from System.Windows import Application
from System.Windows.Controls import UserControl
from System.Windows.Browser import HtmlPage
from System import EventHandler
from System.ComponentModel import BackgroundWorker, DoWorkEventHandler


class App:
    
    def __init__(self):

        # HTML DOM elements
        self.input = HtmlPage.Document.GetElementById("input")
        self.source = HtmlPage.Document.GetElementById("output")
        self.language = HtmlPage.Document.GetElementById("lang")
        self.message = HtmlPage.Document.GetElementById("load_message")
        self.message_element = HtmlPage.Document.GetElementById("loading")
        
        # start initial pygmentize    
        self.start_pygmentize()
        
        # register events
        self.input.AttachEvent('onkeyup', EventHandler( self.update_handler )) 
        self.language.AttachEvent('onchange', EventHandler( self.update_handler ))

    
    def show_message(self, message):
        
        self.message.SetProperty("innerHTML",message)
        self.message_element.SetStyleAttribute("display", "block");
    
    
    def hide_message(self):

        self.message.SetProperty("innerHTML","")
        self.message_element.SetStyleAttribute("display", "none");

    
    def start_pygmentize(self):
        
        # update application state
        self.input_changed = False        
        self.pygmentizing = True
        self.show_message("pygmentizing..")
        
        # get paremters
        input = self.input.GetProperty("value")
        language = self.language.value
       
        # setup background worker
        worker = BackgroundWorker()
        worker.DoWork += DoWorkEventHandler(self.worker)
        worker.RunWorkerCompleted += self.complete
        
        # start the worker
        worker.RunWorkerAsync( (input,language) )


    def worker(self, sender, e):
        
        # do work off UI thread. 
        e.Result = self.pygmentize_text(e.Argument[0],e.Argument[1])
        

    # handle language or input changes by pygmentizing 
    def update_handler(self, sender, e):
        
        if self.pygmentizing:
        
            # worker is in progress, so note just note input had change
            self.input_changed = True
        
        else:
        
            # worker is idle, so start it
            self.start_pygmentize()
                
    def pygmentize_text(self, text, language):
        # attempt to pygmentize input with current language 
        try:

            from pygments import highlight
            from pygments.lexers import get_lexer_by_name
            from pygments.formatters import HtmlFormatter
                
            lexer = get_lexer_by_name( language, stripall=True)
            formatter = HtmlFormatter(linenos=False, cssclass="source")
            markup = highlight(text, lexer, formatter)

            return markup

        except:

            return "Error Generating Markup"    
    
    def complete(self, sender, e):

        if e.Error:

            # handle errors/exceptions in worker
            self.source.SetProperty("innerHTML",e.Error.Message)
        
        else: 
        
            # show the result
            self.source.SetProperty("innerHTML",e.Result)
        
        if self.input_changed:
 
            # input has changed, starty pygmentize again
            self.start_pygmentize()
       
        else:
            
            # no work queued
            self.pygmentizing = False
            self.hide_message()

            
# Do it!    
App()