"""
***************************************************************************
    RasterLayerHistogram.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"

import warnings

from qgis.core import (
    QgsProcessingException,
    QgsProcessingParameterBand,
    QgsProcessingParameterFileDestination,
    QgsProcessingParameterNumber,
    QgsProcessingParameterRasterLayer,
)
from qgis.PyQt.QtCore import QCoreApplication

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import raster


class RasterLayerHistogram(QgisAlgorithm):
    INPUT = "INPUT"
    BINS = "BINS"
    OUTPUT = "OUTPUT"
    BAND = "BAND"

    def group(self):
        return self.tr("Plots")

    def groupId(self):
        return "plots"

    def __init__(self):
        super().__init__()

    def initAlgorithm(self, config=None):
        self.addParameter(
            QgsProcessingParameterRasterLayer(self.INPUT, self.tr("Input layer"))
        )
        self.addParameter(
            QgsProcessingParameterBand(self.BAND, self.tr("Band number"), 1, self.INPUT)
        )
        self.addParameter(
            QgsProcessingParameterNumber(
                self.BINS, self.tr("number of bins"), minValue=2, defaultValue=10
            )
        )

        self.addParameter(
            QgsProcessingParameterFileDestination(
                self.OUTPUT, self.tr("Histogram"), self.tr("HTML files (*.html)")
            )
        )

    def name(self):
        return "rasterlayerhistogram"

    def displayName(self):
        return self.tr("Raster layer histogram")

    def shortDescription(self):
        return self.tr("Generates a histogram with the values of a raster layer.")

    def shortHelpString(self):
        return self.tr(
            "This algorithm generates a histogram with the values of a raster layer.\n"
            "The raster layer must have a single band."
        )

    def processAlgorithm(self, parameters, context, feedback):
        try:
            # importing plotly throws Python warnings from within the library - filter these out
            with warnings.catch_warnings():
                warnings.filterwarnings("ignore", category=ResourceWarning)
                warnings.filterwarnings("ignore", category=ImportWarning)
                import plotly as plt
                import plotly.graph_objs as go
        except ImportError:
            raise QgsProcessingException(
                QCoreApplication.translate(
                    "RasterLayerHistogram",
                    "This algorithm requires the Python “plotly” library. Please install this library and try again.",
                )
            )

        layer = self.parameterAsRasterLayer(parameters, self.INPUT, context)
        band = self.parameterAsInt(parameters, self.BAND, context)
        nbins = self.parameterAsInt(parameters, self.BINS, context)

        output = self.parameterAsFileOutput(parameters, self.OUTPUT, context)

        # ALERT: this is potentially blocking if the layer is too big
        values = raster.scanraster(layer, feedback, band)

        valueslist = [v for v in values if v is not None]
        data = [go.Histogram(x=valueslist, nbinsx=nbins)]
        plt.offline.plot(data, filename=output, auto_open=False)

        return {self.OUTPUT: output}
