#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# plot_lenz2017.py
# An example of how to query the Lenz, Hensley & Doré (2017) dust map.
#
# Copyright (C) 2018  Gregory M. Green
#
# dustmaps is free software: you can redistribute it and/or modify
# it under the terms of either:
#
# - The GNU General Public License as published by the Free Software Foundation,
#   either version 2 of the License, or (at your option) any later version, or
# - The 2-Clause BSD License (also known as the Simplified BSD License).
#
# You should have received copies of the GNU General Public License
# and the BSD License along with this program.
#

from __future__ import print_function, division

import numpy as np
import os.path

try:
    import PIL.Image
except ImportError as error:
    print('This example requires Pillow or PIL.\n'
          'See <http://pillow.readthedocs.io/en/stable/installation.html>.')
    raise error

from astropy.coordinates import SkyCoord
import astropy.units as u

from dustmaps.lenz2017 import Lenz2017Query


def numpy2pil(a, vmin, vmax):
    a = np.clip((a - vmin) / (vmax - vmin), 0., 1.)
    a = (254.99 * a).astype('u1')
    return PIL.Image.fromarray(a)


def main():
    w,h = (2056,1024)
    l_0 = 0.

    # Create a grid of coordinates
    print('Creating grid of coordinates...')
    l = np.linspace(-180.+l_0, 180.+l_0, 2*w)
    b = np.linspace(-90., 90., 2*h+2)
    b = b[1:-1]
    l,b = np.meshgrid(l, b)

    l += (np.random.random(l.shape) - 0.5) * 360./(2.*w)
    b += (np.random.random(l.shape) - 0.5) * 180./(2.*h)

    coords = SkyCoord(l*u.deg, b*u.deg, frame='galactic')

    # Set up Lenz+(2017) query object
    print('Loading Lenz+(2017) map...')
    q = Lenz2017Query()

    print('Querying map...')
    ebv = q.query(coords)

    # Convert the output array to a PIL image and save
    print('Saving image...')
    img = numpy2pil(ebv[::-1,::-1], 0., 0.05)
    img = img.resize((w,h), resample=PIL.Image.LANCZOS)
    fname = 'lenz2017.png'
    img.save(fname)

    return 0


if __name__ == '__main__':
    main()
