import streamlit as st
import math
import matplotlib.pyplot as plt
import numpy as np

def calculate_pipe_diameter(flow_rate, velocity):
    """Calculate the pipe diameter using the formula:
    Diameter = sqrt((4 * Flow Rate) / (pi * Velocity))
    """
    if velocity <= 0:
        return None  # Velocity must be greater than zero

    diameter = math.sqrt((4 * flow_rate) / (math.pi * velocity))
    return diameter

def main():
    st.set_page_config(page_title="Pipe Sizing Helper", page_icon="🔧", layout="centered")
    st.title("🔧 Pipe Sizing Helper")
    st.write("This tool calculates the recommended pipe diameter based on flow rate and permissible velocity.")

    # Input fields
    flow_rate = st.number_input(
        "Enter Flow Rate (m³/s):",
        min_value=0.0,
        format="%.4f",
        help="The volumetric flow rate of the fluid (e.g., 0.1 for 0.1 m³/s)."
    )

    velocity = st.number_input(
        "Enter Permissible Velocity (m/s):",
        min_value=0.01,
        format="%.2f",
        help="The maximum allowable velocity of the fluid in the pipe."
    )

    # Button to calculate pipe diameter
    calculate_button = st.button("🔄 Generate Pipe Diameter")

    if calculate_button:
        if velocity > 0:
            diameter = calculate_pipe_diameter(flow_rate, velocity)
            if diameter:
                st.success(f"The recommended pipe diameter is {diameter:.4f} meters.")
            else:
                st.error("Invalid input. Please ensure flow rate and velocity are positive values.")
        else:
            st.error("Velocity must be greater than zero.")

    # Graphical visualization
    st.markdown("### Pipe Diameter Visualization")
    st.write("This graph shows the relationship between pipe diameter and velocity for the specified flow rate.")

    min_velocity = st.sidebar.number_input("Minimum Velocity (m/s):", min_value=0.01, value=0.5, step=0.1, format="%.2f")
    max_velocity = st.sidebar.number_input("Maximum Velocity (m/s):", min_value=min_velocity + 0.1, value=5.0, step=0.1, format="%.2f")

    velocities = np.linspace(min_velocity, max_velocity, 100)
    diameters = [calculate_pipe_diameter(flow_rate, v) for v in velocities]

    fig, ax = plt.subplots()
    ax.plot(velocities, diameters, label="Pipe Diameter vs Velocity", color="blue")
    ax.set_xlabel("Velocity (m/s)")
    ax.set_ylabel("Pipe Diameter (m)")
    ax.set_title("Recommended Pipe Diameter Across Velocity Range")
    ax.grid(True)
    ax.legend()

    st.pyplot(fig)

    # Sidebar for additional information
    st.sidebar.header("About the App")
    st.sidebar.markdown("This application helps you calculate the recommended pipe diameter for a given flow rate and velocity.")
    st.sidebar.markdown("---")
    st.sidebar.info("Uses basic fluid mechanics principles for pipe sizing calculations.")

    # Footer
    st.markdown("---")
    st.markdown("**Developed by [Your Name]**")

if __name__ == "__main__":
    main()