import torch
import torch.nn as nn
from model.TWDGCN.DGCRU import DDGCRNCell
from model.TWDGCN.ConnectionMatrix import ConnectionMatrix


class DGCRM(nn.Module):
    def __init__(self, node_num, dim_in, dim_out, cheb_k, embed_dim, num_layers=1):
        super(DGCRM, self).__init__()
        assert num_layers >= 1, 'At least one DGCRM layer is required.'

        self.node_num = node_num
        self.input_dim = dim_in
        self.num_layers = num_layers
        self.conn = ConnectionMatrix()

        # Initialize DGCRM cells
        self.DGCRM_cells = nn.ModuleList([
            DDGCRNCell(node_num, dim_in, dim_out, cheb_k, embed_dim)
            if i == 0 else
            DDGCRNCell(node_num, dim_out, dim_out, cheb_k, embed_dim)
            for i in range(num_layers)
        ])

    def forward(self, x, init_state, node_embeddings):
        """
        Forward pass of the DGCRM model.

        Parameters:
        - x: Input tensor of shape (B, T, N, D)
        - init_state: Initial hidden states of shape (num_layers, B, N, hidden_dim)
        - node_embeddings: Node embeddings
        """
        assert x.shape[2] == self.node_num and x.shape[3] == self.input_dim

        seq_length = x.shape[1]
        current_inputs = x
        output_hidden = []

        for i in range(self.num_layers):
            state = init_state[i]
            inner_states = []
            conn_mtx = self.conn.get(x) # Connectivity matrix

            for t in range(seq_length):
                state = self.DGCRM_cells[i](current_inputs[:, t, :, :], state,
                                            [node_embeddings[0][:, t, :, :], node_embeddings[1]],
                                            conn_mtx[t])
                inner_states.append(state)

            output_hidden.append(state)
            current_inputs = torch.stack(inner_states, dim=1)

        return current_inputs, output_hidden

    def init_hidden(self, batch_size):
        """
        Initialize hidden states for DGCRM layers.

        Parameters:
        - batch_size: Size of the batch

        Returns:
        - Initial hidden states tensor
        """
        return torch.stack([
            self.DGCRM_cells[i].init_hidden_state(batch_size)
            for i in range(self.num_layers)
        ], dim=0)


class TWDGCN(nn.Module):
    def __init__(self, args):
        super(TWDGCN, self).__init__()

        self.num_node = args['num_nodes']
        self.input_dim = args['input_dim']
        self.hidden_dim = args['rnn_units']
        self.output_dim = args['output_dim']
        self.horizon = args['horizon']
        self.num_layers = args['num_layers']
        self.use_day = args['use_day']
        self.use_week = args['use_week']
        self.default_graph = args['default_graph']

        self.node_embeddings1 = nn.Parameter(torch.randn(self.num_node, args['embed_dim']), requires_grad=True)
        self.node_embeddings2 = nn.Parameter(torch.randn(self.num_node, args['embed_dim']), requires_grad=True)
        self.T_i_D_emb = nn.Parameter(torch.empty(288, args['embed_dim']))
        self.D_i_W_emb = nn.Parameter(torch.empty(7, args['embed_dim']))

        self.dropout1 = nn.Dropout(p=0.1)
        self.dropout2 = nn.Dropout(p=0.1)

        self.encoder1 = DGCRM(self.num_node, self.input_dim, self.hidden_dim, args['cheb_order'], args['embed_dim'],
                              self.num_layers)
        self.encoder2 = DGCRM(self.num_node, self.input_dim, self.hidden_dim, args['cheb_order'], args['embed_dim'],
                              self.num_layers)

        # Predictor
        self.end_conv1 = nn.Conv2d(1, self.horizon * self.output_dim, kernel_size=(1, self.hidden_dim), bias=True)
        self.end_conv2 = nn.Conv2d(1, self.horizon * self.output_dim, kernel_size=(1, self.hidden_dim), bias=True)
        self.end_conv3 = nn.Conv2d(1, self.horizon * self.output_dim, kernel_size=(1, self.hidden_dim), bias=True)

    def forward(self, source):
        """
        Forward pass of the DDGCRN model.

        Parameters:
        - source: Input tensor of shape (B, T_1, N, D)
        - mode: Control mode for the forward pass

        Returns:
        - Output tensor
        """
        node_embedding1 = self.node_embeddings1

        if self.use_day:
            t_i_d_data = source[..., 1]
            T_i_D_emb = self.T_i_D_emb[(t_i_d_data * 288).long()]
            node_embedding1 = node_embedding1 * T_i_D_emb

        if self.use_week:
            d_i_w_data = source[..., 2]
            D_i_W_emb = self.D_i_W_emb[d_i_w_data.long()]
            node_embedding1 = node_embedding1 * D_i_W_emb

        node_embeddings = [node_embedding1, self.node_embeddings1]
        source = source[..., 0].unsqueeze(-1)

        init_state1 = self.encoder1.init_hidden(source.shape[0])
        output, _ = self.encoder1(source, init_state1, node_embeddings)
        output = self.dropout1(output[:, -1:, :, :])
        output1 = self.end_conv1(output)

        source1 = self.end_conv2(output)
        source2 = source[:, -self.horizon:, ...] - source1

        init_state2 = self.encoder2.init_hidden(source2.shape[0])
        output2, _ = self.encoder2(source2, init_state2, node_embeddings)
        output2 = self.dropout2(output2[:, -1:, :, :])
        output2 = self.end_conv3(output2)

        return output1 + output2