#!/usr/bin/env python3

#    Copyright (C) 2013 Christian T. Jacobs.

#    This file is part of PyQSO.

#    PyQSO is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    PyQSO is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with PyQSO.  If not, see <http://www.gnu.org/licenses/>.

from gi.repository import Gtk, GObject
import logging
from datetime import datetime
try:
    import numpy
    logging.info("Using version %s of numpy." % (numpy.__version__))
    import matplotlib
    logging.info("Using version %s of matplotlib." % (matplotlib.__version__))
    matplotlib.use('Agg')
    matplotlib.rcParams['font.size'] = 10.0
    import mpl_toolkits.basemap
    logging.info("Using version %s of mpl_toolkits.basemap." % (mpl_toolkits.basemap.__version__))
    from matplotlib.backends.backend_gtk3cairo import FigureCanvasGTK3Cairo as FigureCanvas
    have_necessary_modules = True
except ImportError as e:
    logging.warning(e)
    logging.warning("Could not import a non-standard Python module needed by the GreyLine class, or the version of the non-standard module is too old. Check that all the PyQSO dependencies are satisfied.")
    have_necessary_modules = False


class GreyLine(Gtk.VBox):

    """ A tool for visualising the grey line. """

    def __init__(self, parent):
        """ Set up the drawing canvas and the timer which will re-plot the grey line every 30 minutes.

        :arg parent: The parent Gtk window.
        """
        logging.debug("Setting up the grey line...")
        Gtk.VBox.__init__(self, spacing=2)
        self.parent = parent

        if(have_necessary_modules):
            self.fig = matplotlib.figure.Figure()
            self.canvas = FigureCanvas(self.fig)  # For embedding in the Gtk application
            self.pack_start(self.canvas, True, True, 0)
            self.refresh_event = GObject.timeout_add(1800000, self.draw)  # Re-draw the grey line automatically after 30 minutes (if the grey line tool is visible).

        self.show_all()

        logging.debug("Grey line ready!")

        return

    def draw(self):
        """ Draw the world map and the grey line on top of it.

        :returns: Always returns True to satisfy the GObject timer, unless the necessary GreyLine dependencies are not satisfied (in which case, the method returns False so as to not re-draw the canvas).
        :rtype: bool
        """

        if(have_necessary_modules):
            if(self.parent.toolbox.tools.get_current_page() != 1 or not self.parent.toolbox.get_visible()):
                # Don't re-draw if the grey line is not visible.
                return True  # We need to return True in case this is method was called by a timer event.
            else:
                logging.debug("Drawing the grey line...")
                # Re-draw the grey line
                self.fig.clf()
                sub = self.fig.add_subplot(111)

                # Draw the map of the world. This is based on the example from:
                # http://matplotlib.org/basemap/users/examples.html
                m = mpl_toolkits.basemap.Basemap(projection='mill', lon_0=0, ax=sub, resolution='c', fix_aspect=False)
                m.drawcountries(linewidth=0.5)
                m.drawcoastlines(linewidth=0.5)
                m.drawparallels(numpy.arange(-90, 90, 30), labels=[1, 0, 0, 0])
                m.drawmeridians(numpy.arange(m.lonmin, m.lonmax+30, 60), labels=[0, 0, 0, 1])
                m.drawmapboundary(fill_color='lightblue')
                m.fillcontinents(color='darkgreen', lake_color='lightblue')
                m.nightshade(datetime.utcnow())  # Add in the grey line using UTC time. Note that this requires NetCDF.
                logging.debug("Grey line drawn.")
                return True
        else:
            return False  # Don't try to re-draw the canvas if the necessary modules to do so could not be imported.