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

"""
***************************************************************************
    PostGISExecuteAndLoadSQL.py
    ---------------------
    Date                 : May 2018
    Copyright            : (C) 2018 by Anita Graser
    Email                : anitagraser at gmx dot at
    ---------------------
    based on PostGISExecuteSQL.py by  Victor Olaya and Carterix Geomatics
***************************************************************************
*                                                                         *
*   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__ = 'Anita Graser'
__date__ = 'May 2018'
__copyright__ = '(C) 2018, Anita Graser'

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

__revision__ = '$Format:%H$'

from qgis.core import (Qgis, QgsProcessingException, QgsProcessingParameterString, QgsApplication, QgsVectorLayer, QgsProject, QgsProcessingParameterFeatureSink, QgsProcessing, QgsFeatureRequest, QgsFeature, QgsFeatureSink)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
from processing.tools import postgis


class PostGISExecuteAndLoadSQL(QgisAlgorithm):

    DATABASE = 'DATABASE'
    SQL = 'SQL'
    OUTPUT = 'OUTPUT'

    def group(self):
        return self.tr('Database')

    def groupId(self):
        return 'database'

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

    def initAlgorithm(self, config=None):
        db_param = QgsProcessingParameterString(
            self.DATABASE,
            self.tr('Database (connection name)'))
        db_param.setMetadata({
            'widget_wrapper': {
                'class': 'processing.gui.wrappers_postgis.ConnectionWidgetWrapper'}})
        self.addParameter(db_param)
        self.addParameter(QgsProcessingParameterString(self.SQL, self.tr('SQL query (must return unique id and geom field)'), multiLine=True))
        self.addParameter(QgsProcessingParameterFeatureSink(
            self.OUTPUT,
            self.tr("Output layer"),
            QgsProcessing.TypeVectorAnyGeometry))

    def name(self):
        return 'postgisexecuteandloadsql'

    def displayName(self):
        return self.tr('PostGIS execute and load SQL')

    def processAlgorithm(self, parameters, context, feedback):
        connection = self.parameterAsString(parameters, self.DATABASE, context)
        #db = postgis.GeoDB.from_name(connection)
        uri = postgis.uri_from_name(connection)
        sql = self.parameterAsString(parameters, self.SQL, context).replace('\n', ' ')
        QgsApplication.messageLog().logMessage(str(sql), level=Qgis.Info)
        uri.setDataSource("","("+sql+")", "geom", "","id")
        vlayer = QgsVectorLayer(uri.uri(), "layername", "postgres")
        QgsApplication.messageLog().logMessage("Valid layer: "+str(vlayer.isValid()), level=Qgis.Info)
        #QgsProject.instance().addMapLayer(vlayer)
        (sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
                                               vlayer.fields(), vlayer.wkbType(), vlayer.sourceCrs())
 
        features = vlayer.getFeatures(QgsFeatureRequest())
        for feat in features:
            out_feat = QgsFeature()
            out_feat.setGeometry(feat.geometry())
            out_feat.setAttributes(feat.attributes())
            sink.addFeature(out_feat, QgsFeatureSink.FastInsert)
 
        return {self.OUTPUT: dest_id}