app.py

import streamlit as st
from streamlit_folium import st_folium
import folium
from datetime import datetime

# Streamlit App
st.title("Weather Explorer 🌍☀️")

st.markdown("Search and click a location on the map to get current and historical temperature data.")

# Date input (defaults to today)
default_date = datetime.utcnow().date()
date_input = st.text_input("Enter Date (YYYY-MM-DD)", value=str(default_date))

# Latitude and Longitude Inputs (initialized empty)
lat_input = st.text_input("Latitude", value="")
lon_input = st.text_input("Longitude", value="")

# Map setup
st.subheader("Select a location on the map:")
m = folium.Map(location=[20, 0], zoom_start=2)
map_data = st_folium(m, width=700, height=500)

# If user clicks on the map, populate the lat/lon fields
if map_data and map_data.get("last_clicked"):
    clicked_lat = map_data["last_clicked"]["lat"]
    clicked_lon = map_data["last_clicked"]["lng"]
    st.session_state['clicked_lat'] = clicked_lat
    st.session_state['clicked_lon'] = clicked_lon

# Pre-fill lat/lon if available
if 'clicked_lat' in st.session_state and 'clicked_lon' in st.session_state:
    lat_input = st.text_input("Latitude", value=str(st.session_state['clicked_lat']))
    lon_input = st.text_input("Longitude", value=str(st.session_state['clicked_lon']))

# 'Enter' Button
if st.button("Enter"):
    if lat_input and lon_input and date_input:
        try:
            # Convert input to correct types
            lat = float(lat_input)
            lon = float(lon_input)
            selected_date = datetime.strptime(date_input, "%Y-%m-%d").date()
            
            st.success(f"Fetching weather data for {lat:.4f}, {lon:.4f} on {selected_date}")

            # --------- Replace below with actual data fetching ----------
            # Example placeholder (replace with real ECMWF or API call)
            current_temp = 25  # Placeholder: current temperature
            historical_min_temp = 15  # Placeholder: historical minimum
            historical_max_temp = 35  # Placeholder: historical maximum

            st.metric("Current Temperature (°C)", f"{current_temp}°C")
            st.metric(f"Historical Min (°C) on {selected_date.strftime('%B %d')}", f"{historical_min_temp}°C")
            st.metric(f"Historical Max (°C) on {selected_date.strftime('%B %d')}", f"{historical_max_temp}°C")

        except ValueError:
            st.error("Please enter valid latitude, longitude, and date values.")

    else:
        st.error("Please provide all inputs (date, latitude, longitude).")