from fastapi import FastAPI, HTTPException, Query
from starlette.responses import JSONResponse
from obspy.clients.fdsn import Client
from obspy.core.utcdatetime import UTCDateTime
import logging
from datetime import date

# Configure logging
logging.basicConfig(level=logging.INFO)

# Initialize the FastAPI app
app = FastAPI(
    title="Dynamic Earthquake Catalog API",
    description="A robust API to fetch earthquake data from the IRIS FDSN web service using URL parameters.",
    version="2.1.0",
)

# Initialize the IRIS FDSN client
try:
    client = Client("IRIS")
    logging.info("Successfully initialized IRIS FDSN client.")
except Exception as e:
    client = None
    logging.error(f"Could not initialize IRIS FDSN client on startup: {e}")

@app.get("/")
def greet_json():
    """
    A simple 'Hello World' endpoint.
    """
    return {"Hello": "World!", "message": "Go to /docs to try the dynamic earthquake endpoint.  cwadayi \n https://cwadayi-python-app.hf.space/earthquakes?start_date=2024-07-01&end_date=2024-07-07&min_magnitude=5.0"}

@app.get("/earthquakes")
async def get_earthquake_catalog(
    start_date: date = Query(default="2024-01-01", description="Start date in YYYY-MM-DD format"),
    end_date: date = Query(default="2024-01-07", description="End date in YYYY-MM-DD format"),
    min_magnitude: float = Query(default=4.5, description="Minimum earthquake magnitude (e.g., 5.5)", gt=0, le=10)
):
    """
    Fetches earthquake data based on date and magnitude parameters provided in the URL.
    """
    if not client:
        raise HTTPException(status_code=503, detail="The IRIS FDSN client is not available.")
    
    if start_date > end_date:
        raise HTTPException(status_code=400, detail="The start_date cannot be after the end_date.")

    try:
        starttime = UTCDateTime(start_date)
        endtime = UTCDateTime(end_date)

        logging.info(f"Fetching events from {starttime} to {endtime} with min magnitude {min_magnitude}.")
        catalog = client.get_events(
            starttime=starttime,
            endtime=endtime,
            minmagnitude=min_magnitude,
        )
        logging.info(f"Found {len(catalog)} events. Now processing.")

        earthquake_list = []
        for event in catalog:
            try:
                origin = event.preferred_origin()
                magnitude = event.preferred_magnitude()

                if not origin or not magnitude:
                    continue

                # --- Key Change Start ---
                # Safely get the description using getattr. This avoids errors if the 'descriptions'
                # attribute doesn't exist, by providing a default empty list [].
                place = "N/A"
                descriptions = getattr(event, 'descriptions', [])
                if descriptions:
                    place = descriptions[0].text
                # --- Key Change End ---

                earthquake_list.append({
                    "time": origin.time.isoformat(),
                    "latitude": origin.latitude,
                    "longitude": origin.longitude,
                    "depth_km": origin.depth / 1000.0 if origin.depth is not None else None,
                    "magnitude": magnitude.mag,
                    "magnitude_type": magnitude.magnitude_type,
                    "place": place,
                })
            except Exception as e:
                logging.warning(f"Skipping event due to unexpected processing error: {e}")
                continue
        
        logging.info(f"Successfully processed {len(earthquake_list)} events.")
        return JSONResponse(content={"earthquakes": earthquake_list})

    except Exception as e:
        logging.error(f"A major error occurred during the request: {e}")
        raise HTTPException(status_code=500, detail=f"An internal error occurred: {e}")