# -*- coding: utf-8 -*-
"""
geohashgen.py
***************************************************************************
*                                                                         *
*   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__ = "Thang Quach"
__date__ = "2024-11-20"
__copyright__ = "(L) 2024, Thang Quach"

from qgis.core import (
    QgsApplication,
    QgsProject,
    QgsProcessingLayerPostProcessorInterface,
    QgsProcessingParameterExtent,
    QgsProcessingParameterNumber,
    QgsProcessingException,
    QgsProcessingParameterFeatureSink,
    QgsProcessingAlgorithm,
    QgsFields,
    QgsField,
    QgsFeature,
    QgsGeometry,
    QgsWkbTypes,
    QgsCoordinateReferenceSystem,
    QgsVectorLayer,
    QgsPalLayerSettings,
    QgsVectorLayerSimpleLabeling,
)
from qgis.PyQt.QtGui import QIcon, QColor
from qgis.PyQt.QtCore import QCoreApplication, Qt
from qgis.utils import iface
from qgis.PyQt.QtCore import QVariant
from qgis.core import QgsCoordinateTransform
import os

from ...utils.geohash_alphabet import geohash_child_chars
from ...utils.help_footer import social_links_footer
from vgrid.utils.geometry import graticule_dggs_metrics
from shapely.geometry import box
from vgrid.conversion.dggs2geo.geohash2geo import geohash2geo
from ...settings import settings
from vgrid.utils.constants import INITIAL_GEOHASHES
from vgrid.utils.io import validate_coordinate
from ...utils.latlon import epsg4326
from vgrid.utils.constants import DGGS_TYPES


class GeohashGen(QgsProcessingAlgorithm):
    EXTENT = "EXTENT"
    RESOLUTION = "RESOLUTION"
    OUTPUT = "OUTPUT"

    LOC = QgsApplication.locale()[:2]

    def translate(self, string):
        return QCoreApplication.translate("Processing", string)

    def tr(self, *string):
        # Translate to Vietnamese: arg[0] - English (translate), arg[1] - Vietnamese
        if self.LOC == "vi":
            if len(string) == 2:
                return string[1]
            else:
                return self.translate(string[0])
        else:
            return self.translate(string[0])

    def createInstance(self):
        return GeohashGen()

    def name(self):
        return "geohash_gen"

    def icon(self):
        return QIcon(
            os.path.join(
                os.path.dirname(os.path.dirname(__file__)),
                "../images/generator/grid_quad.svg",
            )
        )

    def displayName(self):
        return self.tr("Geohash", "Geohash")

    def group(self):
        return self.tr("Generator", "Generator")

    def groupId(self):
        return "generator"

    def tags(self):
        return self.tr("DGGS, grid, Geohash, generator").split(",")

    txt_en = "Geohash DGGS Generator"
    txt_vi = "Geohash DGGS Generator"
    figure = "../images/tutorial/grid_geohash.png"

    def shortHelpString(self):
        footer = (
            '''<div align="center">
                      <img src="'''
            + os.path.join(os.path.dirname(os.path.dirname(__file__)), self.figure)
            + """">
                    </div>
                    <div align="right">
                      <p align="right">
                      <b>"""
            + self.tr("Author: Thang Quach", "Author: Thang Quach")
            + """</b>
                      </p>"""
            + social_links_footer()
            + """
                    </div>
                    """
        )
        return self.tr(self.txt_en, self.txt_vi) + footer

    def initAlgorithm(self, config=None):
        param = QgsProcessingParameterExtent(
            self.EXTENT, self.tr("Canvas extent"), optional=True
        )
        self.addParameter(param)

        min_res = DGGS_TYPES["geohash"]["min_res"]
        max_res = DGGS_TYPES["geohash"]["max_res"]
        param = QgsProcessingParameterNumber(
            self.RESOLUTION,
            self.tr(f"Resolution [{min_res}..{max_res}]"),
            QgsProcessingParameterNumber.Integer,
            defaultValue=1,
            minValue=min_res,
            maxValue=max_res,
            optional=False,
        )
        self.addParameter(param)

        param = QgsProcessingParameterFeatureSink(self.OUTPUT, "Geohash")
        self.addParameter(param)

    def prepareAlgorithm(self, parameters, context, feedback):
        self.resolution = self.parameterAsInt(parameters, self.RESOLUTION, context)
        # Get the extent parameter
        self.canvas_extent = self.parameterAsExtent(parameters, self.EXTENT, context)
        # Ensure that when resolution > 4, the extent must be set
        if self.resolution > 4 and (
            self.canvas_extent is None or self.canvas_extent.isEmpty()
        ):
            feedback.reportError(
                "For performance reason, when resolution is greater than 4, the canvas extent must be set."
            )
            return False

        return True

    def outputFields(self):
        output_fields = QgsFields()
        output_fields.append(QgsField("geohash", QVariant.String))
        output_fields.append(QgsField("resolution", QVariant.Int))
        output_fields.append(QgsField("center_lat", QVariant.Double))
        output_fields.append(QgsField("center_lon", QVariant.Double))
        output_fields.append(QgsField("cell_width", QVariant.Double))
        output_fields.append(QgsField("cell_height", QVariant.Double))
        output_fields.append(QgsField("cell_area", QVariant.Double))
        output_fields.append(QgsField("cell_perimeter", QVariant.Double))
        return output_fields

    def expand_geohash(self, gh, target_length, writer, fields, feedback):
        """Recursive function to expand geohashes to target RESOLUTION and write them."""
        if len(gh) == target_length:
            cell_polygon = geohash2geo(gh)
            cell_geometry = QgsGeometry.fromWkt(cell_polygon.wkt)
            geohash_feature = QgsFeature(fields)
            geohash_feature.setGeometry(cell_geometry)

            (
                center_lat,
                center_lon,
                cell_width,
                cell_height,
                cell_area,
                cell_perimeter,
            ) = graticule_dggs_metrics(cell_polygon)
            geohash_feature.setAttributes(
                [
                    gh,
                    self.resolution,
                    center_lat,
                    center_lon,
                    cell_width,
                    cell_height,
                    cell_area,
                    cell_perimeter,
                ]
            )

            writer.addFeature(geohash_feature)
            return

        # pragma: allowlist secret — public geohash base32 alphabet, not credentials
        for char in geohash_child_chars():
            self.expand_geohash(gh + char, target_length, writer, fields, feedback)
            if feedback.isCanceled():
                return

    def expand_geohash_within_bbox(
        self, gh, target_length, writer, fields, extent_bbox, feedback
    ):
        cell_polygon = geohash2geo(gh)
        if not cell_polygon.intersects(extent_bbox):
            return

        if len(gh) == target_length:
            cell_geometry = QgsGeometry.fromWkt(cell_polygon.wkt)
            geohash_feature = QgsFeature(fields)
            geohash_feature.setGeometry(cell_geometry)

            (
                center_lat,
                center_lon,
                cell_width,
                cell_height,
                cell_area,
                cell_perimeter,
            ) = graticule_dggs_metrics(cell_polygon)
            geohash_feature.setAttributes(
                [
                    gh,
                    self.resolution,
                    center_lat,
                    center_lon,
                    cell_width,
                    cell_height,
                    cell_area,
                    cell_perimeter,
                ]
            )

            writer.addFeature(geohash_feature)
            return

        # pragma: allowlist secret — public geohash base32 alphabet, not credentials
        for char in geohash_child_chars():
            self.expand_geohash_within_bbox(
                gh + char, target_length, writer, fields, extent_bbox, feedback
            )
            if feedback.isCanceled():
                return

    def processAlgorithm(self, parameters, context, feedback):
        fields = self.outputFields()

        # Get the output sink and its destination ID (this handles both file and temporary layers)
        (sink, dest_id) = self.parameterAsSink(
            parameters,
            self.OUTPUT,
            context,
            fields,
            QgsWkbTypes.Polygon,
            QgsCoordinateReferenceSystem("EPSG:4326"),
        )

        if sink is None:
            raise QgsProcessingException("Failed to create output sink")

        canvas_crs = QgsProject.instance().crs()

        if self.canvas_extent is None or self.canvas_extent.isEmpty():
            min_lon, min_lat, max_lon, max_lat = -180, -90, 180, 90  # Whole world
            total_cells = 32**self.resolution
            feedback.pushInfo(f"Total cells to be generated: {total_cells}.")
            for idx, gh in enumerate(INITIAL_GEOHASHES):
                self.expand_geohash(gh, self.resolution, sink, fields, feedback)
                feedback.setProgress(int((idx / total_cells) * 100))
                if feedback.isCanceled():
                    break
        else:
            try:
                min_lon, min_lat, max_lon, max_lat = (
                    self.canvas_extent.xMinimum(),
                    self.canvas_extent.yMinimum(),
                    self.canvas_extent.xMaximum(),
                    self.canvas_extent.yMaximum(),
                )
                # Transform extent to EPSG:4326 if needed
                if epsg4326 != canvas_crs:
                    trans_to_4326 = QgsCoordinateTransform(
                        canvas_crs, epsg4326, QgsProject.instance()
                    )
                    transformed_extent = trans_to_4326.transform(self.canvas_extent)
                    min_lon, min_lat, max_lon, max_lat = (
                        transformed_extent.xMinimum(),
                        transformed_extent.yMinimum(),
                        transformed_extent.xMaximum(),
                        transformed_extent.yMaximum(),
                    )
            except Exception:
                min_lon, min_lat, max_lon, max_lat = -180, -90, 180, 90

            min_lon, min_lat, max_lon, max_lat = validate_coordinate(
                min_lon, min_lat, max_lon, max_lat
            )
            extent_bbox = box(min_lon, min_lat, max_lon, max_lat)
            total_geohashes = len(INITIAL_GEOHASHES)
            intersected_geohashes = []
            for gh in INITIAL_GEOHASHES:
                cell_polygon = geohash2geo(gh)
                if cell_polygon.intersects(extent_bbox):
                    intersected_geohashes.append(gh)

            for idx, gh in enumerate(intersected_geohashes):
                feedback.setProgress(int((idx / total_geohashes) * 100))
                self.expand_geohash_within_bbox(
                    gh, self.resolution, sink, fields, extent_bbox, feedback
                )
                if feedback.isCanceled():
                    break

        feedback.pushInfo("Geohash DGGS generation completed.")

        if context.willLoadLayerOnCompletion(dest_id):
            lineColor = settings.geohashColor
            fontColor = QColor("#000000")
            context.layerToLoadOnCompletionDetails(dest_id).setPostProcessor(
                StylePostProcessor.create(lineColor, fontColor)
            )
        return {self.OUTPUT: dest_id}


class StylePostProcessor(QgsProcessingLayerPostProcessorInterface):
    instance = None
    line_color = None
    font_color = None

    def __init__(self, line_color, font_color):
        self.line_color = line_color
        self.font_color = font_color
        super().__init__()

    def postProcessLayer(self, layer, context, feedback):
        if not isinstance(layer, QgsVectorLayer):
            return
        sym = layer.renderer().symbol().symbolLayer(0)
        sym.setBrushStyle(Qt.BrushStyle.NoBrush)
        sym.setStrokeColor(self.line_color)
        if settings.gridLabel:
            label = QgsPalLayerSettings()
            label.fieldName = "geohash"
            format = label.format()
            format.setColor(self.font_color)
            format.setSize(8)
            label.setFormat(format)
            labeling = QgsVectorLayerSimpleLabeling(label)
            layer.setLabeling(labeling)
            layer.setLabelsEnabled(True)

        iface.layerTreeView().refreshLayerSymbology(layer.id())
        root = QgsProject.instance().layerTreeRoot()
        layer_node = root.findLayer(layer.id())
        if layer_node:
            layer_node.setCustomProperty("showFeatureCount", True)

        # iface.mapCanvas().setExtent(layer.extent())
        iface.mapCanvas().refresh()

    # Hack to work around sip bug!
    @staticmethod
    def create(line_color, font_color) -> "StylePostProcessor":
        """
        Returns a new instance of the post processor, keeping a reference to the sip
        wrapper so that sip doesn't get confused with the Python subclass and call
        the base wrapper implementation instead... ahhh sip, you wonderful piece of sip
        """
        StylePostProcessor.instance = StylePostProcessor(line_color, font_color)
        return StylePostProcessor.instance
