from django.conf import settings
from django import template
import os, os.path
import Image
from django.utils.safestring import mark_safe

register = template.Library()

def src_and_size(filename, args=''):

    if filename is None:
        return ''
    if filename.startswith(settings.MEDIA_URL):
        full_filename = filename[len(settings.MEDIA_URL):]

    full_filename = os.path.join(settings.MEDIA_ROOT, full_filename)

    if not os.path.exists(full_filename):
        print "Warning, miniature not found: %s" % filename
        return
    image = Image.open(full_filename)

    return mark_safe('width="%s" height="%s" src="%s"' % (image.size[0],
                                                          image.size[1],
                                                          filename))

register.filter(src_and_size)

def thumbnail(filename, args=''):
    def get_basename(filename):
        basename = extension = ''
        arr = filename.rsplit('.', 1)
        basename = arr[0]
        if len(arr)>1:
            extension = arr[1]
        return basename,extension

    if filename=='':
        return

    width = None
    height = None

    if filename.startswith(settings.MEDIA_URL):
        filename = filename[len(settings.MEDIA_URL):]

    basename,extension = get_basename(filename)
    miniature = basename # +'_t'

    resizeByWidth = False
    resizeByHeight  = False
    for arg in args.split(','):
        arg = arg.strip()
        key,val = arg.split('=', 1)
        if key=='width':
            if not resizeByHeight:
                resizeByWidth = True
            width = int(val)
            miniature+='_w_'+val
        elif key=='height':
            if not resizeByWidth:
                resizeByHeight = True
            height = int(val)
            miniature+='_h_'+val

    if width==None and height==None :
        raise template.TemplateSyntaxError, "thumbnail filter requires arguments (width and/or height)"

    miniature += '.'+extension
    miniature = "%s/._t_%s" % (os.path.dirname(miniature),
                               os.path.basename(miniature))

    miniature_filename = os.path.join(settings.MEDIA_ROOT, miniature)
    miniature_url = os.path.join(settings.MEDIA_URL, miniature)
    filename = os.path.join(settings.MEDIA_ROOT, filename)

    if not os.path.exists(filename):
        print "Warning, miniature not created for non-exising file: %s" % filename
        return

    if not os.path.exists(miniature_filename) or (os.path.getmtime(filename) > os.path.getmtime(miniature_filename)):
         image = Image.open(filename)

         if resizeByWidth:
             new_height = int(image.size[1] * width / image.size[0])
             if (height is not None) and new_height>height:
                 new_height = height
                 new_width = int(image.size[0] * height / image.size[1])
             else:
                 new_width = width
         elif resizeByHeight:
             new_width = int(image.size[0] * height / image.size[1])
             if (width is not None) and new_width>width:
                 new_width = width
                 new_height = int(image.size[1] * width / image.size[0])
             else:
                 new_height = height

         try:
             image.thumbnail([new_width,new_height],Image.ANTIALIAS)
             image.save(miniature_filename, image.format)
         except IOError, e:
             print 'DjHDGutils: thumbnail.py: IOError %s for file: %s.' % (e,filename)
             return

    return miniature_url

register.filter(thumbnail)

@register.simple_tag
def thumbnail_url(url, width, height):
    args=[]
    if width:
        args.append('width=%s' % width)
    if height:
        args.append('height=%s' % height)
    return thumbnail(url, ",".join(args))