#!/usr/bin/env python
# -*- coding: utf-8 -*-
############################################################################
#
# MODULE:       d.explanation.plot
# AUTHOR(S):    Vaclav Petras <wenzeslaus gmail com>
#
# PURPOSE:      Draw plot for manual explaining a raster operation
# COPYRIGHT:    (C) 2017 by Vaclav Petras the GRASS Development Team
#
#               This program is free software under the GNU General
#               Public License (>=v2). Read the file COPYING that
#               comes with GRASS for details.
#
#############################################################################

#%module
#% description: Draw a plot of multiple rasters to explain a raster operation for example a + b = c
#% keyword: display
#% keyword: manual
#% keyword: raster
#%end
#%option G_OPT_R_INPUT
#% key: a
#%end
#%option G_OPT_R_INPUT
#% key: b
#%end
#%option G_OPT_R_INPUT
#% key: c
#%end
#%option
#% key: label_a
#% type: string
#% required: no
#% description: Label above the raster
#%end
#%option
#% key: label_b
#% type: string
#% required: no
#% description: Label above the raster
#%end
#%option
#% key: label_c
#% type: string
#% required: no
#% description: Label above the raster
#%end


import sys
import os
import grass.script as gs

# i18N
import gettext
gettext.install('grassmods', os.path.join(os.getenv("GISBASE"), 'locale'))


def main():
    options, flags = gs.parser()

    raster_1 = options['a']
    raster_2 = options['b']
    raster_3 = options['c']

    # TODO: add also labels below the images
    label_1 = options['label_a']
    label_2 = options['label_b']
    label_3 = options['label_c']

    # TODO: make fonts customizable
    label_font = 'FreeSans:Regular'
    rast_num_font = 'FreeMono:Regular'
    operator_font = 'FreeMono:Regular'

    # TODO: make sizes customizable
    label_font_size = 6
    operator_font_size = 10

    # although we set things explicitly for customization,
    # set font also globally (for the process) for things we don't set
    os.environ['GRASS_FONT'] = label_font

    # TODO: move the positions to variables, esp. the centered things
    # and the initial vertical position

    # TODO: add operators/text before and after the raster images
    # TODO: make the operators customizable
    gs.run_command('d.text', text='+', color='black',
                   at=(33, 40), align='cc',
                   font=operator_font, size=operator_font_size)
    gs.run_command('d.text', text='->', color='black',
                   at=(66, 40), align='cc',
                   font=operator_font, size=operator_font_size)

    if label_1:
        gs.run_command('d.text', text=label_1, color='black',
                       at=(10, 60), align='cc',
                       font=label_font, size=label_font_size)
    if label_2:
        gs.run_command('d.text', text=label_2, color='black',
                       at=(45, 60), align='cc',
                       font=label_font, size=label_font_size)
    if label_3:
        gs.run_command('d.text', text=label_3, color='black',
                       at=(80, 60), align='cc',
                       font=label_font, size=label_font_size)

    # TODO: create frames internally using the env variable so that the
    # subsequent commands are not influenced

    gs.run_command('d.frame', frame='f1', at=(25, 50, 5, 30), flags='c')
    gs.run_command('d.rast', map=raster_1)
    gs.run_command('d.rast.num', map=raster_1, font=rast_num_font)
    gs.run_command('d.frame', frame='f2', at=(25, 50, 40, 65), flags='c')
    gs.run_command('d.rast', map=raster_2)
    gs.run_command('d.rast.num', map=raster_2, font=rast_num_font)
    # TODO: third one should be optional for: a -> b
    gs.run_command('d.frame', frame='f3', at=(25, 50, 75, 100), flags='c')
    gs.run_command('d.rast', map=raster_3)
    gs.run_command('d.rast.num', map=raster_3, font=rast_num_font)
    # TODO: add fourth one for: a + b + c -> d
    # (more seems to be too much for this method and style)


if __name__ == "__main__":
    sys.exit(main())