"""
Utility classes for working with the Keyhole Markup Language (KML).
"""

import sys


class KmlObject(object):
    """
    The base class of all KML elements, according to the reference:
    
      http://code.google.com/apis/kml/documentation/kmlreference.html

    Every other class in this module should derive from
    KmlObject. This class provides a default constructor which creates
    some necessary attributes, and default implementations of to_kml()
    and render().

    The to_kml() methods of our subclasses will, in general, generate
    an opening tag, render themselves (whatever that means), and then
    generate a closing tag. A call to render() generally returns the
    element's text, and renders its children recursively.
    """
    
    def __init__(self, initial_text=''):
        self.children = []
        self.text = initial_text

        
    def to_kml(self):
        return self.render()


    def render(self):
        kml = self.text

        for c in self.children:
            kml += c.to_kml()

        return kml



class Color(KmlObject):
    
    def to_kml(self):
        kml = '<color>'
        kml += self.render()
        kml += "</color>\n"
        return kml

    
        
class Document(KmlObject):
    
    def __init__(self, initial_text=''):
        super(Document, self).__init__(initial_text)
        self.styles = []

        
    def to_kml(self):
        kml =  "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
        kml += "<kml xmlns=\"http://www.opengis.net/kml/2.2\">\n"
        kml += "<Document>\n"

        kml += self.render()

        kml += "</Document>\n"
        kml += "</kml>\n"

        return kml


    def render(self):
        kml = ''
        
        for s in self.styles:
            kml += s.to_kml()
            
        for c in self.children:
            kml += c.to_kml()

        return kml



class Description(KmlObject):
    
    def to_kml(self):
        kml = '<description>'
        kml += self.render()
        kml += "</description>\n"
        return kml
    


class Name(KmlObject):
    
    def to_kml(self):
        kml = '<name>'
        kml += self.render()
        kml += "</name>\n"
        return kml



class Placemark(KmlObject):

    def to_kml(self):
        kml = "<Placemark>\n"
        kml += self.render()
        kml += "</Placemark>\n"
        return kml



class PolyStyle(KmlObject):

    def to_kml(self):
        kml = "<PolyStyle>\n"
        kml += self.render()
        kml += "</PolyStyle>\n"
        return kml


        
class Style(KmlObject):

    def __init__(self, initial_text='', initial_id=None):
        super(Style, self).__init__(initial_text)
        self.id = initial_id

        
    def to_kml(self):
        kml = ''
        
        if (self.id == None):
            kml += "<Style>\n"
        else:
            kml += ("<Style id=\"%s\">\n" % self.id)

        kml += self.render()
        kml += "</Style>\n"
        
        return kml



class StyleUrl(KmlObject):

    def to_kml(self):
        kml = '<styleUrl>'
        kml += self.render()
        kml += "</styleUrl>\n"
        return kml


        
class RawText(KmlObject):
    pass