import streamlit as st
import math

# Function to calculate pipe diameter based on flow rate and velocity
def calculate_diameter(flow_rate, velocity):
    # Using formula: D = sqrt((4 * Q) / (pi * V))
    diameter = math.sqrt((4 * flow_rate) / (math.pi * velocity))
    return diameter

# Streamlit user interface
def main():
    st.title("Pipe Sizing Helper")
    st.write("This app calculates the recommended pipe diameter based on given flow rate and velocity.")

    # Input fields for flow rate and velocity
    flow_rate = st.number_input("Enter the flow rate (m³/s):", min_value=0.0, step=0.01)
    velocity = st.number_input("Enter the permissible velocity (m/s):", min_value=0.1, step=0.1)

    # Check if both inputs are positive and valid
    if flow_rate > 0 and velocity > 0:
        # Calculate the pipe diameter
        diameter = calculate_diameter(flow_rate, velocity)
        st.write(f"Recommended pipe diameter: {diameter:.2f} meters")
    else:
        st.write("Please enter valid flow rate and velocity.")

if __name__ == "__main__":
    main()