app.py

import streamlit as st
import wntr
import os
import pandas as pd
import plotly.express as px
from wntr_utils import run_simulation, plot_network_map

st.set_page_config(page_title="WNTR-QGIS Streamlit", layout="wide")

st.title("💧 WNTR-QGIS-style Water Network Analyzer")

# Upload file section
uploaded_file = st.file_uploader("Upload EPANET .inp File", type=["inp"])

@st.cache_resource
def load_wn_model(file_path):
    return wntr.network.WaterNetworkModel(file_path)

if uploaded_file:
    # Save uploaded file temporarily
    with open("temp.inp", "wb") as f:
        f.write(uploaded_file.read())
    
    try:
        with st.spinner("Loading water network model..."):
            wn = load_wn_model("temp.inp")
            st.success("Model loaded successfully!")

        # User chooses simulation engine
        sim_choice = st.radio("Choose Simulation Engine", ["EpanetSimulator", "WntrSimulator"])

        with st.spinner("Running simulation..."):
            results = run_simulation(wn, sim_choice)
            st.success("Simulation completed!")

        # Choose metric and time step
        st.subheader("📊 Result Viewer")
        metric = st.selectbox("Select Node Metric", ["pressure", "head"])
        timestep = st.slider("Select Time Step", 0, len(results.node["pressure"].index)-1)

        # Plot map
        with st.spinner("Plotting network map..."):
            fig = plot_network_map(wn, results, metric, timestep)
            st.plotly_chart(fig, use_container_width=True)

    except Exception as e:
        st.error(f"❌ An error occurred: {e}")

else:
    st.info("👈 Please upload a valid EPANET `.inp` file to begin.")