import os
import sys

from mp_api.client import MPRester
from pymatgen.io.vasp import Poscar


API_KEY = os.getenv('MP_APIKEY')
if API_KEY is None:
    print("\nError: Can not get MP API Key from the environment var MP_APIKEY\n")
    input("Press ENTER to terminate>>\n")
    exit()

argv = sys.argv
narg = len(argv)
if narg <= 1:
    print("\nError: Chemical formula must be given as the first arg\n")
    input("Press ENTER to terminate>>\n")
    exit()

formula = argv[1]


mpr = MPRester(API_KEY)
if mpr is None:
    print(f"\nError: Can not get MPRester using the given API_KEY [{API_KEY}]\n")
    input("Press ENTER to terminate>>\n")
    exit()

search_criteria = {"formula": formula}
results = mpr.summary.search(**search_criteria)

if results:
    material_id = results[0].material_id
    print(f"Found material_id for CsCl: {material_id}")

    structure = mpr.get_structure_by_material_id(material_id)

    poscar = Poscar(structure)
    poscar.write_file('POSCAR')

    print(f"POSCAR file for {formula} has been created.")
else:
    print(f"No materials found for {formula}.")

print()
input("Press ENTER to terminate>>\n")