from django.core.exceptions import ImproperlyConfigured

from django.db import models

from django.contrib.admin.options import flatten_fieldsets, BaseModelAdmin

from django.contrib.admin.options import HORIZONTAL, VERTICAL

__all__ = ['validate']

def validate(cls, model):

    """

    Does basic ModelAdmin option validation. Calls custom validation

    classmethod in the end if it is provided in cls. The signature of the

    custom validation classmethod should be: def validate(cls, model).

    """

    # Before we can introspect models, they need to be fully loaded so that

    # inter-relations are set up correctly. We force that here.

    models.get_apps()

    opts = model._meta

    validate_base(cls, model)

    # list_display

    if hasattr(cls, 'list_display'):

        check_isseq(cls, 'list_display', cls.list_display)

        for idx, field in enumerate(cls.list_display):

            if not callable(field):

                if not hasattr(cls, field):

                    if not hasattr(model, field):

                        try:

                            opts.get_field(field)

                        except models.FieldDoesNotExist:

                            raise ImproperlyConfigured("%s.list_display[%d], %r is not a callable or an attribute of %r or found in the model %r."

                                % (cls.__name__, idx, field, cls.__name__, model._meta.object_name))

                    else:

                        # getattr(model, field) could be an X_RelatedObjectsDescriptor

                        f = fetch_attr(cls, model, opts, "list_display[%d]" % idx, field)

                        if isinstance(f, models.ManyToManyField):

                            raise ImproperlyConfigured("'%s.list_display[%d]', '%s' is a ManyToManyField which is not supported."

                                % (cls.__name__, idx, field))

    # list_display_links

    if hasattr(cls, 'list_display_links'):

        check_isseq(cls, 'list_display_links', cls.list_display_links)

        for idx, field in enumerate(cls.list_display_links):

            fetch_attr(cls, model, opts, 'list_display_links[%d]' % idx, field)

            if field not in cls.list_display:

                raise ImproperlyConfigured("'%s.list_display_links[%d]'"

                        "refers to '%s' which is not defined in 'list_display'."

                        % (cls.__name__, idx, field))

    # list_filter

    if hasattr(cls, 'list_filter'):

        check_isseq(cls, 'list_filter', cls.list_filter)

        for idx, field in enumerate(cls.list_filter):

            get_field(cls, model, opts, 'list_filter[%d]' % idx, field)

    # list_per_page = 100

    if hasattr(cls, 'list_per_page') and not isinstance(cls.list_per_page, int):

        raise ImproperlyConfigured("'%s.list_per_page' should be a integer."

                % cls.__name__)

    # list_editable

    if hasattr(cls, 'list_editable') and cls.list_editable:

        check_isseq(cls, 'list_editable', cls.list_editable)

        for idx, field_name in enumerate(cls.list_editable):

            try:

                field = opts.get_field_by_name(field_name)[0]

            except models.FieldDoesNotExist:

                raise ImproperlyConfigured("'%s.list_editable[%d]' refers to a "

                    "field, '%s', not defined on %s."

                    % (cls.__name__, idx, field_name, model.__name__))

            if field_name not in cls.list_display:

                raise ImproperlyConfigured("'%s.list_editable[%d]' refers to "

                    "'%s' which is not defined in 'list_display'."

                    % (cls.__name__, idx, field_name))

            if field_name in cls.list_display_links:

                raise ImproperlyConfigured("'%s' cannot be in both '%s.list_editable'"

                    " and '%s.list_display_links'"

                    % (field_name, cls.__name__, cls.__name__))

            if not cls.list_display_links and cls.list_display[0] in cls.list_editable:

                raise ImproperlyConfigured("'%s.list_editable[%d]' refers to"

                    " the first field in list_display, '%s', which can't be"

                    " used unless list_display_links is set."

                    % (cls.__name__, idx, cls.list_display[0]))

            if not field.editable:

                raise ImproperlyConfigured("'%s.list_editable[%d]' refers to a "

                    "field, '%s', which isn't editable through the admin."

                    % (cls.__name__, idx, field_name))

    # search_fields = ()

    if hasattr(cls, 'search_fields'):

        check_isseq(cls, 'search_fields', cls.search_fields)

    # date_hierarchy = None

    if cls.date_hierarchy:

        f = get_field(cls, model, opts, 'date_hierarchy', cls.date_hierarchy)

        if not isinstance(f, (models.DateField, models.DateTimeField)):

            raise ImproperlyConfigured("'%s.date_hierarchy is "

                    "neither an instance of DateField nor DateTimeField."

                    % cls.__name__)

    # ordering = None

    if cls.ordering:

        check_isseq(cls, 'ordering', cls.ordering)

        for idx, field in enumerate(cls.ordering):

            if field == '?' and len(cls.ordering) != 1:

                raise ImproperlyConfigured("'%s.ordering' has the random "

                        "ordering marker '?', but contains other fields as "

                        "well. Please either remove '?' or the other fields."

                        % cls.__name__)

            if field == '?':

                continue

            if field.startswith('-'):

                field = field[1:]

            # Skip ordering in the format field1__field2 (FIXME: checking

            # this format would be nice, but it's a little fiddly).

            if '__' in field:

                continue

            get_field(cls, model, opts, 'ordering[%d]' % idx, field)

    # list_select_related = False

    # save_as = False

    # save_on_top = False

    for attr in ('list_select_related', 'save_as', 'save_on_top'):

        if not isinstance(getattr(cls, attr), bool):

            raise ImproperlyConfigured("'%s.%s' should be a boolean."

                    % (cls.__name__, attr))

    # inlines = []

    if hasattr(cls, 'inlines'):

        check_isseq(cls, 'inlines', cls.inlines)

        for idx, inline in enumerate(cls.inlines):

            if not issubclass(inline, BaseModelAdmin):

                raise ImproperlyConfigured("'%s.inlines[%d]' does not inherit "

                        "from BaseModelAdmin." % (cls.__name__, idx))

            if not inline.model:

                raise ImproperlyConfigured("'model' is a required attribute "

                        "of '%s.inlines[%d]'." % (cls.__name__, idx))

            if not issubclass(inline.model, models.Model):

                raise ImproperlyConfigured("'%s.inlines[%d].model' does not "

                        "inherit from models.Model." % (cls.__name__, idx))

            validate_base(inline, inline.model)

            validate_inline(inline, cls, model)

def validate_inline(cls, parent, parent_model):

    # model is already verified to exist and be a Model

    if cls.fk_name: # default value is None

        f = get_field(cls, cls.model, cls.model._meta, 'fk_name', cls.fk_name)

        if not isinstance(f, models.ForeignKey):

            raise ImproperlyConfigured("'%s.fk_name is not an instance of "

                    "models.ForeignKey." % cls.__name__)

    # extra = 3

    # formset

    if hasattr(cls, 'formset') and not issubclass(cls.formset, BaseModelFormSet):

        raise ImproperlyConfigured("'%s.formset' does not inherit from "

                "BaseModelFormSet." % cls.__name__)

    # exclude

    if hasattr(cls, 'exclude') and cls.exclude:

        if fk and fk.name in cls.exclude:

            raise ImproperlyConfigured("%s cannot exclude the field "

                    "'%s' - this is the foreign key to the parent model "

                    "%s." % (cls.__name__, fk.name, parent_model.__name__))

def validate_base(cls, model):

    opts = model._meta

    # raw_id_fields

    if hasattr(cls, 'raw_id_fields'):

        check_isseq(cls, 'raw_id_fields', cls.raw_id_fields)

        for idx, field in enumerate(cls.raw_id_fields):

            f = get_field(cls, model, opts, 'raw_id_fields', field)

            if not isinstance(f, (models.ForeignKey, models.ManyToManyField)):

                raise ImproperlyConfigured("'%s.raw_id_fields[%d]', '%s' must "

                        "be either a ForeignKey or ManyToManyField."

                        % (cls.__name__, idx, field))

    # fields

    if cls.fields: # default value is None

        check_isseq(cls, 'fields', cls.fields)

        for field in cls.fields:

            check_formfield(cls, model, opts, 'fields', field)

        if cls.fieldsets:

            raise ImproperlyConfigured('Both fieldsets and fields are specified in %s.' % cls.__name__)

        if len(cls.fields) > len(set(cls.fields)):

            raise ImproperlyConfigured('There are duplicate field(s) in %s.fields' % cls.__name__)

    # fieldsets

    if cls.fieldsets: # default value is None

        check_isseq(cls, 'fieldsets', cls.fieldsets)

        for idx, fieldset in enumerate(cls.fieldsets):

            check_isseq(cls, 'fieldsets[%d]' % idx, fieldset)

            if len(fieldset) != 2:

                raise ImproperlyConfigured("'%s.fieldsets[%d]' does not "

                        "have exactly two elements." % (cls.__name__, idx))

            check_isdict(cls, 'fieldsets[%d][1]' % idx, fieldset[1])

            if 'fields' not in fieldset[1]:

                raise ImproperlyConfigured("'fields' key is required in "

                        "%s.fieldsets[%d][1] field options dict."

                        % (cls.__name__, idx))

        flattened_fieldsets = flatten_fieldsets(cls.fieldsets)

        if len(flattened_fieldsets) > len(set(flattened_fieldsets)):

            raise ImproperlyConfigured('There are duplicate field(s) in %s.fieldsets' % cls.__name__)

    # form

    if hasattr(cls, 'form') and not issubclass(cls.form, BaseModelForm):

        raise ImproperlyConfigured("%s.form does not inherit from "

                "BaseModelForm." % cls.__name__)

    # filter_vertical

    if hasattr(cls, 'filter_vertical'):

        check_isseq(cls, 'filter_vertical', cls.filter_vertical)

        for idx, field in enumerate(cls.filter_vertical):

            f = get_field(cls, model, opts, 'filter_vertical', field)

            if not isinstance(f, models.ManyToManyField):

                raise ImproperlyConfigured("'%s.filter_vertical[%d]' must be "

                    "a ManyToManyField." % (cls.__name__, idx))

    # filter_horizontal

    if hasattr(cls, 'filter_horizontal'):

        check_isseq(cls, 'filter_horizontal', cls.filter_horizontal)

        for idx, field in enumerate(cls.filter_horizontal):

            f = get_field(cls, model, opts, 'filter_horizontal', field)

            if not isinstance(f, models.ManyToManyField):

                raise ImproperlyConfigured("'%s.filter_horizontal[%d]' must be "

                    "a ManyToManyField." % (cls.__name__, idx))

    # radio_fields

    if hasattr(cls, 'radio_fields'):

        check_isdict(cls, 'radio_fields', cls.radio_fields)

        for field, val in cls.radio_fields.items():

            f = get_field(cls, model, opts, 'radio_fields', field)

            if not (isinstance(f, models.ForeignKey) or f.choices):

                raise ImproperlyConfigured("'%s.radio_fields['%s']' "

                        "is neither an instance of ForeignKey nor does "

                        "have choices set." % (cls.__name__, field))

            if not val in (HORIZONTAL, VERTICAL):

                raise ImproperlyConfigured("'%s.radio_fields['%s']' "

                        "is neither admin.HORIZONTAL nor admin.VERTICAL."

                        % (cls.__name__, field))

    # prepopulated_fields

    if hasattr(cls, 'prepopulated_fields'):

        check_isdict(cls, 'prepopulated_fields', cls.prepopulated_fields)

        for field, val in cls.prepopulated_fields.items():

            f = get_field(cls, model, opts, 'prepopulated_fields', field)

            if isinstance(f, (models.DateTimeField, models.ForeignKey,

                models.ManyToManyField)):

                raise ImproperlyConfigured("'%s.prepopulated_fields['%s']' "

                        "is either a DateTimeField, ForeignKey or "

                        "ManyToManyField. This isn't allowed."

                        % (cls.__name__, field))

            check_isseq(cls, "prepopulated_fields['%s']" % field, val)

            for idx, f in enumerate(val):

                get_field(cls, model, opts, "prepopulated_fields['%s'][%d]" % (field, idx), f)

def check_isseq(cls, label, obj):

    if not isinstance(obj, (list, tuple)):

        raise ImproperlyConfigured("'%s.%s' must be a list or tuple." % (cls.__name__, label))

def check_isdict(cls, label, obj):

    if not isinstance(obj, dict):

        raise ImproperlyConfigured("'%s.%s' must be a dictionary." % (cls.__name__, label))

def get_field(cls, model, opts, label, field):

    try:

        return opts.get_field(field)

    except models.FieldDoesNotExist:

        raise ImproperlyConfigured("'%s.%s' refers to field '%s' that is missing from model '%s'."

                % (cls.__name__, label, field, model.__name__))

def check_formfield(cls, model, opts, label, field):

    if getattr(cls.form, 'base_fields', None):

        try:

            cls.form.base_fields[field]

        except KeyError:

            raise ImproperlyConfigured("'%s.%s' refers to field '%s' that "

                "is missing from the form." % (cls.__name__, label, field))

    else:

        fields = fields_for_model(model)