#!/usr/bin/env python
############################################################################
#
# MODULE:       d.vect.colhist 
# AUTHOR:       Moritz Lennert
# PURPOSE:      Draws the histogram of values in a vector attribute column
#
# COPYRIGHT:    (c) 2017 Moritz Lennert, and 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: Draws the histogram of values in a vector attribute column
#% keyword: display
#% keyword: vector
#% keyword: geology
#%end
#%option G_OPT_V_MAP
#%end
#%option G_OPT_V_FIELD
#%end
#%option G_OPT_DB_COLUMN
#% key: column
#% description: Attribute column containing azimuth
#% required: yes
#%end
#%option G_OPT_DB_WHERE
#%end
#%option G_OPT_F_OUTPUT
#% key: plot_output
#% label: Name for graphic output file for plot (extension decides format, - for screen)
#% required: yes
#% answer: -
#%end
#%option
#% key: bins
#% type: integer
#% description: Number of bins in histogram
#% answer: 30
#% required: no
#%end


import sys
import matplotlib #required by windows
matplotlib.use('wxAGG') #required by windows
import matplotlib.pyplot as plt
import grass.script as gscript


def main():
    vector = options['map']
    layer = options['layer']
    column = options['column']
    bins = int(options['bins'])
    plot_output = options['plot_output']
    where = options['where'] if options['where'] else None

    if where:
        data=[float(x) for x in gscript.read_command('v.db.select',
                                                     map_=vector,
                                                     layer=layer,
                                                     column=column,
                                                     where=where,
                                                     flags='c').splitlines()]
    else:
        data=[float(x) for x in gscript.read_command('v.db.select',
                                                     map_=vector,
                                                     layer=layer,
                                                     column=column,
                                                     flags='c').splitlines()]
   
    plt.hist(data, bins=bins)
    if plot_output == '-':
       plt.show()
    else:
       plt.savefig(plot_output)

if __name__ == "__main__":
    options, flags = gscript.parser()
    main()