'''

@author: olivier.massot, 2018
'''
import importlib
import inspect
import logging
import pkgutil
from qgis.core import QgsProject, QgsWkbTypes, QgsGeometry, QgsPoint

from PyQt5.QtCore import QVariant, QDate, Qt
import yaml

from core.checking import BaseChecker
from core.constants import USER_DATA
from plugins import processing


logger = logging.getLogger("mncheck")


def list_schemas():
    import schemas
    return [name for _, name, ispkg in pkgutil.iter_modules(schemas.__path__) if not (ispkg or name[0] == '_')]

def get_schema(schema_name):
    return importlib.import_module("schemas." + schema_name)

def get_checkers(schema):
    return [cls for _, cls in inspect.getmembers(schema, predicate=inspect.isclass) \
            if issubclass(cls, BaseChecker) and not cls is BaseChecker]

def get_user_data():
    try:
        with open(USER_DATA, 'r') as f:
            return yaml.load(f.read()) or {}
    except FileNotFoundError:
        return {}

def dump_user_data(conf):
    with open(USER_DATA, 'w+') as f:
        return yaml.dump(conf, f)


class QgsModel():
    
    GEOM_UNKNOWN = 0
    GEOM_POINT = 1
    GEOM_LINE = 2
    GEOM_POLYGON = 3
    GEOM_MULTIPOINT = 4
    GEOM_MULTILINE = 5
    GEOM_MULTIPOLYGON = 6
    
    layername = ""
    required = True
    geom_type = 0
    bounding_box = (0,0,1,1)
    schema = {}
    pk = ""

    def __init__(self, qgs_feature):
        self._feature = qgs_feature
        
        if self.pk:
            # On affecte une valeur par defaut à la clef primaire pour éviter des erreurs en cascade au chargement des données
            setattr(self, self.pk, None)
        
        for attr, value in self.attributes().items():
            if isinstance(value, QVariant):
                value = value.value() if not value.isNull() else ""
            if isinstance(value, QDate):
                value = value.toString("dd/MM/yyyy")
            setattr(self, attr, value)
    
    def __repr__(self):
        try:
            return "{} {}".format(self.__class__.__name__, getattr(self, self.pk))
        except AttributeError:
            return f"{self.__class__.__name__} (code manquant)"
    
    @property
    def feature(self):
        return self._feature
    
    def attributes(self):
        return dict(zip([f.name() for f in self._feature.fields()], self._feature.attributes()))
    
    @property
    def geom(self):
        if not self._feature:
            return None
        return self._feature.geometry()
    
    def is_geometry_valid(self):
        return self.geom and self.geom.isGeosValid()
        
    def get_geom_type(self):
        return QgsWkbTypes.singleType(self._feature.geometry().wkbType()) if self.geom else None
    
    @classmethod
    def get_geom_name(cls, wkb):
        try:
            return QgsWkbTypes.displayString(wkb)
        except (ValueError, TypeError):
            return "<unknown>"
        
    def get_bounding_box(self):
        bb = self.geom.boundingBox()
        return (bb.xMinimum(), bb.yMinimum(), bb.xMaximum(), bb.yMaximum())
    
    def get_points(self):
        if not self.geom or self.geom.isNull():
            return []
        
        multi_geom = QgsGeometry()
        temp_geom = []
        
        if self.geom.type() == 0: # it's a point
            if self.geom.isMultipart():
                temp_geom = self.geom.asMultiPoint()
            else:
                temp_geom.append(self.geom.asPoint())
        elif self.geom.type() == 1: # it's a line
            if self.geom.isMultipart():
                multi_geom = self.geom.asMultiPolyline() #multi_geog is a multiline
                for i in multi_geom: #i is a line
                    temp_geom.extend( i )
            else:
                temp_geom = self.geom.asPolyline()
        elif self.geom.type() == 2: # it's a polygon
            if self.geom.isMultipart():
                multi_geom = self.geom.asMultiPolygon() #multi_geom is a multipolygon
                for i in multi_geom: #i is a polygon
                    for j in i: #j is a line
                        temp_geom.extend( j )
            else:
                multi_geom = self.geom.asPolygon() #multi_geom is a polygon
                for i in multi_geom: #i is a line
                    temp_geom.extend( i )
                
        return [QgsPoint(p) for p in temp_geom]

    @classmethod
    def full_buffer(cls, distance):
        layer = next((l for l in QgsProject.instance().mapLayers().values() if l.name().lower() == cls.layername.lower()))

        result = processing.run("native:buffer", {'INPUT':layer.dataProvider().dataSourceUri(),  #@UndefinedVariable
                                                 'DISTANCE':distance,
                                                 'SEGMENTS':5,
                                                 'END_CAP_STYLE':0,
                                                 'JOIN_STYLE':0,
                                                 'MITER_LIMIT':2,
                                                 'DISSOLVE':True,
                                                 'OUTPUT':'memory:mncheck_temp'})

        try:
            buffer = next((f for f in result['OUTPUT'].getFeatures()))
        except StopIteration:
            return QgsGeometry.fromPolygonXY([])
        
        if not buffer.geometry().isGeosValid():
            raise ValueError("Buffer: géométrie invalide")
        return buffer.geometry()



def validate(schema_name):
    try:
        schema = get_schema(schema_name)
    except ModuleNotFoundError:
        logger.critical(f"Le schéma {schema_name} n'existe pas")
        return
    
    results = schema.checker.run()
    
    return results