"""
/***************************************************************************
Name                 : DB Manager
Description          : Database manager plugin for QGIS
Date                 : Oct 13, 2011
copyright            : (C) 2011 by Giuseppe Sucameli
email                : brush.tyler@gmail.com

The content of this file is based on
- PG_Manager by Martin Dobias (GPLv2 license)
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/
"""

from qgis.PyQt import uic
from qgis.PyQt.QtCore import Qt, QFileInfo
from qgis.PyQt.QtWidgets import QDialog, QFileDialog, QMessageBox

from qgis.core import (
    QgsDataSourceUri,
    QgsVectorDataProvider,
    QgsVectorLayer,
    QgsMapLayerType,
    QgsProviderRegistry,
    QgsCoordinateReferenceSystem,
    QgsVectorLayerExporter,
    QgsProject,
    QgsSettings,
)
from qgis.gui import QgsMessageViewer
from qgis.utils import OverrideCursor, iface

from .gui_utils import GuiUtils

Ui_Dialog, _ = uic.loadUiType(GuiUtils.get_ui_file_path("DlgImportVector.ui"))


class DlgImportVector(QDialog, Ui_Dialog):
    HAS_INPUT_MODE, ASK_FOR_INPUT_MODE = list(range(2))

    def __init__(self, inLayer, outDb, outUri, parent=None):
        QDialog.__init__(self, parent)
        self.inLayer = inLayer
        self.db = outDb
        self.outUri = outUri
        self.setupUi(self)

        supportCom = self.db.supportsComment()
        if not supportCom:
            self.chkCom.setVisible(False)
            self.editCom.setVisible(False)

        self.default_pk = "id"
        self.default_geom = "geom"

        self.mode = (
            self.ASK_FOR_INPUT_MODE if self.inLayer is None else self.HAS_INPUT_MODE
        )

        # used to delete the inlayer whether created inside this dialog
        self.inLayerMustBeDestroyed = False

        self.populateSchemas()
        self.populateTables()
        self.populateLayers()
        self.populateEncodings()

        # updates of UI
        self.setupWorkingMode(self.mode)
        self.cboSchema.currentIndexChanged.connect(self.populateTables)
        self.widgetSourceSrid.setCrs(QgsProject.instance().crs())
        self.widgetTargetSrid.setCrs(QgsProject.instance().crs())
        self.updateInputLayer()

    def setupWorkingMode(self, mode):
        """hide the widget to select a layer/file if the input layer is already set"""
        self.wdgInput.setVisible(mode == self.ASK_FOR_INPUT_MODE)
        self.resize(450, 350)

        self.cboTable.setEditText(self.outUri.table())

        if mode == self.ASK_FOR_INPUT_MODE:
            self.btnChooseInputFile.clicked.connect(self.chooseInputFile)
            self.cboInputLayer.currentTextChanged.connect(self.updateInputLayer)

            self.editPrimaryKey.setText(self.default_pk)
            self.editGeomColumn.setText(self.default_geom)

            self.chkLowercaseFieldNames.setEnabled(
                self.db.hasLowercaseFieldNamesOption()
            )
            if not self.chkLowercaseFieldNames.isEnabled():
                self.chkLowercaseFieldNames.setChecked(False)
        else:
            # set default values
            self.checkSupports()
            self.updateInputLayer()

    def checkSupports(self):
        """update options available for the current input layer"""
        allowSpatial = self.db.connector.hasSpatialSupport()
        hasGeomType = self.inLayer and self.inLayer.isSpatial()
        isShapefile = (
            self.inLayer
            and self.inLayer.providerType() == "ogr"
            and self.inLayer.storageType() == "ESRI Shapefile"
        )

        self.chkGeomColumn.setEnabled(allowSpatial and hasGeomType)
        if not self.chkGeomColumn.isEnabled():
            self.chkGeomColumn.setChecked(False)

        self.chkSourceSrid.setEnabled(allowSpatial and hasGeomType)
        if not self.chkSourceSrid.isEnabled():
            self.chkSourceSrid.setChecked(False)
        self.chkTargetSrid.setEnabled(allowSpatial and hasGeomType)
        if not self.chkTargetSrid.isEnabled():
            self.chkTargetSrid.setChecked(False)

        self.chkSinglePart.setEnabled(allowSpatial and hasGeomType and isShapefile)
        if not self.chkSinglePart.isEnabled():
            self.chkSinglePart.setChecked(False)

        self.chkSpatialIndex.setEnabled(allowSpatial and hasGeomType)
        if not self.chkSpatialIndex.isEnabled():
            self.chkSpatialIndex.setChecked(False)

        self.chkLowercaseFieldNames.setEnabled(self.db.hasLowercaseFieldNamesOption())
        if not self.chkLowercaseFieldNames.isEnabled():
            self.chkLowercaseFieldNames.setChecked(False)

    def populateLayers(self):
        self.cboInputLayer.clear()
        for nodeLayer in QgsProject.instance().layerTreeRoot().findLayers():
            layer = nodeLayer.layer()
            # TODO: add import raster support!
            if layer is not None and layer.type() == QgsMapLayerType.VectorLayer:
                self.cboInputLayer.addItem(layer.name(), layer.id())

        # set the current index of the combo box to the active layer in the layer tree (if found in combo box)
        if iface is not None and iface.activeLayer():
            index = self.cboInputLayer.findData(iface.activeLayer().id())
            if index != -1:
                self.cboInputLayer.setCurrentIndex(index)

    def deleteInputLayer(self):
        """unset the input layer, then destroy it but only if it was created from this dialog"""
        if self.mode == self.ASK_FOR_INPUT_MODE and self.inLayer:
            if self.inLayerMustBeDestroyed:
                self.inLayer.deleteLater()
            self.inLayer = None
            self.inLayerMustBeDestroyed = False
            return True
        return False

    def chooseInputFile(self):
        vectorFormats = QgsProviderRegistry.instance().fileVectorFilters()
        # get last used dir and format
        settings = QgsSettings()
        lastDir = settings.value("/db_manager/lastUsedDir", "")
        lastVectorFormat = settings.value("/UI/lastVectorFileFilter", "")
        # ask for a filename
        filename, lastVectorFormat = QFileDialog.getOpenFileName(
            self,
            self.tr("Choose the file to import"),
            lastDir,
            vectorFormats,
            lastVectorFormat,
        )
        if filename == "":
            return
        # store the last used dir and format
        settings.setValue("/db_manager/lastUsedDir", QFileInfo(filename).filePath())
        settings.setValue("/UI/lastVectorFileFilter", lastVectorFormat)

        self.cboInputLayer.setCurrentIndex(-1)
        self.cboInputLayer.setEditText(filename)

    def reloadInputLayer(self):
        """Creates the input layer and update available options"""
        if self.mode != self.ASK_FOR_INPUT_MODE:
            return True

        self.deleteInputLayer()

        index = self.cboInputLayer.currentIndex()
        if index < 0:
            filename = self.cboInputLayer.currentText()
            if filename == "":
                return False

            layerName = QFileInfo(filename).completeBaseName()
            layer = QgsVectorLayer(filename, layerName, "ogr")
            if not layer.isValid() or layer.type() != QgsMapLayerType.VectorLayer:
                layer.deleteLater()
                return False

            self.inLayer = layer
            self.inLayerMustBeDestroyed = True

        else:
            layerId = self.cboInputLayer.itemData(index)
            self.inLayer = QgsProject.instance().mapLayer(layerId)
            self.inLayerMustBeDestroyed = False

        self.checkSupports()
        return True

    def updateInputLayer(self):
        if not self.reloadInputLayer() or not self.inLayer:
            return False

        # update the output table name, pk and geom column
        self.cboTable.setEditText(self.inLayer.name())

        srcUri = QgsDataSourceUri(self.inLayer.source())
        pk = srcUri.keyColumn() if srcUri.keyColumn() else self.default_pk
        self.editPrimaryKey.setText(pk)
        geom = srcUri.geometryColumn() if srcUri.geometryColumn() else self.default_geom
        self.editGeomColumn.setText(geom)

        srcCrs = self.inLayer.crs()
        if not srcCrs.isValid():
            srcCrs = QgsCoordinateReferenceSystem("EPSG:4326")
        self.widgetSourceSrid.setCrs(srcCrs)
        self.widgetTargetSrid.setCrs(srcCrs)

        return True

    def populateSchemas(self):
        if not self.db:
            return

        self.cboSchema.clear()
        schemas = self.db.schemas()
        if schemas is None:
            self.hideSchemas()
            return

        index = -1
        for schema in schemas:
            self.cboSchema.addItem(schema.name)
            if schema.name == self.outUri.schema():
                index = self.cboSchema.count() - 1
        self.cboSchema.setCurrentIndex(index)

    def hideSchemas(self):
        self.cboSchema.setEnabled(False)

    def populateTables(self):
        if not self.db:
            return

        currentText = self.cboTable.currentText()

        schemas = self.db.schemas()
        if schemas is not None:
            schema_name = self.cboSchema.currentText()
            matching_schemas = [x for x in schemas if x.name == schema_name]
            tables = matching_schemas[0].tables() if len(matching_schemas) > 0 else []
        else:
            tables = self.db.tables()

        self.cboTable.clear()
        for table in tables:
            self.cboTable.addItem(table.name)

        self.cboTable.setEditText(currentText)

    def populateEncodings(self):
        # populate the combo with supported encodings
        self.cboEncoding.addItems(QgsVectorDataProvider.availableEncodings())

        self.cboEncoding.insertItem(0, self.tr("Automatic"), "")
        self.cboEncoding.setCurrentIndex(0)

    def accept(self):
        if self.mode == self.ASK_FOR_INPUT_MODE:
            # create the input layer (if not already done) and
            # update available options
            self.reloadInputLayer()

        # sanity checks
        if self.inLayer is None:
            QMessageBox.critical(
                self,
                self.tr("Import to Database"),
                self.tr("Input layer missing or not valid."),
            )
            return

        if self.cboTable.currentText() == "":
            QMessageBox.critical(
                self,
                self.tr("Import to Database"),
                self.tr("Output table name is required."),
            )
            return

        if self.chkSourceSrid.isEnabled() and self.chkSourceSrid.isChecked():
            if not self.widgetSourceSrid.crs().isValid():
                QMessageBox.critical(
                    self,
                    self.tr("Import to Database"),
                    self.tr("Invalid source srid: must be a valid crs."),
                )
                return

        if self.chkTargetSrid.isEnabled() and self.chkTargetSrid.isChecked():
            if not self.widgetTargetSrid.crs().isValid():
                QMessageBox.critical(
                    self,
                    self.tr("Import to Database"),
                    self.tr("Invalid target srid: must be a valid crs."),
                )
                return

        with OverrideCursor(Qt.CursorShape.WaitCursor):
            # store current input layer crs and encoding, so I can restore it
            prevInCrs = self.inLayer.crs()
            prevInEncoding = self.inLayer.dataProvider().encoding()

            try:
                schema = (
                    self.outUri.schema()
                    if not self.cboSchema.isEnabled()
                    else self.cboSchema.currentText()
                )
                table = self.cboTable.currentText()

                # get pk and geom field names from the source layer or use the
                # ones defined by the user
                srcUri = QgsDataSourceUri(self.inLayer.source())

                pk = (
                    srcUri.keyColumn()
                    if not self.chkPrimaryKey.isChecked()
                    else self.editPrimaryKey.text()
                )
                if not pk:
                    pk = self.default_pk

                if self.inLayer.isSpatial() and self.chkGeomColumn.isEnabled():
                    geom = (
                        srcUri.geometryColumn()
                        if not self.chkGeomColumn.isChecked()
                        else self.editGeomColumn.text()
                    )
                    if not geom:
                        geom = self.default_geom
                else:
                    geom = None

                options = {}
                if (
                    self.chkLowercaseFieldNames.isEnabled()
                    and self.chkLowercaseFieldNames.isChecked()
                ):
                    pk = pk.lower()
                    if geom:
                        geom = geom.lower()
                    options["lowercaseFieldNames"] = True

                # get output params, update output URI
                self.outUri.setDataSource(schema, table, geom, "", pk)
                typeName = self.db.dbplugin().typeName()
                providerName = self.db.dbplugin().providerName()
                if typeName == "gpkg":
                    uri = self.outUri.database()
                    options["update"] = True
                    options["driverName"] = "GPKG"
                    options["layerName"] = table
                else:
                    uri = self.outUri.uri(False)

                if self.chkDropTable.isChecked():
                    options["overwrite"] = True

                if self.chkSinglePart.isEnabled() and self.chkSinglePart.isChecked():
                    options["forceSinglePartGeometryType"] = True

                outCrs = QgsCoordinateReferenceSystem()
                if self.chkTargetSrid.isEnabled() and self.chkTargetSrid.isChecked():
                    outCrs = self.widgetTargetSrid.crs()

                # update input layer crs and encoding
                if self.chkSourceSrid.isEnabled() and self.chkSourceSrid.isChecked():
                    inCrs = self.widgetSourceSrid.crs()
                    self.inLayer.setCrs(inCrs)

                if (
                    self.chkEncoding.isEnabled()
                    and self.chkEncoding.isChecked()
                    and self.cboEncoding.currentData() is None
                ):
                    enc = self.cboEncoding.currentText()
                    self.inLayer.setProviderEncoding(enc)

                onlySelected = self.chkSelectedFeatures.isChecked()

                # do the import!
                ret, errMsg = QgsVectorLayerExporter.exportLayer(
                    self.inLayer, uri, providerName, outCrs, onlySelected, options
                )
            except Exception as e:
                ret = -1
                errMsg = str(e)

            finally:
                # restore input layer crs and encoding
                self.inLayer.setCrs(prevInCrs)
                self.inLayer.setProviderEncoding(prevInEncoding)

        if ret != 0:
            output = QgsMessageViewer()
            output.setTitle(self.tr("Import to Database"))
            output.setMessageAsPlainText(self.tr("Error {0}\n{1}").format(ret, errMsg))
            output.showMessage()
            return

        # create spatial index
        if self.chkSpatialIndex.isEnabled() and self.chkSpatialIndex.isChecked():
            self.db.connector.createSpatialIndex((schema, table), geom)

        # add comment on table
        supportCom = self.db.supportsComment()
        if self.chkCom.isEnabled() and self.chkCom.isChecked() and supportCom:
            # using connector executing COMMENT ON TABLE query (with editCome.text() value)
            com = self.editCom.toPlainText()
            self.db.connector.commentTable(schema, table, com)

        self.db.connection().reconnect()
        self.db.refresh()
        QMessageBox.information(
            self, self.tr("Import to Database"), self.tr("Import was successful.")
        )
        return QDialog.accept(self)

    def closeEvent(self, event):
        # destroy the input layer instance but only if it was created
        # from this dialog!
        self.deleteInputLayer()
        QDialog.closeEvent(self, event)