import gradio as gr
import wntr
import traceback
import tempfile
import os
import shutil

def run_simulation (inp_file):
    try:
         # Create temporary working directory
        work_dir = tempfile.mkdtemp()
        inp_path = os.path.join(work_dir, "network.inp")

        # Save uploaded file to temp path
        shutil.copy(inp_file.name, inp_path)
        # Gradio returns a file path string (not a file object)
        wn = wntr.network.WaterNetworkModel(inp_file)
        sim = wntr.sim.EpanetSimulator(wn)
        results = sim.run_sim()

        # Extract node head values at time index 0
        heads = results.node["head"].iloc[0]
        report = "\n".join(
            f"{node_id}: Head = {head:.2f} m"
            for node_id, head in heads.items()
        )

        return report

    except Exception as e:
        tb = traceback.format_exc()
        return f"❌ Simulation failed:\n{e}\n\n{tb}"

# Define Gradio interface
iface = gr.Interface(
    fn=run_simulation,
    inputs=gr.File(label="Upload EPANET .inp file"),
    outputs="text",
    title="💧 EPANET Simulation Tool (Gradio + WNTR)",
    description="Upload a valid EPANET `.inp` file. This tool simulates hydraulic head at all nodes using the WNTR library.",
    allow_flagging="never"
)

# Hugging Face Docker requires 0.0.0.0 and port 7860
if __name__ == "__main__":
    print("🚀 Gradio app is launching...")
    iface.launch(server_name="0.0.0.0", server_port=7860)