"""
***************************************************************************
    HypsometricCurves.py
    ---------------------
    Date                 : November 2014
    Copyright            : (C) 2014 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__ = "November 2014"
__copyright__ = "(C) 2014, Alexander Bruy"

import os
import csv

from osgeo import gdal, ogr, osr

gdal.UseExceptions()
ogr.UseExceptions()
osr.UseExceptions()

from qgis.core import (
    QgsRectangle,
    QgsGeometry,
    QgsFeatureRequest,
    QgsProcessingException,
    QgsProcessing,
    QgsProcessingParameterBoolean,
    QgsProcessingParameterNumber,
    QgsProcessingParameterRasterLayer,
    QgsProcessingParameterFeatureSource,
    QgsProcessingParameterFolderDestination,
)

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

from qgis.PyQt.QtCore import QCoreApplication


class HypsometricCurves(QgisAlgorithm):
    INPUT_DEM = "INPUT_DEM"
    BOUNDARY_LAYER = "BOUNDARY_LAYER"
    STEP = "STEP"
    USE_PERCENTAGE = "USE_PERCENTAGE"
    OUTPUT_DIRECTORY = "OUTPUT_DIRECTORY"

    def group(self):
        return self.tr("Raster terrain analysis")

    def groupId(self):
        return "rasterterrainanalysis"

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

    def initAlgorithm(self, config=None):
        self.addParameter(
            QgsProcessingParameterRasterLayer(self.INPUT_DEM, self.tr("DEM to analyze"))
        )
        self.addParameter(
            QgsProcessingParameterFeatureSource(
                self.BOUNDARY_LAYER,
                self.tr("Boundary layer"),
                [QgsProcessing.SourceType.TypeVectorPolygon],
            )
        )
        self.addParameter(
            QgsProcessingParameterNumber(
                self.STEP,
                self.tr("Step"),
                type=QgsProcessingParameterNumber.Type.Double,
                minValue=0.0,
                defaultValue=100.0,
            )
        )
        self.addParameter(
            QgsProcessingParameterBoolean(
                self.USE_PERCENTAGE,
                self.tr("Use % of area instead of absolute value"),
                defaultValue=False,
            )
        )

        self.addParameter(
            QgsProcessingParameterFolderDestination(
                self.OUTPUT_DIRECTORY, self.tr("Hypsometric curves")
            )
        )

    def name(self):
        return "hypsometriccurves"

    def displayName(self):
        return self.tr("Hypsometric curves")

    def processAlgorithm(self, parameters, context, feedback):
        try:
            import numpy
        except ImportError:
            raise QgsProcessingException(
                QCoreApplication.translate(
                    "HypsometricCurves",
                    "This algorithm requires the Python “numpy” library. Please install this library and try again.",
                )
            )

        raster_layer = self.parameterAsRasterLayer(parameters, self.INPUT_DEM, context)
        target_crs = raster_layer.crs()
        rasterPath = raster_layer.source()

        source = self.parameterAsSource(parameters, self.BOUNDARY_LAYER, context)
        if source is None:
            raise QgsProcessingException(
                self.invalidSourceError(parameters, self.BOUNDARY_LAYER)
            )

        step = self.parameterAsDouble(parameters, self.STEP, context)
        percentage = self.parameterAsBoolean(parameters, self.USE_PERCENTAGE, context)

        outputPath = self.parameterAsString(parameters, self.OUTPUT_DIRECTORY, context)
        if not os.path.exists(outputPath):
            os.makedirs(outputPath)

        rasterDS = gdal.Open(rasterPath, gdal.GA_ReadOnly)
        geoTransform = rasterDS.GetGeoTransform()
        rasterBand = rasterDS.GetRasterBand(1)
        noData = rasterBand.GetNoDataValue()

        cellXSize = abs(geoTransform[1])
        cellYSize = abs(geoTransform[5])
        rasterXSize = rasterDS.RasterXSize
        rasterYSize = rasterDS.RasterYSize

        rasterBBox = QgsRectangle(
            geoTransform[0],
            geoTransform[3] - cellYSize * rasterYSize,
            geoTransform[0] + cellXSize * rasterXSize,
            geoTransform[3],
        )
        rasterGeom = QgsGeometry.fromRect(rasterBBox)

        crs = osr.SpatialReference()
        crs.ImportFromProj4(str(target_crs.toProj()))

        memVectorDriver = ogr.GetDriverByName("Memory")
        memRasterDriver = gdal.GetDriverByName("MEM")

        features = source.getFeatures(
            QgsFeatureRequest().setDestinationCrs(
                target_crs, context.transformContext()
            )
        )
        total = 100.0 / source.featureCount() if source.featureCount() else 0

        for current, f in enumerate(features):
            if not f.hasGeometry():
                continue

            if feedback.isCanceled():
                break

            geom = f.geometry()
            intersectedGeom = rasterGeom.intersection(geom)

            if intersectedGeom.isEmpty():
                feedback.pushInfo(
                    self.tr(
                        "Feature {0} does not intersect raster or "
                        "entirely located in NODATA area"
                    ).format(f.id())
                )
                continue

            fName = os.path.join(
                outputPath, f"histogram_{source.sourceName()}_{f.id()}.csv"
            )

            ogrGeom = ogr.CreateGeometryFromWkt(intersectedGeom.asWkt())
            bbox = intersectedGeom.boundingBox()
            xMin = bbox.xMinimum()
            xMax = bbox.xMaximum()
            yMin = bbox.yMinimum()
            yMax = bbox.yMaximum()

            (startColumn, startRow) = raster.mapToPixel(xMin, yMax, geoTransform)
            (endColumn, endRow) = raster.mapToPixel(xMax, yMin, geoTransform)

            width = endColumn - startColumn
            height = endRow - startRow

            srcOffset = (startColumn, startRow, width, height)
            srcArray = rasterBand.ReadAsArray(*srcOffset)

            if srcOffset[2] == 0 or srcOffset[3] == 0:
                feedback.pushInfo(
                    self.tr("Feature {0} is smaller than raster " "cell size").format(
                        f.id()
                    )
                )
                continue

            newGeoTransform = (
                geoTransform[0] + srcOffset[0] * geoTransform[1],
                geoTransform[1],
                0.0,
                geoTransform[3] + srcOffset[1] * geoTransform[5],
                0.0,
                geoTransform[5],
            )

            memVDS = memVectorDriver.CreateDataSource("out")
            memLayer = memVDS.CreateLayer("poly", crs, ogr.wkbPolygon)

            ft = ogr.Feature(memLayer.GetLayerDefn())
            ft.SetGeometry(ogrGeom)
            memLayer.CreateFeature(ft)
            ft.Destroy()

            rasterizedDS = memRasterDriver.Create(
                "", srcOffset[2], srcOffset[3], 1, gdal.GDT_Byte
            )
            rasterizedDS.SetGeoTransform(newGeoTransform)
            gdal.RasterizeLayer(rasterizedDS, [1], memLayer, burn_values=[1])
            rasterizedArray = rasterizedDS.ReadAsArray()

            srcArray = numpy.nan_to_num(srcArray)
            masked = numpy.ma.MaskedArray(
                srcArray,
                mask=numpy.logical_or(
                    srcArray == noData, numpy.logical_not(rasterizedArray)
                ),
            )

            self.calculateHypsometry(
                f.id(), fName, feedback, masked, cellXSize, cellYSize, percentage, step
            )

            memVDS = None
            rasterizedDS = None
            feedback.setProgress(int(current * total))

        rasterDS = None

        return {self.OUTPUT_DIRECTORY: outputPath}

    def calculateHypsometry(self, fid, fName, feedback, data, pX, pY, percentage, step):
        out = dict()
        d = data.compressed()
        if d.size == 0:
            feedback.pushInfo(
                self.tr(
                    "Feature {0} does not intersect raster or "
                    "entirely located in NODATA area"
                ).format(fid)
            )
            return

        minValue = d.min()
        maxValue = d.max()
        startValue = minValue
        tmpValue = minValue + step
        while startValue < maxValue:
            out[tmpValue] = ((startValue <= d) & (d < tmpValue)).sum()
            startValue = tmpValue
            tmpValue += step

        if percentage:
            multiplier = 100.0 / len(d.flat)
        else:
            multiplier = pX * pY

        for k, v in out.items():
            out[k] = v * multiplier

        prev = None
        for i in sorted(out.items()):
            if prev is None:
                out[i[0]] = i[1]
            else:
                out[i[0]] = i[1] + out[prev]
            prev = i[0]

        with open(fName, "w", newline="", encoding="utf-8") as out_file:
            writer = csv.writer(out_file)
            writer.writerow([self.tr("Area"), self.tr("Elevation")])

            for i in sorted(out.items()):
                writer.writerow([i[1], i[0]])
