from typing import List

from flask import current_app, url_for
from flask_babel import gettext as __

from .api import BaseApi, expose
from .basemanager import BaseManager
from .security.decorators import permission_name, protect


class MenuItem(object):
    def __init__(
        self, name, href="", icon="", label="", childs=None, baseview=None, cond=None
    ):
        self.name = name
        self.href = href
        self.icon = icon
        self.label = label
        self.childs = childs or []
        self.baseview = baseview
        self.cond = cond

    def should_render(self) -> bool:
        return bool(self.cond()) if self.cond is not None else True

    def get_url(self):
        if not self.href:
            if not self.baseview:
                return ""
            else:
                return url_for(f"{self.baseview.endpoint}.{self.baseview.default_view}")
        else:
            try:
                return url_for(self.href)
            except Exception:
                return self.href

    def __repr__(self):
        return self.name


class Menu(object):
    def __init__(self, reverse=True, extra_classes=""):
        self.menu = []
        if reverse:
            extra_classes = extra_classes + "navbar-inverse"
        self.extra_classes = extra_classes

    @property
    def reverse(self):
        return "navbar-inverse" in self.extra_classes

    def get_list(self):
        return self.menu

    def get_flat_name_list(self, menu: "Menu" = None, result: List = None) -> List:
        menu = menu or self.menu
        result = result or []
        for item in menu:
            result.append(item.name)
            if item.childs:
                result.extend(self.get_flat_name_list(menu=item.childs, result=result))
        return result

    def get_data(self, menu=None):
        menu = menu or self.menu
        ret_list = []

        allowed_menus = current_app.appbuilder.sm.get_user_menu_access(
            self.get_flat_name_list()
        )

        for i, item in enumerate(menu):
            if not item.should_render():
                continue

            if item.name == "-" and not i == len(menu) - 1:
                ret_list.append("-")
            elif item.name not in allowed_menus:
                continue
            elif item.childs:
                ret_list.append(
                    {
                        "name": item.name,
                        "icon": item.icon,
                        "label": __(str(item.label)),
                        "childs": self.get_data(menu=item.childs),
                    }
                )
            else:
                ret_list.append(
                    {
                        "name": item.name,
                        "icon": item.icon,
                        "label": __(str(item.label)),
                        "url": item.get_url(),
                    }
                )
        return ret_list

    def find(self, name, menu=None):
        """
        Finds a menu item by name and returns it.

        :param name:
            The menu item name.
        """
        menu = menu or self.menu
        for i in menu:
            if i.name == name:
                return i
            else:
                if i.childs:
                    ret_item = self.find(name, menu=i.childs)
                    if ret_item:
                        return ret_item

    def add_category(self, category, icon="", label="", parent_category=""):
        label = label or category
        if parent_category == "":
            self.menu.append(MenuItem(name=category, icon=icon, label=label))
        else:
            self.find(category).childs.append(
                MenuItem(name=category, icon=icon, label=label)
            )

    def add_link(
        self,
        name,
        href="",
        icon="",
        label="",
        category="",
        category_icon="",
        category_label="",
        baseview=None,
        cond=None,
    ):
        label = label or name
        category_label = category_label or category
        if category == "":
            self.menu.append(
                MenuItem(
                    name=name,
                    href=href,
                    icon=icon,
                    label=label,
                    baseview=baseview,
                    cond=cond,
                )
            )
        else:
            menu_item = self.find(category)
            if menu_item:
                new_menu_item = MenuItem(
                    name=name,
                    href=href,
                    icon=icon,
                    label=label,
                    baseview=baseview,
                    cond=cond,
                )
                menu_item.childs.append(new_menu_item)
            else:
                self.add_category(
                    category=category, icon=category_icon, label=category_label
                )
                new_menu_item = MenuItem(
                    name=name,
                    href=href,
                    icon=icon,
                    label=label,
                    baseview=baseview,
                    cond=cond,
                )
                self.find(category).childs.append(new_menu_item)

    def add_separator(self, category="", cond=None):
        menu_item = self.find(category)
        if menu_item:
            menu_item.childs.append(MenuItem("-", cond=cond))
        else:
            raise Exception(
                "Menu separator does not have correct category {}".format(category)
            )


class MenuApi(BaseApi):
    resource_name = "menu"
    openapi_spec_tag = "Menu"

    @expose("/", methods=["GET"])
    @protect(allow_browser_login=True)
    @permission_name("get")
    def get_menu_data(self):
        """An endpoint for retreiving the menu.
        ---
        get:
          description: >-
            Get the menu data structure.
            Returns a forest like structure with the menu the user has access to
          responses:
            200:
              description: Get menu data
              content:
                application/json:
                  schema:
                    type: object
                    properties:
                      result:
                        description: Menu items in a forest like data structure
                        type: array
                        items:
                          type: object
                          properties:
                            name:
                              description: >-
                                The internal menu item name, maps to permission_name
                              type: string
                            label:
                              description: Pretty name for the menu item
                              type: string
                            icon:
                              description: Icon name to show for this menu item
                              type: string
                            url:
                              description: The URL for the menu item
                              type: string
                            childs:
                              type: array
                              items:
                                type: object
            401:
              $ref: '#/components/responses/401'
        """
        return self.response(200, result=current_app.appbuilder.menu.get_data())


class MenuApiManager(BaseManager):
    def register_views(self):
        if self.appbuilder.app.config.get("FAB_ADD_MENU_API", True):
            self.appbuilder.add_api(MenuApi)
