import json
import logging
import os
import shutil
import sys
import webbrowser

from ctypes import windll
from functools import wraps
from uuid import uuid1
from threading import Event
from cefpython3 import cefpython as cef
from copy import copy
from time import sleep

from webview.js.css import disable_text_select
from webview.js import dom
from webview import _debug, _user_agent
from webview.util import parse_api_js, default_html, js_bridge_call


sys.excepthook = cef.ExceptHook
instances = {}

logger = logging.getLogger(__name__)

settings = {}

command_line_switches = {}


def _set_dpi_mode(enabled):
    """
    """
    try:
        import _winreg as winreg  # Python 2
    except ImportError:
        import winreg  # Python 3

    try:
        dpi_support = winreg.OpenKey(winreg.HKEY_CURRENT_USER,
                                     r'Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers',
                                     0, winreg.KEY_ALL_ACCESS)
    except WindowsError:
        dpi_support = winreg.CreateKeyEx(winreg.HKEY_CURRENT_USER,
                                         r'Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers',
                                         0, winreg.KEY_ALL_ACCESS)

    try:
        subprocess_path = os.path.join(sys._MEIPASS, 'subprocess.exe')
    except:
        subprocess_path = os.path.join(os.path.dirname(cef.__file__), 'subprocess.exe')

    if enabled:
        winreg.SetValueEx(dpi_support, subprocess_path, 0, winreg.REG_SZ, '~HIGHDPIAWARE')
    else:
        winreg.DeleteValue(dpi_support, subprocess_path)

    winreg.CloseKey(dpi_support)


class JSBridge:
    def __init__(self, window, eval_events):
        self.results = {}
        self.window = window
        self.eval_events = eval_events

    def return_result(self, result, uid):
        self.results[uid] = json.loads(result) if result else None
        self.eval_events[uid].set()

    def call(self, func_name, param, value_id):
        js_bridge_call(self.window, func_name, param, value_id)


renderer = 'cef'


class Browser:
    def __init__(self, window, handle, browser):
        self.window = window
        self.handle = handle
        self.browser = browser
        self.text_select = window.text_select
        self.uid = window.uid
        self.loaded = window.loaded
        self.shown = window.shown
        self.inner_hwnd = self.browser.GetWindowHandle()
        self.eval_events = {}
        self.js_bridge = JSBridge(window, self.eval_events)
        self.initialized = False

    def initialize(self):
        if self.initialized:
            return

        self.browser.GetJavascriptBindings().Rebind()
        self.browser.ExecuteJavascript(parse_api_js(self.window, 'cef'))

        if not self.text_select:
            self.browser.ExecuteJavascript(disable_text_select)

        self.browser.ExecuteJavascript(dom.src)

        sleep(0.1)  # wait for window.pywebview to load
        self.initialized = True
        self.loaded.set()

    def close(self):
        self.browser.CloseBrowser(True)

    def resize(self, width, height):
        windll.user32.SetWindowPos(self.inner_hwnd, 0, 0, 0, width - 16, height - 38,
                                   0x0002 | 0x0004 | 0x0010)
        self.browser.NotifyMoveOrResizeStarted()

    def evaluate_js(self, code):
        self.loaded.wait()
        eval_script = """
            try {{
                window.external.return_result({0}, '{1}');
            }} catch(e) {{
                console.error(e.stack);
                window.external.return_result(null, '{1}');
            }}
        """

        id_ = uuid1().hex[:8]
        self.eval_events[id_] = Event()
        self.browser.ExecuteJavascript(eval_script.format(code, id_))
        self.eval_events[id_].wait()  # result is obtained via JSBridge.return_result

        result = copy(self.js_bridge.results[id_])

        del self.eval_events[id_]
        del self.js_bridge.results[id_]

        return result

    def get_current_url(self):
        self.loaded.wait()
        return self.browser.GetUrl()

    def load_url(self, url):
        self.initialized = False
        self.loaded.clear()
        self.browser.LoadUrl(url)

    def load_html(self, html):
        self.initialized = False
        self.loaded.clear()
        self.browser.LoadUrl('data:text/html,{0}'.format(html))


def find_instance(browser):
    for instance in instances.values():
        if instance.browser is browser:
            return instance

    return None


class LoadHandler(object):
    def OnBeforePopup(self, **args):
        url = args['target_url']
        user_gesture = args['user_gesture']

        if user_gesture:
            webbrowser.open(url)

        return True

    def OnLoadingStateChange(self, browser, is_loading, **_):
        instance = find_instance(browser)

        if instance is not None:
            if is_loading:
                instance.initialized = False
            else:
                instance.initialize()
        else:
            logger.debug('CEF instance is not found %s ' % browser)


def _cef_call(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        uid = args[-1]

        if uid not in instances:
            raise Exception('CEF window with uid {0} does not exist'.format(uid))

        return func(*args, **kwargs)

    return wrapper


def init(window):
    global _initialized

    if not _initialized:
        if sys.platform == 'win32':
            _set_dpi_mode(True)

        default_settings = {
            'multi_threaded_message_loop': True,
            'context_menu': {
                'enabled': _debug
            }
        }

        default_command_line_switches = {
            "enable-media-stream": ""
        }

        if not _debug:
            default_settings['remote_debugging_port'] = -1

        if _user_agent:
            default_settings['user_agent'] = _user_agent

        try:  # set paths under Pyinstaller's one file mode
            default_settings.update({
                'resources_dir_path': sys._MEIPASS,
                'locales_dir_path': os.path.join(sys._MEIPASS, 'locales'),
                'browser_subprocess_path': os.path.join(sys._MEIPASS, 'subprocess.exe'),
            })
        except Exception:
            pass

        all_settings = dict(default_settings, **settings)
        all_command_line_switches = dict(default_command_line_switches, **command_line_switches)
        cef.Initialize(settings=all_settings, commandLineSwitches=all_command_line_switches)
        cef.DpiAware.EnableHighDpiSupport()

        _initialized = True


def create_browser(window, handle, alert_func):
    def _create():
        real_url = 'data:text/html,{0}'.format(window.html) if window.html else window.real_url or 'data:text/html,{0}'.format(default_html)
        cef_browser = cef.CreateBrowserSync(window_info=window_info, url=real_url)
        browser = Browser(window, handle, cef_browser)

        bindings = cef.JavascriptBindings()
        bindings.SetObject('external', browser.js_bridge)
        bindings.SetFunction('alert', alert_func)

        cef_browser.SetJavascriptBindings(bindings)
        cef_browser.SetClientHandler(LoadHandler())

        instances[window.uid] = browser
        window.shown.set()

    window_info = cef.WindowInfo()
    window_info.SetAsChild(handle)
    cef.PostTask(cef.TID_UI, _create)


@_cef_call
def load_html(html, uid):
    instance = instances[uid]
    instance.load_html(html)


@_cef_call
def load_url(url, uid):
    instance = instances[uid]
    instance.load_url(url)


@_cef_call
def evaluate_js(code, uid):
    instance = instances[uid]
    return instance.evaluate_js(code)


@_cef_call
def get_current_url(uid):
    instance = instances[uid]
    url = instance.get_current_url()

    if url.startswith('data:text/html,'):
        return None
    else:
        return url


@_cef_call
def resize(width, height, uid):
    instance = instances[uid]
    instance.resize(width, height)


@_cef_call
def close_window(uid):
    instance = instances[uid]
    instance.close()
    del instances[uid]


def shutdown():
    try:
        if os.path.exists('blob_storage'):
            shutil.rmtree('blob_storage')

        if os.path.exists('webrtc_event_logs'):
            shutil.rmtree('webrtc_event_logs')

        if os.path.exists('error.log'):
            os.remove('error.log')

        if sys.platform == 'win32':
            _set_dpi_mode(False)

    except Exception as e:
        logger.debug(e, exc_info=True)

    cef.Shutdown()


_initialized = False