from django.apps import AppConfig, apps
from django.core.checks import Error, Warning, register


class TextConfig(AppConfig):
    name = "djangocms_text"
    verbose_name = "django CMS Rich Text"
    default_auto_field = "django.db.models.BigAutoField"
    inline_models: dict[str, str] = {}

    def ready(self):
        self.inline_models = discover_inline_editable_models()
        register(check_ckeditor_settings)
        register(check_no_cms_config)


def discover_inline_editable_models() -> dict[str, str]:
    # Find frontend-editable models and plugins

    from django.contrib.admin import site

    registered_inline_fields = ["HTMLFormField", "CharField"]
    inline_models: dict[str, str] = {}
    blacklist_apps: list[str] = []

    for model, modeladmin in site._registry.items():
        if model._meta.app_label in blacklist_apps:
            continue

        for field_name in getattr(modeladmin, "frontend_editable_fields", []):
            try:
                form = modeladmin.get_form(request=None, fields=(field_name,))  # Worth a try
            except Exception:
                form = getattr(modeladmin, "form", None)
            if form:
                field_instance = form.base_fields.get(field_name, None)
                if field_instance.__class__.__name__ in registered_inline_fields:
                    inline_models[f"{model._meta.app_label}-{model._meta.model_name}-{field_name}"] = (
                        field_instance.__class__.__name__
                    )

    if apps.is_installed("cms"):
        # also check the plugins
        from cms.plugin_pool import plugin_pool

        for plugin in plugin_pool.plugins.values():
            model = plugin.model
            if model._meta.app_label in blacklist_apps:
                continue
            for field_name in getattr(plugin, "frontend_editable_fields", []):
                form = plugin.form
                field_instance = form.base_fields.get(field_name, None)
                if field_instance.__class__.__name__ in registered_inline_fields:
                    inline_models[f"{model._meta.app_label}-{model._meta.model_name}-{field_name}"] = (
                        field_instance.__class__.__name__
                    )

    return inline_models


def check_ckeditor_settings(app_configs, **kwargs) -> list:  # pragma: no cover
    from django.conf import settings

    change_msg = (
        "Please use the TEXT_ADDITIONAL_ATTRIBUTES setting with a dictionary instead. "
        "Have an entry for each tag and specify allowed attributes for the tag as a set."
    )
    warnings: list[Warning] = []
    if getattr(settings, "TEXT_ADDITIONAL_TAGS", None):
        warnings.append(
            Warning(
                f"The TEXT_ADDITIONAL_TAGS setting is deprecated and will be removed in a future release.\n"
                f"{change_msg}",
                f"TEXT_ADDITIONAL_ATTRIBUTES = "
                f"""{{{", ".join([f'"{tag}": set()' for tag in settings.TEXT_ADDITIONAL_TAGS])}\"}}\n""",
                id="text.W001",
                obj="settings.TEXT_ADDITIONAL_TAGS",
            )
        )
    if not isinstance(getattr(settings, "TEXT_ADDITIONAL_ATTRIBUTES", dict()), dict):
        warnings.append(
            Warning(
                f"The TEXT_ADDITIONAL_ATTRIBUTES setting has changed.\n{change_msg}",
                f'TEXT_ADDITIONAL_ATTRIBUTES = {{"*": {set(settings.TEXT_ADDITIONAL_ATTRIBUTES)}}}\n',
                id="text.W002",
                obj="settings.TEXT_ADDITIONAL_ATTRIBUTES",
            )
        )
    if check_ckeditor_cms_plugin_settings(settings):
        warnings.append(
            Warning(
                "The CKEDITOR_SETTINGS toolbar setting has changed: Instead of 'cmsplugins' use 'CMSPlugins'.",
                hint="Replace 'cmsplugins' by 'CMSPlugins' in CKEDITOR_SETTINGS.",
                id="text.W003",
            )
        )

    return warnings


def check_ckeditor_cms_plugin_settings(settings: object) -> list:  # pragma: no cover
    def recursive_replace(config_list: list, old: str, new: str):
        """Replace target string in toolbar lists and return True if any change occurred."""
        changed = False
        for index, item in enumerate(config_list):
            if isinstance(item, list):
                changed = changed or recursive_replace(item, old, new)
            elif isinstance(item, dict) and "items" in item:
                changed = changed or recursive_replace(item["items"], old, new)
            elif item == old:
                config_list[index] = new
                changed = True
        return changed

    if hasattr(settings, "CKEDITOR_SETTINGS"):
        ckeditor_settings = settings.CKEDITOR_SETTINGS
        change_required = False

        for key, value in ckeditor_settings.items():
            if "toolbar" in key and isinstance(value, list):
                change_required = change_required or recursive_replace(
                    ckeditor_settings[key], "cmsplugins", "CMSPlugins"
                )
        return change_required
    return False


def check_no_cms_config(app_configs, **kwargs) -> list:  # pragma: no cover
    from django.conf import settings

    if "cms" in settings.INSTALLED_APPS:
        return []

    migration_modules = getattr(settings, "MIGRATION_MODULES", {})
    if "djangocms_text" in migration_modules and migration_modules["djangocms_text"] is None:
        return []

    return [
        Error(
            "When using djangocms-text outside django-cms, deactivate migrations for it. Migrations are only "
            "needed when using djangocms-text within django-cms. They will fail otherwise.",
            hint="Add \"'djangocms_text': None\" to your MIGRATION_MODULES setting.",
            id="djangocms_text.E001",
        )
    ]