from django.core import urlresolvers

from django.contrib.sitemaps import Sitemap

from django.contrib.gis.db.models.fields import GeometryField

from django.db import models

class KMLSitemap(Sitemap):

    """

    A minimal hook to produce KML sitemaps.

    """

    geo_format = 'kml'

    def __init__(self, locations=None):

        # If no locations specified, then we try to build for

        # every model in installed applications.

        self.locations = self._build_kml_sources(locations)

    def _build_kml_sources(self, sources):

        """

        Goes through the given sources and returns a 3-tuple of

        the application label, module name, and field name of every

        GeometryField encountered in the sources.

        If no sources are provided, then all models.

        """

        kml_sources = []

        if sources is None:

            sources = models.get_models()

        for source in sources:

            if isinstance(source, models.base.ModelBase):

                for field in source._meta.fields:

                    if isinstance(field, GeometryField):

                        kml_sources.append((source._meta.app_label,

                                            source._meta.module_name,

                                            field.name))

            elif isinstance(source, (list, tuple)):

                if len(source) != 3: 

                    raise ValueError('Must specify a 3-tuple of (app_label, module_name, field_name).')

                kml_sources.append(source)

            else:

                raise TypeError('KML Sources must be a model or a 3-tuple.')

        return kml_sources

    def get_urls(self, page=1):

        """

        This method is overrridden so the appropriate `geo_format` attribute

        is placed on each URL element.

        """

        urls = Sitemap.get_urls(self, page=page)

        for url in urls: url['geo_format'] = self.geo_format

        return urls

    def items(self):

        return self.locations

    def location(self, obj):

        return urlresolvers.reverse('django.contrib.gis.sitemaps.views.%s' % self.geo_format,

                                    kwargs={'label' : obj[0], 

                                            'model' : obj[1],

                                            'field_name': obj[2],

                                            }

                                    )

class KMZSitemap(KMLSitemap):

    geo_format = 'kmz'