#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Nov 27 18:07:14 2021

@author: Changyong.Cao@noaa.gov
A barebone Python program to extract a small area from the VIIRS I1 band in h5 format.

Output: display image on screen for the small area  
"""

import h5py  #, glob, sys, getopt, argparse, re, os
#from osgeo import gdal, gdal_array, osr
import numpy as np
#from gisfunctions import GetGeographicInfo
#from gisfunctions import GetDatasetList
from matplotlib import pyplot as plt
# from array import array
# import sys
# import os


#LA Port: the center lat/lon of the area of interest
#This needs to be changed depending on the input data:
Plat=33.7185
Plon=-118.2673
I1='GIMGO-SVI01_npp_d20191001_t2055079_e2100482_b41080_c20211202181848054653_noac_ops.h5'

f = h5py.File(I1, "r")
print('h5file:',f.keys())
theLat="/All_Data/VIIRS-IMG-GEO_All/Latitude"
theLon="/All_Data/VIIRS-IMG-GEO_All/Longitude"
lat=f.get(theLat)
lat=abs(np.array(lat)-Plat)
lon=f.get(theLon)
lon=abs(np.array(lon)-Plon)
X=abs(lat+lon)
Pmin=np.argwhere(X == np.min(X))
print(Pmin.shape)
Cx=Pmin[0,0]
Cy=Pmin[0,1]
print(Cx,Cy)
print(lat)
b=1
img=f.get("/All_Data/VIIRS-I1-SDR_All/Radiance")

plt.imshow(img,vmin=0,vmax=20,cmap="gray")

ce=f.get("/All_Data/VIIRS-I1-SDR_All/RadianceFactors")
print('c0:',ce[0],ce[1])
#img=np.subtract(img,ce[1])*ce[0]
#img=(img+ce[1])*ce[0]
#This is probably the correct equation:
img=img*ce[0]+ce[1]

s=300
x1=Cx-s
if (x1 < 0): x1=1        
x2=Cx+s
if (x2 < 0): x2=1        
y1=Cy-s
if (y1 < 0): y1=1        
y2=Cy+s
if (y2< 0): y1=1

subimg=img[x1:x2,y1:y2]
subimg=np.fliplr(subimg)
subimg=np.flipud(subimg)
#subimg=np.rot90(subimg,k=-1)
plt.imshow(subimg,vmin=0,vmax=25,cmap="gray")

lat=f.get(theLat)
lat2=lat[x1,y1]
lat1=lat[x2,y2]

lon=f.get(theLon)
lon1=lon[x1,y1]
lon2=lon[x2,y2]

print("location:",lon1,lat1,lon2,lat2)