import gradio as gr
import torch
import spacy
import subprocess
import nltk
from nltk.corpus import wordnet
from gensim import downloader as api
from gramformer import Gramformer

# Ensure necessary NLTK data is downloaded
nltk.download('wordnet')
nltk.download('omw-1.4')

# Ensure the spaCy model is installed
try:
    nlp = spacy.load("en_core_web_sm")
except OSError:
    subprocess.run(["python", "-m", "spacy", "download", "en_core_web_sm"])
    nlp = spacy.load("en_core_web_sm")

# Load a smaller Word2Vec model from Gensim's pre-trained models
word_vectors = api.load("glove-wiki-gigaword-50")

# Check for GPU and set the device accordingly
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

# Load Gramformer for grammar correction (model 2 for correction)
gf = Gramformer(models=2, use_gpu=torch.cuda.is_available())

# AI detection model and tokenizer remain the same as before
from transformers import AutoTokenizer, AutoModelForSequenceClassification
tokenizer_ai = AutoTokenizer.from_pretrained("distilbert-base-uncased-finetuned-sst-2-english")
model_ai = AutoModelForSequenceClassification.from_pretrained("distilbert-base-uncased-finetuned-sst-2-english").to(device)

# AI detection function using DistilBERT
def detect_ai_generated(text):
    inputs = tokenizer_ai(text, return_tensors="pt", truncation=True, max_length=512).to(device)
    with torch.no_grad():
        outputs = model_ai(**inputs)
        probabilities = torch.softmax(outputs.logits, dim=1)
    ai_probability = probabilities[0][1].item()  # Probability of being AI-generated
    return f"AI-Generated Content Probability: {ai_probability * 100:.2f}%"

# Function to get synonyms using NLTK WordNet
def get_synonyms_nltk(word, pos):
    synsets = wordnet.synsets(word, pos=pos)
    if synsets:
        lemmas = synsets[0].lemmas()
        return [lemma.name() for lemma in lemmas]
    return []

# Function to check and correct tenses and verbs using spaCy
def check_tense_and_correct(text):
    doc = nlp(text)
    corrected_text = []
    
    for token in doc:
        # Checking for verbs and their tense
        if token.pos_ == 'VERB':
            tense = token.tag_  # Get the specific tense tag (e.g., VBZ, VBD, VBG, etc.)
            
            if tense == 'VBZ':  # 3rd person singular present
                corrected_text.append(token.lemma_)  # Replace with base form (example: goes -> go)
            elif tense == 'VBD':  # Past tense
                corrected_text.append(token.text)  # Keep past tense as is
            elif tense == 'VBG':  # Gerund/Present participle
                corrected_text.append(token.text)  # Keep it unchanged for now
            else:
                corrected_text.append(token.text)  # For other cases, append the word as is
        else:
            corrected_text.append(token.text)
    
    return ' '.join(corrected_text)

# Function to capitalize the first letter of sentences and proper nouns
def capitalize_sentences_and_nouns(text):
    doc = nlp(text)
    corrected_text = []

    for sent in doc.sents:
        sentence = []
        for token in sent:
            if token.i == sent.start:  # First word of the sentence
                sentence.append(token.text.capitalize())
            elif token.pos_ == "PROPN":  # Proper noun
                sentence.append(token.text.capitalize())
            else:
                sentence.append(token.text)
        corrected_text.append(' '.join(sentence))

    return ' '.join(corrected_text)

# Paraphrasing function using spaCy and NLTK
def paraphrase_with_spacy_nltk(text):
    doc = nlp(text)
    paraphrased_words = []
    
    for token in doc:
        # Map spaCy POS tags to WordNet POS tags
        pos = None
        if token.pos_ in {"NOUN"}:
            pos = wordnet.NOUN
        elif token.pos_ in {"VERB"}:
            pos = wordnet.VERB
        elif token.pos_ in {"ADJ"}:
            pos = wordnet.ADJ
        elif token.pos_ in {"ADV"}:
            pos = wordnet.ADV
        
        synonyms = get_synonyms_nltk(token.text.lower(), pos) if pos else []
        
        # Replace with a synonym only if it makes sense
        if synonyms and token.pos_ in {"NOUN", "VERB", "ADJ", "ADV"} and synonyms[0] != token.text.lower():
            paraphrased_words.append(synonyms[0])
        else:
            paraphrased_words.append(token.text)
    
    # Join the words back into a sentence
    paraphrased_sentence = ' '.join(paraphrased_words)
    
    # Capitalize sentences and proper nouns
    corrected_text = capitalize_sentences_and_nouns(paraphrased_sentence)
    
    return corrected_text

# Function to correct grammar using Gramformer
def correct_grammar(text):
    corrected_sentences = gf.correct(text)
    return corrected_sentences[0] if corrected_sentences else text

# Combined function: Paraphrase -> Tense Check -> Capitalization -> Grammar Correction
def paraphrase_and_correct(text):
    # Step 1: Paraphrase the text
    paraphrased_text = paraphrase_with_spacy_nltk(text)
    
    # Step 2: Check tense and verbs, and attempt correction
    tense_checked_text = check_tense_and_correct(paraphrased_text)
    
    # Step 3: Capitalize sentences and proper nouns
    capitalized_text = capitalize_sentences_and_nouns(tense_checked_text)
    
    # Step 4: Correct grammar using Gramformer
    final_text = correct_grammar(capitalized_text)
    
    return final_text

# Gradio interface definition
with gr.Blocks() as interface:
    with gr.Row():
        with gr.Column():
            text_input = gr.Textbox(lines=5, label="Input Text")
            detect_button = gr.Button("AI Detection")
            paraphrase_button = gr.Button("Paraphrase & Correct")
        with gr.Column():
            output_text = gr.Textbox(label="Output")

    detect_button.click(detect_ai_generated, inputs=text_input, outputs=output_text)
    paraphrase_button.click(paraphrase_and_correct, inputs=text_input, outputs=output_text)

# Launch the Gradio app
interface.launch(debug=False)