import streamlit as st
from PIL import Image

# Set Page Config
st.set_page_config(
    page_title="HVAC System Calculator",
    page_icon="⚙️",  # Changed to an engineering-related icon
    layout="wide",
    initial_sidebar_state="expanded",
)

# Title and Description
st.title("⚙️ MEP HVAC System Calculator")
st.markdown("""
An interactive tool for MEP engineers to perform HVAC calculations:
- **CFM to Ton Conversion**
- **Heat Load Calculation**
- **System Selection**
- **AC Unit Requirements**

Use the sidebar to select tasks and input space parameters. Detailed recommendations are provided after the calculations.
""")

# Sidebar for User Input
st.sidebar.title("User Input")
task = st.sidebar.selectbox("Choose a Task", [
    "CFM to Ton Conversion",
    "Heat Load Calculation",
    "System Selection",
    "AC Unit Requirements"
])

# Functions for calculations
def cfm_to_ton(cfm):
    return cfm / 400

def calculate_heat_load(volume, occupants, appliances):
    return (volume * 5) + (occupants * 500) + appliances

def recommend_system(heat_load):
    if heat_load <= 24000:
        return "Split AC", "Up to 24,000 BTU"
    elif heat_load <= 60000:
        return "Package Unit", "24,001 - 60,000 BTU"
    elif heat_load <= 120000:
        return "FAU (Forced Air Unit)", "60,001 - 120,000 BTU"
    else:
        return "EAU (Evaporative Air Unit)", "120,001+ BTU"

def calculate_ac_units(heat_load, capacity_per_unit):
    return int((heat_load / capacity_per_unit) + 0.5)

# Task-specific logic
if task == "CFM to Ton Conversion":
    st.header("CFM to Ton Conversion")
    cfm = st.number_input("Enter CFM (Cubic Feet per Minute)", min_value=0.0, step=1.0)
    if st.button("Convert"):
        if cfm:
            tons = cfm_to_ton(cfm)
            st.success(f"Equivalent Tons: {tons:.2f}")
            st.markdown("### Description and Recommendation")
            st.write("CFM (Cubic Feet per Minute) is the volume of air moved per minute. Converting it into tons helps select the appropriate HVAC system.")

elif task == "Heat Load Calculation":
    st.header("Heat Load Calculation")
    st.markdown("Enter the dimensions of the space:")
    col1, col2, col3 = st.columns(3)
    with col1:
        length = st.number_input("Length (in feet)", min_value=0.0, step=1.0)
    with col2:
        width = st.number_input("Width (in feet)", min_value=0.0, step=1.0)
    with col3:
        height = st.number_input("Height (in feet)", min_value=0.0, step=1.0)

    col4, col5 = st.columns(2)
    with col4:
        occupants = st.number_input("Number of Occupants", min_value=0, step=1)
    with col5:
        appliances = st.number_input("Appliances Heat Load (in BTU)", min_value=0.0, step=100.0)

    if st.button("Calculate Heat Load"):
        volume = length * width * height
        if volume:
            heat_load = calculate_heat_load(volume, occupants, appliances)
            st.success(f"Heat Load: {heat_load:.2f} BTU")
            st.markdown("### Description and Recommendation")
            st.write("Heat load is essential for determining the cooling requirements. Ensure to account for appliance and occupant heat contributions.")

elif task == "System Selection":
    st.header("System Selection")
    heat_load = st.number_input("Enter Heat Load (in BTU)", min_value=0.0, step=100.0)
    if st.button("Recommend System"):
        if heat_load:
            system, details = recommend_system(heat_load)
            st.success(f"Recommended System: {system}")
            st.info(f"Details: {details}")
            st.markdown("### Description and Recommendation")
            st.write(f"{system} systems are typically used for spaces requiring {details} cooling capacity. Consult with a professional for final selection.")

elif task == "AC Unit Requirements":
    st.header("AC Unit Requirements")
    col1, col2 = st.columns(2)
    with col1:
        heat_load = st.number_input("Enter Total Heat Load (in BTU)", min_value=0.0, step=100.0)
    with col2:
        capacity_per_unit = st.number_input("Capacity per Unit (in BTU)", min_value=1000.0, step=100.0)

    if st.button("Calculate Units"):
        if heat_load and capacity_per_unit:
            units_required = calculate_ac_units(heat_load, capacity_per_unit)
            st.success(f"Number of AC Units Required: {units_required}")
            st.markdown("### Description and Recommendation")
            st.write(f"For a total heat load of {heat_load:.2f} BTU, {units_required} unit(s) with a capacity of {capacity_per_unit:.2f} BTU each are required.")

# Footer
st.markdown("---")
st.markdown("Built with ❤️ using Streamlit for MEP Engineers")