import logging

import pygments
from django.utils.encoding import force_unicode
from django.utils.safestring import mark_safe
from reviewboard.attachments.mimetypes import MimetypeHandler
from reviewboard.extensions.base import Extension
from reviewboard.extensions.hooks import FileAttachmentThumbnailHook


class XMLMimetype(MimetypeHandler):
    # Generate thumbnails for these mimetypes
    supported_mimetypes = ['application/xml', 'text/xml']

    def get_thumbnail(self):
        # This renders the XML using pygments to syntax highlight it. The
        # HTML will then be stuck inside the thumbnail element styled to
        # use a small font and clipped to the size of the thumbnail box.
        f = self.attachment.file.file
        f.open()

        try:
            # Only use the first 2000 characters
            data_string = f.read(2000)
        except (ValueError, IOError), e:
            logging.error('Failed to read from file attachment %s: %s'
                          % (self.attachment.pk, e))

        f.close()

        html = pygments.highlight(force_unicode(data_string),
                                  pygments.lexers.XmlLexer(),
                                  pygments.formatters.HtmlFormatter())

        return mark_safe('<div class="file-thumbnail-clipped">%s</div>'
                         % html)


class XMLThumbnailExtension(Extension):
    def initialize(self):
        FileAttachmentThumbnailHook(self, [XMLMimetype])