# Copyright 2011 WebDriver committers
# Copyright 2011 Google Inc.
#
# Licensed 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.

"""
The ActionChains implementation,
"""
from selenium.webdriver.remote.command import Command
from selenium.webdriver.common.keys import Keys

class ActionChains(object):
    """
    ActionChains are a way to automate low level interactions such as 
    mouse movements, mouse button actions, key press, and context menu interactions.
    This is useful for doing more complex actions like hover over and drag and drop. 

    Generate user actions.
       When you call methods for actions on the ActionChains object, 
       the actions are stored in a queue in the ActionChains object. 
       When you call perform(), the events are fired in the order they 
       are queued up.

    ActionChains can be used in a chain pattern::

        menu = driver.find_element_by_css_selector(".nav")
        hidden_submenu = driver.find_element_by_css_selector(".nav #submenu1")

        ActionChains(driver).move_to_element(menu).click(hidden_submenu).perform()

    Or actions can be queued up one by one, then performed.::

        menu = driver.find_element_by_css_selector(".nav")
        hidden_submenu = driver.find_element_by_css_selector(".nav #submenu1")

        actions = ActionChains(driver)
        actions.move_to_element(menu)
        actions.click(hidden_submenu)
        actions.perform()

    Either way, the actions are performed in the order they are called, one after 
    another.
    """

    def __init__(self, driver):
        """
        Creates a new ActionChains.

        :Args:
         - driver: The WebDriver instance which performs user actions.
        """
        self._driver = driver
        self._actions = []

    def perform(self):
        """
        Performs all stored actions.
        """
        for action in self._actions:
            action()

    def click(self, on_element=None):
        """
        Clicks an element.

        :Args:
         - on_element: The element to click.
           If None, clicks on current mouse position.
        """
        if on_element: self.move_to_element(on_element)
        self._actions.append(lambda:
            self._driver.execute(Command.CLICK, {'button': 0}))
        return self

    def click_and_hold(self, on_element=None):
        """
        Holds down the left mouse button on an element.

        :Args:
         - on_element: The element to mouse down.
           If None, clicks on current mouse position.
        """
        if on_element: self.move_to_element(on_element)
        self._actions.append(lambda:
            self._driver.execute(Command.MOUSE_DOWN, {}))
        return self

    def context_click(self, on_element=None):
        """
        Performs a context-click (right click) on an element.

        :Args:
         - on_element: The element to context-click.
           If None, clicks on current mouse position.
        """
        if on_element: self.move_to_element(on_element)
        self._actions.append(lambda:
            self._driver.execute(Command.CLICK, {'button': 2}))
        return self

    def double_click(self, on_element=None):
        """
        Double-clicks an element.

        :Args:
         - on_element: The element to double-click.
           If None, clicks on current mouse position.
        """
        if on_element: self.move_to_element(on_element)
        self._actions.append(lambda:
            self._driver.execute(Command.DOUBLE_CLICK, {}))
        return self

    def drag_and_drop(self, source, target):
        """
        Holds down the left mouse button on the source element,
           then moves to the target element and releases the mouse button.

        :Args:
         - source: The element to mouse down.
         - target: The element to mouse up.
        """
        self.click_and_hold(source)
        self.release(target)
        return self

    def drag_and_drop_by_offset(self, source, xoffset, yoffset):
        """
        Holds down the left mouse button on the source element,
           then moves to the target offset and releases the mouse button.

        :Args:
         - source: The element to mouse down.
         - xoffset: X offset to move to.
         - yoffset: Y offset to move to.
        """
        self.click_and_hold(source)
        self.move_by_offset(xoffset, yoffset)
        self.release()
        return self

    def key_down(self, value, element=None):
        """
        Sends a key press only, without releasing it.
           Should only be used with modifier keys (Control, Alt and Shift).

        :Args:
         - value: The modifier key to send. Values are defined in `Keys` class.
         - element: The element to send keys.
           If None, sends a key to current focused element.
        
        Example, pressing ctrl+c::

            ActionsChains(driver).key_down(Keys.CONTROL).send_keys('c').key_up(Keys.CONTROL).perform()

        """
        if element: self.click(element)
        self._actions.append(lambda:
            self._driver.execute(Command.SEND_KEYS_TO_ACTIVE_ELEMENT, {
                "value": self._keys_to_typing(value) }))
        return self

    def key_up(self, value, element=None):
        """
        Releases a modifier key.

        :Args:
         - value: The modifier key to send. Values are defined in Keys class.
         - element: The element to send keys.
           If None, sends a key to current focused element.

        Example, pressing ctrl+c::

            ActionsChains(driver).key_down(Keys.CONTROL).send_keys('c').key_up(Keys.CONTROL).perform()

        """
        if element: self.click(element)
        self._actions.append(lambda:
            self._driver.execute(Command.SEND_KEYS_TO_ACTIVE_ELEMENT, {
                "value": self._keys_to_typing(value) }))
        return self

    def move_by_offset(self, xoffset, yoffset):
        """
        Moving the mouse to an offset from current mouse position.

        :Args:
         - xoffset: X offset to move to, as a positive or negative integer.
         - yoffset: Y offset to move to, as a positive or negative integer.
        """
        self._actions.append(lambda:
            self._driver.execute(Command.MOVE_TO, {
                'xoffset': int(xoffset),
                'yoffset': int(yoffset)}))
        return self

    def move_to_element(self, to_element):
        """
        Moving the mouse to the middle of an element.

        :Args:
         - to_element: The WebElement to move to.
        """
        self._actions.append(lambda:
            self._driver.execute(Command.MOVE_TO, {'element': to_element.id}))
        return self

    def move_to_element_with_offset(self, to_element, xoffset, yoffset):
        """
        Move the mouse by an offset of the specified element.
           Offsets are relative to the top-left corner of the element.

        :Args:
         - to_element: The WebElement to move to.
         - xoffset: X offset to move to.
         - yoffset: Y offset to move to.
        """
        self._actions.append(lambda:
            self._driver.execute(Command.MOVE_TO, {
                'element': to_element.id,
                'xoffset': int(xoffset),
                'yoffset': int(yoffset)}))
        return self

    def release(self, on_element=None):
        """
        Releasing a held mouse button on an element.

        :Args:
         - on_element: The element to mouse up.
           If None, releases on current mouse position.
        """
        if on_element: self.move_to_element(on_element)
        self._actions.append(lambda:
            self._driver.execute(Command.MOUSE_UP, {}))
        return self

    def send_keys(self, *keys_to_send):
        """
        Sends keys to current focused element.

        :Args:
         - keys_to_send: The keys to send.  Modifier keys constants can be found in the 
         'Keys' class.
        """
        self._actions.append(lambda:
            self._driver.execute(Command.SEND_KEYS_TO_ACTIVE_ELEMENT, 
              { 'value': self._keys_to_typing(keys_to_send)}))
        return self

    def send_keys_to_element(self, element, *keys_to_send):
        """
        Sends keys to an element.

        :Args:
         - element: The element to send keys.
         - keys_to_send: The keys to send.  Modifier keys constants can be found in the 
         'Keys' class.
        """
        self._actions.append(lambda:
            element.send_keys(*keys_to_send))
        return self

    def _keys_to_typing(self, value):
        typing = []
        for val in value:
            if isinstance(val, Keys):
                typing.append(val)
            elif isinstance(val, int):
                val = str(val)
                for i in range(len(val)):
                    typing.append(val[i])
            else:
                for i in range(len(val)):
                    typing.append(val[i])
        return typing

    # Context manager so ActionChains can be used in a 'with .. as' statements.
    def __enter__(self):
        return self # Return created instance of self.

    def __exit__(self, _type, _value, _traceback):
        pass # Do nothing, does not require additional cleanup.
