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

"""
***************************************************************************
    ZonalStatistics.py
    ---------------------
    Date                 : September 2016
    Copyright            : (C) 2016 by Alexander Bruy
    Email                : alexander dot bruy 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__ = 'Alexander Bruy'
__date__ = 'September 2016'
__copyright__ = '(C) 2016, Alexander Bruy'

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

__revision__ = '0c5774c0685d4b6f3e92a086234455708d1cd427'

import os
from collections import OrderedDict

from qgis.PyQt.QtGui import QIcon

from qgis.analysis import QgsZonalStatistics
from qgis.core import (QgsProcessing,
                       QgsProcessingAlgorithm,
                       QgsProcessingParameterVectorLayer,
                       QgsProcessingParameterRasterLayer,
                       QgsProcessingParameterString,
                       QgsProcessingParameterBand,
                       QgsProcessingParameterEnum,
                       QgsProcessingOutputVectorLayer)

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm

pluginPath = os.path.split(os.path.split(os.path.dirname(__file__))[0])[0]


class ZonalStatistics(QgisAlgorithm):

    INPUT_RASTER = 'INPUT_RASTER'
    RASTER_BAND = 'RASTER_BAND'
    INPUT_VECTOR = 'INPUT_VECTOR'
    COLUMN_PREFIX = 'COLUMN_PREFIX'
    STATISTICS = 'STATS'

    def icon(self):
        return QIcon(os.path.join(pluginPath, 'images', 'zonalstats.png'))

    def group(self):
        return self.tr('Raster analysis')

    def groupId(self):
        return 'rasteranalysis'

    def flags(self):
        return super().flags() | QgsProcessingAlgorithm.FlagNoThreading

    def __init__(self):
        super().__init__()
        self.bandNumber = None
        self.columnPrefix = None
        self.selectedStats = None
        self.vectorLayer = None
        self.raster_interface = None
        self.raster_crs = None
        self.raster_units_per_pixel_x = None
        self.raster_units_per_pixel_y = None

    def initAlgorithm(self, config=None):
        self.STATS = OrderedDict([(self.tr('Count'), QgsZonalStatistics.Count),
                                  (self.tr('Sum'), QgsZonalStatistics.Sum),
                                  (self.tr('Mean'), QgsZonalStatistics.Mean),
                                  (self.tr('Median'), QgsZonalStatistics.Median),
                                  (self.tr('Std. dev.'), QgsZonalStatistics.StDev),
                                  (self.tr('Min'), QgsZonalStatistics.Min),
                                  (self.tr('Max'), QgsZonalStatistics.Max),
                                  (self.tr('Range'), QgsZonalStatistics.Range),
                                  (self.tr('Minority'), QgsZonalStatistics.Minority),
                                  (self.tr('Majority (mode)'), QgsZonalStatistics.Majority),
                                  (self.tr('Variety'), QgsZonalStatistics.Variety),
                                  (self.tr('Variance'), QgsZonalStatistics.Variance),
                                  (self.tr('All'), QgsZonalStatistics.All)])

        self.addParameter(QgsProcessingParameterRasterLayer(self.INPUT_RASTER,
                                                            self.tr('Raster layer')))
        self.addParameter(QgsProcessingParameterBand(self.RASTER_BAND,
                                                     self.tr('Raster band'),
                                                     1,
                                                     self.INPUT_RASTER))
        self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT_VECTOR,
                                                            self.tr('Vector layer containing zones'),
                                                            [QgsProcessing.TypeVectorPolygon]))
        self.addParameter(QgsProcessingParameterString(self.COLUMN_PREFIX,
                                                       self.tr('Output column prefix'), '_'))
        keys = list(self.STATS.keys())
        self.addParameter(QgsProcessingParameterEnum(self.STATISTICS,
                                                     self.tr('Statistics to calculate'),
                                                     keys,
                                                     allowMultiple=True, defaultValue=[0, 1, 2]))
        self.addOutput(QgsProcessingOutputVectorLayer(self.INPUT_VECTOR,
                                                      self.tr('Zonal statistics'),
                                                      QgsProcessing.TypeVectorPolygon))

    def name(self):
        return 'zonalstatistics'

    def displayName(self):
        return self.tr('Zonal statistics')

    def prepareAlgorithm(self, parameters, context, feedback):
        self.bandNumber = self.parameterAsInt(parameters, self.RASTER_BAND, context)
        self.columnPrefix = self.parameterAsString(parameters, self.COLUMN_PREFIX, context)
        st = self.parameterAsEnums(parameters, self.STATISTICS, context)

        keys = list(self.STATS.keys())
        self.selectedStats = 0
        for i in st:
            self.selectedStats |= self.STATS[keys[i]]

        self.vectorLayer = self.parameterAsVectorLayer(parameters, self.INPUT_VECTOR, context)
        rasterLayer = self.parameterAsRasterLayer(parameters, self.INPUT_RASTER, context)
        self.raster_interface = rasterLayer.dataProvider().clone()
        self.raster_crs = rasterLayer.crs()
        self.raster_units_per_pixel_x = rasterLayer.rasterUnitsPerPixelX()
        self.raster_units_per_pixel_y = rasterLayer.rasterUnitsPerPixelY()
        return True

    def processAlgorithm(self, parameters, context, feedback):
        zs = QgsZonalStatistics(self.vectorLayer,
                                self.raster_interface,
                                self.raster_crs,
                                self.raster_units_per_pixel_x,
                                self.raster_units_per_pixel_y,
                                self.columnPrefix,
                                self.bandNumber,
                                QgsZonalStatistics.Statistics(self.selectedStats))
        zs.calculateStatistics(feedback)
        return {self.INPUT_VECTOR: self.vectorLayer}
