from django.conf import settings
from django.contrib.auth.models import User, Group
from django.db import models
from django.db import transaction
from django.utils.translation import ugettext_lazy as _
from guardian.shortcuts import assign, remove_perm, get_perms
from ldt.core.models import Document
from ldt.security import (get_current_user_or_admin, set_current_user, 
    get_current_user)
from ldt.security.manager import SafeManager
from ldt.security.models import SafeModel
from sorl.thumbnail import ImageField
from tagging.models import Tag
from utils import (create_ldt, copy_ldt, create_empty_iri, update_iri, 
    generate_uuid)
from ldt.utils import generate_hash 
import datetime
import lxml.etree
import mimetypes
import os.path
import re
import tagging.fields
import uuid
import logging
from shutil import rmtree, move
from django.core.files.storage import default_storage
#from ldt.core.models import Document, Owner


class Author(SafeModel):

    handle = models.CharField(max_length=255, unique=True, blank=True, null=True)
    email = models.EmailField(unique=False, blank=True, null=True)
    firstname = models.CharField(max_length=512, blank=True, null=True)
    lastname = models.CharField(max_length=512, blank=True, null=True)
    
    def __unicode__(self):
        return unicode(self.id) + " - " + self.handle + ", " + self.email + ", " + self.firstname + " " + self.lastname

    class Meta:
        permissions = (
                       ('view_author', 'Can view author'),
                       )

class Media(SafeModel):
    external_id = models.CharField(max_length=1024, null=True, blank=True, verbose_name=_('media.external_id'))
    external_permalink = models.URLField(max_length=1024, verify_exists=False, null=True, blank=True, verbose_name=_('media.external_permalink'))
    external_publication_url = models.URLField(max_length=1024, verify_exists=True, null=True, blank=True, verbose_name=_('media.external_publication_url'))
    external_src_url = models.CharField(max_length=1024, null=True, blank=True, verbose_name=_('media.external_src_url'))
    creation_date = models.DateTimeField(auto_now_add=True, verbose_name=_('media.creation_date'))
    media_creation_date = models.DateTimeField(null=True, blank=True, verbose_name=_('media.media_creation_date'))
    update_date = models.DateTimeField(auto_now=True, verbose_name=_('media.update_date'))
    videopath = models.CharField(max_length=1024, null=True, blank=True, verbose_name=_('media.videopath'))
    duration = models.IntegerField(null=True, blank=True, verbose_name=_('media.duration'))
    creator = models.ForeignKey(User, blank=True, null=True, verbose_name=_('media.creator'))
    description = models.TextField(null=True, blank=True, verbose_name=_('description'))
    title = models.CharField(max_length=1024, null=True, blank=True, verbose_name=_('title'))
    src = models.CharField(max_length=1024, verbose_name=_('media.src'))
    #TODO: use a fixed length char field
    src_hash = models.CharField(max_length=128, unique=True, verbose_name=_('media.src_hash'), blank=True)
    mimetype_field = models.CharField(max_length=512, null=True, blank=True, verbose_name=_('media.mimetype'))
    
    class Meta:
        permissions = (
                       ('view_media', 'Can view media'),
                       )
        
    def mimetype(): #@NoSelf
        def fget(self):
            if self.mimetype_field :
                return self.mimetype_field
            elif self.src:
                return mimetypes.guess_type(self.src.rstrip())[0]
            else:
                return None
        
        def fset(self, value):
            self.mimetype_field = value
        
        return locals()
    mimetype = property(**mimetype())
    
    def stream_src(): #@NoSelf
        
        def fget(self):
            res_src = self.src.rstrip()
            if self.videopath and self.videopath.startswith("rtmp://") and "mp3:" not in res_src and "mp4:" not in res_src:
                extension = res_src.split(".")[-1]
                res_src = {
                    'flv': lambda s: s,
                    'mp3': lambda s: "%s:%s" % ("mp3", res_src[:-4]),
                    'mp4': lambda s: "%s:%s" % ("mp4", res_src),
                    'f4v': lambda s: "%s:%s" % ("mp4", res_src),
                    'mov': lambda s: "%s:%s" % ("mp4", res_src),
                }.get(extension, lambda s:s)(res_src)
            return res_src
        
        return locals()
    
    stream_src = property(**stream_src())
    
    def is_public(): #@NoSelf
        
        def fget(self):
            if self.pk:
                everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
                if 'view_media' in get_perms(everyone, self):
                    return True
            return False
        
        def fset(self, value):
            if self.pk:
                everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
                if value:
                    assign('ldt_utils.view_media', everyone, self.media_obj)               
                else:
                    remove_perm('ldt_utils.view_media', everyone, self.media_obj)
        
        return locals()
    
    is_public = property(**is_public())
    
    def save(self, *args, **kwargs):
        self.src_hash = generate_hash(self.src)
        super(Media, self).save(*args, **kwargs)
        for content in self.content_set.all():
            content.sync_iri_file()
    
    def __unicode__(self):
        strings = []
        if self.title:
            strings.append(unicode(self.title))
        else:
            strings.append(unicode(self.src))
        if self.external_id:
            strings.append(unicode(self.external_id))
        return "|".join(strings)


class ContentManager(SafeManager):
    
    def __init__(self):
        super(ContentManager, self).__init__(check_perm=False)
        
    def get_by_natural_key(self, iri_id):
        return self.get(iri_id=iri_id)

class Content(SafeModel):
    objects = ContentManager()
    
    iri_id = models.CharField(max_length=255, unique=True, default=generate_uuid, verbose_name=_('content.iri_id'))
    iriurl = models.CharField(max_length=1024, verbose_name=_('content.iriurl'))
    creation_date = models.DateTimeField(auto_now_add=True, verbose_name=_('content.creation_date'))
    update_date = models.DateTimeField(auto_now=True, verbose_name=_('content.update_date'))
    title = models.CharField(max_length=1024, null=True, blank=True, verbose_name=_('content.title'))
    description = models.TextField(null=True, blank=True, verbose_name=_('content.description'))
    authors = models.ManyToManyField(Author, blank=True, verbose_name=_('content.authors'))
    duration = models.IntegerField(null=True, blank=True, verbose_name=_('content.duration'))
    content_creation_date = models.DateTimeField(null=True, blank=True, verbose_name=_('content.content_creation_date'))
    tags = tagging.fields.TagField(max_length=2048, null=True, blank=True)
    media_obj = models.ForeignKey('Media', blank=True, null=True)
    image = ImageField(upload_to="thumbnails/contents/", default=settings.DEFAULT_CONTENT_ICON, max_length=200)
    front_project = models.ForeignKey('Project', null=True, blank=True)
        
    class Meta:
        ordering = ["title"]
        permissions = (
                       ('view_content', 'Can view content'),
                       )
        
    def __init__(self, *args, **kwargs):
        
        super(Content, self).__init__(*args, **kwargs)
        
        if not hasattr(Content, 'pol_positive'):
            self.__add_polemic_attributes()
        
    def delete(self):
        super(Content, self).delete()
        iri_file_path = self.iri_file_path()
        thumbnail = os.path.join(settings.MEDIA_ROOT, unicode(self.image))
        if os.path.exists(iri_file_path):
            dir = os.path.dirname(iri_file_path)
            temp = os.path.join(os.path.join(os.path.dirname(dir), "temp"), self.iri_id)             
            try:
                move(dir, temp)
            except Exception, e:
                raise e
        if os.path.exists(thumbnail):
            if os.path.basename(thumbnail) != os.path.basename(settings.DEFAULT_CONTENT_ICON):
                temp_thumbnail = os.path.join(os.path.dirname(thumbnail), "temp")
                try:    
                    if not os.path.exists(temp_thumbnail):
                        os.makedirs(temp_thumbnail)
                    move(thumbnail, os.path.join(temp_thumbnail, os.path.basename(thumbnail)))            
                except Exception, e:
                    raise e

    #del .iri, and .png from temp directory
    def commit(self):
        iri_file_path=self.iri_file_path()
        dir = os.path.dirname(iri_file_path)
        temp = os.path.join(os.path.join(os.path.dirname(dir), "temp"), self.iri_id)
        thumbnail = os.path.join(settings.MEDIA_ROOT, unicode(self.image))
        temp_thumbnail = os.path.join(os.path.dirname(thumbnail), "temp")
        if os.path.exists(temp):
            default_storage.delete(os.path.join(temp, os.path.basename(self.iriurl)))
            os.rmdir(temp)
        if os.path.exists(temp_thumbnail):
            default_storage.delete(os.path.join(temp_thumbnail, os.path.basename(thumbnail)))
            os.rmdir(temp_thumbnail)
        
    #move .iri, and .png to there original directory
    def rollback(self):
        iri_file_path=self.iri_file_path()
        dir = os.path.dirname(iri_file_path)
        temp = os.path.join(os.path.join(os.path.dirname(dir), "temp"), self.iri_id)
        thumbnail = os.path.join(settings.MEDIA_ROOT, unicode(self.image))
        temp_thumbnail = os.path.join(os.path.dirname(thumbnail), "temp")
        if os.path.exists(temp):
            move(temp, dir)
            os.rmdir(os.path.dirname(temp))
        if os.path.exists(temp_thumbnail):
            move(os.path.join(temp_thumbnail, os.path.basename(thumbnail)), os.path.dirname(thumbnail))
            os.rmdir(temp_thumbnail)
    
    def natural_key(self):
        return self.iri_id
        
    # added for import
    def get_by_natural_key(self, iri_id):
        return self.get(iri_id=iri_id)

    def get_duration(self):
        if self.duration is None:
            doc = lxml.etree.parse(self.iri_file_path())
            res = doc.xpath("/iri/body/medias/media[@id='video']/video")
            if len(res) > 0:
                try:
                    self.duration = int(res[0].get(u'dur', 0) or 0)
                except:
                    self.duration = 0
            else:
                self.duration = 0
            self.save()
        return self.duration    
    
    
    def mimetype(): #@NoSelf
        def fget(self):
            if self.media_obj:
                return self.media_obj.mimetype
            else:
                return None
        return locals()
    
    mimetype = property(**mimetype())
            
    def sync_iri_file(self):
        # create iri file if needed
        created = False
        try:
            iri_file_path = self.iri_file_path()
            if not os.path.exists(iri_file_path):
                dir = os.path.dirname(iri_file_path)
                if not os.path.exists(dir):
                    os.makedirs(dir)
                created = True
                file = open(iri_file_path, "w")
                create_empty_iri(file, self, "IRI")
            else:
                created = False
                update_iri(iri_file_path, self, "IRI")
                
        except Exception, e:
            if created:
                if os.path.exists(iri_file_path):
                    os.remove(iri_file_path)
            raise e
        
        
    #TODO: better manage the change in .iri name and error scenario (save in temp file + rename
    def save(self, *args, **kwargs):
        
        create_front_project = False
        
        if not self.pk:
            create_front_project = True
              

        super(Content, self).save(*args, **kwargs)
        
        if create_front_project: 
            # We need a primary key for self in create_project, so
            # save() has to be called first
            self.create_front_project()
            assign('ldt_utils.change_content', get_current_user(), self)
            
        # update it
        # To put after project creation, to assume transaction
        self.sync_iri_file()

            
    def __unicode__(self):
        return str(self.id) + ": " + self.iri_id
        
    def iri_url(self, web_url=settings.WEB_URL):
        if 'http' in self.iriurl or 'https' in self.iriurl:
            return self.iriurl
        else:
            return unicode(web_url) + unicode(settings.MEDIA_URL) + u"ldt/" + unicode(self.iriurl)
    
    def iri_file_path(self):
        return os.path.join(os.path.join(os.path.join(settings.MEDIA_ROOT, "ldt"), self.iri_id), os.path.basename(self.iriurl))

    def iri_url_template(self):
        return "${web_url}${media_url}ldt/" + unicode(self.iri_id) + "/" + os.path.basename(self.iriurl)


    def __get_empty_media(self):
        if settings.EMPTY_MEDIA_EXTERNALID:
            empty_media = Media.objects.get(external_id=settings.EMPTY_MEDIA_EXTERNALID)
            return empty_media
        else:
            return None
            
    
    def stream_src(): #@NoSelf
        
        def fget(self):
            if self.media_obj is not None:
                return self.media_obj.stream_src
            else:
                empty_media = self.__get_empty_media()
                if empty_media:
                    return empty_media.stream_src
                else:
                    return ""
        
        return locals()
    
    stream_src = property(**stream_src())
    
    def videopath(): #@NoSelf
        doc = """simulate videopath""" #@UnusedVariable
       
        def fget(self):
            if self.media_obj is None:
                empty_media = self.__get_empty_media()
                if empty_media:
                    return empty_media.videopath
                else:
                    return None
            else:
                return self.media_obj.videopath
           
        def fset(self, value):
            if self.media_obj is not None:
                self.media_obj.videopath = value
                      
        return locals()
       
    videopath = property(**videopath())

    def src(): #@NoSelf
        doc = """simulate videopath""" #@UnusedVariable
       
        def fget(self):
            if self.media_obj is None:
                empty_media = self.__get_empty_media()
                if empty_media:
                    return empty_media.src
                else:
                    return None
            else:
                return self.media_obj.src
           
        def fset(self, value):
            if self.media_obj is None or self.media_obj.src != value:
                media, created = Media.objects.get_or_create(src=value, defaults={'src':value})                #@UnusedVariable
                self.media_obj = media
                self.save()
                      
        return locals()
       
    src = property(**src())

    def external_id(): #@NoSelf
        doc = """simulate externalid""" #@UnusedVariable
       
        def fget(self):
            if self.media_obj is None:
                empty_media = self.__get_empty_media()
                if empty_media:
                    return empty_media.external_id
                else: 
                    return None
            else:
                return self.media_obj.external_id
           
        def fset(self, value):
            if self.media_obj is not None:
                self.media_obj.external_id = value
                      
        return locals()
       
    external_id = property(**external_id())
    
    def is_public(): #@NoSelf
        
        def fget(self):
            if self.pk:
                everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
                if 'view_content' in get_perms(everyone, self):
                    return True
            return False
        
        def fset(self, value):
            if self.pk:
                everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
                if value:
                    assign('ldt_utils.view_content', everyone, self)              
                else:
                    remove_perm('ldt_utils.view_content', everyone, self)
        
        return locals()
    
    is_public = property(**is_public())
    
    def create_front_project(self):
        old_user = get_current_user_or_admin()
            
        if old_user.is_superuser:
            admin = old_user
        else:
            admin = User.objects.filter(is_superuser=True)[0]
            
        set_current_user(admin)
        self.front_project = Project.create_project(admin, 'front project : %s' % self.title, [self], cuttings=['chapitrage', 'contributions'] )
        self.front_project.publish(allow_write=True)            
        self.save()
        set_current_user(old_user)
    
    
    def get_or_create_front_project(self):
        front_proj = self.front_project
        if front_proj:
            proj = front_proj
        else:
            # The main project for the content
            proj = Project.safe_objects.filter(contents__in=[self], state=2)
            if not proj:
                self.create_front_project()
                proj = self.front_project
            else:
                proj = proj[0]
        return proj

    
    # Tag management
    def get_tags(self):
        return Tag.objects.get_for_object(self)
    
    
    # add polemic attributes and polemic attribute rates to class Content
    def __add_polemic_attributes(self):
        for element in POL_INDICES.keys():
            if element.startswith('pol_'):                    
                Content.add_to_class(element, property(self.__make_getter(element)))
                Content.add_to_class("%s_rate" % element, property(self.__make_rate(element)))  

    def __make_getter(self, i):
        def inner_getter(self):
            if self.stat_annotation is None:
                return 0;
            else:                
                l = self.stat_annotation.polemics_volume
                return l[POL_INDICES[i]]
        return inner_getter
        
    def __make_rate(self, i):
        def inner_rate(self):
            if self.stat_annotation is None or self.stat_annotation.nb_annotations <= 0:
                return 0
            return int(getattr(self, i) / float(self.stat_annotation.nb_annotations) * 100 )
        return inner_rate   
    
                    
    def annotation_volume(): #@NoSelf        
        def fget(self):
            if self.stat_annotation is None:
                return [0]*settings.DIVISIONS_FOR_STAT_ANNOTATION
            else:
                return self.stat_annotation.annotation_volume
                    
        return locals()
    
    annotation_volume = property(**annotation_volume())
    
    
    def nb_annotations(): #@NoSelf
        def fget(self):
            if self.stat_annotation is None:
                return 0
            else:
                return self.stat_annotation.nb_annotations
            
        return locals()
    
    nb_annotations = property(**nb_annotations())

POL_INDICES = {
    'pol_positive' : 0,
    'pol_negative' : 1,
    'pol_reference' : 2,
    'pol_question' : 3,               
}    


class ContentStat(models.Model):
    
    def __init__(self, *args, **kwargs):                
        super(ContentStat, self).__init__(*args, **kwargs)
        if self.annotation_volume_str is None and self.polemics_volume_str is None:
            self.__init_empty_stat()
    
    content = models.OneToOneField(Content, blank=False, null=False, related_name='stat_annotation', verbose_name=_("content_stat.content"), unique=True, db_index=True)
    annotation_volume_str = models.CommaSeparatedIntegerField(max_length=1024, null=True, blank=True, verbose_name=_("content_stat.annotations_volume"))
    polemics_volume_str = models.CommaSeparatedIntegerField(max_length=1024, null=True, blank=True, verbose_name=_("content_stat.polemics_volume"))
    nb_annotations = models.IntegerField(null=False, blank=False, verbose_name=_('content.nb_annotation'), default=0, db_index=True)
    last_annotated = models.DateTimeField(default=datetime.datetime.now, verbose_name=_('content.last_annotated'), blank=True, null=True) #@UndefinedVariable
    
    def __init_empty_stat(self):
        self.annotation_volume_str = ','.join(['0']*settings.DIVISIONS_FOR_STAT_ANNOTATION)
        self.polemics_volume_str = ','.join(['0']*len(settings.SYNTAX.keys()))
        self.nb_annotations = 0
        self.last_annotated = None
        
    def __list2str(self, l):
        return ','.join([str(c) for c in l])
        
    def __str2list(self, s):
        return [int(x) for x in s.split(',')] 

    def annotation_volume(): #@NoSelf
        
        def fget(self):
            return self.__str2list(self.annotation_volume_str)

        def fset(self, value):
            self.annotation_volume_str = self.__list2str(value)
            
        return locals()
    
    annotation_volume = property(**annotation_volume())
    
    def polemics_volume(): #@NoSelf
        
        def fget(self):
            return self.__str2list(self.polemics_volume_str)

        def fset(self, value):
            self.polemics_volume_str = self.__list2str(value)
            
        return locals()
    
    polemics_volume = property(**polemics_volume())


    
    
class Project(Document, SafeModel):  
    STATE_CHOICES = (
    (1, 'edition'),
    (2, 'published'),
    (3, 'moderated'),
    (4, 'rejected'),
    (5, 'deleted')
    )
    ldt_id = models.CharField(max_length=255, unique=True)
    ldt = models.TextField(null=True)
    title = models.CharField(max_length=1024)
    contents = models.ManyToManyField(Content)
    creation_date = models.DateTimeField(auto_now_add=True)
    modification_date = models.DateTimeField(auto_now=True)
    created_by = models.CharField(_("created by"), max_length=70)
    changed_by = models.CharField(_("changed by"), max_length=70)
    state = models.IntegerField(choices=STATE_CHOICES, default=1)
    description = models.TextField(null=True, blank=True)    
    image = ImageField(upload_to="thumbnails/projects/", default=settings.DEFAULT_PROJECT_ICON, max_length=200)
    
    class Meta:
        ordering = ["title"]
        permissions = (
                       ('view_project', 'Can view project'),
                       )

    def __setattr__(self, name, value):
        super(Project, self).__setattr__(name,value)
        if name == "ldt" and hasattr(self, "__ldt_encoded"):
            del self.__ldt_encoded
        

    def __unicode__(self):
        return unicode(self.id) + u"::" + unicode(self.ldt_id) + u"::" + unicode(self.title)
    
    def get_description(self, doc=None):
        
        if doc is None:
            doc = lxml.etree.fromstring(self.ldt)
        
        res = doc.xpath("/iri/project")
        if len(res) > 0:
            return res[0].get(u'abstract')
        else:
            return None
        
    def stream_mode(): #@NoSelf
        def fget(self):
            modes = []
            for content in self.contents.all():
                mimetype = content.mimetype
                if mimetype:
                    mode = mimetype.split("/")[0]
                    if "audio" == mode or "video" == mode:
                        modes.append(mode)
                    else:
                        modes.append("video")
                else:
                    modes.append("video")
            def filter_video(current, item):
                if not current:
                    return item
                elif current == item:
                    return item
                else:
                    return "video"
            return reduce(filter_video, modes)
        return locals()
    
    stream_mode = property(**stream_mode())

    @staticmethod
    def create_project(user, title, contents, description='', groups=[], set_icon=True, cuttings=[]):
#        owner = Owner.objects.get(user=user) #@UndefinedVariable
        owner = user
        project = Project(title=title, owner=owner, description=description)
        project.ldt_id = str(uuid.uuid1()) #@UndefinedVariable
        project.created_by = user.username
        project.changed_by = user.username
        project.state = 1                        
        project.save()
        assign('view_project', user, project)
        assign('change_project', user, project)           
                        
        for content in contents:
            project.contents.add(content)        
        
        if set_icon:
            project.set_icon()
        project.save()
               
        return create_ldt(project, user, cuttings)


    def copy_project(self, user, title, description='', group=None):
        project = Project(title=title, owner=user, description=description)
        project = copy_ldt(self, project, user)
        assign('view_project', user, project)
        assign('change_project', user, project)
        if group:
            assign('view_project', group, project)
        for content in self.contents.all():
            project.contents.add(content)
        return project
    
    def publish(self, allow_write=False):
        if not self.pk:
            self.save()
        self.state = 2
        everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
        assign('ldt_utils.view_project', everyone, self)
        if allow_write:
            assign('ldt_utils.change_project', everyone, self)
        self.save()
        
    def unpublish(self):
        if not self.pk:
            self.save()
        self.state = 1
        everyone = Group.objects.get(name=settings.PUBLIC_GROUP_NAME)
        remove_perm('ldt_utils.view_project', everyone, self)
        remove_perm('ldt_utils.change_project', everyone, self)
        self.save()
        
        
    def set_icon(self):
        default_image = os.path.basename(settings.DEFAULT_CONTENT_ICON)

        for content in self.contents.all():
            add_image = False
            try:
                current_image = content.image.file.name
            except IOError:
                add_image = True
            
            if add_image or current_image != default_image:
                self.image = content.image
                return True
            
        self.image = settings.DEFAULT_PROJECT_ICON
        return False
    
    def check_access(self, user):
        if (user and user.is_staff) or self.state == 2: 
            return True
        else:
            return False
        
    def has_annotations(self):
        nb_annot = 0
        doc = lxml.etree.fromstring(self.ldt)
        res = doc.xpath("/iri/annotations/content/ensemble/decoupage")
        for r in res:
            nb_annot = nb_annot + r.find('elements').__len__()
        if nb_annot == 0:
            return False
        else:
            return True
        
    def ldt_encoded(): #@NoSelf
        
        def fget(self):
            if self.ldt is None:
                return None
            if not hasattr(self, "__ldt_encoded"):
                m = re.match("<\?xml.*?encoding\s*?=\s*?['\"]([A-Za-z][A-Za-z0-9._-]*)['\"].*?\?>", self.ldt.lstrip(), re.I|re.M|re.U)
                if m and m.group(1):
                    encoding = m.group(1)
                else:
                    encoding = 'utf-8'
                self.__ldt_encoded = self.ldt.encode(encoding)
            return self.__ldt_encoded
            
        return locals()
    
    ldt_encoded = property(**ldt_encoded())
                
    
    
class Segment(SafeModel):
    
    project_obj = models.ForeignKey(Project, null=True)
    content = models.ForeignKey(Content)
    project_id = models.CharField(max_length=255, unique=False, blank=True, null=True, db_index=True)
    iri_id = models.CharField(max_length=255, unique=False, db_index=True)
    ensemble_id = models.CharField(max_length=512, unique=False, db_index=True)
    cutting_id = models.CharField(max_length=512, unique=False, db_index=True)    
    element_id = models.CharField(max_length=512, unique=False, db_index=True)
    tags = tagging.fields.TagField(max_length=2048, null=True, blank=True, unique=False)
    title = models.CharField(max_length=2048, unique=False, null=True, blank=True)
    duration = models.IntegerField(null=True)
    start_ts = models.IntegerField(null=True)
    author = models.CharField(max_length=1024, unique=False, null=True, blank=True)
    date = models.CharField(max_length=128, unique=False, null=True, blank=True)
    abstract = models.TextField(null=True, blank=True)
    polemics = models.IntegerField(null=True, blank=True, default=0)
    id_hash = models.CharField(max_length=128, unique=True, blank=True)
    audio_src = models.CharField(max_length=255, unique=False, null=True, blank=True)
    audio_href = models.CharField(max_length=512, unique=False, null=True, blank=True)
    
    
    # All combinations of polemic hashtags can be represented by a combination of 
    # 4 bits, 1 if the hashtag is in the tweet, 0 else. We use the order OK, KO, Q, REF
    # and convert the resulting string into an integer to store the polemic values.
    # mask contains all possible polemic values
    mask = {
            'OK': set([8,9,10,11,12,13,14,15]),
            'KO': set([4,5,6,7,12,13,14,15]),
            'Q': set([2,3,6,7,10,11,14,15]),
            'REF': set([1,3,5,7,9,11,13,15]),
            }
    
    def is_polemic(self, polemic_keyword): # OK, KO, Q, REF 
        if self.polemics in self.mask[polemic_keyword]:
            return True
        return False
    
    def get_polemic(self, polemic_keywords):
        value = set(range(16))
        
        for keyword in self.mask.keys():
            if keyword in polemic_keywords:
                value = value.intersection(self.mask[keyword])
            else:
                value.difference_update(self.mask[keyword])
            
        return value.pop()
    
    def save(self, *args, **kwargs):
        self.id_hash = generate_hash(self.__unicode__())
        super(Segment, self).save(*args, **kwargs)

    
    def __unicode__(self):
        return "/".join((unicode(self.project_id), unicode(self.iri_id), unicode(self.ensemble_id), unicode(self.cutting_id), unicode(self.element_id)))
    
    class Meta:
        permissions = (
                       ('view_segment', 'Can view segment'),
                       )
