from __future__ import print_function

import os
import sys

import numpy as np
import datetime as dt

###########################################

   ##
   ##  This script is used to read NSIDC IMS data:
   ##  National Ice Center's Interactive Multisensor Snow and Ice Mapping System
   ##     https://nsidc.org/data/G02156
   ##  Support included onl for 4km resolution.
   ##
   ##  input file in ASCII format specified on the command line
   ##  load the data into the numpy array
   ##

if len(sys.argv) == 2:
    # Read the input file as the first argument
    input_file = os.path.expandvars(sys.argv[1])
    try:
        # Print some output to verify that this script ran
        print("Input File: " + repr(input_file))
        lines = open(input_file, 'r').readlines()[30:]
        d = []
        for line in lines:
          d += line.rstrip()
        met_data = np.rot90(np.asarray(d, dtype='float').reshape(6144, 6144).transpose()).copy()
        print(repr(met_data.shape))
        met_data[met_data == 0] = -9999
        met_data = met_data.copy()
        print("Data Shape: " + repr(met_data.shape))
        print("Data Type:  " + repr(met_data.dtype))
    except NameError:
        print("Can't find the input file")
else:
    print("Must specify exactly one input file.")
    sys.exit(1)

###########################################

   ##
   ## parse time info from file name
   ## 

valid = dt.datetime.strptime(os.path.basename(input_file), "ims%Y%j_4km_v1.3.asc")
init  = valid;

   ##
   ##  create the metadata dictionary
   ##

attrs = {
   'valid': valid.strftime("%Y%m%d_%H%M%S"),
   'init':   init.strftime("%Y%m%d_%H%M%S"),
   'lead':  '00',
   'accum': '00',

   'name':      'snowC',
   'long_name': 'Ice Mapping System Snow Categories',
   'level':     'Surface',
   'units':     'Type',

   'grid': {
       'name':        '4km Polar Stereographic',
       'type' :       'Polar Stereographic',
       'hemisphere':  'N',
       'scale_lat':   60.0,
       'lat_pin':     90.0,
       'lon_pin':      0.0,
       'x_pin':     3072.0,
       'y_pin':     3072.0,
       'lon_orient': -80.0,
       'd_km':         4.0,
       'r_km':      6371.2,
       'nx':        6144,
       'ny':        6144
   }
}

print("Attributes: " + repr(attrs))