from collections import OrderedDict

from django.db import models
from django.utils.translation import ugettext_lazy as _
from shapely.geometry import LineString, mapping

from c3nav.mapdata.fields import GeometryField
from c3nav.mapdata.models.access import AccessRestrictionMixin
from c3nav.mapdata.models.base import TitledMixin
from c3nav.mapdata.models.geometry.space import SpaceGeometryMixin
from c3nav.mapdata.utils.json import format_geojson


class GraphNode(SpaceGeometryMixin, models.Model):
    """
    A graph node
    """
    geometry = GeometryField('point')

    class Meta:
        verbose_name = _('Graph Node')
        verbose_name_plural = _('Graph Nodes')
        default_related_name = 'graphnodes'

    def get_geojson_properties(self, *args, **kwargs) -> dict:
        result = super().get_geojson_properties(*args, **kwargs)
        return result


class WayType(TitledMixin, models.Model):
    """
    A special way type
    """
    color = models.CharField(max_length=32, verbose_name=_('edge color'))

    class Meta:
        verbose_name = _('Way Type')
        verbose_name_plural = _('Way Types')
        default_related_name = 'waytypes'


class GraphEdge(AccessRestrictionMixin, models.Model):
    """
    A directed edge connecting two graph nodes
    """
    from_node = models.ForeignKey(GraphNode, on_delete=models.PROTECT, related_name='edges_from_here',
                                  verbose_name=_('from node'))
    to_node = models.ForeignKey(GraphNode, on_delete=models.PROTECT, related_name='edges_to_here',
                                verbose_name=_('to node'))
    waytype = models.ForeignKey(WayType, null=True, blank=True, on_delete=models.PROTECT, verbose_name=_('Way Type'))

    class Meta:
        verbose_name = _('Graph Edge')
        verbose_name_plural = _('Graph Edges')
        default_related_name = 'graphedges'
        unique_together = (('from_node', 'to_node'), )

    def to_geojson(self, instance=None) -> dict:
        geometry = LineString([self.from_node.geometry, self.to_node.geometry])
        result = OrderedDict((
            ('type', 'Feature'),
            ('properties', OrderedDict((
                ('id', self.pk),
                ('type', 'graphedge'),
                ('from_node', self.from_node_id),
                ('to_node', self.to_node_id),
            ))),
            ('geometry', format_geojson(mapping(geometry), round=False)),
        ))
        if self.waytype_id is not None:
            result['properties']['color'] = self.waytype.color
        return result