import os
import io
import json
import requests
from typing import Dict, List, Any, Optional
from fastapi import FastAPI, HTTPException, Body
from pydantic import BaseModel
import torch
from transformers import AutoTokenizer, AutoModelForSequenceClassification
from newspaper import Article
from bs4 import BeautifulSoup
import easyocr
from PIL import Image
import google.generativeai as genai
from datetime import datetime
import logging
from fastapi.middleware.cors import CORSMiddleware

# Setup logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger("TruthLens")

# Initialize FastAPI app
app = FastAPI(title="TruthLens Backend")

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Load Hugging Face model (RoBERTa-based fake news detector)
MODEL_NAME = "Pulk17/Fake-News-Detection"
tokenizer = None
model = None

def load_model():
    """Lazy load the Hugging Face model"""
    global tokenizer, model
    if tokenizer is None or model is None:
        print("Loading Hugging Face model...")
        tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME)
        model = AutoModelForSequenceClassification.from_pretrained(MODEL_NAME)
        model.eval()
    return tokenizer, model

# Environment variables
# Ensure you set these in your environment or .env file
GOOGLE_FACT_CHECK_API_KEY = os.environ.get('GOOGLE_FACT_CHECK_API_KEY', '')
HIVE_API_KEY = os.environ.get('HIVE_API_KEY', '')
GEMINI_API_KEY = os.environ.get('GEMINI_API_KEY', '')

# Initialize Gemini
if GEMINI_API_KEY:
    genai.configure(api_key=GEMINI_API_KEY)
    gemini_model = genai.GenerativeModel('gemini-pro')
else:
    gemini_model = None

# Request Models
class TextRequest(BaseModel):
    text: str

class UrlRequest(BaseModel):
    url: str

class ImageRequest(BaseModel):
    image_url: str

# Source Credibility Database
CREDIBLE_SOURCES = {
    "apnews.com": "Associated Press",
    "reuters.com": "Reuters",
    "bbc.com": "BBC News",
    "bbc.co.uk": "BBC News",
    "nytimes.com": "The New York Times",
    "npr.org": "NPR",
    "pbs.org": "PBS NewsHour",
    "wsj.com": "The Wall Street Journal",
    "bloomberg.com": "Bloomberg",
    "theguardian.com": "The Guardian",
    "washingtonpost.com": "The Washington Post",
    "propublica.org": "ProPublica",
    "aljazeera.com": "Al Jazeera",
    "economist.com": "The Economist",
    "forbes.com": "Forbes"
}

SATIRE_SOURCES = {
    "theonion.com": "The Onion",
    "babylonbee.com": "The Babylon Bee",
    "clickhole.com": "ClickHole",
    "newyorker.com/humor/borowitz-report": "The Borowitz Report",
    "thebeaverton.com": "The Beaverton",
    "cracked.com": "Cracked",
    "dailymash.co.uk": "The Daily Mash",
    "waterfordwhispersnews.com": "Waterford Whispers News"
}

# Helper functions
def get_fact_checks(text: str) -> List[Dict[str, str]]:
    """Get fact checks from Google Fact Check Tools API"""
    if not GOOGLE_FACT_CHECK_API_KEY:
        return []
    
    try:
        # Extract key claims (first 100 chars as query)
        query = text[:100]
        
        url = "https://factchecktools.googleapis.com/v1alpha1/claims:search"
        params = {
            "query": query,
            "key": GOOGLE_FACT_CHECK_API_KEY,
            "languageCode": "en"
        }
        
        response = requests.get(url, params=params, timeout=10)
        
        if response.status_code == 200:
            data = response.json()
            claims = data.get('claims', [])
            
            fact_checks = []
            for claim in claims[:3]:  # Top 3 fact checks
                fact_check = {
                    "claim": claim.get('text', ''),
                    "claimant": claim.get('claimant', ''),
                    "rating": claim.get('claimReview', [{}])[0].get('textualRating', 'Unknown'),
                    "url": claim.get('claimReview', [{}])[0].get('url', '')
                }
                fact_checks.append(fact_check)
            
            return fact_checks
        else:
            print(f"Fact check API error: {response.status_code}")
            return []
            
    except Exception as e:
        print(f"Error getting fact checks: {e}")
        return []

def extract_claims_with_gemini(text: str) -> List[str]:
    """Use Gemini to extract key factual claims for building a search query"""
    if not gemini_model:
        return [text[:100]]
    
    try:
        prompt = f"""
        Extract the single most important factual claim from the following text that can be used to search in a fact-check database. 
        Output ONLY the extracted claim string, nothing else.
        
        Text: {text[:1000]}
        """
        response = gemini_model.generate_content(prompt)
        if response and hasattr(response, 'text'):
            claim = response.text.strip()
            return [claim] if claim else [text[:100]]
        return [text[:100]]
    except Exception as e:
        print(f"Gemini claim extraction error: {e}")
        return [text[:100]]

def generate_explanation_with_gemini(text: str, label: str, confidence: float, fact_checks: List[Dict]) -> str:
    """Use Gemini to explain the reasoning behind the detection result"""
    if not gemini_model:
        return f"The news has been classified as {label} with {confidence:.2%} confidence."
    
    try:
        fact_check_context = ""
        if fact_checks:
            fact_check_context = "Relevant fact checks found:\n" + "\n".join([f"- {fc['claim']} (Rating: {fc['rating']})" for fc in fact_checks])
        
        prompt = f"""
        Act as a professional fact-checker for an app called TruthLens. 
        Analyze the following news text and the AI detection result.
        
        News Text: {text[:1000]}
        AI Classification: {label}
        Confidence: {confidence:.2%}
        {fact_check_context}
        
        Provide a concise, human-readable explanation (2-3 sentences) explaining why this news is likely {label}. 
        Focus on style, source (if present), or specific fact-check evidence.
        """
        response = gemini_model.generate_content(prompt)
        if response and hasattr(response, 'text'):
            return response.text.strip()
        return f"The model identified this content as {label} with {confidence:.2%} confidence."
    except Exception as e:
        print(f"Gemini explanation error: {e}")
        return f"Analysis complete: The model identified this content as {label}."

def detect_ai_image(image_bytes: bytes) -> Dict[str, Any]:
    """Detect AI-generated content using Hive Moderation API"""
    if not HIVE_API_KEY:
        return {"probability": 0.0, "generator": None}
    
    try:
        url = "https://api.hivemoderation.com/v2/task/sync"
        
        headers = {
            "Authorization": f"Token {HIVE_API_KEY}",
            "Content-Type": "application/json"
        }
        
        # Convert image to base64
        import base64
        image_b64 = base64.b64encode(image_bytes).decode('utf-8')
        
        payload = {
            "image": image_b64,
            "models": ["ai_generated"]
        }
        
        response = requests.post(url, headers=headers, json=payload, timeout=30)
        
        if response.status_code == 200:
            data = response.json()
            ai_generated = data.get('status', [{}])[0].get('response', {}).get('output', [{}])[0]
            
            return {
                "probability": ai_generated.get('score', 0.0),
                "generator": ai_generated.get('class', None)
            }
        else:
            print(f"Hive API error: {response.status_code}")
            return {"probability": 0.0, "generator": None}
            
    except Exception as e:
        print(f"Error detecting AI image: {e}")
        return {"probability": 0.0, "generator": None}

def calculate_risk_level(
    label: str,
    confidence: float,
    fact_checks: List[Dict],
    image_ai_result: Optional[Dict] = None
) -> str:
    """Calculate overall risk level"""
    
    # Base risk on label and confidence
    if label == "FAKE" and confidence > 0.8:
        base_risk = "high"
    elif label == "FAKE" and confidence > 0.5:
        base_risk = "medium"
    elif label == "REAL" and confidence > 0.8:
        base_risk = "low"
    else:
        base_risk = "medium"
    
    # Adjust based on fact checks
    if fact_checks:
        fake_ratings = sum(1 for fc in fact_checks if 'false' in fc['rating'].lower() or 'fake' in fc['rating'].lower() or 'satire' in fc['rating'].lower())
        if fake_ratings >= 2:
            base_risk = "high"
    
    # Adjust based on AI image detection
    if image_ai_result and image_ai_result['probability'] > 0.7:
        if base_risk == "low":
            base_risk = "medium"
        elif base_risk == "medium":
            base_risk = "high"
    
    return base_risk

def check_source_credibility(url: str) -> Dict[str, Any]:
    """Check if the URL belongs to a known credible or satire source"""
    from urllib.parse import urlparse
    
    try:
        domain = urlparse(url).netloc.lower()
        if domain.startswith("www."):
            domain = domain[4:]
            
        # Check Satire first
        for satire_domain, name in SATIRE_SOURCES.items():
            if satire_domain in url.lower():
                return {"status": "satire", "name": name, "label": "FAKE", "confidence": 1.0}
        
        # Check Credible
        if domain in CREDIBLE_SOURCES:
            return {"status": "credible", "name": CREDIBLE_SOURCES[domain], "label": "REAL", "confidence": 0.95}
            
        return {"status": "unknown", "name": None, "label": None, "confidence": 0.0}
    except Exception as e:
        print(f"Error checking credibility: {e}")
        return {"status": "unknown", "name": None, "label": None, "confidence": 0.0}

def extract_article_text(url: str) -> str:
    """Extract article text from URL using newspaper3k"""
    try:
        article = Article(url)
        article.download()
        article.parse()
        return article.text
    except Exception as e:
        print(f"Error extracting article with newspaper3k: {e}")
        # Fallback to BeautifulSoup
        try:
            response = requests.get(url, timeout=30)
            soup = BeautifulSoup(response.content, 'html.parser')
            
            # Remove script and style elements
            for script in soup(["script", "style"]):
                script.decompose()
            
            # Get text
            text = soup.get_text()
            
            # Clean up whitespace
            lines = (line.strip() for line in text.splitlines())
            chunks = (phrase.strip() for line in lines for phrase in line.split("  "))
            text = ' '.join(chunk for chunk in chunks if chunk)
            
            return text
        except Exception as e2:
            logger.error(f"Error with BeautifulSoup fallback: {e2}")
            return ""

@app.get("/")
async def root():
    return {"status": "healthy", "service": "TruthLens API"}

# Endpoints

@app.post("/detect-text")
async def detect_text(request: TextRequest, skip_extras: bool = False):
    """Detect fake news in text with optional fact-check and explanation"""
    try:
        text = request.text
        if not text:
            raise HTTPException(status_code=400, detail="Text is required")
        
        # Load model
        tok, mdl = load_model()
        
        # Tokenize and predict
        inputs = tok(text, return_tensors="pt", truncation=True, max_length=512, padding=True)
        
        with torch.no_grad():
            outputs = mdl(**inputs)
            logits = outputs.logits
            probabilities = torch.softmax(logits, dim=1)
            prediction = torch.argmax(probabilities, dim=1).item()
            confidence = probabilities[0][prediction].item()
        
        label = "REAL" if prediction == 1 else "FAKE"
        
        if skip_extras:
            return {
                "input_type": "text",
                "label": label,
                "confidence": confidence,
                "timestamp": datetime.now().isoformat()
            }
        
        # Enhanced Fact Checking with Gemini
        extracted_claims = extract_claims_with_gemini(text)
        fact_checks = get_fact_checks(extracted_claims[0])
        
        # Gemini Explanation
        explanation = generate_explanation_with_gemini(text, label, confidence, fact_checks)
        
        risk_level = calculate_risk_level(label, confidence, fact_checks)
        
        return {
            "input_type": "text",
            "text": text,
            "label": label,
            "confidence": confidence,
            "explanation": explanation,
            "fact_checks": fact_checks,
            "risk_level": risk_level,
            "timestamp": datetime.now().isoformat()
        }
        
    except Exception as e:
        print(f"Error in detect_text: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))

@app.post("/detect-url")
async def detect_url(request: UrlRequest, skip_extras: bool = False):
    """Detect fake news in URL with optional fact-check and explanation"""
    try:
        url = request.url
        if not url:
            raise HTTPException(status_code=400, detail="URL is required")
        
        # 1. Check Source Credibility First
        source_info = check_source_credibility(url)
        
        article_text = extract_article_text(url)
        if not article_text:
            raise HTTPException(status_code=400, detail="Failed to extract article text from URL")
        
        tok, mdl = load_model()
        
        inputs = tok(article_text, return_tensors="pt", truncation=True, max_length=512, padding=True)
        
        with torch.no_grad():
            outputs = mdl(**inputs)
            logits = outputs.logits
            probabilities = torch.softmax(logits, dim=1)
            prediction = torch.argmax(probabilities, dim=1).item()
            confidence = probabilities[0][prediction].item()
        
        label = "REAL" if prediction == 1 else "FAKE"
        
        # Override with source credibility if it's definitive
        if source_info["status"] == "satire":
            label = "FAKE"
            confidence = 1.0
        elif source_info["status"] == "credible" and label == "FAKE":
            # If a credible source is flagged as fake, we lower risk but keep label
            # or we could trust the source more. Let's provide it in metadata.
            pass
        
        if skip_extras:
            return {
                "input_type": "url",
                "label": label,
                "confidence": confidence,
                "source_metadata": source_info,
                "timestamp": datetime.now().isoformat()
            }
        
        # Enhanced Fact Checking with Gemini
        extracted_claims = extract_claims_with_gemini(article_text)
        fact_checks = get_fact_checks(extracted_claims[0])
        
        # Gemini Explanation
        explanation = generate_explanation_with_gemini(
            f"Source: {source_info['name'] if source_info['name'] else 'Unknown'}. Content: {article_text}", 
            label, 
            confidence, 
            fact_checks
        )
        
        risk_level = calculate_risk_level(label, confidence, fact_checks)
        
        return {
            "input_type": "url",
            "url": url,
            "source_metadata": source_info,
            "text": article_text[:500],
            "label": label,
            "confidence": confidence,
            "explanation": explanation,
            "fact_checks": fact_checks,
            "risk_level": risk_level,
            "timestamp": datetime.now().isoformat()
        }
        
    except Exception as e:
        print(f"Error in detect_url: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))

@app.post("/detect-image")
async def detect_image(request: ImageRequest, skip_extras: bool = False):
    try:
        image_url = request.image_url
        logger.info(f"Processing image: {image_url}")
        if not image_url:
            raise HTTPException(status_code=400, detail="Image URL is required")
        
        response = requests.get(image_url, timeout=30)
        response.raise_for_status()
        image_bytes = response.content
        
        reader = easyocr.Reader(['en'])
        # EasyOCR can read from bytes directly
        ocr_results = reader.readtext(image_bytes)
        extracted_text = ' '.join([result[1] for result in ocr_results])
        
        image_ai_result = detect_ai_image(image_bytes)
        
        if extracted_text.strip():
            tok, mdl = load_model()
            inputs = tok(extracted_text, return_tensors="pt", truncation=True, max_length=512, padding=True)
            
            with torch.no_grad():
                outputs = mdl(**inputs)
                logits = outputs.logits
                probabilities = torch.softmax(logits, dim=1)
                prediction = torch.argmax(probabilities, dim=1).item()
                confidence = probabilities[0][prediction].item()
            
            label = "REAL" if prediction == 1 else "FAKE"
            
            if skip_extras:
                return {
                    "input_type": "image",
                    "label": label,
                    "confidence": confidence,
                    "image_ai_result": image_ai_result,
                    "timestamp": datetime.now().isoformat()
                }
                
            # Enhanced Fact Checking with Gemini
            extracted_claims = extract_claims_with_gemini(extracted_text)
            fact_checks = get_fact_checks(extracted_claims[0])
        else:
            label = "FAKE" if image_ai_result['probability'] > 0.7 else "REAL"
            confidence = image_ai_result['probability'] if label == "FAKE" else (1 - image_ai_result['probability'])
            fact_checks = []
            
            if skip_extras:
                return {
                    "input_type": "image",
                    "label": label,
                    "confidence": confidence,
                    "image_ai_result": image_ai_result,
                    "timestamp": datetime.now().isoformat()
                }
        
        # Gemini Explanation
        explanation = generate_explanation_with_gemini(extracted_text if extracted_text else "No text found in image", label, confidence, fact_checks)
        
        risk_level = calculate_risk_level(label, confidence, fact_checks, image_ai_result)
        
        return {
            "input_type": "image",
            "image_url": image_url,
            "text": extracted_text[:500] if extracted_text else None,
            "label": label,
            "confidence": confidence,
            "explanation": explanation,
            "fact_checks": fact_checks,
            "image_ai_result": image_ai_result,
            "risk_level": risk_level,
            "timestamp": datetime.now().isoformat()
        }
        
    except Exception as e:
        print(f"Error in detect_image: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)