import numpy as np
import pandas as pd
import torch
import csv
import gensim.downloader
import torch
from nltk import word_tokenize

class NeuralNetwork(torch.nn.Module):
    def __init__(self, input_size, hidden_size, num_classes):
        super(NeuralNetwork, self).__init__()
        self.l1 = torch.nn.Linear(input_size, hidden_size)
        self.l2 = torch.nn.Linear(hidden_size, num_classes)

    def forward(self, x):
        x = self.l1(x)
        x = torch.relu(x)
        x = self.l2(x)
        x = torch.sigmoid(x)
        return x

print('STEP 1 - LOAD DATA')
names = ['content', 'id', 'label']
train_data_content = pd.read_table('train/in.tsv', error_bad_lines=False, header=None, quoting=csv.QUOTE_NONE, names=names[:2])
train_data_labels = pd.read_table('train/expected.tsv', error_bad_lines=False, header=None, quoting=csv.QUOTE_NONE, names=names[2:])
dev_data = pd.read_table('dev-0/in.tsv', error_bad_lines=False, header=None, quoting=csv.QUOTE_NONE, names=names[:2])
test_data = pd.read_table('test-A/in.tsv', error_bad_lines=False, header=None, quoting=csv.QUOTE_NONE, names=names[:2])

print('STEP 2 - SET PARAMS')
hidden_size = int(input('Hidden units size: ') or '600')
epochs = int(input("Epochs: ") or '5')
batch_size = int(input("Batch size: ") or '15')

print('STEP 3 - PREPROCESSING')
# lowercase all content
X_train = train_data_content['content'].str.lower()
y_train = train_data_labels['label']
X_dev = dev_data['content'].str.lower()
X_test = test_data['content'].str.lower()

# tokenize datasets
X_train = [word_tokenize(content) for content in X_train]
X_dev = [word_tokenize(content) for content in X_dev]
X_test = [word_tokenize(content) for content in X_test]

# use Google word2vec algorithm
word2vec = gensim.downloader.load('word2vec-google-news-300')
X_train = [np.mean([word2vec[word] for word in content if word in word2vec] or [np.zeros(300)], axis=0) for content in X_train]
X_dev = [np.mean([word2vec[word] for word in content if word in word2vec] or [np.zeros(300)], axis=0) for content in X_dev]
X_test = [np.mean([word2vec[word] for word in content if word in word2vec] or [np.zeros(300)], axis=0) for content in X_test]

print('STEP 4 - MODEL TRAINING')
#prepare neural model

model = NeuralNetwork(300, hidden_size, 1)
criterion = torch.nn.BCELoss()
optimizer = torch.optim.SGD(model.parameters(), lr=0.01)

for epoch in range(epochs):
    model.train()
    for i in range(0, y_train.shape[0], batch_size):
        X = X_train[i:i+batch_size]
        X = torch.tensor(X)
        y = y_train[i:i+batch_size]
        y = torch.tensor(y.astype(np.float32).to_numpy()).reshape(-1, 1)
        outputs = model(X.float())
        loss = criterion(outputs, y)
        optimizer.zero_grad()
        loss.backward()
        optimizer.step()

print('STEP 5 - PREDICTION')
y_dev, y_test = [], []
model.eval()
with torch.no_grad():
    for i in range(0, len(X_dev), batch_size):
        X = X_dev[i:i+batch_size]
        X = torch.tensor(X)
        outputs = model(X.float())
        prediction = (outputs > 0.5)
        y_dev += prediction.tolist()
    for i in range(0, len(X_test), batch_size):
        X = X_test[i:i+batch_size]
        X = torch.tensor(X)
        outputs = model(X.float())
        y = (outputs > 0.5)
        y_test += prediction.tolist()

print('STEP 6 - EXPORT RESULTS')
# export results to tsv
y_dev = np.asarray(y_dev, dtype=np.int32)
y_test = np.asarray(y_test, dtype=np.int32)
y_dev.tofile('./dev-0/out.tsv', sep='\n')
y_test.tofile('./test-A/out.tsv', sep='\n')