from sklearn.metrics.pairwise import paired_distances

from sklearn.decomposition import PCA

from sklearn import metrics

from sklearn.cluster import KMeans

import torch

import torch.nn as nn

from torch.autograd import Variable

from torch.nn import Parameter

import torch.nn.functional as F

import torch.optim as optim

from torch.utils.data import DataLoader, TensorDataset

from layers import NBLoss, ZINBLoss, MeanAct, DispAct

import numpy as np

import math, os

def buildNetwork2(layers, type, activation="relu"):

    net = []

    for i in range(1, len(layers)):

        net.append(nn.Linear(layers[i-1], layers[i]))

        net.append(nn.BatchNorm1d(layers[i], affine=True))

        if activation=="relu":

            net.append(nn.ReLU())

        elif activation=="selu":

            net.append(nn.SELU())

        elif activation=="sigmoid":

            net.append(nn.Sigmoid())

        elif activation=="elu":

            net.append(nn.ELU())

    return nn.Sequential(*net)

class scMultiCluster(nn.Module):

    def __init__(self, input_dim1, input_dim2,

            encodeLayer=[], decodeLayer1=[], decodeLayer2=[], tau=1., t=10, device="cuda",

            activation="elu", sigma1=2.5, sigma2=.1, alpha=1., gamma=1., phi1=0.0001, phi2=0.0001, cutoff = 0.5):

        super(scMultiCluster, self).__init__()

        self.tau=tau

        self.input_dim1 = input_dim1

        self.input_dim2 = input_dim2

        self.cutoff = cutoff

        self.activation = activation

        self.sigma1 = sigma1

        self.sigma2 = sigma2

        self.alpha = alpha

        self.gamma = gamma

        self.phi1 = phi1

        self.phi2 = phi2

        self.t = t

        self.device = device

        self.encoder = buildNetwork2([input_dim1+input_dim2]+encodeLayer, type="encode", activation=activation)

        self.decoder1 = buildNetwork2(decodeLayer1, type="decode", activation=activation)

        self.decoder2 = buildNetwork2(decodeLayer2, type="decode", activation=activation)       

        self.dec_mean1 = nn.Sequential(nn.Linear(decodeLayer1[-1], input_dim1), MeanAct())

        self.dec_disp1 = nn.Sequential(nn.Linear(decodeLayer1[-1], input_dim1), DispAct())

        self.dec_mean2 = nn.Sequential(nn.Linear(decodeLayer2[-1], input_dim2), MeanAct())

        self.dec_disp2 = nn.Sequential(nn.Linear(decodeLayer2[-1], input_dim2), DispAct())

        self.dec_pi1 = nn.Sequential(nn.Linear(decodeLayer1[-1], input_dim1), nn.Sigmoid())

        self.dec_pi2 = nn.Sequential(nn.Linear(decodeLayer2[-1], input_dim2), nn.Sigmoid())

        self.zinb_loss = ZINBLoss()

        self.z_dim = encodeLayer[-1]

    def save_model(self, path):

        torch.save(self.state_dict(), path)

    def load_model(self, path):

        pretrained_dict = torch.load(path, map_location=lambda storage, loc: storage)

        model_dict = self.state_dict()

        pretrained_dict = {k: v for k, v in pretrained_dict.items() if k in model_dict}

        model_dict.update(pretrained_dict) 

        self.load_state_dict(model_dict)

    def cal_latent(self, z):

        sum_y = torch.sum(torch.square(z), dim=1)

        num = -2.0 * torch.matmul(z, z.t()) + torch.reshape(sum_y, [-1, 1]) + sum_y

        num = num / self.alpha

        num = torch.pow(1.0 + num, -(self.alpha + 1.0) / 2.0)

        zerodiag_num = num - torch.diag(torch.diag(num))

        latent_p = (zerodiag_num.t() / torch.sum(zerodiag_num, dim=1)).t()

        return num, latent_p

    def kmeans_loss(self, z):

        dist1 = self.tau*torch.sum(torch.square(z.unsqueeze(1) - self.mu), dim=2)

        temp_dist1 = dist1 - torch.reshape(torch.mean(dist1, dim=1), [-1, 1])

        q = torch.exp(-temp_dist1)

        q = (q.t() / torch.sum(q, dim=1)).t()

        q = torch.pow(q, 2)

        q = (q.t() / torch.sum(q, dim=1)).t()

        dist2 = dist1 * q

        return dist1, torch.mean(torch.sum(dist2, dim=1))

    def target_distribution(self, q):

        p = q**2 / q.sum(0)

        return (p.t() / p.sum(1)).t()

    def forward(self, x1, x2):

        x = torch.cat([x1+torch.randn_like(x1)*self.sigma1, x2+torch.randn_like(x2)*self.sigma2], dim=-1)

        h = self.encoder(x)

        h1 = self.decoder1(h)

        mean1 = self.dec_mean1(h1)

        disp1 = self.dec_disp1(h1)

        pi1 = self.dec_pi1(h1)

        h2 = self.decoder2(h)

        mean2 = self.dec_mean2(h2)

        disp2 = self.dec_disp2(h2)

        pi2 = self.dec_pi2(h2)

        x0 = torch.cat([x1, x2], dim=-1)

        h0 = self.encoder(x0)

        num, lq = self.cal_latent(h0)

        return h0, num, lq, mean1, mean2, disp1, disp2, pi1, pi2

    def forwardAE(self, x1, x2):

        x = torch.cat([x1+torch.randn_like(x1)*self.sigma1, x2+torch.randn_like(x2)*self.sigma2], dim=-1)

        h = self.encoder(x)

        h1 = self.decoder1(h)

        mean1 = self.dec_mean1(h1)

        disp1 = self.dec_disp1(h1)

        pi1 = self.dec_pi1(h1)

        h2 = self.decoder2(h)

        mean2 = self.dec_mean2(h2)

        disp2 = self.dec_disp2(h2)

        pi2 = self.dec_pi2(h2)

        x0 = torch.cat([x1, x2], dim=-1)

        h0 = self.encoder(x0)

        num, lq = self.cal_latent(h0)

        return h0, num, lq, mean1, mean2, disp1, disp2, pi1, pi2

    def encodeBatch(self, X1, X2, batch_size=256):

        use_cuda = torch.cuda.is_available()

        if use_cuda:

            self.to(self.device)

        encoded = []

        self.eval()

        num = X1.shape[0]

        num_batch = int(math.ceil(1.0*X1.shape[0]/batch_size))

        for batch_idx in range(num_batch):

            x1batch = X1[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

            x2batch = X2[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

            inputs1 = Variable(x1batch)

            inputs2 = Variable(x2batch)

            z,_,_,_,_,_,_,_,_ = self.forwardAE(inputs1, inputs2)

            encoded.append(z.data)

        encoded = torch.cat(encoded, dim=0)

        return encoded

    def kldloss(self, p, q):

        c1 = -torch.sum(p * torch.log(q), dim=-1)

        c2 = -torch.sum(p * torch.log(p), dim=-1)

        return torch.mean(c1 - c2)

    def pretrain_autoencoder(self, X1, X_raw1, sf1, X2, X_raw2, sf2, 

            batch_size=256, lr=0.001, epochs=400, ae_save=True, ae_weights='AE_weights.pth.tar'):

        num_batch = int(math.ceil(1.0*X1.shape[0]/batch_size))

        dataset = TensorDataset(torch.Tensor(X1), torch.Tensor(X_raw1), torch.Tensor(sf1), torch.Tensor(X2), torch.Tensor(X_raw2), torch.Tensor(sf2))

        dataloader = DataLoader(dataset, batch_size=batch_size, shuffle=True)

        print("Pretraining stage")

        optimizer = optim.Adam(filter(lambda p: p.requires_grad, self.parameters()), lr=lr, amsgrad=True)

        num = X1.shape[0]

        for epoch in range(epochs):

            loss_val = 0

            recon_loss1_val = 0

            recon_loss2_val = 0

            kl_loss_val = 0

            for batch_idx, (x1_batch, x_raw1_batch, sf1_batch, x2_batch, x_raw2_batch, sf2_batch) in enumerate(dataloader):

                x1_tensor = Variable(x1_batch).to(self.device)

                x_raw1_tensor = Variable(x_raw1_batch).to(self.device)

                sf1_tensor = Variable(sf1_batch).to(self.device)

                x2_tensor = Variable(x2_batch).to(self.device)

                x_raw2_tensor = Variable(x_raw2_batch).to(self.device)

                sf2_tensor = Variable(sf2_batch).to(self.device)

                zbatch, z_num, lqbatch, mean1_tensor, mean2_tensor, disp1_tensor, disp2_tensor, pi1_tensor, pi2_tensor = self.forwardAE(x1_tensor, x2_tensor)

                recon_loss1 = self.zinb_loss(x=x_raw1_tensor, mean=mean1_tensor, disp=disp1_tensor, pi=pi1_tensor, scale_factor=sf1_tensor)

                recon_loss2 = self.zinb_loss(x=x_raw2_tensor, mean=mean2_tensor, disp=disp2_tensor, pi=pi2_tensor, scale_factor=sf2_tensor)

                lpbatch = self.target_distribution(lqbatch)

                lqbatch = lqbatch + torch.diag(torch.diag(z_num))

                lpbatch = lpbatch + torch.diag(torch.diag(z_num))

                kl_loss = self.kldloss(lpbatch, lqbatch) 

                if epoch+1 >= epochs * self.cutoff:

                   loss = recon_loss1 + recon_loss2 + kl_loss * self.phi1

                else:

                   loss = recon_loss1 + recon_loss2

                optimizer.zero_grad()

                loss.backward()

                optimizer.step()

                loss_val += loss.item() * len(x1_batch)

                recon_loss1_val += recon_loss1.item() * len(x1_batch)

                recon_loss2_val += recon_loss2.item() * len(x2_batch)

                if epoch+1 >= epochs * self.cutoff:

                    kl_loss_val += kl_loss.item() * len(x1_batch)

            loss_val = loss_val/num

            recon_loss1_val = recon_loss1_val/num

            recon_loss2_val = recon_loss2_val/num

            kl_loss_val = kl_loss_val/num

            if epoch%self.t == 0:

               print('Pretrain epoch {}, Total loss:{:.6f}, ZINB loss1:{:.6f}, ZINB loss2:{:.6f}, KL loss:{:.6f}'.format(epoch+1, loss_val, recon_loss1_val, recon_loss2_val, kl_loss_val))

        if ae_save:

            torch.save({'ae_state_dict': self.state_dict(),

                    'optimizer_state_dict': optimizer.state_dict()}, ae_weights)

    def save_checkpoint(self, state, index, filename):

        newfilename = os.path.join(filename, 'FTcheckpoint_%d.pth.tar' % index)

        torch.save(state, newfilename)

    def fit(self, X1, X_raw1, sf1, X2, X_raw2, sf2, y=None, lr=1., n_clusters = 4,

            batch_size=256, num_epochs=10, update_interval=1, tol=1e-3, save_dir=""):

        '''X: tensor data'''

        use_cuda = torch.cuda.is_available()

        if use_cuda:

            self.to(self.device)

        print("Clustering stage")

        X1 = torch.tensor(X1).to(self.device)

        X_raw1 = torch.tensor(X_raw1).to(self.device)

        sf1 = torch.tensor(sf1).to(self.device)

        X2 = torch.tensor(X2).to(self.device)

        X_raw2 = torch.tensor(X_raw2).to(self.device)

        sf2 = torch.tensor(sf2).to(self.device)

        self.mu = Parameter(torch.Tensor(n_clusters, self.z_dim), requires_grad=True)

        optimizer = optim.Adadelta(filter(lambda p: p.requires_grad, self.parameters()), lr=lr, rho=.95)

        print("Initializing cluster centers with kmeans.")

        kmeans = KMeans(n_clusters, n_init=20)

        Zdata = self.encodeBatch(X1, X2, batch_size=batch_size)

        #latent

        self.y_pred = kmeans.fit_predict(Zdata.data.cpu().numpy())

        self.y_pred_last = self.y_pred

        self.mu.data.copy_(torch.Tensor(kmeans.cluster_centers_))

        if y is not None:

            ami = np.round(metrics.adjusted_mutual_info_score(y, self.y_pred), 5)

            nmi = np.round(metrics.normalized_mutual_info_score(y, self.y_pred), 5)

            ari = np.round(metrics.adjusted_rand_score(y, self.y_pred), 5)

            print('Initializing k-means: AMI= %.4f, NMI= %.4f, ARI= %.4f' % (ami, nmi, ari))

        self.train()

        num = X1.shape[0]

        num_batch = int(math.ceil(1.0*X1.shape[0]/batch_size))

        final_ami, final_nmi, final_ari, final_epoch = 0, 0, 0, 0

        for epoch in range(num_epochs):

            if epoch%update_interval == 0:

                Zdata = self.encodeBatch(X1, X2, batch_size=batch_size)

                dist, _ = self.kmeans_loss(Zdata)

                self.y_pred = torch.argmin(dist, dim=1).data.cpu().numpy()

                if y is not None:

                    #acc2 = np.round(cluster_acc(y, self.y_pred), 5)

                    final_ami = ami = np.round(metrics.adjusted_mutual_info_score(y, self.y_pred), 5)

                    final_nmi = nmi = np.round(metrics.normalized_mutual_info_score(y, self.y_pred), 5)

                    final_ari = ari = np.round(metrics.adjusted_rand_score(y, self.y_pred), 5)

                    final_epoch = epoch+1

                    print('Clustering   %d: AMI= %.4f, NMI= %.4f, ARI= %.4f' % (epoch+1, ami, nmi, ari))

                # check stop criterion

                delta_label = np.sum(self.y_pred != self.y_pred_last).astype(np.float32) / num

                self.y_pred_last = self.y_pred

                if epoch>0 and delta_label < tol:

                   print('delta_label ', delta_label, '< tol ', tol)

                   print("Reach tolerance threshold. Stopping training.")

                   break

                #save current model

                # if (epoch>0 and delta_label < tol) or epoch%10 == 0:

                    # self.save_checkpoint({'epoch': epoch+1,

                            # 'state_dict': self.state_dict(),

                            # 'mu': self.mu,

                            # 'y_pred': self.y_pred,

                            # 'y_pred_last': self.y_pred_last,

                            # 'y': y

                            # }, epoch+1, filename=save_dir)

            # train 1 epoch for clustering loss

            loss_val = 0.0

            recon_loss1_val = 0.0

            recon_loss2_val = 0.0

            cluster_loss_val = 0.0

            kl_loss_val = 0.0

            for batch_idx in range(num_batch):

                x1_batch = X1[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                x_raw1_batch = X_raw1[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                sf1_batch = sf1[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                x2_batch = X2[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                x_raw2_batch = X_raw2[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                sf2_batch = sf2[batch_idx*batch_size : min((batch_idx+1)*batch_size, num)]

                inputs1 = Variable(x1_batch)

                rawinputs1 = Variable(x_raw1_batch)

                sfinputs1 = Variable(sf1_batch)

                inputs2 = Variable(x2_batch)

                rawinputs2 = Variable(x_raw2_batch)

                sfinputs2 = Variable(sf2_batch)

                zbatch, z_num, lqbatch, mean1_tensor, mean2_tensor, disp1_tensor, disp2_tensor, pi1_tensor, pi2_tensor = self.forward(inputs1, inputs2)

                _, cluster_loss = self.kmeans_loss(zbatch)

                recon_loss1 = self.zinb_loss(x=rawinputs1, mean=mean1_tensor, disp=disp1_tensor, pi=pi1_tensor, scale_factor=sfinputs1)

                recon_loss2 = self.zinb_loss(x=rawinputs2, mean=mean2_tensor, disp=disp2_tensor, pi=pi2_tensor, scale_factor=sfinputs2)

                target2 = self.target_distribution(lqbatch)

                lqbatch = lqbatch + torch.diag(torch.diag(z_num))

                target2 = target2 + torch.diag(torch.diag(z_num))

                kl_loss = self.kldloss(target2, lqbatch)

                loss = recon_loss1 + recon_loss2 + kl_loss * self.phi2 + cluster_loss * self.gamma

                optimizer.zero_grad()

                loss.backward()

#                torch.nn.utils.clip_grad_norm_(self.mu, 1)

                optimizer.step()

                cluster_loss_val += cluster_loss.data * len(inputs1)

                recon_loss1_val += recon_loss1.data * len(inputs1)

                recon_loss2_val += recon_loss2.data * len(inputs2)

                kl_loss_val += kl_loss.data * len(inputs1)

                loss_val = cluster_loss_val + recon_loss1_val + recon_loss2_val + kl_loss_val

            if epoch%self.t == 0:

               print("#Epoch %d: Total: %.6f Clustering Loss: %.6f ZINB Loss1: %.6f ZINB Loss2: %.6f KL Loss: %.6f" % (

                     epoch + 1, loss_val / num, cluster_loss_val / num, recon_loss1_val / num, recon_loss2_val / num, kl_loss_val / num))

        return self.y_pred, final_epoch