import json
import re
from collections import defaultdict
import torch
import torch.nn as nn
import torch.optim as optim

def flatten_json_data(json_file_path):
    with open(json_file_path, 'r', encoding='utf-8') as f:
        data = json.load(f)

    flattened_data = []
    for dataset in data:
        for section in ["conversation_samples", "technical_terminology"]:
            if section in dataset:
                for category, samples in dataset[section].items():
                    for item in samples:
                        if "balochi" in item and "english" in item and "urdu" in item and "persian" in item: # Check if all keys are present
                            for balochi_sentence, english_sentence, urdu_sentence, persian_sentence in zip(item['balochi'], item['english'], item['urdu'], item['persian']):
                                flattened_data.append({
                                    "context": item.get('context', category),
                                    "balochi": balochi_sentence,
                                    "english": english_sentence,
                                    "urdu": urdu_sentence,
                                    "persian": persian_sentence
                                })
    return flattened_data

def parse_tsv_data(tsv_file_path):
    data = []
    with open(tsv_file_path, 'r', encoding='utf-8') as f:
        for line in f:
            balochi, english = line.strip().split('\t')
            data.append({"balochi": balochi, "english": english})
    return data

def create_vocab(tokenized_sentences):
    vocab = defaultdict(lambda: len(vocab))
    vocab['<PAD>'] = 0
    vocab['<UNK>'] = 1 # Add unknown token
    for sentence in tokenized_sentences:
        for word in sentence:
            vocab[word]
    return dict(vocab)

def tokenize_text(text):
    return re.findall(r"[\w']+(?:ء)?|[\u0600-\u06FF]+|[؟،۔٬؛٪٫٬]+|\S", text)

class SimpleRNNTranslator(nn.Module):
    def __init__(self, input_size, output_size, hidden_size):
        super(SimpleRNNTranslator, self).__init__()
        self.hidden_size = hidden_size
        self.embedding = nn.Embedding(input_size, hidden_size)
        self.rnn = nn.RNN(hidden_size, hidden_size, batch_first=True)
        self.fc = nn.Linear(hidden_size, output_size)

    def forward(self, x):
        embedded = self.embedding(x)  # Shape: [batch_size, seq_len, hidden_size]
        output, _ = self.rnn(embedded)  # Shape: [batch_size, seq_len, hidden_size]
        output = self.fc(output)  # Shape: [batch_size, seq_len, output_size]
        return output


def train_model(flattened_data, num_epochs=10, hidden_size=256, learning_rate=0.001):
    # Tokenize sentences
    balochi_sentences = [tokenize_text(entry['balochi']) for entry in flattened_data]
    english_sentences = [tokenize_text(entry['english']) for entry in flattened_data]

    # Create vocabularies
    balochi_vocab = create_vocab(balochi_sentences)
    english_vocab = create_vocab(english_sentences)

    input_size = len(balochi_vocab)
    output_size = len(english_vocab)

    # Use a unified max sequence length
    max_seq_len = max(
        max(len(sentence) for sentence in balochi_sentences),
        max(len(sentence) for sentence in english_sentences)
    )

    def encode_sentences(sentences, vocab, max_len):
        encoded = [
            [vocab.get(word, vocab['<UNK>']) for word in sentence] + [0] * (max_len - len(sentence))
            for sentence in sentences
        ]
        return torch.LongTensor(encoded)

    # Encode inputs and targets with the same max_seq_len
    X = encode_sentences(balochi_sentences, balochi_vocab, max_seq_len)  # Shape: [batch_size, max_seq_len]
    Y = encode_sentences(english_sentences, english_vocab, max_seq_len)  # Shape: [batch_size, max_seq_len]

    # Initialize model, loss, and optimizer
    model = SimpleRNNTranslator(input_size, output_size, hidden_size)
    criterion = nn.CrossEntropyLoss(ignore_index=0)  # Ignore padding token during loss computation
    optimizer = optim.Adam(model.parameters(), lr=learning_rate)

    # Training loop
    for epoch in range(num_epochs):
        model.train()
        optimizer.zero_grad()

        # Forward pass
        outputs = model(X)  # Shape: [batch_size, max_seq_len, output_size]
        outputs = outputs.view(-1, output_size)  # Flatten outputs for loss computation

        # Flatten target tensor
        target = Y.view(-1)  # Shape: [batch_size * max_seq_len]

        # Compute loss
        loss = criterion(outputs, target)

        # Backward pass and optimization
        loss.backward()
        optimizer.step()

        print(f"Epoch [{epoch + 1}/{num_epochs}], Loss: {loss.item():.4f}")

    return model, balochi_vocab, english_vocab, max_seq_len

def translate(model, balochi_sentence, balochi_vocab, english_vocab, max_balochi_len, max_output_len=20):
    tokenized_sentence = tokenize_text(balochi_sentence)
    encoded_sentence = [balochi_vocab.get(word, balochi_vocab['<UNK>']) for word in tokenized_sentence]
    padded_sentence = encoded_sentence + [0] * (max_balochi_len - len(encoded_sentence))
    input_tensor = torch.LongTensor([padded_sentence])

    # Initialize decoding
    model.eval()
    with torch.no_grad():
        output_tensor = model(input_tensor)  # Shape: [batch_size, seq_len, output_size]
        predicted_indices = torch.argmax(output_tensor, dim=2)[0]  # Take the first (and only) batch
        reverse_english_vocab = {idx: word for word, idx in english_vocab.items()}
        predicted_words = [reverse_english_vocab.get(idx.item(), '<UNK>') for idx in predicted_indices]
    
    return " ".join(predicted_words[:max_output_len])


# Example usage
json_file_path = "mergedv1.json"  # Replace with your JSON file path
tsv_file_path = "data_bal_en.tsv"  # Replace with your TSV file path

# Load and combine data
flattened_json_data = flatten_json_data(json_file_path)
flattened_tsv_data = parse_tsv_data(tsv_file_path)
flattened_data = flattened_json_data + flattened_tsv_data

# Check if data was loaded
if not flattened_data:
    print("Error: No data loaded from JSON or TSV. Check file paths and formats.")
else:
    model, balochi_vocab, english_vocab, max_balochi_len = train_model(flattened_data)

    balochi_input = "تئو چے کنغ پسند کنئے؟"
    translated_sentence = translate(model, balochi_input, balochi_vocab, english_vocab, max_balochi_len)
    print(f"Balochi Input: {balochi_input}")
    print(f"Translated Output: {translated_sentence}")