"""
***************************************************************************
    grass_algorithm.py
    ---------------------
    Date                 : February 2015
    Copyright            : (C) 2014-2015 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__ = "February 2015"
__copyright__ = "(C) 2012-2015, Victor Olaya"

import importlib
import math
import os
import sys
import uuid
import warnings
from pathlib import Path
from typing import Optional

from qgis.core import (
    Qgis,
    QgsApplication,
    QgsCoordinateReferenceSystem,
    QgsMapLayer,
    QgsMapLayerType,
    QgsMessageLog,
    QgsProcessing,
    QgsProcessingAlgorithm,
    QgsProcessingContext,
    QgsProcessingException,
    QgsProcessingOutputHtml,
    QgsProcessingParameterBoolean,
    QgsProcessingParameterCrs,
    QgsProcessingParameterDefinition,
    QgsProcessingParameterEnum,
    QgsProcessingParameterExtent,
    QgsProcessingParameterFeatureSource,
    QgsProcessingParameterField,
    QgsProcessingParameterFile,
    QgsProcessingParameterFileDestination,
    QgsProcessingParameterFolderDestination,
    QgsProcessingParameterMultipleLayers,
    QgsProcessingParameterNumber,
    QgsProcessingParameterPoint,
    QgsProcessingParameterRange,
    QgsProcessingParameterRasterDestination,
    QgsProcessingParameterRasterLayer,
    QgsProcessingParameterString,
    QgsProcessingParameterVectorDestination,
    QgsProcessingParameterVectorLayer,
    QgsProcessingUtils,
    QgsProviderRegistry,
    QgsRasterLayer,
    QgsVectorFileWriter,
    QgsVectorLayer,
)
from qgis.PyQt.QtCore import QCoreApplication, QUrl
from qgis.utils import iface

with warnings.catch_warnings():
    warnings.filterwarnings("ignore", category=DeprecationWarning)
    from osgeo import ogr

from processing.core.parameters import getParameterFromString
from processing.core.ProcessingConfig import ProcessingConfig
from processing.tools.system import getTempFilename, isWindows

from grassprovider.grass_utils import GrassUtils
from grassprovider.parsed_description import ParsedDescription

pluginPath = os.path.normpath(
    os.path.join(os.path.split(os.path.dirname(__file__))[0], os.pardir)
)


class GrassAlgorithm(QgsProcessingAlgorithm):
    GRASS_OUTPUT_TYPE_PARAMETER = "GRASS_OUTPUT_TYPE_PARAMETER"
    GRASS_MIN_AREA_PARAMETER = "GRASS_MIN_AREA_PARAMETER"
    GRASS_SNAP_TOLERANCE_PARAMETER = "GRASS_SNAP_TOLERANCE_PARAMETER"
    GRASS_REGION_EXTENT_PARAMETER = "GRASS_REGION_PARAMETER"
    GRASS_REGION_CELLSIZE_PARAMETER = "GRASS_REGION_CELLSIZE_PARAMETER"
    GRASS_REGION_ALIGN_TO_RESOLUTION = "GRASS_REGION_ALIGN_TO_RESOLUTION"
    GRASS_RASTER_FORMAT_OPT = "GRASS_RASTER_FORMAT_OPT"
    GRASS_RASTER_FORMAT_META = "GRASS_RASTER_FORMAT_META"
    GRASS_VECTOR_DSCO = "GRASS_VECTOR_DSCO"
    GRASS_VECTOR_LCO = "GRASS_VECTOR_LCO"
    GRASS_VECTOR_EXPORT_NOCAT = "GRASS_VECTOR_EXPORT_NOCAT"

    OUTPUT_TYPES = ["auto", "point", "line", "area"]
    QGIS_OUTPUT_TYPES = {
        QgsProcessing.SourceType.TypeVectorAnyGeometry: "auto",
        QgsProcessing.SourceType.TypeVectorPoint: "point",
        QgsProcessing.SourceType.TypeVectorLine: "line",
        QgsProcessing.SourceType.TypeVectorPolygon: "area",
    }

    def __init__(
        self,
        description_file: Optional[Path] = None,
        json_definition: Optional[dict] = None,
        description_folder: Optional[Path] = None,
    ):
        super().__init__()
        self._name = ""
        self._display_name = ""
        self._short_description = ""
        self._group = ""
        self._groupId = ""
        self.grass_name = ""
        self.params = []
        self.hardcodedStrings = []
        self.inputLayers = []
        self.commands = []
        self.outputCommands = []
        self.exportedLayers = {}
        self.fileOutputs = {}
        self._description_file: Optional[Path] = description_file
        self._json_definition: Optional[dict] = json_definition
        self._description_folder: Optional[Path] = description_folder

        # Default GRASS parameters
        self.region = None
        self.cellSize = None
        self.snapTolerance = None
        self.outputType = None
        self.minArea = None
        self.alignToResolution = None

        # destination Crs for combineLayerExtents, will be set from layer or mapSettings
        self.destination_crs = QgsCoordinateReferenceSystem()

        # Load parameters from a description file
        if self._description_file is not None:
            self._define_characteristics_from_file()
        else:
            self._define_characteristics_from_json()

        self.numExportedLayers = 0
        # Do we need this anymore?
        self.uniqueSuffix = str(uuid.uuid4()).replace("-", "")

        # Use the ext mechanism
        self.module = None
        try:
            extpath = None
            ext_name = None
            if self._description_file:
                ext_name = self.name().replace(".", "_")
                extpath = self._description_file.parents[1].joinpath(
                    "ext", ext_name + ".py"
                )
            elif self._json_definition.get("ext_path"):
                ext_name = self._json_definition["ext_path"]
                extpath = self._description_folder.parents[0].joinpath(
                    "ext", ext_name + ".py"
                )

            # this check makes it a bit faster
            if extpath and extpath.exists():
                spec = importlib.util.spec_from_file_location(
                    "grassprovider.ext." + ext_name, extpath
                )
                self.module = importlib.util.module_from_spec(spec)
                spec.loader.exec_module(self.module)

        except Exception as e:
            QgsMessageLog.logMessage(
                self.tr("Failed to load: {0}\n{1}").format(extpath, e),
                "Processing",
                Qgis.MessageLevel.Critical,
            )
            pass

    def createInstance(self):
        return self.__class__(
            description_file=self._description_file,
            json_definition=self._json_definition,
            description_folder=self._description_folder,
        )

    def name(self):
        return self._name

    def displayName(self):
        return self._display_name

    def shortDescription(self):
        return self._short_description

    def group(self):
        return self._group

    def groupId(self):
        return self._groupId

    def icon(self):
        return QgsApplication.getThemeIcon("/providerGrass.svg")

    def svgIconPath(self):
        return QgsApplication.iconPath("providerGrass.svg")

    def flags(self):
        # TODO - maybe it's safe to background thread this?
        return (
            super().flags()
            | QgsProcessingAlgorithm.Flag.FlagNoThreading
            | QgsProcessingAlgorithm.Flag.FlagDisplayNameIsLiteral
        )

    def tr(self, string: str):
        return QCoreApplication.translate(self.__class__.__name__, string)

    def helpUrl(self):
        helpPath = GrassUtils.grassHelpPath()
        if helpPath == "":
            return None

        if os.path.exists(helpPath):
            return QUrl.fromLocalFile(
                os.path.join(helpPath, f"{self.grass_name}.html")
            ).toString()
        else:
            return helpPath + f"{self.grass_name}.html"

    def initAlgorithm(self, config=None):
        """
        Algorithm initialization
        """
        for p in self.params:
            # We use createOutput argument for automatic output creation
            self.addParameter(p, True)

    def _define_characteristics_from_file(self):
        """
        Create algorithm parameters and outputs from a text file.
        """
        results = ParsedDescription.parse_description_file(self._description_file)
        self._define_characteristics_from_parsed_description(results)

    def _define_characteristics_from_json(self):
        """
        Create algorithm parameters and outputs from JSON definition.
        """
        results = ParsedDescription.from_dict(self._json_definition)
        self._define_characteristics_from_parsed_description(results)

    def _define_characteristics_from_parsed_description(
        self, description: ParsedDescription
    ):
        """
        Create algorithm parameters and outputs from parsed description
        """
        self.grass_name = description.grass_command
        self._name = description.name
        self._short_description = description.short_description
        self._display_name = description.display_name
        self._group = description.group
        self._groupId = description.group_id
        self.hardcodedStrings = description.hardcoded_strings[:]

        self.params = []

        has_raster_input: bool = False
        has_vector_input: bool = False

        has_raster_output: bool = False
        has_vector_outputs: bool = False

        for param_string in description.param_strings:
            try:
                parameter = getParameterFromString(param_string, "GrassAlgorithm")
            except Exception as e:
                QgsMessageLog.logMessage(
                    self.tr("Could not open GRASS GIS algorithm: {0}").format(
                        self._name
                    ),
                    self.tr("Processing"),
                    Qgis.MessageLevel.Critical,
                )
                raise e

            if parameter is None:
                continue

            self.params.append(parameter)
            if isinstance(
                parameter,
                (
                    QgsProcessingParameterVectorLayer,
                    QgsProcessingParameterFeatureSource,
                ),
            ):
                has_vector_input = True
            elif isinstance(parameter, QgsProcessingParameterRasterLayer):
                has_raster_input = True
            elif isinstance(parameter, QgsProcessingParameterMultipleLayers):
                if parameter.layerType() < 3 or parameter.layerType() == 5:
                    has_vector_input = True
                elif parameter.layerType() == 3:
                    has_raster_input = True
            elif isinstance(parameter, QgsProcessingParameterVectorDestination):
                has_vector_outputs = True
            elif isinstance(parameter, QgsProcessingParameterRasterDestination):
                has_raster_output = True

        param = QgsProcessingParameterExtent(
            self.GRASS_REGION_EXTENT_PARAMETER,
            self.tr("GRASS GIS region extent"),
            optional=True,
        )
        param.setFlags(
            param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
        )
        self.params.append(param)

        if has_raster_output or has_raster_input:
            # Add a cellsize parameter
            param = QgsProcessingParameterNumber(
                self.GRASS_REGION_CELLSIZE_PARAMETER,
                self.tr("GRASS GIS region cellsize (leave 0 for default)"),
                type=QgsProcessingParameterNumber.Type.Double,
                minValue=0.0,
                maxValue=sys.float_info.max + 1,
                defaultValue=0.0,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

        if has_raster_output:
            # Add a createopt parameter for format export
            param = QgsProcessingParameterString(
                self.GRASS_RASTER_FORMAT_OPT,
                self.tr("Output Rasters format options (createopt)"),
                multiLine=True,
                optional=True,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            param.setHelp(self.tr("Creation options should be comma separated"))
            self.params.append(param)

            # Add a metadata parameter for format export
            param = QgsProcessingParameterString(
                self.GRASS_RASTER_FORMAT_META,
                self.tr("Output Rasters format metadata options (metaopt)"),
                multiLine=True,
                optional=True,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            param.setHelp(self.tr("Metadata options should be comma separated"))
            self.params.append(param)

        if has_vector_input:
            param = QgsProcessingParameterNumber(
                self.GRASS_SNAP_TOLERANCE_PARAMETER,
                self.tr("v.in.ogr snap tolerance (-1 = no snap)"),
                type=QgsProcessingParameterNumber.Type.Double,
                minValue=-1.0,
                maxValue=sys.float_info.max + 1,
                defaultValue=-1.0,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)
            param = QgsProcessingParameterNumber(
                self.GRASS_MIN_AREA_PARAMETER,
                self.tr("v.in.ogr min area"),
                type=QgsProcessingParameterNumber.Type.Double,
                minValue=0.0,
                maxValue=sys.float_info.max + 1,
                defaultValue=0.0001,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

        if has_vector_outputs:
            # Add an optional output type
            param = QgsProcessingParameterEnum(
                self.GRASS_OUTPUT_TYPE_PARAMETER,
                self.tr("v.out.ogr output type"),
                self.OUTPUT_TYPES,
                defaultValue=0,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

            # Add a DSCO parameter for format export
            param = QgsProcessingParameterString(
                self.GRASS_VECTOR_DSCO,
                self.tr("v.out.ogr output data source options (dsco)"),
                multiLine=True,
                optional=True,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

            # Add a LCO parameter for format export
            param = QgsProcessingParameterString(
                self.GRASS_VECTOR_LCO,
                self.tr("v.out.ogr output layer options (lco)"),
                multiLine=True,
                optional=True,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

            # Add a -c flag for export
            param = QgsProcessingParameterBoolean(
                self.GRASS_VECTOR_EXPORT_NOCAT,
                self.tr(
                    "Also export features without category (not labeled). Otherwise only features with category are exported"
                ),
                False,
            )
            param.setFlags(
                param.flags() | QgsProcessingParameterDefinition.Flag.FlagAdvanced
            )
            self.params.append(param)

    def getDefaultCellSize(self):
        """
        Determine a default cell size from all the raster layers.
        """
        cellsize = 0.0
        layers = [l for l in self.inputLayers if isinstance(l, QgsRasterLayer)]

        for layer in layers:
            cellsize = max(layer.rasterUnitsPerPixelX(), cellsize)

        if cellsize == 0.0:
            cellsize = 100.0

        return cellsize

    def grabDefaultGrassParameters(self, parameters, context):
        """
        Imports default GRASS parameters (EXTENT, etc) into
        object attributes for faster retrieving.
        """
        # GRASS region extent
        self.region = self.parameterAsExtent(
            parameters, self.GRASS_REGION_EXTENT_PARAMETER, context
        )
        # GRASS cell size
        if self.parameterDefinition(self.GRASS_REGION_CELLSIZE_PARAMETER):
            self.cellSize = self.parameterAsDouble(
                parameters, self.GRASS_REGION_CELLSIZE_PARAMETER, context
            )
        # GRASS snap tolerance
        self.snapTolerance = self.parameterAsDouble(
            parameters, self.GRASS_SNAP_TOLERANCE_PARAMETER, context
        )
        # GRASS min area
        self.minArea = self.parameterAsDouble(
            parameters, self.GRASS_MIN_AREA_PARAMETER, context
        )
        # GRASS output type
        self.outputType = self.parameterAsString(
            parameters, self.GRASS_OUTPUT_TYPE_PARAMETER, context
        )
        # GRASS align to resolution
        self.alignToResolution = self.parameterAsBoolean(
            parameters, self.GRASS_REGION_ALIGN_TO_RESOLUTION, context
        )

    def processAlgorithm(self, original_parameters, context, feedback):
        if isWindows():
            path = GrassUtils.grassPath()
            if path == "":
                raise QgsProcessingException(
                    self.tr(
                        "GRASS GIS folder is not configured. Please "
                        "configure it before running GRASS GIS algorithms."
                    )
                )

        version = GrassUtils.installedVersion(True)
        if version is None:
            raise QgsProcessingException(
                self.tr(
                    "Problem with GRASS installation: GRASS was not found or is not correctly installed"
                )
            )

        # make a copy of the original parameters dictionary - it gets modified by grass algorithms
        parameters = {k: v for k, v in original_parameters.items()}

        # Create brand new commands lists
        self.commands = []
        self.outputCommands = []
        self.exportedLayers = {}
        self.fileOutputs = {}

        # If GRASS session has been created outside of this algorithm then
        # get the list of layers loaded in GRASS otherwise start a new
        # session
        existingSession = GrassUtils.sessionRunning
        if existingSession:
            self.exportedLayers = GrassUtils.getSessionLayers()
        else:
            GrassUtils.startGrassSession()

        # Handle default GRASS parameters
        self.grabDefaultGrassParameters(parameters, context)

        # Handle ext functions for inputs/command/outputs
        for fName in ["Inputs", "Command", "Outputs"]:
            fullName = f"process{fName}"
            if self.module and hasattr(self.module, fullName):
                getattr(self.module, fullName)(self, parameters, context, feedback)
            else:
                getattr(self, fullName)(parameters, context, feedback)

        # Run GRASS
        loglines = [self.tr("GRASS GIS execution commands")]
        for line in self.commands:
            feedback.pushCommandInfo(line)
            loglines.append(line)
        if ProcessingConfig.getSetting(GrassUtils.GRASS_LOG_COMMANDS):
            QgsMessageLog.logMessage(
                "\n".join(loglines), self.tr("Processing"), Qgis.MessageLevel.Info
            )

        GrassUtils.executeGrass(self.commands, feedback, self.outputCommands)

        # If the session has been created outside of this algorithm, add
        # the new GRASS GIS layers to it otherwise finish the session
        if existingSession:
            GrassUtils.addSessionLayers(self.exportedLayers)
        else:
            GrassUtils.endGrassSession()

        # Return outputs map
        outputs = {}
        for out in self.outputDefinitions():
            outName = out.name()
            if outName in parameters:
                if outName in self.fileOutputs:
                    outputs[outName] = self.fileOutputs[outName]
                else:
                    outputs[outName] = parameters[outName]
                if isinstance(out, QgsProcessingOutputHtml):
                    if self.module and hasattr(self.module, "convertToHtml"):
                        func = getattr(self.module, "convertToHtml")
                        func(self, self.fileOutputs[outName], outputs)
                    else:
                        self.convertToHtml(self.fileOutputs[outName])
        return outputs

    def processInputs(self, parameters, context, feedback):
        """Prepare the GRASS import commands"""
        inputs = [
            p
            for p in self.parameterDefinitions()
            if isinstance(
                p,
                (
                    QgsProcessingParameterVectorLayer,
                    QgsProcessingParameterFeatureSource,
                    QgsProcessingParameterRasterLayer,
                    QgsProcessingParameterMultipleLayers,
                ),
            )
        ]
        for param in inputs:
            paramName = param.name()
            if paramName not in parameters:
                continue
            # Handle Null parameter
            if parameters[paramName] is None:
                continue
            elif (
                isinstance(parameters[paramName], str)
                and len(parameters[paramName]) == 0
            ):
                continue

            # Raster inputs needs to be imported into temp GRASS DB
            if isinstance(param, QgsProcessingParameterRasterLayer):
                if paramName not in self.exportedLayers:
                    self.loadRasterLayerFromParameter(paramName, parameters, context)
            # Vector inputs needs to be imported into temp GRASS DB
            elif isinstance(
                param,
                (
                    QgsProcessingParameterFeatureSource,
                    QgsProcessingParameterVectorLayer,
                ),
            ):
                if paramName not in self.exportedLayers:
                    # Attribute tables are also vector inputs
                    if QgsProcessing.SourceType.TypeFile in param.dataTypes():
                        self.loadAttributeTableFromParameter(
                            paramName, parameters, context
                        )
                    else:
                        self.loadVectorLayerFromParameter(
                            paramName,
                            parameters,
                            context,
                            external=None,
                            feedback=feedback,
                        )
            # For multiple inputs, process each layer
            elif isinstance(param, QgsProcessingParameterMultipleLayers):
                layers = self.parameterAsLayerList(parameters, paramName, context)
                for idx, layer in enumerate(layers):
                    layerName = f"{paramName}_{idx}"
                    # Add a raster layer
                    if layer.type() == QgsMapLayerType.RasterLayer:
                        self.loadRasterLayer(layerName, layer, context)
                    # Add a vector layer
                    elif layer.type() == QgsMapLayerType.VectorLayer:
                        self.loadVectorLayer(
                            layerName, layer, context, external=None, feedback=feedback
                        )

        self.postInputs(context)

    def postInputs(self, context: QgsProcessingContext):
        """
        After layer imports, we need to update some internal parameters
        """
        # If projection has not already be set, use the project
        self.setSessionProjectionFromProject(context)

        # Build GRASS region
        if self.region.isEmpty():
            self.region = QgsProcessingUtils.combineLayerExtents(
                self.inputLayers, self.destination_crs, context
            )
        command = f"g.region n={self.region.yMaximum()} s={self.region.yMinimum()} e={self.region.xMaximum()} w={self.region.xMinimum()}"
        # Handle cell size
        if self.parameterDefinition(self.GRASS_REGION_CELLSIZE_PARAMETER):
            if self.cellSize:
                cellSize = self.cellSize
            else:
                cellSize = self.getDefaultCellSize()
            command += f" res={cellSize}"

        # Handle align to resolution
        if self.alignToResolution:
            command += " -a"

        # Add the default parameters commands
        self.commands.append(command)

        QgsMessageLog.logMessage(
            self.tr("processInputs end. Commands: {}").format(self.commands),
            "Grass",
            Qgis.MessageLevel.Info,
        )

    def processCommand(self, parameters, context, feedback, delOutputs=False):
        """
        Prepare the GRASS algorithm command
        :param parameters:
        :param context:
        :param delOutputs: do not add outputs to commands.
        """
        noOutputs = [
            o
            for o in self.parameterDefinitions()
            if o not in self.destinationParameterDefinitions()
        ]
        command = f"{self.grass_name} "
        command += "{}".join(self.hardcodedStrings)

        # Add algorithm command
        for param in noOutputs:
            paramName = param.name()
            value = None

            # Exclude default GRASS parameters
            if paramName in [
                self.GRASS_REGION_CELLSIZE_PARAMETER,
                self.GRASS_REGION_EXTENT_PARAMETER,
                self.GRASS_MIN_AREA_PARAMETER,
                self.GRASS_SNAP_TOLERANCE_PARAMETER,
                self.GRASS_OUTPUT_TYPE_PARAMETER,
                self.GRASS_REGION_ALIGN_TO_RESOLUTION,
                self.GRASS_RASTER_FORMAT_OPT,
                self.GRASS_RASTER_FORMAT_META,
                self.GRASS_VECTOR_DSCO,
                self.GRASS_VECTOR_LCO,
                self.GRASS_VECTOR_EXPORT_NOCAT,
            ]:
                continue

            # Raster and vector layers
            if isinstance(
                param,
                (
                    QgsProcessingParameterRasterLayer,
                    QgsProcessingParameterVectorLayer,
                    QgsProcessingParameterFeatureSource,
                ),
            ):
                if paramName in self.exportedLayers:
                    value = self.exportedLayers[paramName]
                else:
                    value = self.parameterAsCompatibleSourceLayerPath(
                        parameters,
                        paramName,
                        context,
                        QgsVectorFileWriter.supportedFormatExtensions(),
                    )
            # MultipleLayers
            elif isinstance(param, QgsProcessingParameterMultipleLayers):
                layers = self.parameterAsLayerList(parameters, paramName, context)
                values = []
                for idx in range(len(layers)):
                    layerName = f"{paramName}_{idx}"
                    values.append(self.exportedLayers[layerName])
                value = ",".join(values)
            # For booleans, we just add the parameter name
            elif isinstance(param, QgsProcessingParameterBoolean):
                if self.parameterAsBoolean(parameters, paramName, context):
                    command += f" {paramName}"
            # For Extents, remove if the value is null
            elif isinstance(param, QgsProcessingParameterExtent):
                if self.parameterAsExtent(parameters, paramName, context):
                    value = self.parameterAsString(parameters, paramName, context)
            # For enumeration, we need to grab the string value
            elif isinstance(param, QgsProcessingParameterEnum):
                # Handle multiple values
                if param.allowMultiple():
                    indexes = self.parameterAsEnums(parameters, paramName, context)
                else:
                    indexes = [self.parameterAsEnum(parameters, paramName, context)]
                if indexes:
                    value = '"{}"'.format(
                        ",".join([param.options()[i] for i in indexes])
                    )
            # For strings, we just translate as string
            elif isinstance(param, QgsProcessingParameterString):
                data = self.parameterAsString(parameters, paramName, context)
                # if string is empty, we don't add it
                if len(data) > 0:
                    value = (
                        f'"{self.parameterAsString(parameters, paramName, context)}"'
                    )
            # For fields, we just translate as string
            elif isinstance(param, QgsProcessingParameterField):
                value = ",".join(self.parameterAsFields(parameters, paramName, context))
            elif isinstance(param, QgsProcessingParameterFile):
                if self.parameterAsString(parameters, paramName, context):
                    value = (
                        f'"{self.parameterAsString(parameters, paramName, context)}"'
                    )
            elif isinstance(param, QgsProcessingParameterPoint):
                if self.parameterAsString(parameters, paramName, context):
                    # parameter specified, evaluate as point
                    # TODO - handle CRS transform
                    point = self.parameterAsPoint(parameters, paramName, context)
                    value = f"{point.x()},{point.y()}"
            # For numbers, we translate as a string
            elif isinstance(
                param, (QgsProcessingParameterNumber, QgsProcessingParameterPoint)
            ):
                value = self.parameterAsString(parameters, paramName, context)
            elif isinstance(param, QgsProcessingParameterRange):
                v = self.parameterAsRange(parameters, paramName, context)
                if (
                    param.flags() & QgsProcessingParameterDefinition.Flag.FlagOptional
                ) and (math.isnan(v[0]) or math.isnan(v[1])):
                    continue
                else:
                    value = f"{v[0]},{v[1]}"
            elif isinstance(param, QgsProcessingParameterCrs):
                if self.parameterAsCrs(parameters, paramName, context):
                    # TODO: ideally we should be exporting to WKT here, but it seems not all grass algorithms
                    # will accept a wkt string for a crs value (e.g. r.tileset)
                    value = f'"{self.parameterAsCrs(parameters, paramName, context).toProj()}"'
            # For everything else, we assume that it is a string
            else:
                value = f'"{self.parameterAsString(parameters, paramName, context)}"'
            if value:
                command += " {}={}".format(paramName.replace("~", ""), value)

        # Handle outputs
        if not delOutputs:
            for out in self.destinationParameterDefinitions():
                # We exclude hidden parameters
                if out.flags() & QgsProcessingParameterDefinition.Flag.FlagHidden:
                    continue
                outName = out.name()
                # For File destination
                if isinstance(out, QgsProcessingParameterFileDestination):
                    if outName in parameters and parameters[outName] is not None:
                        outPath = self.parameterAsFileOutput(
                            parameters, outName, context
                        )
                        self.fileOutputs[outName] = outPath
                        # for HTML reports, we need to redirect stdout
                        if out.defaultFileExtension().lower() == "html":
                            if outName == "html":
                                # for "fake" outputs redirect command stdout
                                command += f' > "{outPath}"'
                            else:
                                # for real outputs only output itself should be redirected
                                command += f' {outName}=- > "{outPath}"'
                        else:
                            command += f' {outName}="{outPath}"'
                # For folders destination
                elif isinstance(out, QgsProcessingParameterFolderDestination):
                    # We need to add a unique temporary basename
                    uniqueBasename = outName + self.uniqueSuffix
                    command += f" {outName}={uniqueBasename}"
                else:
                    if outName in parameters and parameters[outName] is not None:
                        # We add an output name to make sure it is unique if the session
                        # uses this algorithm several times.
                        uniqueOutputName = outName + self.uniqueSuffix
                        command += f" {outName}={uniqueOutputName}"

                        # Add output file to exported layers, to indicate that
                        # they are present in GRASS
                        self.exportedLayers[outName] = uniqueOutputName

        command += " --overwrite"
        self.commands.append(command)
        QgsMessageLog.logMessage(
            self.tr("processCommands end. Commands: {}").format(self.commands),
            "Grass",
            Qgis.MessageLevel.Info,
        )

    def vectorOutputType(self, parameters, context):
        """Determine vector output types for outputs"""
        self.outType = "auto"
        if self.parameterDefinition(self.GRASS_OUTPUT_TYPE_PARAMETER):
            typeidx = self.parameterAsEnum(
                parameters, self.GRASS_OUTPUT_TYPE_PARAMETER, context
            )
            self.outType = "auto" if typeidx is None else self.OUTPUT_TYPES[typeidx]

    def processOutputs(self, parameters, context, feedback):
        """Prepare the GRASS v.out.ogr commands"""
        # Determine general vector output type
        self.vectorOutputType(parameters, context)

        for out in self.destinationParameterDefinitions():
            outName = out.name()
            if outName not in parameters:
                # skipped output
                continue

            if isinstance(out, QgsProcessingParameterRasterDestination):
                self.exportRasterLayerFromParameter(outName, parameters, context)
            elif isinstance(out, QgsProcessingParameterVectorDestination):
                self.exportVectorLayerFromParameter(outName, parameters, context)
            elif isinstance(out, QgsProcessingParameterFolderDestination):
                self.exportRasterLayersIntoDirectory(outName, parameters, context)

    def loadRasterLayerFromParameter(
        self, name, parameters, context: QgsProcessingContext, external=None, band=1
    ):
        """
        Creates a dedicated command to load a raster into
        the temporary GRASS DB.
        :param name: name of the parameter.
        :param parameters: algorithm parameters dict.
        :param context: algorithm context.
        :param external: use r.external if True, r.in.gdal otherwise.
        :param band: imports only specified band. None for all bands.
        """
        layer = self.parameterAsRasterLayer(parameters, name, context)
        self.loadRasterLayer(name, layer, context, external, band)

    def loadRasterLayer(
        self,
        name,
        layer,
        context: QgsProcessingContext,
        external=None,
        band=1,
        destName=None,
    ):
        """
        Creates a dedicated command to load a raster into
        the temporary GRASS DB.
        :param name: name of the parameter.
        :param layer: QgsMapLayer for the raster layer.
        :param context: Processing context
        :param external: use r.external if True, r.in.gdal if False.
        :param band: imports only specified band. None for all bands.
        :param destName: force the destination name of the raster.
        """
        if external is None:
            external = ProcessingConfig.getSetting(GrassUtils.GRASS_USE_REXTERNAL)
        self.inputLayers.append(layer)
        self.setSessionProjectionFromLayer(layer, context)
        if not destName:
            destName = f"rast_{os.path.basename(getTempFilename(context=context))}"
        self.exportedLayers[name] = destName

        if layer.providerType() == "postgresraster":
            source = ""
            uri = layer.dataProvider().uri()
            source = f"PG: {uri.connectionInfo()}"
            schema = uri.schema()
            if schema:
                source += f" schema='{schema}'"
            table = uri.table()
            source += f" table='{table}'"
            column = uri.param("column") or uri.geometryColumn()
            if column:
                source += f" column='{column}'"
            is_tiled = any(
                [
                    layer.dataProvider().xSize() != layer.dataProvider().xBlockSize(),
                    layer.dataProvider().ySize() != layer.dataProvider().yBlockSize(),
                ]
            )
            source += f" mode={2 if is_tiled else 1}"
            where = layer.dataProvider().subsetString()
            if where:
                source += f" where='{where}'"
        else:
            source = os.path.normpath(layer.source())

        command = '{} input="{}" {}output="{}" --overwrite -o'.format(
            "r.external" if external else "r.in.gdal",
            source,
            f"band={band} " if band else "",
            destName,
        )
        self.commands.append(command)

    def exportRasterLayerFromParameter(
        self, name, parameters, context, colorTable=True
    ):
        """
        Creates a dedicated command to export a raster from
        temporary GRASS DB into a file via gdal.
        :param name: name of the parameter.
        :param parameters: Algorithm parameters dict.
        :param context: Algorithm context.
        :param colorTable: preserve color Table.
        """
        fileName = self.parameterAsOutputLayer(parameters, name, context)
        if not fileName:
            return

        fileName = os.path.normpath(fileName)
        grassName = f"{name}{self.uniqueSuffix}"
        outFormat = GrassUtils.getRasterFormatFromFilename(fileName)
        createOpt = self.parameterAsString(
            parameters, self.GRASS_RASTER_FORMAT_OPT, context
        )
        metaOpt = self.parameterAsString(
            parameters, self.GRASS_RASTER_FORMAT_META, context
        )
        self.exportRasterLayer(
            grassName, fileName, colorTable, outFormat, createOpt, metaOpt
        )

        self.fileOutputs[name] = fileName

    def exportRasterLayer(
        self,
        grassName,
        fileName,
        colorTable=True,
        outFormat="GTiff",
        createOpt=None,
        metaOpt=None,
    ):
        """
        Creates a dedicated command to export a raster from
        temporary GRASS DB into a file via gdal.
        :param grassName: name of the raster to export.
        :param fileName: file path of raster layer.
        :param colorTable: preserve color Table.
        :param outFormat: file format for export.
        :param createOpt: creation options for format.
        :param metaOpt: metadata options for export.
        """
        createOpt = createOpt or GrassUtils.GRASS_RASTER_FORMATS_CREATEOPTS.get(
            outFormat
        )

        for cmd in [self.commands, self.outputCommands]:
            # Adjust region to layer before exporting
            cmd.append(f"g.region raster={grassName}")
            cmd.append(
                'r.out.gdal -t -m{} input="{}" output="{}" format="{}" {}{} --overwrite'.format(
                    "" if colorTable else " -c",
                    grassName,
                    fileName,
                    outFormat,
                    f' createopt="{createOpt}"' if createOpt else "",
                    f' metaopt="{metaOpt}"' if metaOpt else "",
                )
            )

    def exportRasterLayersIntoDirectory(
        self, name, parameters, context, colorTable=True, wholeDB=False
    ):
        """
        Creates a dedicated loop command to export rasters from
        temporary GRASS DB into a directory via gdal.
        :param name: name of the output directory parameter.
        :param parameters: Algorithm parameters dict.
        :param context: Algorithm context.
        :param colorTable: preserve color Table.
        :param wholeDB: export every raster layer from the GRASSDB
        """
        # Grab directory name and temporary basename
        outDir = os.path.normpath(self.parameterAsString(parameters, name, context))
        basename = ""
        if not wholeDB:
            basename = name + self.uniqueSuffix

        # Add a loop export from the basename
        for cmd in [self.commands, self.outputCommands]:
            # TODO Format/options support
            if isWindows():
                cmd.append(f"if not exist {outDir} mkdir {outDir}")
                cmd.append(
                    "for /F %%r IN ('g.list type^=rast pattern^=\"{}*\"') do r.out.gdal -m{} input=%%r output={}/%%r.tif {}".format(
                        basename,
                        " -t" if colorTable else "",
                        outDir,
                        '--overwrite -c createopt="TFW=YES,COMPRESS=LZW"',
                    )
                )
            else:
                cmd.append(f"for r in $(g.list type=rast pattern='{basename}*'); do")
                cmd.append(
                    "  r.out.gdal -m{0} input=${{r}} output={1}/${{r}}.tif {2}".format(
                        " -t" if colorTable else "",
                        outDir,
                        '--overwrite -c createopt="TFW=YES,COMPRESS=LZW"',
                    )
                )
                cmd.append("done")

    def loadVectorLayerFromParameter(
        self, name, parameters, context, feedback, external=False
    ):
        """
        Creates a dedicated command to load a vector into
        the temporary GRASS DB.
        :param name: name of the parameter
        :param parameters: Parameters of the algorithm.
        :param context: Processing context
        :param external: use v.external (v.in.ogr if False).
        """
        layer = self.parameterAsVectorLayer(parameters, name, context)

        is_ogr_disk_based_layer = (
            layer is not None and layer.dataProvider().name() == "ogr"
        )
        if is_ogr_disk_based_layer:
            # we only support direct reading of disk based ogr layers -- not ogr postgres layers, etc
            source_parts = QgsProviderRegistry.instance().decodeUri(
                "ogr", layer.source()
            )
            if not source_parts.get("path"):
                is_ogr_disk_based_layer = False
            elif source_parts.get("layerId"):
                # no support for directly reading layers by id in grass
                is_ogr_disk_based_layer = False

        if not is_ogr_disk_based_layer:
            # parameter is not a vector layer or not an OGR layer - try to convert to a source compatible with
            # grass OGR inputs and extract selection if required
            path = self.parameterAsCompatibleSourceLayerPath(
                parameters,
                name,
                context,
                QgsVectorFileWriter.supportedFormatExtensions(),
                feedback=feedback,
            )
            ogr_layer = QgsVectorLayer(path, "", "ogr")
            self.loadVectorLayer(
                name, ogr_layer, context, external=external, feedback=feedback
            )
        else:
            # already an ogr disk based layer source
            self.loadVectorLayer(
                name, layer, context, external=external, feedback=feedback
            )

    def loadVectorLayer(
        self, name, layer, context: QgsProcessingContext, external=False, feedback=None
    ):
        """
        Creates a dedicated command to load a vector into
        temporary GRASS DB.
        :param name: name of the parameter
        :param layer: QgsMapLayer for the vector layer.
        :param context: Processing context
        :param external: use v.external (v.in.ogr if False).
        :param feedback: feedback object
        """
        # TODO: support multiple input formats
        if external is None:
            external = ProcessingConfig.getSetting(GrassUtils.GRASS_USE_VEXTERNAL)

        source_parts = QgsProviderRegistry.instance().decodeUri("ogr", layer.source())
        file_path = source_parts.get("path")
        layer_name = source_parts.get("layerName")

        # safety check: we can only use external for ogr layers which support random read
        if external:
            if feedback is not None:
                feedback.pushInfo(
                    self.tr("Attempting to use v.external for direct layer read")
                )
            ds = ogr.Open(file_path)
            if ds is not None:
                ogr_layer = ds.GetLayer()
                if ogr_layer is None or not ogr_layer.TestCapability(ogr.OLCRandomRead):
                    if feedback is not None:
                        feedback.reportError(
                            self.tr(
                                "Cannot use v.external: layer does not support random read"
                            )
                        )
                    external = False
            else:
                if feedback is not None:
                    feedback.reportError(
                        self.tr("Cannot use v.external: error reading layer")
                    )
                external = False

        self.inputLayers.append(layer)
        self.setSessionProjectionFromLayer(layer, context)
        destFilename = f"vector_{os.path.basename(getTempFilename(context=context))}"
        self.exportedLayers[name] = destFilename
        command = '{}{}{} input="{}"{} output="{}" --overwrite -o'.format(
            "v.external" if external else "v.in.ogr",
            f" min_area={self.minArea}" if not external else "",
            f" snap={self.snapTolerance}" if not external else "",
            os.path.normpath(file_path),
            f' layer="{layer_name}"' if layer_name else "",
            destFilename,
        )
        if layer.subsetString():
            escaped_subset = layer.subsetString().replace('"', '\\"')
            command += f' where="{escaped_subset}"'

        self.commands.append(command)

    def exportVectorLayerFromParameter(
        self, name, parameters, context, layer=None, nocats=False
    ):
        """
        Creates a dedicated command to export a vector from
        a QgsProcessingParameter.
        :param name: name of the parameter.
        :param context: parameters context.
        :param layer: for vector with multiples layers, exports only one layer.
        :param nocats: do not export GRASS categories.
        """
        fileName = os.path.normpath(
            self.parameterAsOutputLayer(parameters, name, context)
        )
        grassName = f"{name}{self.uniqueSuffix}"

        # Find if there is a dataType
        dataType = self.outType
        if self.outType == "auto":
            parameter = self.parameterDefinition(name)
            if parameter:
                layerType = parameter.dataType()
                if layerType in self.QGIS_OUTPUT_TYPES:
                    dataType = self.QGIS_OUTPUT_TYPES[layerType]

        outFormat = QgsVectorFileWriter.driverForExtension(
            os.path.splitext(fileName)[1]
        ).replace(" ", "_")
        dsco = self.parameterAsString(parameters, self.GRASS_VECTOR_DSCO, context)
        lco = self.parameterAsString(parameters, self.GRASS_VECTOR_LCO, context)
        exportnocat = self.parameterAsBoolean(
            parameters, self.GRASS_VECTOR_EXPORT_NOCAT, context
        )
        self.exportVectorLayer(
            grassName,
            fileName,
            layer,
            nocats,
            dataType,
            outFormat,
            dsco,
            lco,
            exportnocat,
        )

        self.fileOutputs[name] = fileName

    def exportVectorLayer(
        self,
        grassName,
        fileName,
        layer=None,
        nocats=False,
        dataType="auto",
        outFormat=None,
        dsco=None,
        lco=None,
        exportnocat=False,
    ):
        """
        Creates a dedicated command to export a vector from
        temporary GRASS DB into a file via OGR.
        :param grassName: name of the vector to export.
        :param fileName: file path of vector layer.
        :param dataType: export only this type of data.
        :param layer: for vector with multiples layers, exports only one layer.
        :param nocats: do not export GRASS categories.
        :param outFormat: file format for export.
        :param dsco: datasource creation options for format.
        :param lco: layer creation options for format.
        :param exportnocat: do not export features without categories.
        """
        if outFormat is None:
            outFormat = QgsVectorFileWriter.driverForExtension(
                os.path.splitext(fileName)[1]
            ).replace(" ", "_")

        for cmd in [self.commands, self.outputCommands]:
            cmd.append(
                'v.out.ogr{} type="{}" input="{}" output="{}" format="{}" {}{}{}{} --overwrite'.format(
                    "" if nocats else "",
                    dataType,
                    grassName,
                    fileName,
                    outFormat,
                    f"layer={layer}" if layer else "",
                    f' dsco="{dsco}"' if dsco else "",
                    f' lco="{lco}"' if lco else "",
                    " -c" if exportnocat else "",
                )
            )

    def loadAttributeTableFromParameter(self, name, parameters, context):
        """
        Creates a dedicated command to load an attribute table
        into the temporary GRASS DB.
        :param name: name of the parameter
        :param parameters: Parameters of the algorithm.
        :param context: Processing context
        """
        table = self.parameterAsVectorLayer(parameters, name, context)
        self.loadAttributeTable(name, table, context)

    def loadAttributeTable(
        self, name, layer, context: QgsProcessingContext, destName=None
    ):
        """
        Creates a dedicated command to load an attribute table
        into the temporary GRASS DB.
        :param name: name of the input parameter.
        :param layer: a layer object to import from.
        :param context: processing context
        :param destName: force the name for the table into GRASS DB.
        """
        self.inputLayers.append(layer)
        if not destName:
            destName = f"table_{os.path.basename(getTempFilename(context=context))}"
        self.exportedLayers[name] = destName
        command = f'db.in.ogr --overwrite input="{os.path.normpath(layer.source())}" output="{destName}"'
        self.commands.append(command)

    def exportAttributeTable(self, grassName, fileName, outFormat="CSV", layer=1):
        """
        Creates a dedicated command to export an attribute
        table from the temporary GRASS DB into a file via ogr.
        :param grassName: name of the parameter.
        :param fileName: file path of raster layer.
        :param outFormat: file format for export.
        :param layer: In GRASS a vector can have multiple layers.
        """
        for cmd in [self.commands, self.outputCommands]:
            cmd.append(
                f'db.out.ogr input="{grassName}" output="{fileName}" layer={layer} format={outFormat} --overwrite'
            )

    def setSessionProjectionFromProject(self, context: QgsProcessingContext):
        """
        Set the projection from the project.
        We create a WKT definition which is transmitted to Grass
        """
        if not GrassUtils.projectionSet and iface:
            self.setSessionProjection(
                iface.mapCanvas().mapSettings().destinationCrs(), context
            )

    def setSessionProjectionFromLayer(
        self, layer: QgsMapLayer, context: QgsProcessingContext
    ):
        """
        Set the projection from a QgsVectorLayer.
        We create a WKT definition which is transmitted to Grass
        """
        if not GrassUtils.projectionSet:
            self.setSessionProjection(layer.crs(), context)

    def setSessionProjection(self, crs, context: QgsProcessingContext):
        """
        Set the session projection to the specified CRS
        """
        self.destination_crs = crs
        file_name = GrassUtils.exportCrsWktToFile(crs, context)
        command = f'g.proj -c wkt="{file_name}"'
        self.commands.append(command)
        GrassUtils.projectionSet = True

    def convertToHtml(self, fileName):
        # Read HTML contents
        lines = []
        with open(fileName, encoding="utf-8") as f:
            lines = f.readlines()

        if len(lines) > 1 and "<html>" not in lines[0]:
            # Then write into the HTML file
            with open(fileName, "w", encoding="utf-8") as f:
                f.write("<html><head>")
                f.write(
                    '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head>'
                )
                f.write("<body><p>")
                for line in lines:
                    f.write(f"{line}</br>")
                f.write("</p></body></html>")

    def canExecute(self):
        message = GrassUtils.checkGrassIsInstalled()
        return not message, message

    def checkParameterValues(self, parameters, context):
        grass_parameters = {k: v for k, v in parameters.items()}
        if self.module:
            if hasattr(self.module, "checkParameterValuesBeforeExecuting"):
                func = getattr(self.module, "checkParameterValuesBeforeExecuting")
                return func(self, grass_parameters, context)
        return super().checkParameterValues(grass_parameters, context)
