import hashlib
import os
from flask import Flask, request, render_template, redirect

app = Flask(__name__)

# Global storage for the current challenge
current_challenge = {}

# Redirect root URL to get-challenge
@app.route('/', methods=['GET'])
def index():
    return redirect('/get-challenge')  # Redirect to the challenge page

# Generate a nonce and difficulty for the client
@app.route('/get-challenge', methods=['GET'])
def get_challenge():
    global current_challenge
    nonce = os.urandom(16).hex()  # Generate a random 16-byte nonce
    difficulty = 4  # Set the difficulty (number of leading zeros)
    current_challenge = {'nonce': nonce, 'difficulty': difficulty}
    return render_template('challenge.html', nonce=nonce, difficulty=difficulty)

# Verify the solution provided by the client
@app.route('/verify', methods=['POST'])
def verify_solution():
    solution = request.form['solution']
    nonce = current_challenge['nonce']
    difficulty = current_challenge['difficulty']

    # Recompute the hash with the client's solution
    hash_result = hashlib.sha256((nonce + solution).encode()).hexdigest()

    # Check if the hash has the required number of leading zeros
    if hash_result.startswith('0' * difficulty):
        return render_template('result.html', status="Success! Solution is correct.")
    else:
        return render_template('result.html', status="Failed. Incorrect solution.")

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=6969)