import urllib, urlparse, string, os, datetime, logging
import troggle.mptt as mptt
from django.forms import ModelForm
from django.db import models
from django.contrib import admin
from django.core.files.storage import FileSystemStorage
from django.contrib.auth.models import User
from django.contrib.contenttypes.models import ContentType
from django.conf import settings
from decimal import Decimal, getcontext
from django.core.urlresolvers import reverse
from imagekit.models import ImageModel
getcontext().prec=2 #use 2 significant figures for decimal calculations

from models_survex import *

logging.basicConfig(level=logging.DEBUG,
                           filename=settings.LOGFILE,
                           filemode='w')

#This class is for adding fields and methods which all of our models will have.
class TroggleModel(models.Model):
    new_since_parsing = models.BooleanField(default=False, editable=False)
    
    def object_name(self):
        return self._meta.object_name

    def get_admin_url(self):
        return settings.URL_ROOT + "/admin/expo/" + self.object_name().lower() + "/" + str(self.pk)

    class Meta:
	    abstract = True

class TroggleImageModel(ImageModel):
    new_since_parsing = models.BooleanField(default=False, editable=False)
    
    def object_name(self):
        return self._meta.object_name

    def get_admin_url(self):
        return settings.URL_ROOT + "/admin/expo/" + self.object_name.lower() + "/" + str(self.pk)

    class Meta:
	    abstract = True

class Expedition(TroggleModel):
    year        = models.CharField(max_length=20, unique=True)
    name        = models.CharField(max_length=100)
    date_from  = models.DateField(blank=True,null=True)
    date_to    = models.DateField(blank=True,null=True)
    
    def __unicode__(self):
        return self.year

    class Meta:
        ordering = ('-year',)
        get_latest_by = 'date_from'
    
    def get_absolute_url(self):
        #return settings.URL_ROOT + "/expedition/%s" % self.year
        return urlparse.urljoin(settings.URL_ROOT, reverse('expedition',args=[self.year]))
    
    
    # lose these two functions (inelegant, and we may create a file with the dates that we can load from)
    def GuessDateFrom(self):
	try:
		return self.logbookentry_set.order_by('date')[0].date
	except IndexError:
		pass

    def GuessDateTo(self):		# returns the date of the last logbook entry in the expedition
	try:
		return self.logbookentry_set.order_by('date')[-1].date
	except IndexError:
		pass

    def ListDays(self):
	if self.date_from and self.date_to:
		res=[]
		date=self.date_from
		while date <= self.date_to:
			res.append(date)
			date+=datetime.timedelta(days=1)
		return res
	elif self.GuessDateFrom() and self.GuessDateTo(): 	# if we don't have the real dates, try it with the dates taken from the earliest and latest logbook entries
		date=self.GuessDateFrom()
		while date <= self.GuessDateTo():
			res.append(date)
			date+=datetime.timedelta(days=1)
		return res

    


class Person(TroggleModel):
    first_name  = models.CharField(max_length=100)
    last_name   = models.CharField(max_length=100)
    is_vfho     = models.BooleanField(help_text="VFHO is the Vereines f&uuml;r H&ouml;hlenkunde in Obersteier, a nearby Austrian caving club.")    
    mug_shot    = models.CharField(max_length=100, blank=True,null=True)
    blurb = models.TextField(blank=True,null=True)
    
    #href        = models.CharField(max_length=200)
    orderref    = models.CharField(max_length=200)  # for alphabetic 
    
    #the below have been removed and made methods. I'm not sure what the b in bisnotable stands for. - AC 16 Feb
    #notability  = models.FloatField()               # for listing the top 20 people
    #bisnotable  = models.BooleanField()
    user	= models.OneToOneField(User, null=True, blank=True)
    def get_absolute_url(self):
        return urlparse.urljoin(settings.URL_ROOT,reverse('person',kwargs={'first_name':self.first_name,'last_name':self.last_name}))

    class Meta:
	    verbose_name_plural = "People"
    class Meta:
        ordering = ('orderref',)  # "Wookey" makes too complex for: ('last_name', 'first_name') 
    
    def __unicode__(self):
        if self.last_name:
            return "%s %s" % (self.first_name, self.last_name)
        return self.first_name

# Below are no longer needed. Use {{ person.personexpedition_set.all.0.expedition }} for Firstexpedition, and {{ person.personexpedition_set.latest.expedition }} for Lastexpedition
    # these ought to be possible by piping through |min in the template, or getting the first of an ordered list
#    def Firstexpedition(self):
#        return self.personexpedition_set.order_by('expedition')[0]
#    def Lastexpedition(self):
#        return self.personexpedition_set.order_by('-expedition')[0]
    
    def notability(self):
        notability = Decimal(0)
        for personexpedition in self.personexpedition_set.all():
             if not personexpedition.is_guest:
                notability += Decimal(1) / (2012 - int(personexpedition.expedition.year))
        return notability

    def bisnotable(self):
        return self.notability() > Decimal(1)/Decimal(3)
    
    #def Sethref(self):
        #if self.last_name:
            #self.href = self.first_name.lower() + "_" + self.last_name.lower()
            #self.orderref = self.last_name + " " + self.first_name
        #else:
          #  self.href = self.first_name.lower()
            #self.orderref = self.first_name
        #self.notability = 0.0  # set temporarily
        

class PersonExpedition(TroggleModel):
    expedition  = models.ForeignKey(Expedition)
    person      = models.ForeignKey(Person)
    date_from   = models.DateField(blank=True,null=True)
    date_to     = models.DateField(blank=True,null=True)
    is_guest    = models.BooleanField(default=False)  
    COMMITTEE_CHOICES = (
        ('leader','Expo leader'),
        ('medical','Expo medical officer'),
        ('treasurer','Expo treasurer'),
        ('sponsorship','Expo sponsorship coordinator'),
        ('research','Expo research coordinator'),
        )
    expo_committee_position = models.CharField(blank=True,null=True,choices=COMMITTEE_CHOICES,max_length=200)
    nickname    = models.CharField(max_length=100,blank=True,null=True)
    
    def GetPersonroles(self):
        res = [ ]
        for personrole in self.personrole_set.order_by('survex_block'):
            if res and res[-1]['survexpath'] == personrole.survex_block.survexpath:
                res[-1]['roles'] += ", " + str(personrole.role)
            else:
                res.append({'date':personrole.survex_block.date, 'survexpath':personrole.survex_block.survexpath, 'roles':str(personrole.role)})
        return res

    class Meta:
        ordering = ('expedition',)
        #order_with_respect_to = 'expedition'
	get_latest_by = 'expedition'
    
    def GetPersonChronology(self):
        res = { }
        for persontrip in self.persontrip_set.all():
            a = res.setdefault(persontrip.date, { })
            a.setdefault("persontrips", [ ]).append(persontrip)
        for personrole in self.personrole_set.all():
            a = res.setdefault(personrole.survex_block.date, { })
            b = a.setdefault("personroles", { })
            survexpath = personrole.survex_block.survexpath
            
            if b.get(survexpath):
                b[survexpath] += ", " + str(personrole.role)
            else:
                b[survexpath] = str(personrole.role)
# needs converting dict into list            
        return sorted(res.items())

    # possibly not useful functions anyway -JT
        # if you can find a better way to make the expo calendar table, be my guest. It isn't possible to do this logic in a django template without writing custom tags.-AC
    def ListDays(self):
        """
        Returns a list of the days the person was on the expedition (i.e. the days that the PersonExpedition was in existance). Needed for expedition calendar.
        """
	if self.date_from and self.date_to:
		res=[]
		date=self.date_from
		while date <= self.date_to:
			res.append(date)
			date+=datetime.timedelta(days=1)
		return res

    def ListDaysTF(self):
        """
        Returns a list of true / false values. Each value corresponds to one day on the expedition; True means the person was there, False means they weren't.
        """
	if self.date_from and self.date_to:
		res=[]
		for date in self.expedition.ListDays():
			res.append(date in self.ListDays())
		return res

    def __unicode__(self):
        return "%s: (%s)" % (self.person, self.expedition)
    
    #why is the below a function in personexpedition, rather than in person? - AC 14 Feb 09
    def name(self):
        if self.nickname:
            return "%s (%s) %s" % (self.person.first_name, self.nickname, self.person.last_name)
        if self.person.last_name:
            return "%s %s" % (self.person.first_name, self.person.last_name)
        return self.person.first_name

    def get_absolute_url(self):
        #return settings.URL_ROOT + '/personexpedition/' + str(self.person.first_name) + '_' + str(self.person.last_name) + '/' +self.expedition.year
	return urlparse.urljoin(settings.URL_ROOT, reverse('personexpedition',kwargs={'first_name':self.person.first_name,'last_name':self.person.last_name,'year':self.expedition.year}))
	
class LogbookEntry(TroggleModel):
    date    = models.DateField()
    expedition  = models.ForeignKey(Expedition,blank=True,null=True)  # yes this is double-
    author  = models.ForeignKey(PersonExpedition,blank=True,null=True)  # the person who writes it up doesn't have to have been on the trip
    title   = models.CharField(max_length=200)
    cave    = models.ForeignKey('Cave',blank=True,null=True)
    place   = models.CharField(max_length=100,blank=True,null=True,help_text="Only use this if you haven't chosen a cave")
    text    = models.TextField()
    slug    = models.SlugField(max_length=50)
    #href    = models.CharField(max_length=100)
    
    
    #logbookentry_next  = models.ForeignKey('LogbookEntry', related_name='pnext', blank=True,null=True)
    #logbookentry_prev  = models.ForeignKey('LogbookEntry', related_name='pprev', blank=True,null=True)

    class Meta:
	   verbose_name_plural = "Logbook Entries"
        # several PersonTrips point in to this object
    class Meta:
        ordering = ('-date',)

    def get_absolute_url(self):
        return urlparse.urljoin(settings.URL_ROOT, reverse('logbookentry',kwargs={'date':self.date,'slug':self.slug}))

    def __unicode__(self):
        return "%s: (%s)" % (self.date, self.title)

    def get_next_by_id(self):
        LogbookEntry.objects.get(id=self.id+1)

    def get_previous_by_id(self):
        LogbookEntry.objects.get(id=self.id-1)

class PersonTrip(TroggleModel):
    person_expedition = models.ForeignKey(PersonExpedition,null=True)
    
        # this will be a foreign key of the place(s) the trip went through
        # possibly a trip has a plurality of triplets pointing into it
    #place           = models.CharField(max_length=100)  
    #date            = models.DateField()    
    time_underground = models.FloatField(help_text="In decimal hours")
    logbook_entry    = models.ForeignKey(LogbookEntry)
    is_logbook_entry_author = models.BooleanField()
    
    def date(self):
        return self.logbook_entry.date

    def place(self):
        if self.logbook_entry.cave:
            return self.logbook_entry.cave
        else:
            return self.logbook_entry.place

    #persontrip_next  = models.ForeignKey('PersonTrip', related_name='pnext', blank=True,null=True)
    #persontrip_prev  = models.ForeignKey('PersonTrip', related_name='pprev', blank=True,null=True)

    def __unicode__(self):
        return "%s %s (%s)" % (self.person_expedition, self.place(), self.date())

    def get_persons_next_trip(self):
	try:
            return PersonTrip.objects.filter(person_expedition__person=self.person_expedition.person, person_expedition__date__gt=self.date)[0]
        except:
	    return

    def get_persons_previous_trip(self):
	try:
            return PersonTrip.objects.filter(person_expedition__person=self.person_expedition.person, person_expedition__date__lt=self.date)[0]
        except:
	    return

#    def get_persons_previous_trip(self):
#
# move following classes into models_cave
#

class Area(TroggleModel):
    short_name = models.CharField(max_length=100)
    name = models.CharField(max_length=200, blank=True, null=True)
    description = models.TextField(blank=True,null=True)
    parent = models.ForeignKey('Area', blank=True, null=True)
    def __unicode__(self):
        if self.parent:
            return unicode(self.parent) + u" - " + unicode(self.short_name)
        else:
            return unicode(self.short_name)
    def kat_area(self):
        if self.short_name in ["1623", "1626"]:
            return self.short_name
        elif self.parent:
            return self.parent.kat_area()

class CaveAndEntrance(TroggleModel):
    cave = models.ForeignKey('Cave')
    entrance = models.ForeignKey('Entrance')
    entrance_letter = models.CharField(max_length=20,blank=True,null=True)
    def __unicode__(self):
        return unicode(self.cave) + unicode(self.entrance_letter)
        
class Cave(TroggleModel):
    # too much here perhaps
    official_name = models.CharField(max_length=160)
    area = models.ManyToManyField(Area, blank=True, null=True)
    kataster_code = models.CharField(max_length=20,blank=True,null=True)
    kataster_number = models.CharField(max_length=10,blank=True, null=True)
    unofficial_number = models.CharField(max_length=60,blank=True, null=True)
    entrances = models.ManyToManyField('Entrance', through='CaveAndEntrance')
    explorers = models.TextField(blank=True,null=True)
    underground_description = models.TextField(blank=True,null=True)
    equipment = models.TextField(blank=True,null=True)
    references = models.TextField(blank=True,null=True)
    survey = models.TextField(blank=True,null=True)
    kataster_status = models.TextField(blank=True,null=True)
    underground_centre_line = models.TextField(blank=True,null=True)
    notes = models.TextField(blank=True,null=True)
    length = models.CharField(max_length=100,blank=True,null=True)
    depth = models.CharField(max_length=100,blank=True,null=True)
    extent = models.CharField(max_length=100,blank=True,null=True)
    survex_file = models.CharField(max_length=100,blank=True,null=True) #should be filefield, need to fix parser first
    
    #href    = models.CharField(max_length=100)
    
    def get_absolute_url(self):
        if self.kataster_number:
            href = self.kataster_number
        elif self.unofficial_number:
            href = self.unofficial_number
        else:
            href = official_name.lower()
        #return settings.URL_ROOT + '/cave/' + href + '/'
	return urlparse.urljoin(settings.URL_ROOT, reverse('cave',kwargs={'cave_id':href,}))

            
        
    def __unicode__(self):
        if self.kataster_number:
            if self.kat_area():
                return self.kat_area() + u": " + self.kataster_number
            else:
                return unicode("l") + u": " + self.kataster_number
        else:
            if self.kat_area():
                return self.kat_area() + u": " + self.unofficial_number
            else:
                return self.unofficial_number

    def get_QMs(self):
        return QM.objects.filter(found_by__cave=self)	
    
    def kat_area(self):
        for a in self.area.all():
            if a.kat_area():
                return a.kat_area()
    def entrances(self):
        return CaveAndEntrance.objects.filter(cave=self)
    def entrancelist(self):
        rs = []
        res = ""
        for e in CaveAndEntrance.objects.filter(cave=self):
            rs.append(e.entrance_letter)
        rs.sort()
        prevR = None
        n = 0
        for r in rs:
            if prevR:
                if chr(ord(prevR) + 1 ) == r:
                    prevR = r
                    n += 1
                else:
                    if n == 0:
                        res += ", " + prevR
                    else:
                        res += "&ndash;" + prevR
            else:
                prevR = r
                n = 0
                res += r
        if n == 0:
            res += ", " + prevR
        else:
            res += "&ndash;" + prevR
        return res



class OtherCaveName(TroggleModel):
    name = models.CharField(max_length=160)
    cave = models.ForeignKey(Cave)
    def __unicode__(self):
        return unicode(self.name)

class SurveyStation(TroggleModel):
    name = models.CharField(max_length=200)
    def __unicode__(self):
        return unicode(self.name)

class Entrance(TroggleModel):
    name = models.CharField(max_length=100, blank=True,null=True)
    entrance_description = models.TextField(blank=True,null=True)
    explorers = models.TextField(blank=True,null=True)
    map_description = models.TextField(blank=True,null=True)
    location_description = models.TextField(blank=True,null=True)
    approach = models.TextField(blank=True,null=True)
    underground_description = models.TextField(blank=True,null=True)
    photo = models.TextField(blank=True,null=True)
    MARKING_CHOICES = (
        ('P', 'Paint'),
        ('P?', 'Paint (?)'),
        ('T', 'Tag'),
        ('T?', 'Tag (?)'),
        ('R', 'Retagged'),
        ('S', 'Spit'),
        ('S?', 'Spit (?)'),
        ('U', 'Unmarked'),
        ('?', 'Unknown'))
    marking = models.CharField(max_length=2, choices=MARKING_CHOICES)
    marking_comment = models.TextField(blank=True,null=True)
    FINDABLE_CHOICES = (
        ('?', 'To be confirmed ...'),
        ('S', 'Surveyed'),
        ('L', 'Lost'),
        ('R', 'Refindable'))
    findability = models.CharField(max_length=1, choices=FINDABLE_CHOICES, blank=True, null=True)
    findability_description = models.TextField(blank=True,null=True)
    alt = models.TextField(blank=True, null=True)
    northing = models.TextField(blank=True, null=True)
    easting = models.TextField(blank=True, null=True)
    tag_station = models.ForeignKey(SurveyStation, blank=True,null=True, related_name="tag_station")
    exact_station = models.ForeignKey(SurveyStation, blank=True,null=True, related_name="exact_station")
    other_station = models.ForeignKey(SurveyStation, blank=True,null=True, related_name="other_station")
    other_description = models.TextField(blank=True,null=True)
    bearings = models.TextField(blank=True,null=True)
    def __unicode__(self):
        a = CaveAndEntrance.objects.filter(entrance = self)
        name = u''
        if self.name:
            name = unicode(self.name) + u' '
        if len(a) == 1:
            return name + unicode(a[0])
        return name + unicode(a)
    def marking_val(self):
        for m in self.MARKING_CHOICES:
            if m[0] == self.marking:
                return m[1]
    def findability_val(self):
        for f in self.FINDABLE_CHOICES:
            if f[0] == self.findability:
                return f[1]
                
class Subcave(TroggleModel):
    description = models.TextField(blank=True, null=True)
    title = models.CharField(max_length=200, )
    cave = models.ForeignKey('Cave', blank=True, null=True, help_text="Only the top-level subcave should be linked to a cave!")
    parent = models.ForeignKey('self', null=True, blank=True, related_name='children')
    #adjoining = models.ManyToManyField('Subcave',blank=True, null=True,)
    legacy_description_path = models.CharField(max_length=600, blank=True, null=True)
    def __unicode__(self):
        return self.title

    def get_absolute_url(self):
        
        ancestor_titles='/'.join([subcave.title for subcave in self.get_ancestors()])
        if ancestor_titles:
            res = '/'.join((self.get_root().cave.get_absolute_url(), ancestor_titles, self.title))
        
        else:
            res = '/'.join((self.get_root().cave.get_absolute_url(), self.title))
            
        return res
            
# This was the old way, before we were using django-mptt

#    def get_absolute_url(self):
#        urlString=self.name
#        if self.parent:
#            parent=self.parent
#            while parent: #recursively walk up the tree, adding parents to the left of the URL
#                urlString=parent.name+'/'+urlString
#                if parent.cave:
#                    cave=parent.cave
#                parent=parent.parent
#            urlString='cave/'+unicode(cave.kataster_number)+'/'+urlString
#        else:
#            urlString='cave/'+unicode(self.cave.kataster_number)+'/'+urlString
            
            
#        return urlparse.urljoin(settings.URL_ROOT, urlString)
try:
    mptt.register(Subcave, order_insertion_by=['title'])
except mptt.AlreadyRegistered:
    print "mptt already registered"

class QM(TroggleModel):
    #based on qm.csv in trunk/expoweb/smkridge/204 which has the fields:
    #"Number","Grade","Area","Description","Page reference","Nearest station","Completion description","Comment"
    found_by = models.ForeignKey(LogbookEntry, related_name='QMs_found',blank=True, null=True )
    ticked_off_by = models.ForeignKey(LogbookEntry, related_name='QMs_ticked_off',null=True,blank=True)
    number = models.IntegerField(help_text="this is the sequential number in the year")
    GRADE_CHOICES=(
	('A', 'A: Large obvious lead'),
	('B', 'B: Average lead'),
	('C', 'C: Tight unpromising lead'),
	('D', 'D: Dig'),
	('X', 'X: Unclimbable aven')
    )
    grade = models.CharField(max_length=1, choices=GRADE_CHOICES)
    location_description = models.TextField(blank=True)
    #should be a foreignkey to surveystation
    nearest_station_description = models.CharField(max_length=400,null=True,blank=True)
    nearest_station = models.CharField(max_length=200,blank=True,null=True)
    area = models.CharField(max_length=100,blank=True,null=True)
    completion_description = models.TextField(blank=True,null=True)
    comment=models.TextField(blank=True,null=True)
    #the below are unneeded- instead use the date fields of the QM's trips
    #dateFound = models.DateField(blank=True)
    #dateKilled = models.DateField(blank=True)
    def __unicode__(self):
	QMnumber=str(self.found_by.cave)+'-'+str(self.found_by.date.year)+"-"+str(self.number)+self.grade
	return str(QMnumber)

    def get_absolute_url(self):
        #return settings.URL_ROOT + '/cave/' + self.found_by.cave.kataster_number + '/' + str(self.found_by.date.year) + '-' + '%02d' %self.number
        return urlparse.urljoin(settings.URL_ROOT, reverse('qm',kwargs={'cave_id':self.found_by.cave.kataster_number,'year':self.found_by.date.year,'qm_id':self.number,'grade':self.grade}))

    def get_next_by_id(self):
        return QM.objects.get(id=self.id+1)

    def get_previous_by_id(self):
        return QM.objects.get(id=self.id-1)

    def wiki_link(self):
        res = '[[cave:' + str(self.found_by.cave.kataster_number) + ' '
        res += 'QM:' + str(self.found_by.date.year) + '-'
        res += str(self.number) + self.grade + ']]'
	return res

photoFileStorage = FileSystemStorage(location=settings.PHOTOS_ROOT, base_url=settings.PHOTOS_URL)
class Photo(TroggleImageModel): 
    caption = models.CharField(max_length=1000,blank=True,null=True)
    contains_logbookentry = models.ForeignKey(LogbookEntry,blank=True,null=True)
    contains_person = models.ManyToManyField(Person,blank=True,null=True)
    file = models.ImageField(storage=photoFileStorage, upload_to='.',)
    is_mugshot = models.BooleanField(default=False)
    contains_cave = models.ForeignKey(Cave,blank=True,null=True)
    contains_entrance = models.ForeignKey(Entrance, related_name="photo_file",blank=True,null=True)
    nearest_survey_point = models.ForeignKey(SurveyStation,blank=True,null=True)
    nearest_QM = models.ForeignKey(QM,blank=True,null=True)
    lon_utm = models.FloatField(blank=True,null=True)
    lat_utm = models.FloatField(blank=True,null=True)
    
    class IKOptions:
        spec_module = 'expo.imagekit_specs'
        cache_dir = 'thumbs'
        image_field = 'file'
        
    #content_type = models.ForeignKey(ContentType)
    #object_id = models.PositiveIntegerField()
    #location = generic.GenericForeignKey('content_type', 'object_id')

    def __unicode__(self):
        return self.caption

scansFileStorage = FileSystemStorage(location=settings.SURVEY_SCANS, base_url=settings.SURVEYS_URL)
def get_scan_path(instance, filename):
    year=instance.survey.expedition.year
    print "WN: ", type(instance.survey.wallet_number), instance.survey.wallet_number
    number="%02d" % instance.survey.wallet_number + str(instance.survey.wallet_letter) #using %02d string formatting because convention was 2009#01
    return os.path.join('./',year,year+r'#'+number,instance.contents+str(instance.number_in_wallet)+r'.jpg')

class ScannedImage(TroggleImageModel): 
    file = models.ImageField(storage=scansFileStorage, upload_to=get_scan_path)
    scanned_by = models.ForeignKey(Person,blank=True, null=True)
    scanned_on = models.DateField(null=True)
    survey = models.ForeignKey('Survey')
    contents = models.CharField(max_length=20,choices=(('notes','notes'),('plan','plan_sketch'),('elevation','elevation_sketch')))
    number_in_wallet = models.IntegerField(null=True)
    lon_utm = models.FloatField(blank=True,null=True)
    lat_utm = models.FloatField(blank=True,null=True)

    class IKOptions:
        spec_module = 'expo.imagekit_specs'
        cache_dir = 'thumbs'
        image_field = 'file'
    #content_type = models.ForeignKey(ContentType)
    #object_id = models.PositiveIntegerField()
    #location = generic.GenericForeignKey('content_type', 'object_id')

    #This is an ugly hack to deal with the #s in our survey scan paths. The correct thing is to write a custom file storage backend which calls urlencode on the name for making file.url but not file.path.
    def correctURL(self):
	return string.replace(self.file.url,r'#',r'%23')
    
    def __unicode__(self):
        return get_scan_path(self,'')

class Survey(TroggleModel):
    expedition = models.ForeignKey('Expedition') #REDUNDANT (logbook_entry)
    wallet_number = models.IntegerField(blank=True,null=True)
    wallet_letter = models.CharField(max_length=1,blank=True,null=True)
    comments = models.TextField(blank=True,null=True)
    location = models.CharField(max_length=400,blank=True,null=True) #REDUNDANT
    subcave = models.ForeignKey('Subcave', blank=True, null=True)
    #notes_scan = models.ForeignKey('ScannedImage',related_name='notes_scan',blank=True, null=True)  	#Replaced by contents field of ScannedImage model
    survex_block  = models.OneToOneField('SurvexBlock',blank=True, null=True)
    logbook_entry = models.ForeignKey('LogbookEntry')
    centreline_printed_on = models.DateField(blank=True, null=True)
    centreline_printed_by = models.ForeignKey('Person',related_name='centreline_printed_by',blank=True,null=True)
    #sketch_scan = models.ForeignKey(ScannedImage,blank=True, null=True) 					#Replaced by contents field of ScannedImage model
    tunnel_file = models.FileField(upload_to='surveyXMLfiles',blank=True, null=True)
    tunnel_main_sketch = models.ForeignKey('Survey',blank=True,null=True)
    integrated_into_main_sketch_on = models.DateField(blank=True,null=True)
    integrated_into_main_sketch_by = models.ForeignKey('Person' ,related_name='integrated_into_main_sketch_by', blank=True,null=True)
    rendered_image = models.ImageField(upload_to='renderedSurveys',blank=True,null=True)
    def __unicode__(self):
        return self.expedition.year+"#"+"%02d" % int(self.wallet_number)

    def notes(self):
	    return self.scannedimage_set.filter(contents='notes')

    def plans(self):
	    return self.scannedimage_set.filter(contents='plan')

    def elevations(self):
	    return self.scannedimage_set.filter(contents='elevation')