#
#    Copyright (C) 2006, 2007, One Laptop Per Child
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

import libxml2
import os
import logging
import base64
import sha
import gobject

_logger = logging.getLogger('model')


class Model(gobject.GObject):
    #__gtype_name__ = 'Model'
    __gsignals__ = {
        'add_link': (gobject.SIGNAL_RUN_FIRST,
                        gobject.TYPE_NONE, ([int]))
        }
        
    ''' The model of the activity. Contains methods to read and write
    the configuration for a browser session to and from xml. 
    '''
    
    def __init__(self, dtdpath):
        gobject.GObject.__init__(self)    
        self.links = []
        self.data = {}
        self.dtdpath = dtdpath
        self.data['name'] = 'first'
        self.session_data = ''
        
        try:
            self.dtd = libxml2.parseDTD(None, os.path.join(self.dtdpath, 'browser.dtd'))
        except libxml2.parserError, e:
            _logger.error('Init: no browser.dtd found ' +str(e))
            self.dtd = None
        self.ctxt = libxml2.newValidCtxt()               

    def add_link(self, url, title, thumb, owner, color):
        print 'model: add link'
        self.links.append( {'hash':sha.new(url).hexdigest(), 'url':url, 'title':title, 'thumb':thumb,
                                  'owner':owner, 'color':color, 'deleted':0} )
        self.emit('add_link', len(self.links)-1)
            
    def read(self, filepath):
        ''' reads the configuration from an xml file '''
        
        try:
            doc = libxml2.parseFile(filepath)
            if doc.validateDtd(self.ctxt, self.dtd):
        
                # get the requested nodes
                xpa = doc.xpathNewContext()
                res = xpa.xpathEval("//*")

                # write their content to the data structure
                for elem in res:
                    attributes = elem.get_properties()
                    if( elem.name == 'link' ):
                        for attribute in attributes:
                            if(attribute.name == 'hash'):
                                hash = attribute.content
                            elif(attribute.name == 'url'):
                                url = attribute.content
                            elif(attribute.name == 'title'):
                                title = attribute.content                               
                            elif(attribute.name == 'thumb'):
                                thumb = base64.b64decode(attribute.content)                                
                            elif(attribute.name == 'owner'):
                                owner = attribute.content
                            elif(attribute.name == 'color'):
                                color = attribute.content
                            elif(attribute.name == 'deleted'):
                                deleted = int(attribute.content)
                                
                        self.links.append( {'hash':hash, 'url':url, 'title':title, 'thumb':thumb,
                                            'owner':owner, 'color':color, 'deleted':deleted} )
                
                    elif( elem.name == 'session' ):
                        for attribute in attributes:
                            if(attribute.name == 'data'):                            
                                self.session_data = attribute.content
                        
                    elif( elem.name == 'browser' ):
                        for attribute in attributes:
                            if(attribute.name == 'name'):                            
                                self.data['name'] = attribute.content
                                
                xpa.xpathFreeContext()
            else:
                _logger.error('Read: Error in validation of the file')
                doc.freeDoc()
                return 1
            doc.freeDoc()
            return 0
        except libxml2.parserError, e:
            _logger.error('Read: Error parsing file ' +str(e))
            return 2
        
                
    def write(self, filepath):
        ''' writes the configuration to an xml file '''
        doc = libxml2.newDoc("1.0")
        root = doc.newChild(None, "browser", None)
        
        if(self.data.get('name', None) != None):                            
            root.setProp("name", self.data['name'])
        else:
            _logger.error('Write: No name is specified. Can not write session.')
            return 1

        elem = root.newChild(None, "session", None)
        elem.setProp("data", self.session_data)

        for link in self.links:
            elem = root.newChild(None, "link", None)
            elem.setProp("hash", link['hash'])
            elem.setProp("url", link['url'])
            elem.setProp("title", link['title'])
            elem.setProp("thumb", base64.b64encode(link['thumb']))
            elem.setProp("owner", link['owner'])
            elem.setProp("color", link['color'])
            elem.setProp("deleted", str(link['deleted']))
                        
        if doc.validateDtd(self.ctxt, self.dtd):
            doc.saveFormatFile(filepath, 1)
        else:
            _logger.error('Write: Error in validation of the file')
            doc.freeDoc()
            return 2
        doc.freeDoc()
        return 0

    def get_links_ids(self):
        ids = []
        for link in self.links:
            ids.append(link['hash'])
        ids.append('')    
        return ids

    
if __name__ == '__main__':
    model = Model(os.path.dirname(__file__))

    filepath = 'sports.png'

    target = os.open(filepath, os.O_RDONLY)
    filelen = os.stat(filepath).st_size
    data = os.read(target, filelen)
    os.close(target)

    '''
    import sha
    url = 'www.sport.de'
    title = 'sports'
    hash = sha.new(url)
    model.links.append({'hash':hash.hexdigest(), 'url':url, 'title':title})

    url = 'www.jazz.de'
    title = 'more on jazz'
    hash = sha.new(url)
    model.links.append({'hash':hash.hexdigest(), 'url':url, 'title':title})

    url = 'www.taz.de'
    title = 'die zeitung'
    hash = sha.new(url)
    model.links.append({'hash':hash.hexdigest(), 'url':url, 'title':title})
                        
    model.write('/tmp/test.bwr')
    '''
    
    model.read('/tmp/test.bwr')

    model.links.remove(model.links[1])
    
    print model.links