Whether to use the final output MLP. Possibility to skip final :obj:`MLP`.
        output_mlp (dict): Dictionary of layer arguments unpacked in the final classification :obj:`MLP` layer block.
            Defines number of model outputs and activation. Note that DimeNetPP originally defines the output dimension
            via `num_targets`. But this can be set to `out_emb_size` and the `output_mlp` be used for more
            specific control.

    Returns:
        :obj:`tf.keras.models.Model`
    """
    # Make input
    node_input = ks.layers.Input(**inputs[0])
    xyz_input = ks.layers.Input(**inputs[1])
    bond_index_input = ks.layers.Input(**inputs[2])
    angle_index_input = ks.layers.Input(**inputs[3])
    edge_image = ks.layers.Input(**inputs[4])
    lattice = ks.layers.Input(**inputs[5])

    # Atom embedding
    # n = generate_node_embedding(node_input, input_node_shape, input_embedding["nodes"])
    if len(inputs[0]["shape"]) == 1:
        n = EmbeddingDimeBlock(**input_embedding["node"])(node_input)
    else:
        n = node_input

    x = xyz_input
    edi = bond_index_input
    adi = angle_index_input

    # Calculate distances
    pos1, pos2 = NodePosition()([x, edi])
    pos2 = ShiftPeriodicLattice()([pos2, edge_image, lattice])
    d = NodeDistanceEuclidean()([pos1, pos2])
    rbf = BesselBasisLayer(num_radial=num_radial, cutoff=cutoff, envelope_exponent=envelope_exponent)(d)

    # Calculate angles
    v12 = LazySubtract()([pos1, pos2])
    a = EdgeAngle()([v12, adi])
    sbf = SphericalBasisLayer(num_spherical=num_spherical, num_radial=num_radial, cutoff=cutoff,
                              envelope_exponent=envelope_exponent)([d, a, adi])

    # Embedding block
    rbf_emb = Dense(emb_size, use_bias=True, activation=activation,
                    kernel_initializer="kgcnn>glorot_orthogonal")(rbf)
    n_pairs = GatherNodes()([n, edi])
    x = LazyConcatenate(axis=-1)([n_pairs, rbf_emb])
    x = Dense(emb_size, use_bias=True, activation=activation, kernel_initializer="kgcnn>glorot_orthogonal")(x)
    ps = DimNetOutputBlock(emb_size, out_emb_size, num_dense_output, num_targets=num_targets,
                           output_kernel_initializer=output_init)([n, x, rbf, edi])

    # Interaction blocks
    add_xp = LazyAdd()
    for i in range(num_blocks):
        x = DimNetInteractionPPBlock(emb_size, int_emb_size, basis_emb_size, num_before_skip, num_after_skip)(
            [x, rbf, sbf, adi])
        p_update = DimNetOutputBlock(emb_size, out_emb_size, num_dense_output, num_targets=num_targets,
                                     output_kernel_initializer=output_init)([n, x, rbf, edi])
        ps = add_xp([ps, p_update])

    if extensive:
        out = PoolingNodes(pooling_method="sum")(ps)
    else:
        out = PoolingNodes(pooling_method="mean")(ps)

    if use_output_mlp:
        out = MLP(**output_mlp)(out)

    if output_embedding != "graph":
        raise ValueError("Unsupported output embedding for mode `DimeNetPP`.")

    model = ks.models.Model(inputs=[node_input, xyz_input, bond_index_input, angle_index_input, edge_image, lattice],
                            outputs=out)

    model.__kgcnn_model_version__ = __model_version__
    return model
