import os

from django.core.checks import Error, Tags, Warning, register


@register("staticfiles")
def css_install_check(app_configs, **kwargs):
    errors = []

    css_path = os.path.join(
        os.path.dirname(__file__), "static", "wagtailadmin", "css", "core.css"
    )

    if not os.path.isfile(css_path):
        error_hint = (
            """
            Most likely you are running a development (non-packaged) copy of
            Wagtail and have not built the static assets -
            see https://docs.wagtail.org/en/latest/contributing/developing.html

            File not found: %s
        """
            % css_path
        )

        errors.append(
            Warning(
                "CSS for the Wagtail admin is missing",
                hint=error_hint,
                id="wagtailadmin.W001",
            )
        )
    return errors


@register(Tags.admin)
def base_form_class_check(app_configs, **kwargs):
    from wagtail.admin.forms import WagtailAdminPageForm
    from wagtail.models import get_page_models

    errors = []

    for cls in get_page_models():
        if not issubclass(cls.base_form_class, WagtailAdminPageForm):
            errors.append(
                Error(
                    "{}.base_form_class does not extend WagtailAdminPageForm".format(
                        cls.__name__
                    ),
                    hint="Ensure that {}.{} extends WagtailAdminPageForm".format(
                        cls.base_form_class.__module__, cls.base_form_class.__name__
                    ),
                    obj=cls,
                    id="wagtailadmin.E001",
                )
            )

    return errors


@register(Tags.admin)
def get_form_class_check(app_configs, **kwargs):
    from wagtail.admin.forms import WagtailAdminPageForm
    from wagtail.models import get_page_models

    errors = []

    for cls in get_page_models():
        edit_handler = cls.get_edit_handler()
        if not issubclass(edit_handler.get_form_class(), WagtailAdminPageForm):
            errors.append(
                Error(
                    "{cls}.get_edit_handler().get_form_class() does not extend WagtailAdminPageForm".format(
                        cls=cls.__name__
                    ),
                    hint="Ensure that the panel definition for {cls} creates a subclass of WagtailAdminPageForm".format(
                        cls=cls.__name__
                    ),
                    obj=cls,
                    id="wagtailadmin.E002",
                )
            )

    return errors


@register("panels")
def inline_panel_model_panels_check(app_configs, **kwargs):
    from wagtail.models import get_page_models

    errors = []
    page_models = get_page_models()

    for cls in page_models:
        errors.extend(check_panels_in_model(cls))

    # filter out duplicate errors found for the same model
    unique_errors = []
    for error in errors:
        if error.msg not in [e.msg for e in unique_errors]:
            unique_errors.append(error)
    return unique_errors


def check_panels_in_model(cls, context="model"):
    """Check panels configuration uses `panels` when `edit_handler` not in use."""
    from wagtail.admin.panels import InlinePanel, PanelGroup
    from wagtail.models import Page

    errors = []

    if hasattr(cls, "get_edit_handler"):
        # must check the InlinePanel related models
        edit_handler = cls.get_edit_handler()
        for tab in edit_handler.children:
            if isinstance(tab, PanelGroup):
                inline_panel_children = [
                    panel for panel in tab.children if isinstance(panel, InlinePanel)
                ]
                for inline_panel_child in inline_panel_children:
                    errors.extend(
                        check_panels_in_model(
                            inline_panel_child.db_field.related_model,
                            context="InlinePanel model",
                        )
                    )

    if issubclass(cls, Page) or hasattr(cls, "edit_handler"):
        # Pages do not need to be checked for standalone tabbed_panel usage
        # if edit_handler is used on any model, assume config is correct
        return errors

    tabbed_panels = [
        "content_panels",
        "promote_panels",
        "settings_panels",
    ]

    for panel_name in tabbed_panels:
        class_name = cls.__name__
        if not hasattr(cls, panel_name):
            continue

        panel_name_short = panel_name.replace("_panels", "").title()
        error_title = "{}.{} will have no effect on {} editing".format(
            class_name, panel_name, context
        )

        if "InlinePanel" in context:
            error_hint = """Ensure that {} uses `panels` instead of `{}`.
There are no tabs on non-Page model editing within InlinePanels.""".format(
                class_name, panel_name
            )
        else:
            error_hint = """Ensure that {} uses `panels` instead of `{}` \
or set up an `edit_handler` if you want a tabbed editing interface.
There are no default tabs on non-Page models so there will be no \
{} tab for the {} to render in.""".format(
                class_name, panel_name, panel_name_short, panel_name
            )

        error = Warning(error_title, hint=error_hint, obj=cls, id="wagtailadmin.W002")

        errors.append(error)

    return errors


@register("wagtailadmin_base_url")
def wagtail_admin_base_url_check(app_configs, **kwargs):
    from django.conf import settings

    errors = []

    if getattr(settings, "WAGTAILADMIN_BASE_URL", None) is None:
        errors.append(
            Warning(
                "The WAGTAILADMIN_BASE_URL setting is not defined",
                hint="This should be the base URL used to access the Wagtail admin site. "
                "Without this, URLs in notification emails will not display correctly.",
                id="wagtailadmin.W003",
            )
        )

    return errors


@register("file_overwrite")
def file_overwrite_check(app_configs, **kwargs):
    from django import VERSION as DJANGO_VERSION
    from django.conf import settings

    if DJANGO_VERSION >= (5, 1):
        file_storage = getattr(settings, "STORAGES")["default"]["BACKEND"]
    else:
        try:
            file_storage = getattr(settings, "STORAGES")["default"]["BACKEND"]
        except AttributeError:
            file_storage = getattr(settings, "DEFAULT_FILE_STORAGE", None)

    errors = []

    if file_storage == "storages.backends.s3boto3.S3Boto3Storage" and getattr(
        settings, "AWS_S3_FILE_OVERWRITE", True
    ):
        errors.append(
            Warning(
                "The AWS_S3_FILE_OVERWRITE setting is set to True",
                hint="This should be set to False. The incorrect setting can cause documents and "
                "other user-uploaded files to be silently overwritten or deleted.",
                id="wagtailadmin.W004",
            )
        )
    if file_storage == "storages.backends.azure_storage.AzureStorage" and getattr(
        settings, "AZURE_OVERWRITE_FILES", False
    ):
        errors.append(
            Warning(
                "The AZURE_OVERWRITE_FILES setting is set to True",
                hint="This should be set to False. The incorrect setting can cause documents and "
                "other user-uploaded files to be silently overwritten or deleted.",
                id="wagtailadmin.W004",
            )
        )
    if file_storage == "storages.backends.gcloud.GoogleCloudStorage" and getattr(
        settings, "GS_FILE_OVERWRITE", True
    ):
        errors.append(
            Warning(
                "The GS_FILE_OVERWRITE setting is set to True",
                hint="This should be set to False. The incorrect setting can cause documents and "
                "other user-uploaded files to be silently overwritten or deleted.",
                id="wagtailadmin.W004",
            )
        )

    return errors


@register("datetime_format")
def datetime_format_check(app_configs, **kwargs):
    """
    If L10N is enabled, check if WAGTAIL_* formats are compatible with Django input formats.
    See https://docs.djangoproject.com/en/stable/topics/i18n/formatting/#creating-custom-format-files
    See https://docs.wagtail.org/en/stable/reference/settings.html#wagtail-date-format-wagtail-datetime-format-wagtail-time-format
    """

    from django.conf import settings
    from django.utils import formats

    errors = []

    if not getattr(settings, "USE_L10N", False):
        return errors

    for code, label in settings.LANGUAGES:
        for wagtail_setting, django_setting in [
            ("WAGTAIL_DATE_FORMAT", "DATE_INPUT_FORMATS"),
            ("WAGTAIL_DATETIME_FORMAT", "DATETIME_INPUT_FORMATS"),
            ("WAGTAIL_TIME_FORMAT", "TIME_INPUT_FORMATS"),
        ]:
            wagtail_format_value = getattr(settings, wagtail_setting, None)
            if wagtail_format_value is None:
                # Skip the iteration if wagtail_format is not present
                continue

            input_formats = formats.get_format(django_setting, lang=code)
            if wagtail_format_value not in input_formats:
                errors.append(
                    Error(
                        "Configuration error",
                        hint=f"'{wagtail_format_value}' must be in {django_setting} for language {label} ({code}).",
                        obj=wagtail_setting,
                        id="wagtailadmin.E003",
                    )
                )

    return errors