import time
import numpy as np
import tensorflow as tf

from gat.models import GAT
from gat.utils import process

checkpt_file = 'pre_trained/cora/mod_cora.ckpt'

dataset = 'cora'

# training params
batch_size = 1
nb_epochs = 100000
patience = 100
lr = 0.005  # learning rate
l2_coef = 0.0005  # weight decay
hid_units = [8
             ]  # numbers of hidden units per each attention head in each layer
n_heads = [8, 1]  # additional entry for the output layer
residual = False
nonlinearity = tf.nn.elu
model = GAT

print('Dataset: ' + dataset)
print('----- Opt. hyperparams -----')
print('lr: ' + str(lr))
print('l2_coef: ' + str(l2_coef))
print('----- Archi. hyperparams -----')
print('nb. layers: ' + str(len(hid_units)))
print('nb. units per layer: ' + str(hid_units))
print('nb. attention heads: ' + str(n_heads))
print('residual: ' + str(residual))
print('nonlinearity: ' + str(nonlinearity))
print('model: ' + str(model))

adj, features, y_train, y_val, y_test, train_mask, val_mask, test_mask = process.load_data(
    dataset)
features, spars = process.preprocess_features(features)

nb_nodes = features.shape[0]
ft_size = features.shape[1]
nb_classes = y_train.shape[1]

adj = adj.todense()

features = features[np.newaxis]
adj = adj[np.newaxis]
y_train = y_train[np.newaxis]
y_val = y_val[np.newaxis]
y_test = y_test[np.newaxis]
train_mask = train_mask[np.newaxis]
val_mask = val_mask[np.newaxis]
test_mask = test_mask[np.newaxis]

biases = process.adj_to_bias(adj, [nb_nodes], nhood=1)

with tf.Graph().as_default():
    with tf.name_scope('input'):
        ftr_in = tf.placeholder(
            dtype=tf.float32, shape=(batch_size, nb_nodes, ft_size))
        bias_in = tf.placeholder(
            dtype=tf.float32, shape=(batch_size, nb_nodes, nb_nodes))
        lbl_in = tf.placeholder(
            dtype=tf.int32, shape=(batch_size, nb_nodes, nb_classes))
        msk_in = tf.placeholder(dtype=tf.int32, shape=(batch_size, nb_nodes))
        attn_drop = tf.placeholder(dtype=tf.float32, shape=())
        ffd_drop = tf.placeholder(dtype=tf.float32, shape=())
        is_train = tf.placeholder(dtype=tf.bool, shape=())

    logits = model.inference(
        ftr_in,
        nb_classes,
        nb_nodes,
        is_train,
        attn_drop,
        ffd_drop,
        bias_mat=bias_in,
        hid_units=hid_units,
        n_heads=n_heads,
        residual=residual,
        activation=nonlinearity)
    log_resh = tf.reshape(logits, [-1, nb_classes])
    lab_resh = tf.reshape(lbl_in, [-1, nb_classes])
    msk_resh = tf.reshape(msk_in, [-1])
    loss = model.masked_softmax_cross_entropy(log_resh, lab_resh, msk_resh)
    accuracy = model.masked_accuracy(log_resh, lab_resh, msk_resh)

    train_op = model.training(loss, lr, l2_coef)

    saver = tf.train.Saver()

    init_op = tf.group(tf.global_variables_initializer(),
                       tf.local_variables_initializer())

    vlss_mn = np.inf
    vacc_mx = 0.0
    curr_step = 0

    with tf.Session() as sess:
        sess.run(init_op)

        train_loss_avg = 0
        train_acc_avg = 0
        val_loss_avg = 0
        val_acc_avg = 0

        for epoch in range(nb_epochs):
            tr_step = 0
            tr_size = features.shape[0]

            while tr_step * batch_size < tr_size:
                _, loss_value_tr, acc_tr = sess.run(
                    [train_op, loss, accuracy],
                    feed_dict={
                        ftr_in:
                        features[tr_step * batch_size:(tr_step + 1) *
                                 batch_size],
                        bias_in:
                        biases[tr_step * batch_size:(tr_step + 1) *
                               batch_size],
                        lbl_in:
                        y_train[tr_step * batch_size:(tr_step + 1) *
                                batch_size],
                        msk_in:
                        train_mask[tr_step * batch_size:(tr_step + 1) *
                                   batch_size],
                        is_train:
                        True,
                        attn_drop:
                        0.6,
                        ffd_drop:
                        0.6
                    })
                train_loss_avg += loss_value_tr
                train_acc_avg += acc_tr
                tr_step += 1

            vl_step = 0
            vl_size = features.shape[0]

            while vl_step * batch_size < vl_size:
                loss_value_vl, acc_vl = sess.run(
                    [loss, accuracy],
                    feed_dict={
                        ftr_in:
                        features[vl_step * batch_size:(vl_step + 1) *
                                 batch_size],
                        bias_in:
                        biases[vl_step * batch_size:(vl_step + 1) *
                               batch_size],
                        lbl_in:
                        y_val[vl_step * batch_size:(vl_step + 1) * batch_size],
                        msk_in:
                        val_mask[vl_step * batch_size:(vl_step + 1) *
                                 batch_size],
                        is_train:
                        False,
                        attn_drop:
                        0.0,
                        ffd_drop:
                        0.0
                    })
                val_loss_avg += loss_value_vl
                val_acc_avg += acc_vl
                vl_step += 1

            print(
                'Training: loss = %.5f, acc = %.5f | Val: loss = %.5f, acc = %.5f'
                % (train_loss_avg / tr_step, train_acc_avg / tr_step,
                   val_loss_avg / vl_step, val_acc_avg / vl_step))

            if val_acc_avg / vl_step >= vacc_mx or val_loss_avg / vl_step <= vlss_mn:
                if val_acc_avg / vl_step >= vacc_mx and val_loss_avg / vl_step <= vlss_mn:
                    vacc_early_model = val_acc_avg / vl_step
                    vlss_early_model = val_loss_avg / vl_step
                    saver.save(sess, checkpt_file)
                vacc_mx = np.max((val_acc_avg / vl_step, vacc_mx))
                vlss_mn = np.min((val_loss_avg / vl_step, vlss_mn))
                curr_step = 0
            else:
                curr_step += 1
                if curr_step == patience:
                    print('Early stop! Min loss: ', vlss_mn,
                          ', Max accuracy: ', vacc_mx)
                    print('Early stop model validation loss: ',
                          vlss_early_model, ', accuracy: ', vacc_early_model)
                    break

            train_loss_avg = 0
            train_acc_avg = 0
            val_loss_avg = 0
            val_acc_avg = 0

        saver.restore(sess, checkpt_file)

        ts_size = features.shape[0]
        ts_step = 0
        ts_loss = 0.0
        ts_acc = 0.0

        while ts_step * batch_size < ts_size:
            loss_value_ts, acc_ts = sess.run(
                [loss, accuracy],
                feed_dict={
                    ftr_in:
                    features[ts_step * batch_size:(ts_step + 1) * batch_size],
                    bias_in:
                    biases[ts_step * batch_size:(ts_step + 1) * batch_size],
                    lbl_in:
                    y_test[ts_step * batch_size:(ts_step + 1) * batch_size],
                    msk_in:
                    test_mask[ts_step * batch_size:(ts_step + 1) * batch_size],
                    is_train:
                    False,
                    attn_drop:
                    0.0,
                    ffd_drop:
                    0.0
                })
            ts_loss += loss_value_ts
            ts_acc += acc_ts
            ts_step += 1

        print('Test loss:', ts_loss / ts_step, '; Test accuracy:',
              ts_acc / ts_step)

        sess.close()
