# -*- coding: utf-8 -*-

"""
***************************************************************************
    EquivalentNumField.py
    ---------------------
    Date                 : January 2013
    Copyright            : (C) 2013 by Victor Olaya
    Email                : volayaf at gmail dot com
***************************************************************************
*                                                                         *
*   This program 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 2 of the License, or     *
*   (at your option) any later version.                                   *
*                                                                         *
***************************************************************************
"""

__author__ = 'Victor Olaya'
__date__ = 'January 2013'
__copyright__ = '(C) 2013, Victor Olaya'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

import matplotlib.pyplot as plt
import matplotlib.pylab as lab

from PyQt4.QtCore import *
from qgis.core import *

from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
from processing.core.parameters import ParameterNumber
from processing.core.outputs import OutputHTML
from processing.tools import vector
from processing.tools import dataobjects


class VectorLayerHistogram(GeoAlgorithm):

    INPUT = 'INPUT'
    OUTPUT = 'OUTPUT'
    FIELD = 'FIELD'
    BINS = 'BINS'

    def defineCharacteristics(self):
        self.name = 'Vector layer histogram'
        self.group = 'Graphics'

        self.addParameter(ParameterVector(self.INPUT,
            self.tr('Input layer'), [ParameterVector.VECTOR_TYPE_ANY]))
        self.addParameter(ParameterTableField(self.FIELD,
            self.tr('Attribute'), self.INPUT,
            ParameterTableField.DATA_TYPE_NUMBER))
        self.addParameter(ParameterNumber(self.BINS,
            self.tr('number of bins'), 2, None, 10))

        self.addOutput(OutputHTML(self.OUTPUT, self.tr('Output')))

    def processAlgorithm(self, progress):
        layer = dataobjects.getObjectFromUri(
            self.getParameterValue(self.INPUT))
        fieldname = self.getParameterValue(self.FIELD)
        bins = self.getParameterValue(self.BINS)

        output = self.getOutputValue(self.OUTPUT)

        values = vector.values(layer, fieldname)
        plt.close()
        plt.hist(values[fieldname], bins)
        plotFilename = output + '.png'
        lab.savefig(plotFilename)
        f = open(output, 'w')
        f.write('<img src="' + plotFilename + '"/>')
        f.close()