from django.core.exceptions import ObjectDoesNotExist

from django.db import models

from django.utils.html import escape

from django.utils.safestring import mark_safe

from django.utils.text import capfirst

from django.utils.encoding import force_unicode

from django.utils.translation import ugettext as _

def quote(s):

    """

    Ensure that primary key values do not confuse the admin URLs by escaping

    any '/', '_' and ':' characters. Similar to urllib.quote, except that the

    quoting is slightly different so that it doesn't get automatically

    unquoted by the Web browser.

    """

    if not isinstance(s, basestring):

        return s

    res = list(s)

    for i in range(len(res)):

        c = res[i]

        if c in """:/_#?;@&=+$,"<>%\\""":

            res[i] = '_%02X' % ord(c)

    return ''.join(res)

def unquote(s):

    """

    Undo the effects of quote(). Based heavily on urllib.unquote().

    """

    mychr = chr

    myatoi = int

    list = s.split('_')

    res = [list[0]]

    myappend = res.append

    del list[0]

    for item in list:

        if item[1:2]:

            try:

                myappend(mychr(myatoi(item[:2], 16)) + item[2:])

            except ValueError:

                myappend('_' + item)

        else:

            myappend('_' + item)

    return "".join(res)

def flatten_fieldsets(fieldsets):

    """Returns a list of field names from an admin fieldsets structure."""

    field_names = []

    for name, opts in fieldsets:

        for field in opts['fields']:

            # type checking feels dirty, but it seems like the best way here

            if type(field) == tuple:

                field_names.extend(field)

            else:

                field_names.append(field)

    return field_names

def _nest_help(obj, depth, val):

    current = obj

    for i in range(depth):

        current = current[-1]

    current.append(val)

def get_deleted_objects(deleted_objects, perms_needed, user, obj, opts, current_depth, admin_site):

    "Helper function that recursively populates deleted_objects."

    nh = _nest_help # Bind to local variable for performance

    if current_depth > 16:

        return # Avoid recursing too deep.

    opts_seen = []

    for related in opts.get_all_related_objects():

        has_admin = related.model in admin_site._registry

        if related.opts in opts_seen:

            continue

        opts_seen.append(related.opts)

        rel_opts_name = related.get_accessor_name()

        if isinstance(related.field.rel, models.OneToOneRel):

            try:

                sub_obj = getattr(obj, rel_opts_name)

            except ObjectDoesNotExist:

                pass

            else:

                if has_admin:

                    p = '%s.%s' % (related.opts.app_label, related.opts.get_delete_permission())

                    if not user.has_perm(p):

                        perms_needed.add(related.opts.verbose_name)

                        # We don't care about populating deleted_objects now.

                        continue

                if not has_admin:

                    # Don't display link to edit, because it either has no

                    # admin or is edited inline.

                    nh(deleted_objects, current_depth, [u'%s: %s' % (force_unicode(capfirst(related.opts.verbose_name)), sub_obj), []])

                else:

                    # Display a link to the admin page.

                    nh(deleted_objects, current_depth, [mark_safe(u'%s: <a href="../../../../%s/%s/%s/">%s</a>' %

                        (escape(force_unicode(capfirst(related.opts.verbose_name))),

                            related.opts.app_label,

                            related.opts.object_name.lower(),

                            sub_obj._get_pk_val(), sub_obj)), []])

                get_deleted_objects(deleted_objects, perms_needed, user, sub_obj, related.opts, current_depth+2, admin_site)

        else:

            has_related_objs = False

            for sub_obj in getattr(obj, rel_opts_name).all():

                has_related_objs = True

                if not has_admin:

                    # Don't display link to edit, because it either has no

                    # admin or is edited inline.

                    nh(deleted_objects, current_depth, [u'%s: %s' % (force_unicode(capfirst(related.opts.verbose_name)), sub_obj), []])

                else:

                    # Display a link to the admin page.

                    nh(deleted_objects, current_depth, [mark_safe(u'%s: <a href="../../../../%s/%s/%s/">%s</a>' % \

                        (escape(force_unicode(capfirst(related.opts.verbose_name))), related.opts.app_label, related.opts.object_name.lower(), sub_obj._get_pk_val(), escape(sub_obj))), []])

                get_deleted_objects(deleted_objects, perms_needed, user, sub_obj, related.opts, current_depth+2, admin_site)

            # If there were related objects, and the user doesn't have

            # permission to delete them, add the missing perm to perms_needed.

            if has_admin and has_related_objs:

                p = '%s.%s' % (related.opts.app_label, related.opts.get_delete_permission())

                if not user.has_perm(p):

                    perms_needed.add(related.opts.verbose_name)

    for related in opts.get_all_related_many_to_many_objects():

        has_admin = related.model in admin_site._registry

        if related.opts in opts_seen:

            continue

        opts_seen.append(related.opts)

        rel_opts_name = related.get_accessor_name()

        has_related_objs = False

        # related.get_accessor_name() could return None for symmetrical relationships

        if rel_opts_name:

            rel_objs = getattr(obj, rel_opts_name, None)

            if rel_objs:

                has_related_objs = True

        if has_related_objs:

            for sub_obj in rel_objs.all():

                if not has_admin:

                    # Don't display link to edit, because it either has no

                    # admin or is edited inline.

                    nh(deleted_objects, current_depth, [_('One or more %(fieldname)s in %(name)s: %(obj)s') % \

                        {'fieldname': force_unicode(related.field.verbose_name), 'name': force_unicode(related.opts.verbose_name), 'obj': escape(sub_obj)}, []])

                else:

                    # Display a link to the admin page.

                    nh(deleted_objects, current_depth, [

                        mark_safe((_('One or more %(fieldname)s in %(name)s:') % {'fieldname': escape(force_unicode(related.field.verbose_name)), 'name': escape(force_unicode(related.opts.verbose_name))}) + \

                        (u' <a href="../../../../%s/%s/%s/">%s</a>' % \

                            (related.opts.app_label, related.opts.module_name, sub_obj._get_pk_val(), escape(sub_obj)))), []])

        # If there were related objects, and the user doesn't have

        # permission to change them, add the missing perm to perms_needed.

        if has_admin and has_related_objs:

            p = u'%s.%s' % (related.opts.app_label, related.opts.get_change_permission())

            if not user.has_perm(p):

                perms_needed.add(related.opts.verbose_name)