from flask import Flask, request, render_template, redirect, url_for
from transformers import AutoTokenizer, AutoModel
import torch
import os
os.environ["TOKENIZERS_PARALLELISM"] = "false"
app = Flask(__name__)

# Dictionary to store programs and their courses
programs = {}

# Default model name
current_model_name = 'sentence-transformers/all-mpnet-base-v2'

# Function to load the tokenizer and model dynamically
def load_model_and_tokenizer(model_name):
    try:
        tokenizer = AutoTokenizer.from_pretrained(model_name)
        model = AutoModel.from_pretrained(model_name)
        return tokenizer, model, None
    except Exception as e:
        return None, None, str(e)

# Load the initial model and tokenizer
tokenizer, model, error = load_model_and_tokenizer(current_model_name)

def mean_pooling(token_embeddings, mask):
    """Applies mean pooling to token embeddings, considering the mask."""
    mask = mask.unsqueeze(-1).expand(token_embeddings.size())
    sum_embeddings = torch.sum(token_embeddings * mask, dim=1)
    sum_mask = torch.clamp(mask.sum(dim=1), min=1e-9)  # Avoid division by zero
    return sum_embeddings / sum_mask

def compute_plo_embeddings():
    """Computes embeddings for the predefined PLOs."""
    tokens = tokenizer(plos, padding=True, truncation=True, return_tensors='pt')
    mask = tokens['attention_mask']
    with torch.no_grad():
        outputs = model(**tokens)
        return mean_pooling(outputs.last_hidden_state, mask)

# Predefined Program Learning Outcomes (PLOs)
plos = [
    "Analyze a complex computing problem and apply principles of computing and other relevant disciplines to identify solutions.",
    "Design, implement, and evaluate a computing-based solution to meet a given set of computing requirements.",
    "Communicate effectively in a variety of professional contexts.",
    "Recognize professional responsibilities and make informed judgments in computing practice based on legal and ethical principles.",
    "Function effectively as a member or leader of a team engaged in activities appropriate to the program’s discipline.",
    "Support the delivery, use, and management of information systems within an information systems environment."
]

# Compute PLO embeddings (once at startup)
plo_embeddings = compute_plo_embeddings()

def get_similarity(input_sentence):
    """Calculates the similarity between an input sentence and predefined PLOs."""
    tokens = tokenizer(input_sentence, padding=True, truncation=True, return_tensors='pt')
    mask = tokens['attention_mask']

    with torch.no_grad():
        outputs = model(**tokens)
        input_embedding = mean_pooling(outputs.last_hidden_state, mask)

    similarities = torch.nn.functional.cosine_similarity(input_embedding, plo_embeddings)
    return similarities

@app.route('/')
def index():
    """Home page displaying current programs and model status."""
    return render_template('index.html', programs=programs, model_name=current_model_name)

@app.route('/set_model', methods=['POST'])
def set_model():
    """Allows users to dynamically change the model."""
    global tokenizer, model, plo_embeddings, current_model_name

    model_name = request.form['model_name']
    tokenizer, model, error = load_model_and_tokenizer(model_name)

    if error:
        return render_template('index.html', programs=programs, message=f"Error loading model: {error}")

    # Update the global model name and recompute embeddings
    current_model_name = model_name
    plo_embeddings = compute_plo_embeddings()
    return redirect(url_for('index'))

@app.route('/addprogram', methods=['GET', 'POST'])
def add_program():
    """Adds a new program."""
    if request.method == 'POST':
        program_name = request.form['program_name']
        if program_name not in programs:
            programs[program_name] = {}  # Initialize an empty dictionary for courses
        return redirect(url_for('index'))
    return render_template('addprogram.html')

@app.route('/addcourse', methods=['GET', 'POST'])
def create_course():
    """Creates a new course under a specific program."""
    if request.method == 'POST':
        program_name = request.form['program']
        course_name = request.form['course_name']
        outcomes = request.form['course_outcomes'].split('\n')

        if program_name in programs:
            programs[program_name][course_name] = outcomes  # Add course to the selected program

        return redirect(url_for('index'))
    return render_template('addcourse.html', programs=programs)

@app.route('/match', methods=['POST'])
def match_outcomes():
    """Matches course outcomes with predefined PLOs."""
    course_name = request.form['course']
    print(course_name)
    course_outcomes = request.form['course_outcomes'].split('\n')
    results = []

    for co in course_outcomes:
        co = co.strip()
        if co:  # Ensure the outcome is not empty
            similarities = get_similarity(co)
            top_matches_indices = similarities.topk(3).indices.tolist()
            results.append({
                'course_outcome': co,
                'course_name' : course_name,
                'best_matches': top_matches_indices
            })

    return render_template('result.html', course_name =course_name,  results=results)

if __name__ == '__main__':
     app.run(debug=True)