import argparse
import matplotlib
matplotlib.use("Agg")  # Use Agg backend for non-GUI environments

import geopandas as gpd
import matplotlib.pyplot as plt
from pathlib import Path

def plot_geometries(parquet_file: str, save_as: str):
    """
    Plots the geometries inside a GeoParquet file and saves the image instead of showing it.

    Args:
        parquet_file (str): Path to the Parquet file containing geometries.
        save_as (str): Path to save the output plot image.
    """
    parquet_path = Path(parquet_file)
    if not parquet_path.exists():
        raise FileNotFoundError(f"❌ File '{parquet_file}' not found.")

    # Load the Parquet file into a GeoDataFrame
    gdf = gpd.read_parquet(parquet_path)

    # Ensure it has a valid geometry column
    if "geometry" not in gdf.columns:
        raise ValueError("❌ No 'geometry' column found in the file.")

    # Plot the geometries
    fig, ax = plt.subplots(figsize=(8, 8))
    gdf.plot(ax=ax, edgecolor="black", facecolor="lightblue", alpha=0.5)

    # Add labels
    ax.set_title(f"Geometries in {parquet_file}")
    ax.set_xlabel("Longitude")
    ax.set_ylabel("Latitude")

    # Save the figure instead of showing it
    plt.savefig(save_as, dpi=300)
    print(f"✅ Plot saved as {save_as}")

def main():
    parser = argparse.ArgumentParser(description="Plot geometries from a GeoParquet file and save as an image.")
    parser.add_argument("-i", "--input", required=True, help="Path to the input GeoParquet file.")
    parser.add_argument("-o", "--output", required=True, help="Path to save the output plot image.")
    
    args = parser.parse_args()

    try:
        plot_geometries(args.input, args.output)
    except Exception as e:
        print(f"❌ Error: {e}")

if __name__ == "__main__":
    main()