from PyQt5.QtCore import QVariant
from qgis._core import QgsCoordinateReferenceSystem
from qgis.core import QgsFields, QgsField

from .po_waterlevel_reader import PoWaterlevelReader


class PoWaterlevelReaderQgs(PoWaterlevelReader):

    def __init__(self):
        """
        Initialisiert die Super-Klasse und das Koordinaten-System der Features
        """
        super().__init__()
        self.fields = None
        self.crs = QgsCoordinateReferenceSystem(4326, QgsCoordinateReferenceSystem.EpsgCrsId)

    def get_features(self):
        """
        Erzeugt Features aus allen Waterlevels von super.get_waterlevels() oder None im Fehlerfall
        :return: list[QgsFeature] | None
        """
        print("PoWaterlevelReaderQgs::get_features: Erzeuge Features...")

        self.fields = QgsFields()
        self.fields.append(QgsField('shortname', QVariant.String))
        self.fields.append(QgsField('number', QVariant.LongLong))
        self.fields.append(QgsField('agency', QVariant.String))
        self.fields.append(QgsField('timestamp', QVariant.DateTime))
        self.fields.append(QgsField('value', QVariant.Double))
        self.fields.append(QgsField('unit', QVariant.String))
        self.fields.append(QgsField('mean', QVariant.String))
        self.fields.append(QgsField('absolute', QVariant.String))
        self.fields.append(QgsField('water', QVariant.String))

        features = []
        waterlevels = self.get_waterlevels()
        if waterlevels is None or len(waterlevels) == 0:
            # Kein Waterlevel erhalten → Abbruch
            print("PoWaterlevelReaderQgs::get_features: Fehler: Keine Pegelstände erhalten")
            return None

        for waterlevel in waterlevels:
            feature = waterlevel.new_feature(self.fields)
            if feature is not None:
                # Feature-Erzeugung erfolgreich, füge zu Liste hinzu
                features.append(feature)

        print("PoWaterlevelReaderQgs::get_features: %d Features erzeugt" % (len(features),))
        return features