#e_chemistry.py
'''
title: Chemistry Elements Information
author: Michael Tang
date-created: 2021-05-12
'''

import sys
 
 # --- subroutines -- #
### -- INPUTS
def getElem():
    '''
    User enter the Element Symbol
    :return: (str)
    '''
    ELEMENT = input("Element Symbol: ")
    return ELEMENT

### --- PROCESSING
def getIndex(STRING, SYMBOLS):
    '''
    searching for the index number of the element
    :param STRING: (str) Element Symbol
    :param SYMBOLS: (list) of Symbols
    :return (int) Index number
    '''
    for i in range(len(SYMBOLS)):
        if SYMBOLS[i] == STRING:
            return i
    print("The symbol was not found")
    sys.exit()

### - OUTPUT

def dispInfo(INDEX, NAME, ATOMIC_MASS):
    '''
    display the name and atomic mass of the symbol.
    :param INDEX: (int)
    :param NAME (list) of element names
    :param ATOMIC_MASS: (list) of element atomic masses
    :return: (none)
    '''
    print(f"{NAME[INDEX]}: {ATOMIC_MASS[INDEX]} g/mol")

 # --- variables --- #

ElemSym = (
     "H",
     "He",
     "Li",
     "Be"
)
ElemName = (
     "Hydrogen",
     "Helium",
     "Lithium",
     "Beryllium"
)
ElemAtomicM = (
     1.01,
     4.0,
     6.94,
     9.01
)

if __name__ == "__main__":
    # --- MAIN PROGRAM CODE --- #
    ELEM_SYMBOL = getElem()
    ELEM_IND = getIndex(ELEM_SYMBOL, ElemSym)
#    print(ELEM_IND)
    dispInfo(ELEM_IND, ElemName, ElemAtomicM)