# -*- coding: utf-8 -*-
"""Fake_News Generator_Detector.ipynb

Automatically generated by Colab.

Original file is located at
    https://colab.research.google.com/drive/1C8ZWvJVZzTCngwpz788EpcT2lrbBWhYa

### 📰 **Project Description: Fake News Generator & Detector using Generative AI and NLP**
This project is an interactive AI-powered tool that enables users to both generate realistic-looking fake news articles and detect whether a given news text is fake or real using state-of-the-art natural language processing models. It highlights how language models can both create and combat misinformation.

🧰 **The application is built using:**

1. **Transformers Library (by Hugging Face)**:
For loading and using pretrained models — GPT-2 for fake news generation and fine-tuned BERT for fake news detection.

2. **Gradio:** To create a simple, interactive web-based user interface with tabbed sections for generation and detection.

3. **Google Colab / Python:** For backend development, prototyping, and running the application in a cloud-based notebook environment.

🎯 **Project Objectives**

**1. Generate Fake News Text**

Use GPT-2 to simulate fake news articles from user-provided prompts for for awareness and experimentation.

**2. Detect Fake or Real News**

Utilize a fine-tuned BERT model (Pulk17/Fake-News-Detection) to accurately classify news content as fake or real.

**3. Provide an Interactive Interface**

Use Gradio to build a user-friendly web interface.

**4. Demonstrate Dual Use of AI in Misinformation**

Showcase how AI can both create and detect fake news, promoting awareness and responsible AI usage.

**Step 2: Import Required Modules**

 Import libraries for model handling, tokenization, and interface building.
"""

# app.py

import torch
from transformers import GPT2LMHeadModel, GPT2Tokenizer
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import gradio as gr

# Device setup
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")

# Load GPT-2 for fake news generation
gpt2_tokenizer = GPT2Tokenizer.from_pretrained("gpt2")
gpt2_model = GPT2LMHeadModel.from_pretrained("gpt2").to(device)

# Load fine-tuned BERT model for fake news detection
bert_tokenizer = AutoTokenizer.from_pretrained("Pulk17/Fake-News-Detection")
bert_model = AutoModelForSequenceClassification.from_pretrained(
    "Pulk17/Fake-News-Detection"
).to(device)

# Function to generate fake news from a prompt
def generate_fake_news(prompt):
    inputs = gpt2_tokenizer.encode(prompt, return_tensors="pt").to(device)
    outputs = gpt2_model.generate(
        inputs,
        max_length=200,
        num_return_sequences=1,
        no_repeat_ngram_size=2,
        do_sample=True,
        temperature=0.7,
        top_k=50,
        top_p=0.95,
        early_stopping=True
    )
    generated_text = gpt2_tokenizer.decode(outputs[0], skip_special_tokens=True)
    return generated_text

# Function to detect if news is fake or real
def detect_news(text):
    inputs = bert_tokenizer(text, return_tensors="pt", truncation=True, padding=True).to(device)
    with torch.no_grad():
        outputs = bert_model(**inputs)
    logits = outputs.logits
    predicted_class = torch.argmax(logits, dim=1).item()
    confidence = torch.softmax(logits, dim=1)[0][predicted_class].item()
    label = "🟥 Fake News" if predicted_class == 0 else "🟩 Real News"
    return f"{label} (Confidence: {confidence:.2f})"

# Gradio Interface
with gr.Blocks() as demo:
    gr.Markdown("## 📰 Fake News Generator & Detector (GPT-2 + BERT)")

    with gr.Tab("🛠️ Generate Fake News"):
        with gr.Row():
            input_text = gr.Textbox(
                label="Enter a News Headline or Prompt",
                placeholder="e.g. Scientists discover a talking dolphin species near Japan...",
                lines=2
            )
        generate_btn = gr.Button("Generate")
        output_text = gr.Textbox(label="Generated News Article")
        generate_btn.click(generate_fake_news, inputs=input_text, outputs=output_text)

    with gr.Tab("🔍 Detect Fake or Real"):
        with gr.Row():
            detect_input = gr.Textbox(
                label="Enter a News Article or Statement",
                placeholder="Paste a paragraph to detect if it's fake or real...",
                lines=5
            )
        detect_btn = gr.Button("Detect")
        detect_output = gr.Textbox(label="Detection Result")
        detect_btn.click(detect_news, inputs=detect_input, outputs=detect_output)

# Launch the app
demo.launch()