#!/usr/bin/env python
# Wenchang Yang (wenchang@princeton.edu)
# Wed Nov  6 00:06:34 EST 2019
import sys, os.path, os, datetime
import xarray as xr, numpy as np, pandas as pd
#import matplotlib.pyplot as plt

volcs = ['Pinatubo', 'Chichon', 'Agung', 'StMaria']
data_name = 'SIE'
n_years = 5
time_new = xr.cftime_range(start='0001-01', periods=n_years*12, freq='MS', calendar='noleap')
ofile = f'Volc.{data_name}.ens.nc'
 
if __name__ == '__main__':
    if os.path.exists(ofile):
        print('[exists]:', ofile)
        sys.exit()
    tformat = '%Y-%m-%d %H:%M:%S'
    t0 = datetime.datetime.now()
    print('[start]:', t0.strftime(tformat))

    dss = []
    for volc in volcs:
        print(volc)
        ifile = f'{volc}_PI_ens_noleap.{data_name}.nc'
        ds = xr.open_dataset(ifile).assign_coords(time=time_new) 
        dss.append(ds)
    ds = xr.concat(dss, dim=pd.Index(volcs, name='volc'))

    # save the dataset
    ds.to_netcdf(ofile)
    print('[saved]:', ofile)
    
    t1 = datetime.datetime.now()
    print('[total time used]:', f'{(t1-t0).seconds:,} seconds')
    print('[end]:', t1.strftime(tformat))
    print()