from flask import Blueprint, render_template, request, jsonify, current_app, url_for
from flask_login import login_required, current_user
from utils import get_db_connection
import requests
import time
import os
import json
import sys
from concurrent.futures import ThreadPoolExecutor, as_completed
from bs4 import BeautifulSoup
import math
import imgkit

from gemini_classifier import classify_questions_with_gemini
from nova_classifier import classify_questions_with_nova
from json_processor import _process_json_and_generate_pdf
from json_processor import _process_json_and_generate_pdf

neetprep_bp = Blueprint('neetprep_bp', __name__)

# ... (Constants and GraphQL queries remain the same) ...
ENDPOINT_URL = "https://www.neetprep.com/graphql"
USER_ID = "VXNlcjozNTY5Mzcw="

HEADERS = {
    'accept': '*/*',
    'content-type': 'application/json',
    'origin': 'https://www.neetprep.com',
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36',
}

# --- Queries ---
query_template_step1 = 'query GetAttempts {{ testAttempts( limit: {limit}, offset: {offset}, where: {{ userId: "{userId}" }} ) {{ id completed }} }}'
query_template_step2 = 'query GetIncorrectIds {{ incorrectQuestions( testAttemptId: "{attemptId}", first: 200 ) {{ id }} }}'
query_template_step3 = '''
query GetQuestionDetails {{
  question(id: "{questionId}") {{
    id
    question
    options
    correctOptionIndex
    level
    topics(first: 1) {{
      edges {{
        node {{
          name
          subjects(first: 1) {{
            edges {{
              node {{ name }}
            }}
          }}
        }}
      }}
    }}
  }}
}}
'''

def fetch_question_details(q_id):
    """Worker function to fetch details for a single question."""
    result = run_hardcoded_query(query_template_step3, questionId=q_id)
    if result and 'data' in result and 'question' in result['data'] and result['data']['question']:
        return result['data']['question']
    return None

@neetprep_bp.route('/neetprep')
@login_required
def index():
    """Renders the main NeetPrep UI with topics and counts."""
    conn = get_db_connection()
    selected_subject = request.args.get('subject', 'All')
    AVAILABLE_SUBJECTS = ["All", "Biology", "Chemistry", "Physics", "Mathematics"]
    
    neetprep_topic_counts = {}
    unclassified_count = 0
    if current_user.neetprep_enabled:
        # Get NeetPrep question counts per topic, filtered by subject
        if selected_subject != 'All':
            neetprep_topics_query = 'SELECT topic, COUNT(*) as count FROM neetprep_questions WHERE subject = ? GROUP BY topic'
            neetprep_topics = conn.execute(neetprep_topics_query, (selected_subject,)).fetchall()
        else:
            neetprep_topics_query = 'SELECT topic, COUNT(*) as count FROM neetprep_questions GROUP BY topic'
            neetprep_topics = conn.execute(neetprep_topics_query).fetchall()
        neetprep_topic_counts = {row['topic']: row['count'] for row in neetprep_topics}
        unclassified_count = conn.execute("SELECT COUNT(*) as count FROM neetprep_questions WHERE topic = 'Unclassified'").fetchone()['count']


    # Get classified question counts per chapter for the current user, filtered by subject
    query_params = [current_user.id]
    base_query = """
        SELECT q.chapter, COUNT(*) as count 
        FROM questions q
        JOIN sessions s ON q.session_id = s.id
        WHERE s.user_id = ? AND q.subject IS NOT NULL AND q.chapter IS NOT NULL 
    """
    if selected_subject != 'All':
        base_query += " AND q.subject = ? "
        query_params.append(selected_subject)
    
    base_query += " GROUP BY q.chapter"
    
    classified_chapters = conn.execute(base_query, query_params).fetchall()
    classified_chapter_counts = {row['chapter']: row['count'] for row in classified_chapters}

    # Combine the topics
    all_topics = set(neetprep_topic_counts.keys()) | set(classified_chapter_counts.keys())
    
    combined_topics = []
    for topic in sorted(list(all_topics)):
        combined_topics.append({
            'topic': topic,
            'neetprep_count': neetprep_topic_counts.get(topic, 0),
            'my_questions_count': classified_chapter_counts.get(topic, 0)
        })

    conn.close()
    return render_template('neetprep.html', 
                           topics=combined_topics, 
                           unclassified_count=unclassified_count,
                           available_subjects=AVAILABLE_SUBJECTS,
                           selected_subject=selected_subject,
                           neetprep_enabled=current_user.neetprep_enabled)

@neetprep_bp.route('/neetprep/sync', methods=['POST'])
@login_required
def sync_neetprep_data():
    data = request.json
    force_sync = data.get('force', False)
    print(f"NeetPrep sync started by user {current_user.id}. Force sync: {force_sync}")

    try:
        conn = get_db_connection()
        
        if force_sync:
            print("Force sync enabled. Clearing processed attempts and questions tables.")
            conn.execute('DELETE FROM neetprep_processed_attempts')
            conn.execute('DELETE FROM neetprep_questions')
            conn.commit()

        processed_attempts_rows = conn.execute('SELECT attempt_id FROM neetprep_processed_attempts').fetchall()
        processed_attempt_ids = {row['attempt_id'] for row in processed_attempts_rows}
        
        all_attempt_ids = []
        offset = 0
        limit = 100
        print("Fetching test attempts from NeetPrep API...")
        while True:
            result = run_hardcoded_query(query_template_step1, limit=limit, offset=offset, userId=USER_ID)
            if not result or 'data' not in result or not result['data'].get('testAttempts'):
                break
            attempts = result['data']['testAttempts']
            if not attempts: break
            all_attempt_ids.extend([a['id'] for a in attempts if a.get('completed')])
            offset += limit
            time.sleep(0.2)

        new_attempts = [aid for aid in all_attempt_ids if aid not in processed_attempt_ids]
        print(f"Found {len(new_attempts)} new attempts to process.")
        if not new_attempts:
            conn.close()
            return jsonify({'status': 'No new test attempts to sync. Everything is up-to-date.'}), 200

        incorrect_question_ids = set()
        print("Fetching incorrect question IDs for new attempts...")
        for attempt_id in new_attempts:
            result = run_hardcoded_query(query_template_step2, attemptId=attempt_id)
            if result and 'data' in result and result['data'].get('incorrectQuestions'):
                for q in result['data']['incorrectQuestions']:
                    incorrect_question_ids.add(q['id'])
            time.sleep(0.2)

        existing_question_ids_rows = conn.execute('SELECT id FROM neetprep_questions').fetchall()
        existing_question_ids = {row['id'] for row in existing_question_ids_rows}
        new_question_ids = list(incorrect_question_ids - existing_question_ids)
        print(f"Found {len(new_question_ids)} new unique incorrect questions to fetch details for.")

        if not new_question_ids:
            for attempt_id in new_attempts:
                conn.execute('INSERT INTO neetprep_processed_attempts (attempt_id) VALUES (?)', (attempt_id,))
            conn.commit()
            conn.close()
            return jsonify({'status': 'Sync complete. No new questions found, but attempts log updated.'}), 200

        questions_to_insert = []
        total_new = len(new_question_ids)
        completed = 0
        print(f"Fetching details for {total_new} questions...")
        with ThreadPoolExecutor(max_workers=10) as executor:
            future_to_qid = {executor.submit(fetch_question_details, qid): qid for qid in new_question_ids}
            for future in as_completed(future_to_qid):
                q_data = future.result()
                if q_data:
                    topic_name = "Unclassified"
                    try:
                        topic_name = q_data['topics']['edges'][0]['node']['name']
                    except (IndexError, TypeError, KeyError): pass
                    
                    questions_to_insert.append((q_data.get('id'), q_data.get('question'), json.dumps(q_data.get('options', [])), q_data.get('correctOptionIndex'), q_data.get('level', 'N/A'), topic_name, "Unclassified"))
                
                completed += 1
                percentage = int((completed / total_new) * 100)
                sys.stdout.write(f'\rSync Progress: {completed}/{total_new} ({percentage}%)')
                sys.stdout.flush()
        
        print("\nAll questions fetched.")

        if questions_to_insert:
            conn.executemany("INSERT INTO neetprep_questions (id, question_text, options, correct_answer_index, level, topic, subject) VALUES (?, ?, ?, ?, ?, ?, ?)", questions_to_insert)
        
        for attempt_id in new_attempts:
            conn.execute('INSERT INTO neetprep_processed_attempts (attempt_id) VALUES (?)', (attempt_id,))

        conn.commit()
        conn.close()

        return jsonify({'status': f'Sync complete. Added {len(questions_to_insert)} new questions.'}), 200

    except Exception as e:
        current_app.logger.error(f"Error during NeetPrep sync: {repr(e)}")
        if 'conn' in locals() and conn:
            conn.close()
        return jsonify({'error': f"A critical error occurred during sync: {repr(e)}"}), 500

@neetprep_bp.route('/neetprep/classify', methods=['POST'])
@login_required
def classify_unclassified_questions():
    """Classifies all questions marked as 'Unclassified' in batches."""
    print("Starting classification of 'Unclassified' questions.")
    conn = get_db_connection()
    unclassified_questions = conn.execute("SELECT id, question_text FROM neetprep_questions WHERE topic = 'Unclassified'").fetchall()
    total_to_classify = len(unclassified_questions)
    
    if total_to_classify == 0:
        conn.close()
        return jsonify({'status': 'No unclassified questions to process.'})

    batch_size = 10
    num_batches = math.ceil(total_to_classify / batch_size)
    total_classified_count = 0

    print(f"Found {total_to_classify} questions. Processing in {num_batches} batches of {batch_size}.")

    for i in range(num_batches):
        batch_start_time = time.time()
        start_index = i * batch_size
        end_index = start_index + batch_size
        
        batch = unclassified_questions[start_index:end_index]
        
        question_texts = [q['question_text'] for q in batch]
        question_ids = [q['id'] for q in batch]

        print(f"\nProcessing Batch {i+1}/{num_batches}...")

        try:
            # Choose classifier based on user preference
            classifier_model = getattr(current_user, 'classifier_model', 'gemini')
            
            if classifier_model == 'nova':
                print("Classifying with Nova API...")
                classification_result = classify_questions_with_nova(question_texts, start_index=0)
                model_name = "Nova"
            else:
                print("Classifying with Gemini API...")
                classification_result = classify_questions_with_gemini(question_texts, start_index=0)
                model_name = "Gemini"
        
            if not classification_result or not classification_result.get('data'):
                print(f"Batch {i+1} failed: {model_name} API did not return valid data.")
                continue

            update_count_in_batch = 0
            for item in classification_result.get('data', []):
                item_index = item.get('index')
                if item_index is not None and 1 <= item_index <= len(question_ids):
                    # The item['index'] is 1-based, so we convert to 0-based
                    matched_id = question_ids[item_index - 1]
                    new_topic = item.get('chapter_title')
                    if new_topic:
                        conn.execute('UPDATE neetprep_questions SET topic = ? WHERE id = ?', (new_topic, matched_id))
                        update_count_in_batch += 1

            conn.commit()
            total_classified_count += update_count_in_batch
            print(f"Batch {i+1} complete. Classified {update_count_in_batch} questions.")

            # Wait before the next batch
            if i < num_batches - 1:
                print("Waiting 6 seconds before next batch...")
                time.sleep(6)

        except Exception as e:
            print(f"\nAn error occurred during batch {i+1}: {repr(e)}")
            continue
    
    conn.close()
    print(f"\nClassification finished. In total, {total_classified_count} questions were updated.")
    return jsonify({'status': f'Classification complete. Updated {total_classified_count} of {total_to_classify} questions.'})


from rich.table import Table
from rich.console import Console

@neetprep_bp.route('/neetprep/generate', methods=['POST'])
@login_required
def generate_neetprep_pdf():
    if request.is_json:
        data = request.json
    else:
        data = request.form

    pdf_type = data.get('type')
    topics_str = data.get('topics')
    topics = json.loads(topics_str) if topics_str and topics_str != '[]' else []
    source_filter = data.get('source', 'all')  # 'all', 'neetprep', or 'classified'

    conn = get_db_connection()
    all_questions = []

    include_neetprep = source_filter in ['all', 'neetprep'] and current_user.neetprep_enabled
    include_classified = source_filter in ['all', 'classified']

    # Fetch NeetPrep questions if enabled and filter allows
    if include_neetprep:
        if pdf_type == 'quiz' and topics:
            placeholders = ', '.join('?' for _ in topics)
            neetprep_questions_from_db = conn.execute(f"SELECT * FROM neetprep_questions WHERE topic IN ({placeholders})", topics).fetchall()
            for q in neetprep_questions_from_db:
                try:
                    html_content = f"""<html><head><meta charset="utf-8"></head><body>{q['question_text']}</body></html>"""
                    img_filename = f"neetprep_{q['id']}.jpg"
                    img_path = os.path.join(current_app.config['TEMP_FOLDER'], img_filename)
                    imgkit.from_string(html_content, img_path, options={'width': 800})
                    all_questions.append({
                        'image_path': f"/tmp/{img_filename}",
                        'details': {'id': q['id'], 'options': json.loads(q['options']), 'correct_answer_index': q['correct_answer_index'], 'user_answer_index': None, 'source': 'neetprep', 'topic': q['topic'], 'subject': q['subject']}
                    })
                except Exception as e:
                    current_app.logger.error(f"Failed to convert NeetPrep question {q['id']} to image: {e}")

        elif pdf_type == 'all':
            neetprep_questions_from_db = conn.execute("SELECT * FROM neetprep_questions").fetchall()
            for q in neetprep_questions_from_db:
                all_questions.append({"id": q['id'], "question_text": q['question_text'], "options": json.loads(q['options']), "correct_answer_index": q['correct_answer_index'], "user_answer_index": None, "status": "wrong", "source": "neetprep", "custom_fields": {"difficulty": q['level'], "topic": q['topic'], "subject": q['subject']}})

        elif pdf_type == 'selected' and topics:
            placeholders = ', '.join('?' for _ in topics)
            neetprep_questions_from_db = conn.execute(f"SELECT * FROM neetprep_questions WHERE topic IN ({placeholders})", topics).fetchall()
            for q in neetprep_questions_from_db:
                all_questions.append({"id": q['id'], "question_text": q['question_text'], "options": json.loads(q['options']), "correct_answer_index": q['correct_answer_index'], "user_answer_index": None, "status": "wrong", "source": "neetprep", "custom_fields": {"difficulty": q['level'], "topic": q['topic'], "subject": q['subject']}})

    # Fetch classified questions if filter allows
    if include_classified:
        if topics and pdf_type in ['quiz', 'selected']:
            placeholders = ', '.join('?' for _ in topics)
            classified_questions_from_db = conn.execute(f"""
                SELECT q.* FROM questions q JOIN sessions s ON q.session_id = s.id
                WHERE q.chapter IN ({placeholders}) AND s.user_id = ?
            """, (*topics, current_user.id)).fetchall()
            for q in classified_questions_from_db:
                image_info = conn.execute("SELECT processed_filename, note_filename FROM images WHERE id = ?", (q['image_id'],)).fetchone()
                if image_info and image_info['processed_filename']:
                    if pdf_type == 'quiz':
                        all_questions.append({
                            'image_path': f"/processed/{image_info['processed_filename']}",
                            'details': {'id': q['id'], 'options': [], 'correct_answer_index': q['actual_solution'], 'user_answer_index': q['marked_solution'], 'source': 'classified', 'topic': q['chapter'], 'subject': q['subject'], 'note_filename': image_info['note_filename']}
                        })
                    else:
                        all_questions.append({"id": q['id'], "question_text": f"<img src=\"{os.path.join(current_app.config['PROCESSED_FOLDER'], image_info['processed_filename'])}\" />", "options": [], "correct_answer_index": q['actual_solution'], "user_answer_index": q['marked_solution'], "status": q['status'], "source": "classified", "custom_fields": {"subject": q['subject'], "chapter": q['chapter'], "question_number": q['question_number']}})

        elif pdf_type == 'all':
            classified_questions_from_db = conn.execute("""
                SELECT q.* FROM questions q JOIN sessions s ON q.session_id = s.id
                WHERE s.user_id = ? AND q.subject IS NOT NULL AND q.chapter IS NOT NULL
            """, (current_user.id,)).fetchall()
            for q in classified_questions_from_db:
                image_info = conn.execute("SELECT processed_filename FROM images WHERE id = ?", (q['image_id'],)).fetchone()
                if image_info and image_info['processed_filename']:
                    all_questions.append({"id": q['id'], "question_text": f"<img src=\"{os.path.join(current_app.config['PROCESSED_FOLDER'], image_info['processed_filename'])}\" />", "options": [], "correct_answer_index": q['actual_solution'], "user_answer_index": q['marked_solution'], "status": q['status'], "source": "classified", "custom_fields": {"subject": q['subject'], "chapter": q['chapter'], "question_number": q['question_number']}})

    conn.close()

    # Check if topics are required but not provided
    if pdf_type in ['quiz', 'selected'] and not topics:
        return jsonify({'error': 'No topics selected.'}), 400

    if not all_questions:
        return jsonify({'error': 'No questions found for the selected criteria.'}), 404

    if pdf_type == 'quiz':
        return render_template('quiz_v2.html', questions=all_questions)

    test_name = "All Incorrect Questions"
    if pdf_type == 'selected':
        test_name = f"Incorrect Questions - {', '.join(topics)}"

    final_json_output = {
        "version": "2.1", "test_name": test_name,
        "config": { "font_size": 22, "auto_generate_pdf": False, "layout": data.get('layout', {}) },
        "metadata": { "source_book": "NeetPrep & Classified", "student_id": USER_ID, "tags": ", ".join(topics) },
        "questions": all_questions, "view": True
    }

    try:
        result, status_code = _process_json_and_generate_pdf(final_json_output, current_user.id)
        if status_code != 200:
            return jsonify(result), status_code
        
        if result.get('success'):
            return jsonify({'success': True, 'pdf_url': result.get('view_url')})
        else:
            return jsonify({'error': result.get('error', 'Failed to generate PDF via internal call.')}), 500
    except Exception as e:
        current_app.logger.error(f"Failed to call _process_json_and_generate_pdf: {repr(e)}")
        return jsonify({'error': str(e)}), 500

@neetprep_bp.route('/neetprep/edit')
@login_required
def edit_neetprep_questions():
    """Renders the page for editing NeetPrep questions."""
    conn = get_db_connection()
    topics = conn.execute('SELECT DISTINCT topic FROM neetprep_questions ORDER BY topic').fetchall()
    questions = conn.execute('SELECT id, question_text, topic, subject FROM neetprep_questions ORDER BY id').fetchall()
    
    questions_plain = []
    for q in questions:
        q_dict = dict(q)
        soup = BeautifulSoup(q_dict['question_text'], 'html.parser')
        plain_text = soup.get_text(strip=True)
        q_dict['question_text_plain'] = (plain_text[:100] + '...') if len(plain_text) > 100 else plain_text
        questions_plain.append(q_dict)

    conn.close()
    return render_template('neetprep_edit.html', questions=questions_plain, topics=[t['topic'] for t in topics])

@neetprep_bp.route('/neetprep/update_question/<question_id>', methods=['POST'])
@login_required
def update_neetprep_question(question_id):
    """Handles updating a question's metadata."""
    # This route modifies global neetprep data. In a real multi-user app,
    # this should be restricted to admin users. For now, @login_required is a basic protection.
    data = request.json
    new_topic = data.get('topic')
    new_subject = data.get('subject')

    if not new_topic or not new_subject:
        return jsonify({'error': 'Topic and Subject cannot be empty.'}), 400

    try:
        conn = get_db_connection()
        conn.execute(
            'UPDATE neetprep_questions SET topic = ?, subject = ? WHERE id = ?',
            (new_topic, new_subject, question_id)
        )
        conn.commit()
        conn.close()
        return jsonify({'success': True})
    except Exception as e:
        current_app.logger.error(f"Error updating question {question_id}: {repr(e)}")
        return jsonify({'error': str(e)}), 500

@neetprep_bp.route('/neetprep/get_suggestions/<question_id>', methods=['POST'])
@login_required
def get_neetprep_suggestions(question_id):
    """Get AI classification suggestions for a NeetPrep question using NVIDIA NIM."""
    import os
    from nvidia_prompts import BIOLOGY_PROMPT_TEMPLATE, CHEMISTRY_PROMPT_TEMPLATE, PHYSICS_PROMPT_TEMPLATE, MATHEMATICS_PROMPT_TEMPLATE, GENERAL_CLASSIFICATION_PROMPT

    data = request.json or {}
    subject = data.get('subject')  # Can be None for auto-detection

    conn = get_db_connection()
    question = conn.execute('SELECT question_text FROM neetprep_questions WHERE id = ?', (question_id,)).fetchone()
    conn.close()

    if not question:
        return jsonify({'success': True, 'suggestions': ['Unclassified'], 'subject': 'Biology', 'warning': 'Question not found'})

    # Strip HTML from question text for classification
    question_text = question['question_text'] or ''
    if not question_text:
        return jsonify({'success': True, 'suggestions': ['Unclassified'], 'subject': 'Biology', 'warning': 'No question text'})

    soup = BeautifulSoup(question_text, 'html.parser')
    plain_text = soup.get_text(strip=True)

    if not plain_text:
        return jsonify({'success': True, 'suggestions': ['Unclassified'], 'subject': 'Biology', 'warning': 'Empty question text'})

    NVIDIA_API_KEY = os.getenv("NVIDIA_API_KEY")
    if not NVIDIA_API_KEY:
        return jsonify({'error': 'NVIDIA_API_KEY not set', 'suggestions': ['Unclassified'], 'subject': 'Biology'}), 200

    # Get the appropriate prompt template
    def get_nvidia_prompt(subj, input_questions):
        if not subj or subj.lower() == 'auto':
            return GENERAL_CLASSIFICATION_PROMPT.format(input_questions=input_questions)
        if subj.lower() == 'biology': return BIOLOGY_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'chemistry': return CHEMISTRY_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'physics': return PHYSICS_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'mathematics': return MATHEMATICS_PROMPT_TEMPLATE.format(input_questions=input_questions)
        return GENERAL_CLASSIFICATION_PROMPT.format(input_questions=input_questions)

    prompt_content = get_nvidia_prompt(subject, f"1. {plain_text[:500]}")  # Limit text length

    try:
        res = requests.post(
            'https://integrate.api.nvidia.com/v1/chat/completions',
            headers={'Authorization': f'Bearer {NVIDIA_API_KEY}', 'Accept': 'application/json', 'Content-Type': 'application/json'},
            json={"model": "nvidia/nemotron-3-nano-30b-a3b", "messages": [{"content": prompt_content, "role": "user"}], "temperature": 0.2, "top_p": 1, "max_tokens": 1024, "stream": False},
            timeout=30
        )
        res.raise_for_status()
        content = res.json()['choices'][0]['message']['content']

        # Parse JSON from response
        if "```json" in content: content = content.split("```json")[1].split("```")[0].strip()
        elif "```" in content: content = content.split("```")[1].split("```")[0].strip()

        result_data = json.loads(content)
        suggestions = []
        detected_subject = subject or 'Biology'  # Default
        other_subjects = []

        if result_data.get('data'):
            item = result_data['data'][0]
            # Extract detected subject from AI response
            detected_subject = item.get('subject', subject) or 'Biology'
            # Extract other possible subjects
            other_subjects = item.get('other_possible_subjects', [])
            if isinstance(other_subjects, str):
                other_subjects = [other_subjects]

            primary = item.get('chapter_title')
            if primary and primary != 'Unclassified':
                suggestions.append(primary)
            others = item.get('other_possible_chapters', [])
            if isinstance(others, list):
                suggestions.extend([c for c in others if c and c != 'Unclassified'])

        # Always return at least one suggestion
        if not suggestions:
            suggestions = ['Unclassified']

        return jsonify({
            'success': True,
            'suggestions': suggestions[:5],
            'subject': detected_subject,
            'other_possible_subjects': other_subjects
        })

    except Exception as e:
        current_app.logger.error(f"Error getting suggestions for {question_id}: {repr(e)}")
        return jsonify({
            'success': True,
            'suggestions': ['Unclassified'],
            'subject': subject or 'Biology',
            'warning': str(e)
        })

@neetprep_bp.route('/neetprep/get_suggestions_batch', methods=['POST'])
@login_required
def get_neetprep_suggestions_batch():
    """Batch endpoint for getting topic suggestions for multiple NeetPrep questions at once.
    Requires a subject to be specified. Processes up to 8 questions in a single API call."""
    import os
    from nvidia_prompts import BIOLOGY_PROMPT_TEMPLATE, CHEMISTRY_PROMPT_TEMPLATE, PHYSICS_PROMPT_TEMPLATE, MATHEMATICS_PROMPT_TEMPLATE

    data = request.json
    question_ids = data.get('question_ids', [])
    subject = data.get('subject')

    current_app.logger.info(f"[BATCH-NEETPREP] Received request for {len(question_ids)} questions, subject={subject}")

    if not question_ids:
        return jsonify({'error': 'No question_ids provided'}), 400
    if not subject or subject.lower() == 'auto':
        return jsonify({'error': 'Subject must be specified for batch requests'}), 400
    if len(question_ids) > 8:
        return jsonify({'error': 'Maximum 8 questions per batch'}), 400

    NVIDIA_API_KEY = os.getenv("NVIDIA_API_KEY")
    if not NVIDIA_API_KEY:
        return jsonify({'error': 'NVIDIA_API_KEY not set'}), 500

    def get_nvidia_prompt(subj, input_questions):
        if subj.lower() == 'biology': return BIOLOGY_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'chemistry': return CHEMISTRY_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'physics': return PHYSICS_PROMPT_TEMPLATE.format(input_questions=input_questions)
        if subj.lower() == 'mathematics': return MATHEMATICS_PROMPT_TEMPLATE.format(input_questions=input_questions)
        return BIOLOGY_PROMPT_TEMPLATE.format(input_questions=input_questions)

    try:
        conn = get_db_connection()
        questions_data = []

        for idx, qid in enumerate(question_ids):
            question = conn.execute('SELECT question_text FROM neetprep_questions WHERE id = ?', (qid,)).fetchone()
            if question and question['question_text']:
                soup = BeautifulSoup(question['question_text'], 'html.parser')
                plain_text = soup.get_text(strip=True)
                if plain_text:
                    questions_data.append({'id': qid, 'index': idx + 1, 'text': plain_text[:500]})
                    current_app.logger.debug(f"[BATCH-NEETPREP] Question {qid}: got text ({len(plain_text)} chars)")
                else:
                    current_app.logger.warning(f"[BATCH-NEETPREP] Question {qid}: empty plain text after HTML strip")
            else:
                current_app.logger.warning(f"[BATCH-NEETPREP] Question {qid}: not found or no question_text")

        conn.close()

        current_app.logger.info(f"[BATCH-NEETPREP] Got question text for {len(questions_data)}/{len(question_ids)} questions")

        if not questions_data:
            return jsonify({'error': 'Could not obtain question text for any questions'}), 400

        # Build multi-question prompt
        input_questions = "\n".join(f"{q['index']}. {q['text']}" for q in questions_data)
        prompt_content = get_nvidia_prompt(subject, input_questions)

        current_app.logger.info(f"[BATCH-NEETPREP] Sending {len(questions_data)} questions to NVIDIA API")
        current_app.logger.debug(f"[BATCH-NEETPREP] Prompt preview: {input_questions[:500]}...")

        # Make single API call for all questions
        res = requests.post(
            'https://integrate.api.nvidia.com/v1/chat/completions',
            headers={'Authorization': f'Bearer {NVIDIA_API_KEY}', 'Accept': 'application/json', 'Content-Type': 'application/json'},
            json={"model": "nvidia/nemotron-3-nano-30b-a3b", "messages": [{"content": prompt_content, "role": "user"}], "temperature": 0.2, "top_p": 1, "max_tokens": 4096, "stream": False},
            timeout=60
        )
        res.raise_for_status()
        content = res.json()['choices'][0]['message']['content']

        current_app.logger.info(f"[BATCH-NEETPREP] NVIDIA API response length: {len(content)} chars")
        current_app.logger.debug(f"[BATCH-NEETPREP] Raw response: {content[:1000]}...")

        # Parse JSON from response
        if "```json" in content:
            content = content.split("```json")[1].split("```")[0].strip()
        elif "```" in content:
            content = content.split("```")[1].split("```")[0].strip()
        parsed_data = json.loads(content)

        current_app.logger.info(f"[BATCH-NEETPREP] Parsed data has {len(parsed_data.get('data', []))} items")

        # Build results for each question
        results = {}
        fallback_topics = {
            'biology': ['Cell: The Unit of Life', 'Biomolecules', 'Human Reproduction'],
            'chemistry': ['Organic Chemistry – Some Basic Principles and Techniques (GOC)', 'Chemical Bonding and Molecular Structure'],
            'physics': ['Laws of Motion', 'Work, Energy and Power', 'Current Electricity'],
            'mathematics': ['Calculus', 'Algebra', 'Coordinate Geometry']
        }

        if parsed_data.get('data'):
            data_items = parsed_data['data']
            current_app.logger.info(f"[BATCH-NEETPREP] AI returned {len(data_items)} items, we have {len(questions_data)} questions")

            # Helper to extract suggestions from item (handles both old and new format)
            def extract_suggestions(item):
                suggestions = []
                # Try new compact format first, then old format
                primary = item.get('ch') or item.get('chapter_title')
                if primary and primary != 'Unclassified':
                    suggestions.append(primary)
                # Handle alternatives - new format uses 'alt' (string), old uses 'other_possible_chapters' (list)
                alt = item.get('alt')
                if alt and alt != 'Unclassified' and alt != 'null':
                    suggestions.append(alt)
                others = item.get('other_possible_chapters')
                if isinstance(others, list):
                    suggestions.extend([c for c in others if c and c != 'Unclassified'])
                return suggestions

            # Helper to get index from item
            def get_item_index(item):
                return item.get('i') or item.get('index') or 0

            # Try to match by index first, then fall back to order-based matching
            matched_by_index = 0
            for item in data_items:
                item_index = get_item_index(item)
                current_app.logger.debug(f"[BATCH-NEETPREP] Processing item with index={item_index}: {item}")
                matching_q = next((q for q in questions_data if q['index'] == item_index), None)
                if matching_q:
                    matched_by_index += 1
                    suggestions = extract_suggestions(item)

                    if not suggestions:
                        suggestions = fallback_topics.get(subject.lower(), ['Unclassified'])

                    results[matching_q['id']] = {
                        'success': True,
                        'suggestions': suggestions[:5],
                        'subject': subject,
                        'other_possible_subjects': []
                    }
                    current_app.logger.info(f"[BATCH-NEETPREP] Question {matching_q['id']}: matched by index, suggestions={suggestions[:3]}")

            # If index matching failed, try order-based matching
            if matched_by_index == 0 and len(data_items) > 0:
                current_app.logger.warning(f"[BATCH-NEETPREP] Index matching failed, trying order-based matching")
                for i, item in enumerate(data_items):
                    if i < len(questions_data):
                        q = questions_data[i]
                        if q['id'] not in results:
                            suggestions = extract_suggestions(item)

                            if not suggestions:
                                suggestions = fallback_topics.get(subject.lower(), ['Unclassified'])

                            results[q['id']] = {
                                'success': True,
                                'suggestions': suggestions[:5],
                                'subject': subject,
                                'other_possible_subjects': []
                            }
                            current_app.logger.info(f"[BATCH-NEETPREP] Question {q['id']}: matched by order, suggestions={suggestions[:3]}")

        # Fill in any missing results
        for q in questions_data:
            if q['id'] not in results:
                current_app.logger.warning(f"[BATCH-NEETPREP] Question {q['id']}: using fallback (no match in API response)")
                results[q['id']] = {
                    'success': True,
                    'suggestions': fallback_topics.get(subject.lower(), ['Unclassified']),
                    'subject': subject,
                    'other_possible_subjects': []
                }

        current_app.logger.info(f"[BATCH-NEETPREP] Returning results for {len(results)} questions")
        return jsonify({'success': True, 'results': results})

    except Exception as e:
        current_app.logger.error(f"Error in batch suggestions: {repr(e)}")
        fallback_result = {
            'success': True,
            'suggestions': ['Unclassified'],
            'subject': subject,
            'other_possible_subjects': []
        }
        return jsonify({
            'success': False,
            'error': str(e),
            'results': {qid: fallback_result for qid in question_ids}
        })

# ============== BOOKMARK FEATURE ==============

@neetprep_bp.route('/neetprep/collections')
@login_required
def get_bookmark_collections():
    """Get all bookmark collections (sessions of type neetprep_collection) for the user."""
    conn = get_db_connection()
    collections = conn.execute("""
        SELECT s.id, s.name, s.subject, s.tags, s.notes, s.created_at,
               COUNT(b.id) as question_count
        FROM sessions s
        LEFT JOIN neetprep_bookmarks b ON s.id = b.session_id AND b.user_id = ?
        WHERE s.user_id = ? AND s.session_type = 'neetprep_collection'
        GROUP BY s.id
        ORDER BY s.created_at DESC
    """, (current_user.id, current_user.id)).fetchall()
    conn.close()
    return jsonify({'success': True, 'collections': [dict(c) for c in collections]})

@neetprep_bp.route('/neetprep/collections/create', methods=['POST'])
@login_required
def create_bookmark_collection():
    """Create a new bookmark collection (session)."""
    import uuid
    data = request.json
    name = data.get('name', 'New Collection')
    subject = data.get('subject', '')
    tags = data.get('tags', '')
    notes = data.get('notes', '')

    session_id = str(uuid.uuid4())
    conn = get_db_connection()
    conn.execute("""
        INSERT INTO sessions (id, name, subject, tags, notes, user_id, session_type, persist)
        VALUES (?, ?, ?, ?, ?, ?, 'neetprep_collection', 1)
    """, (session_id, name, subject, tags, notes, current_user.id))
    conn.commit()
    conn.close()

    return jsonify({'success': True, 'session_id': session_id, 'name': name})

@neetprep_bp.route('/neetprep/collections/<session_id>', methods=['DELETE'])
@login_required
def delete_bookmark_collection(session_id):
    """Delete a bookmark collection and all its bookmarks."""
    conn = get_db_connection()
    # Verify ownership
    session = conn.execute('SELECT id FROM sessions WHERE id = ? AND user_id = ?', (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    conn.execute('DELETE FROM neetprep_bookmarks WHERE session_id = ? AND user_id = ?', (session_id, current_user.id))
    conn.execute('DELETE FROM sessions WHERE id = ?', (session_id,))
    conn.commit()
    conn.close()

    return jsonify({'success': True})

@neetprep_bp.route('/neetprep/collections/<session_id>/update', methods=['POST'])
@login_required
def update_bookmark_collection(session_id):
    """Update collection metadata."""
    data = request.json
    conn = get_db_connection()

    # Verify ownership
    session = conn.execute('SELECT id FROM sessions WHERE id = ? AND user_id = ?', (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    updates = []
    params = []
    if 'name' in data:
        updates.append('name = ?')
        params.append(data['name'])
    if 'subject' in data:
        updates.append('subject = ?')
        params.append(data['subject'])
    if 'tags' in data:
        updates.append('tags = ?')
        params.append(data['tags'])
    if 'notes' in data:
        updates.append('notes = ?')
        params.append(data['notes'])

    if updates:
        params.append(session_id)
        conn.execute(f"UPDATE sessions SET {', '.join(updates)} WHERE id = ?", params)
        conn.commit()

    conn.close()
    return jsonify({'success': True})

@neetprep_bp.route('/neetprep/bookmark', methods=['POST'])
@login_required
def add_bookmark():
    """Add a question to a collection."""
    data = request.json
    question_id = data.get('question_id')
    session_id = data.get('session_id')
    question_type = data.get('question_type', 'neetprep')  # 'neetprep' or 'classified'

    if not question_id or not session_id:
        return jsonify({'error': 'question_id and session_id are required'}), 400

    conn = get_db_connection()

    # Verify session ownership
    session = conn.execute('SELECT id FROM sessions WHERE id = ? AND user_id = ?', (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    # Check if already bookmarked
    existing = conn.execute(
        'SELECT id FROM neetprep_bookmarks WHERE user_id = ? AND neetprep_question_id = ? AND session_id = ? AND question_type = ?',
        (current_user.id, str(question_id), session_id, question_type)
    ).fetchone()

    if existing:
        conn.close()
        return jsonify({'success': True, 'message': 'Already bookmarked'})

    conn.execute(
        'INSERT INTO neetprep_bookmarks (user_id, neetprep_question_id, session_id, question_type) VALUES (?, ?, ?, ?)',
        (current_user.id, str(question_id), session_id, question_type)
    )
    conn.commit()
    conn.close()

    return jsonify({'success': True})

@neetprep_bp.route('/neetprep/bookmark', methods=['DELETE'])
@login_required
def remove_bookmark():
    """Remove a question from a collection."""
    data = request.json
    question_id = data.get('question_id')
    session_id = data.get('session_id')
    question_type = data.get('question_type', 'neetprep')

    if not question_id or not session_id:
        return jsonify({'error': 'question_id and session_id are required'}), 400

    conn = get_db_connection()

    # Verify session ownership
    session = conn.execute('SELECT id FROM sessions WHERE id = ? AND user_id = ?', (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    conn.execute(
        'DELETE FROM neetprep_bookmarks WHERE user_id = ? AND neetprep_question_id = ? AND session_id = ? AND question_type = ?',
        (current_user.id, str(question_id), session_id, question_type)
    )
    conn.commit()
    conn.close()

    return jsonify({'success': True})

@neetprep_bp.route('/neetprep/bookmark/bulk', methods=['POST'])
@login_required
def bulk_bookmark():
    """Add multiple neetprep questions to a collection at once."""
    data = request.json
    question_ids = data.get('question_ids', [])
    session_id = data.get('session_id')

    if not question_ids or not session_id:
        return jsonify({'error': 'question_ids and session_id are required'}), 400

    conn = get_db_connection()

    # Verify session ownership
    session = conn.execute('SELECT id FROM sessions WHERE id = ? AND user_id = ?', (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    added_count = 0
    for qid in question_ids:
        existing = conn.execute(
            'SELECT id FROM neetprep_bookmarks WHERE user_id = ? AND neetprep_question_id = ? AND session_id = ?',
            (current_user.id, qid, session_id)
        ).fetchone()

        if not existing:
            conn.execute(
                'INSERT INTO neetprep_bookmarks (user_id, neetprep_question_id, session_id) VALUES (?, ?, ?)',
                (current_user.id, qid, session_id)
            )
            added_count += 1

    conn.commit()
    conn.close()

    return jsonify({'success': True, 'added_count': added_count})

@neetprep_bp.route('/neetprep/collections/<session_id>/questions')
@login_required
def get_collection_questions(session_id):
    """Get all questions in a bookmark collection."""
    conn = get_db_connection()

    # Verify ownership
    session = conn.execute('SELECT id, name, subject, tags, notes FROM sessions WHERE id = ? AND user_id = ?',
                          (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    questions = conn.execute("""
        SELECT nq.id, nq.question_text, nq.options, nq.correct_answer_index,
               nq.level, nq.topic, nq.subject, b.created_at as bookmarked_at
        FROM neetprep_bookmarks b
        JOIN neetprep_questions nq ON b.neetprep_question_id = nq.id
        WHERE b.session_id = ? AND b.user_id = ?
        ORDER BY b.created_at DESC
    """, (session_id, current_user.id)).fetchall()

    conn.close()

    return jsonify({
        'success': True,
        'collection': dict(session),
        'questions': [dict(q) for q in questions]
    })

@neetprep_bp.route('/neetprep/collections/<session_id>/view')
@login_required
def view_collection(session_id):
    """View a bookmark collection with its questions."""
    conn = get_db_connection()

    # Verify ownership
    session = conn.execute('SELECT id, name, subject, tags, notes, created_at FROM sessions WHERE id = ? AND user_id = ?',
                          (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        from flask import redirect, flash
        flash('Collection not found', 'danger')
        return redirect(url_for('dashboard.dashboard', filter='collections'))

    # Fetch neetprep questions
    neetprep_questions = conn.execute("""
        SELECT nq.id, nq.question_text, nq.options, nq.correct_answer_index,
               nq.level, nq.topic, nq.subject, b.created_at as bookmarked_at, 'neetprep' as question_type
        FROM neetprep_bookmarks b
        JOIN neetprep_questions nq ON b.neetprep_question_id = nq.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'neetprep'
        ORDER BY nq.topic, b.created_at
    """, (session_id, current_user.id)).fetchall()

    # Fetch classified questions
    classified_questions = conn.execute("""
        SELECT q.id, q.question_text, NULL as options, q.actual_solution as correct_answer_index,
               NULL as level, q.chapter as topic, q.subject, b.created_at as bookmarked_at, 'classified' as question_type,
               i.processed_filename as image_filename, q.question_number
        FROM neetprep_bookmarks b
        JOIN questions q ON CAST(b.neetprep_question_id AS INTEGER) = q.id
        LEFT JOIN images i ON q.image_id = i.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'classified'
        ORDER BY q.chapter, b.created_at
    """, (session_id, current_user.id)).fetchall()

    conn.close()

    # Combine all questions
    all_questions = []
    for q in neetprep_questions:
        qd = dict(q)
        qd['image_filename'] = None
        all_questions.append(qd)
    for q in classified_questions:
        all_questions.append(dict(q))

    # Group questions by topic
    topics = {}
    for q in all_questions:
        topic = q['topic'] or 'Unclassified'
        if topic not in topics:
            topics[topic] = []
        topics[topic].append(q)

    return render_template('collection_view.html',
                          collection=dict(session),
                          questions=all_questions,
                          topics=topics,
                          question_count=len(all_questions))

@neetprep_bp.route('/neetprep/question/<question_id>/collections')
@login_required
def get_question_collections(question_id):
    """Get which collections a question is bookmarked in."""
    conn = get_db_connection()

    collections = conn.execute("""
        SELECT s.id, s.name
        FROM neetprep_bookmarks b
        JOIN sessions s ON b.session_id = s.id
        WHERE b.neetprep_question_id = ? AND b.user_id = ?
    """, (question_id, current_user.id)).fetchall()

    conn.close()

    return jsonify({
        'success': True,
        'collections': [dict(c) for c in collections]
    })

@neetprep_bp.route('/neetprep/bookmarks/batch', methods=['POST'])
@login_required
def get_batch_bookmark_statuses():
    """Get bookmark statuses for multiple questions at once."""
    data = request.get_json()
    question_ids = data.get('question_ids', [])

    if not question_ids:
        return jsonify({'success': True, 'bookmarks': {}})

    conn = get_db_connection()

    # Build query for all question IDs
    placeholders = ','.join(['?' for _ in question_ids])
    query = f"""
        SELECT neetprep_question_id, session_id
        FROM neetprep_bookmarks
        WHERE neetprep_question_id IN ({placeholders}) AND user_id = ?
    """

    bookmarks = conn.execute(query, question_ids + [current_user.id]).fetchall()
    conn.close()

    # Group by question_id
    result = {}
    for b in bookmarks:
        qid = str(b['neetprep_question_id'])
        if qid not in result:
            result[qid] = []
        result[qid].append(b['session_id'])

    return jsonify({
        'success': True,
        'bookmarks': result
    })

@neetprep_bp.route('/neetprep/collections/<session_id>/quiz')
@login_required
def collection_quiz(session_id):
    """Start a quiz from a bookmark collection."""
    conn = get_db_connection()

    # Verify ownership
    session = conn.execute('SELECT id, name FROM sessions WHERE id = ? AND user_id = ?',
                          (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        from flask import redirect, flash
        flash('Collection not found', 'danger')
        return redirect(url_for('dashboard.dashboard', filter='collections'))

    all_questions = []

    # Get neetprep bookmarked questions
    neetprep_questions = conn.execute("""
        SELECT nq.id, nq.question_text, nq.options, nq.correct_answer_index,
               nq.level, nq.topic, nq.subject
        FROM neetprep_bookmarks b
        JOIN neetprep_questions nq ON b.neetprep_question_id = nq.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'neetprep'
        ORDER BY b.created_at
    """, (session_id, current_user.id)).fetchall()

    for q in neetprep_questions:
        try:
            html_content = f"""<html><head><meta charset="utf-8"></head><body>{q['question_text']}</body></html>"""
            img_filename = f"neetprep_{q['id']}.jpg"
            img_path = os.path.join(current_app.config['TEMP_FOLDER'], img_filename)
            imgkit.from_string(html_content, img_path, options={'width': 800})
            all_questions.append({
                'image_path': f"/tmp/{img_filename}",
                'details': {
                    'id': q['id'],
                    'options': json.loads(q['options']) if q['options'] else [],
                    'correct_answer_index': q['correct_answer_index'],
                    'user_answer_index': None,
                    'source': 'neetprep',
                    'topic': q['topic'],
                    'subject': q['subject']
                }
            })
        except Exception as e:
            current_app.logger.error(f"Failed to convert question {q['id']} to image: {e}")

    # Get classified bookmarked questions
    classified_questions = conn.execute("""
        SELECT q.id, q.actual_solution as correct_answer_index, q.marked_solution as user_answer_index,
               q.chapter as topic, q.subject, i.processed_filename, i.note_filename
        FROM neetprep_bookmarks b
        JOIN questions q ON CAST(b.neetprep_question_id AS INTEGER) = q.id
        LEFT JOIN images i ON q.image_id = i.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'classified'
        ORDER BY b.created_at
    """, (session_id, current_user.id)).fetchall()

    for q in classified_questions:
        if q['processed_filename']:
            all_questions.append({
                'image_path': f"/processed/{q['processed_filename']}",
                'details': {
                    'id': q['id'],
                    'options': [],
                    'correct_answer_index': q['correct_answer_index'],
                    'user_answer_index': q['user_answer_index'],
                    'source': 'classified',
                    'topic': q['topic'],
                    'subject': q['subject'],
                    'note_filename': q['note_filename']
                }
            })

    conn.close()

    if not all_questions:
        from flask import redirect, flash
        flash('No questions in this collection', 'warning')
        return redirect(url_for('neetprep_bp.view_collection', session_id=session_id))

    return render_template('quiz_v2.html', questions=all_questions)

@neetprep_bp.route('/neetprep/collections/<session_id>/generate', methods=['POST'])
@login_required
def generate_collection_pdf(session_id):
    """Generate a PDF from a bookmark collection."""
    conn = get_db_connection()

    # Verify ownership
    session = conn.execute('SELECT id, name, subject FROM sessions WHERE id = ? AND user_id = ?',
                          (session_id, current_user.id)).fetchone()
    if not session:
        conn.close()
        return jsonify({'error': 'Collection not found'}), 404

    # Get neetprep bookmarked questions
    neetprep_questions = conn.execute("""
        SELECT nq.id, nq.question_text, nq.options, nq.correct_answer_index,
               nq.level, nq.topic, nq.subject
        FROM neetprep_bookmarks b
        JOIN neetprep_questions nq ON b.neetprep_question_id = nq.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'neetprep'
        ORDER BY nq.topic, b.created_at
    """, (session_id, current_user.id)).fetchall()

    # Get classified bookmarked questions
    classified_questions = conn.execute("""
        SELECT q.id, q.question_text, q.actual_solution as correct_answer_index,
               q.chapter as topic, q.subject, i.processed_filename
        FROM neetprep_bookmarks b
        JOIN questions q ON CAST(b.neetprep_question_id AS INTEGER) = q.id
        LEFT JOIN images i ON q.image_id = i.id
        WHERE b.session_id = ? AND b.user_id = ? AND b.question_type = 'classified'
        ORDER BY q.chapter, b.created_at
    """, (session_id, current_user.id)).fetchall()

    conn.close()

    if not neetprep_questions and not classified_questions:
        return jsonify({'error': 'No questions in this collection'}), 400

    data = request.json or {}
    all_questions = []

    for q in neetprep_questions:
        all_questions.append({
            "id": q['id'],
            "question_text": q['question_text'],
            "options": json.loads(q['options']) if q['options'] else [],
            "correct_answer_index": q['correct_answer_index'],
            "user_answer_index": None,
            "status": "wrong",
            "source": "neetprep",
            "custom_fields": {
                "difficulty": q['level'],
                "topic": q['topic'],
                "subject": q['subject']
            }
        })

    for q in classified_questions:
        if q['processed_filename']:
            # Use absolute path for PDF generation
            abs_img_path = os.path.abspath(os.path.join(current_app.config['PROCESSED_FOLDER'], q['processed_filename']))
            all_questions.append({
                "id": q['id'],
                "question_text": f"<img src=\"{abs_img_path}\" style=\"max-width:100%;\" />",
                "options": [],
                "correct_answer_index": q['correct_answer_index'],
                "user_answer_index": None,
                "status": "wrong",
                "source": "classified",
                "custom_fields": {
                    "topic": q['topic'],
                    "subject": q['subject']
                }
            })

    topics = list(set(q['custom_fields']['topic'] for q in all_questions if q['custom_fields'].get('topic')))

    final_json_output = {
        "version": "2.1",
        "test_name": session['name'] or "Bookmark Collection",
        "config": {"font_size": 22, "auto_generate_pdf": False, "layout": data.get('layout', {})},
        "metadata": {"source_book": "NeetPrep Collection", "tags": ", ".join(topics)},
        "questions": all_questions,
        "view": True
    }

    try:
        result, status_code = _process_json_and_generate_pdf(final_json_output, current_user.id)
        if status_code != 200:
            return jsonify(result), status_code

        if result.get('success'):
            return jsonify({'success': True, 'pdf_url': result.get('view_url')})
        else:
            return jsonify({'error': result.get('error', 'Failed to generate PDF')}), 500
    except Exception as e:
        current_app.logger.error(f"Failed to generate collection PDF: {repr(e)}")
        return jsonify({'error': str(e)}), 500

# ============== END BOOKMARK FEATURE ==============

def run_hardcoded_query(query_template, **kwargs):
    """Helper function to run a GraphQL query."""
    final_query = query_template.format(**kwargs)
    payload = {'query': final_query, 'variables': {}}
    try:
        response = requests.post(ENDPOINT_URL, headers=HEADERS, json=payload, timeout=30)
        response.raise_for_status()
        return response.json()
    except requests.exceptions.RequestException as e:
        current_app.logger.error(f"NeetPrep API Request Error: {repr(e)}")
        return None