"""
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.
    """

    OPEN_TAG = ''
    CLOSE_TAG = ''
    
    def __init__(self, initial_text=''):
        self.children = []
        self.text = initial_text

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


    def render(self):
        kml = self.OPEN_TAG
        kml += self.text

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

        kml += self.CLOSE_TAG + "\n"
        
        return kml


    def print_kml(self):
        print self.OPEN_TAG
        self.render_to_stdout()
        print self.CLOSE_TAG

        
    def render_to_stdout(self):
        if not (len(self.text) == 0):
            print self.text
        
        for c in self.children:
            c.print_kml()



class Color(KmlObject):
    
    OPEN_TAG = '<color>'
    CLOSE_TAG = '</color>'

        
class Document(KmlObject):

    OPEN_TAG = """<?xml version=\"1.0\" encoding=\"UTF-8\"?>
<kml xmlns=\"http://www.opengis.net/kml/2.2\">
<Document>"""

    CLOSE_TAG = """</Document>
    </kml>"""
    
    def __init__(self, initial_text=''):
        super(Document, self).__init__(initial_text)
        self.styles = []

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

        return kml


    def render_to_stdout(self):
        for s in self.styles:
            s.print_kml()
            
        for c in self.children:
            c.print_kml()



class Description(KmlObject):
    
    OPEN_TAG = '<description>'
    CLOSE_TAG = '</description>'



class Name(KmlObject):
    
    OPEN_TAG = '<name>'
    CLOSE_TAG = '</name>'
    


class Placemark(KmlObject):
    
    OPEN_TAG = '<Placemark>'
    CLOSE_TAG = '</Placemark>'
    
    

class PolyStyle(KmlObject):
    
    OPEN_TAG = '<PolyStyle>'
    CLOSE_TAG = '</PolyStyle>'
    

        
class Style(KmlObject):
    
    OPEN_TAG = "<Style id=\"%s\">"
    CLOSE_TAG = '</Style>'
    
    def __init__(self, initial_text='', initial_id=''):
        super(Style, self).__init__(initial_text)
        self.id = initial_id

        
    def to_kml(self):
        kml = ''
        kml += (self.OPEN_TAG % self.id + "\n")
        kml += self.render()
        kml += self.CLOSE_TAG + "\n"
        
        return kml


    def print_kml(self):
        print (self.OPEN_TAG % self.id)
        self.render_to_stdout()
        print self.CLOSE_TAG

    

class StyleUrl(KmlObject):
    
    OPEN_TAG = '<styleUrl>'
    CLOSE_TAG = '</styleUrl>'

    
        
class RawText(KmlObject):
    pass