from django.conf import settings

from django.contrib.gis import geos

from django.template.loader import render_to_string

from django.utils.safestring import mark_safe

class GoogleMapException(Exception): pass

from django.contrib.gis.maps.google.overlays import GPolygon, GPolyline, GMarker

# The default Google Maps URL (for the API javascript)

# TODO: Internationalize for Japan, UK, etc.

GOOGLE_MAPS_URL='http://maps.google.com/maps?file=api&v=%s&key='

class GoogleMap(object):

    "A class for generating Google Maps JavaScript."

    # String constants

    onunload = mark_safe('onunload="GUnload()"') # Cleans up after Google Maps

    vml_css  = mark_safe('v\:* {behavior:url(#default#VML);}') # CSS for IE VML

    xmlns    = mark_safe('xmlns:v="urn:schemas-microsoft-com:vml"') # XML Namespace (for IE VML).

    def __init__(self, key=None, api_url=None, version=None, 

                 center=None, zoom=None, dom_id='map', load_func='gmap_load', 

                 kml_urls=[], polygons=[], polylines=[], markers=[],

                 template='gis/google/js/google-map.js',

                 extra_context={}):

        # The Google Maps API Key defined in the settings will be used

        #  if not passed in as a parameter.  The use of an API key is

        #  _required_.

        if not key:

            try:

                self.key = settings.GOOGLE_MAPS_API_KEY

            except AttributeError:

                raise GoogleMapException('Google Maps API Key not found (try adding GOOGLE_MAPS_API_KEY to your settings).')

        else:

            self.key = key

        # Getting the Google Maps API version, defaults to using the latest ("2.x"),

        #  this is not necessarily the most stable.

        if not version:

            self.version = getattr(settings, 'GOOGLE_MAPS_API_VERSION', '2.x')

        else:

            self.version = version

        # Can specify the API URL in the `api_url` keyword.

        if not api_url:

            self.api_url = mark_safe(getattr(settings, 'GOOGLE_MAPS_URL', GOOGLE_MAPS_URL) % self.version)

        else:

            self.api_url = api_url

        # Setting the DOM id of the map, the load function, the JavaScript

        # template, and the KML URLs array.

        self.dom_id = dom_id

        self.load_func = load_func

        self.template = template

        self.kml_urls = kml_urls

        # Does the user want any GMarker, GPolygon, and/or GPolyline overlays?

        self.polygons, self.polylines, self.markers = [], [], []

        if markers:

            for point in markers:

                if isinstance(point, GMarker): 

                    self.markers.append(point)

                else:

                    self.markers.append(GMarker(point))

        if polygons:

            for poly in polygons:

                if isinstance(poly, GPolygon): 

                    self.polygons.append(poly)

                else:

                    self.polygons.append(GPolygon(poly))

        if polylines:

            for pline in polylines:

                if isinstance(pline, GPolyline):

                    self.polylines.append(pline)

                else:

                    self.polylines.append(GPolyline(pline))

        # If GMarker, GPolygons, and/or GPolylines 

        # are used the zoom will be automatically

        # calculated via the Google Maps API.  If both a zoom level and a

        # center coordinate are provided with polygons/polylines, no automatic

        # determination will occur.

        self.calc_zoom = False

        if self.polygons or self.polylines  or self.markers:

            if center is None or zoom is None:

                self.calc_zoom = True

        # Defaults for the zoom level and center coordinates if the zoom

        # is not automatically calculated.

        if zoom is None: zoom = 4

        self.zoom = zoom

        if center is None: center = (0, 0)

        self.center = center

        # Setting the parameters for the javascript template.

        params = {'calc_zoom' : self.calc_zoom,

                  'center' : self.center,

                  'dom_id' : self.dom_id,

                  'kml_urls' : self.kml_urls,

                  'load_func' : self.load_func,

                  'zoom' : self.zoom,

                  'polygons' : self.polygons,

                  'polylines' : self.polylines,

                  'markers' : self.markers,

                  }

        params.update(extra_context)

        self.js = render_to_string(self.template, params)

    @property

    def body(self):

        "Returns HTML body tag for loading and unloading Google Maps javascript."

        return mark_safe('<body %s %s>' % (self.onload, self.onunload))

    @property

    def onload(self):

        "Returns the `onload` HTML <body> attribute."

        return mark_safe('onload="%s()"' % self.load_func)

    @property

    def api_script(self):

        "Returns the <script> tag for the Google Maps API javascript."

        return mark_safe('<script src="%s%s" type="text/javascript"></script>' % (self.api_url, self.key))

    @property

    def scripts(self):

        "Returns all <script></script> tags required for Google Maps JavaScript."

        return mark_safe('%s\n  <script type="text/javascript">\n//<![CDATA[\n%s//]]>\n  </script>' % (self.api_script, self.js))

    @property

    def style(self):

        "Returns additional CSS styling needed for Google Maps on IE."

        return mark_safe('<style type="text/css">%s</style>' % self.vml_css)

    @property

    def xhtml(self):

        "Returns XHTML information needed for IE VML overlays."

        return mark_safe('<html xmlns="http://www.w3.org/1999/xhtml" %s>' % self.xmlns)