# Licensed to the Software Freedom Conservancy (SFC) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The SFC licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

from typing import Optional, Union

from selenium.common.exceptions import NoSuchElementException, NoSuchFrameException, NoSuchWindowException
from selenium.webdriver.common.alert import Alert
from selenium.webdriver.common.by import By
from selenium.webdriver.remote.webelement import WebElement

from .command import Command


class SwitchTo:
    def __init__(self, driver) -> None:
        import weakref

        self._driver = weakref.proxy(driver)

    @property
    def active_element(self) -> WebElement:
        """Returns the element with focus, or BODY if nothing has focus.

        :Usage:
            ::

                element = driver.switch_to.active_element
        """
        return self._driver.execute(Command.W3C_GET_ACTIVE_ELEMENT)["value"]

    @property
    def alert(self) -> Alert:
        """Switches focus to an alert on the page.

        :Usage:
            ::

                alert = driver.switch_to.alert
        """
        alert = Alert(self._driver)
        _ = alert.text
        return alert

    def default_content(self) -> None:
        """Switch focus to the default frame.

        :Usage:
            ::

                driver.switch_to.default_content()
        """
        self._driver.execute(Command.SWITCH_TO_FRAME, {"id": None})

    def frame(self, frame_reference: Union[str, int, WebElement]) -> None:
        """Switches focus to the specified frame, by index, name, or
        webelement.

        :Args:
         - frame_reference: The name of the window to switch to, an integer representing the index,
                            or a webelement that is an (i)frame to switch to.

        :Usage:
            ::

                driver.switch_to.frame("frame_name")
                driver.switch_to.frame(1)
                driver.switch_to.frame(driver.find_elements(By.TAG_NAME, "iframe")[0])
        """
        if isinstance(frame_reference, str):
            try:
                frame_reference = self._driver.find_element(By.ID, frame_reference)
            except NoSuchElementException:
                try:
                    frame_reference = self._driver.find_element(By.NAME, frame_reference)
                except NoSuchElementException as exc:
                    raise NoSuchFrameException(frame_reference) from exc

        self._driver.execute(Command.SWITCH_TO_FRAME, {"id": frame_reference})

    def new_window(self, type_hint: Optional[str] = None) -> None:
        """Switches to a new top-level browsing context.

        The type hint can be one of "tab" or "window". If not specified the
        browser will automatically select it.

        :Usage:
            ::

                driver.switch_to.new_window("tab")
        """
        value = self._driver.execute(Command.NEW_WINDOW, {"type": type_hint})["value"]
        self._w3c_window(value["handle"])

    def parent_frame(self) -> None:
        """Switches focus to the parent context. If the current context is the
        top level browsing context, the context remains unchanged.

        :Usage:
            ::

                driver.switch_to.parent_frame()
        """
        self._driver.execute(Command.SWITCH_TO_PARENT_FRAME)

    def window(self, window_name: str) -> None:
        """Switches focus to the specified window.

        :Args:
         - window_name: The name or window handle of the window to switch to.

        :Usage:
            ::

                driver.switch_to.window("main")
        """
        self._w3c_window(window_name)

    def _w3c_window(self, window_name: str) -> None:
        def send_handle(h):
            self._driver.execute(Command.SWITCH_TO_WINDOW, {"handle": h})

        try:
            # Try using it as a handle first.
            send_handle(window_name)
        except NoSuchWindowException:
            # Check every window to try to find the given window name.
            original_handle = self._driver.current_window_handle
            handles = self._driver.window_handles
            for handle in handles:
                send_handle(handle)
                current_name = self._driver.execute_script("return window.name")
                if window_name == current_name:
                    return
            send_handle(original_handle)
            raise
