#-----------------------------------------------------------------------------
# Copyright (c) 2012 - 2023, Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
#-----------------------------------------------------------------------------
'''

'''

#-----------------------------------------------------------------------------
# Boilerplate
#-----------------------------------------------------------------------------
from __future__ import annotations

import logging # isort:skip
log = logging.getLogger(__name__)

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

from ..util.dependencies import import_required # isort:skip
import_required("selenium.webdriver",
                "To use bokeh.io image export functions you need selenium "
                "('conda install selenium' or 'pip install selenium')")

# Standard library imports
import atexit
import os
from os.path import devnull
from shutil import which
from typing import Literal

# External imports
from packaging.version import Version
from selenium.webdriver.remote.webdriver import WebDriver

# Bokeh imports
from ..settings import settings

#-----------------------------------------------------------------------------
# Globals and constants
#-----------------------------------------------------------------------------

DriverKind = Literal["firefox", "chromium"]

__all__ = (
    'webdriver_control',
)

#-----------------------------------------------------------------------------
# General API
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Dev API
#-----------------------------------------------------------------------------

def create_firefox_webdriver(scale_factor: float = 1) -> WebDriver:
    firefox = which("firefox")
    if firefox is None:
        raise RuntimeError("firefox is not installed or not present on PATH")

    geckodriver = which("geckodriver")
    if geckodriver is None:
        raise RuntimeError("geckodriver is not installed or not present on PATH")

    import selenium
    from selenium.webdriver.firefox.options import Options
    from selenium.webdriver.firefox.service import Service
    from selenium.webdriver.firefox.webdriver import WebDriver as Firefox

    if Version(selenium.__version__) >= Version("4.11"):
        # Selenium 4.11 defaults to null output:
        # https://github.com/SeleniumHQ/selenium/pull/12103
        service = Service()
    else:
        service = Service(log_path=devnull)

    options = Options()
    options.add_argument("--headless")
    options.set_preference('layout.css.devPixelsPerPx', f'{scale_factor}')

    return Firefox(service=service, options=options)

def create_chromium_webdriver(extra_options: list[str] | None = None, scale_factor: float = 1) -> WebDriver:
    from selenium.webdriver.chrome.options import Options
    from selenium.webdriver.chrome.service import Service
    from selenium.webdriver.chrome.webdriver import WebDriver as Chrome

    executable_path = settings.chromedriver_path()
    if executable_path is None:
        for executable in ["chromedriver", "chromium.chromedriver", "chromedriver-binary"]:
            executable_path = which(executable)
            if executable_path is not None:
                break
        else:
            raise RuntimeError("chromedriver or its variant is not installed or not present on PATH; "
                               "use BOKEH_CHROMEDRIVER_PATH to specify a customized chromedriver's location")

    service = Service(executable_path)

    options = Options()
    options.add_argument("--headless")
    options.add_argument("--hide-scrollbars")
    options.add_argument(f"--force-device-scale-factor={scale_factor}")
    options.add_argument("--force-color-profile=srgb")
    if extra_options:
        for op in extra_options:
            options.add_argument(op)

    if os.getenv("BOKEH_IN_DOCKER") == "1":
        options.add_argument("--no-sandbox")

    return Chrome(service=service, options=options)


def scale_factor_less_than_web_driver_device_pixel_ratio(scale_factor: float, web_driver: WebDriver) -> bool:
    device_pixel_ratio = get_web_driver_device_pixel_ratio(web_driver)
    return device_pixel_ratio >= scale_factor


def get_web_driver_device_pixel_ratio(web_driver: WebDriver) -> float:
    calculate_web_driver_device_pixel_ratio = """\
        return window.devicePixelRatio
    """
    device_pixel_ratio: float = web_driver.execute_script(calculate_web_driver_device_pixel_ratio)
    return device_pixel_ratio

#-----------------------------------------------------------------------------
# Private API
#-----------------------------------------------------------------------------

def _try_create_firefox_webdriver(scale_factor: float = 1) -> WebDriver | None:
    try:
        return create_firefox_webdriver(scale_factor=scale_factor)
    except Exception:
        return None

def _try_create_chromium_webdriver(scale_factor: float = 1) -> WebDriver | None:
    try:
        return create_chromium_webdriver(scale_factor=scale_factor)
    except Exception:
        return None

class _WebdriverState:

    reuse: bool
    kind: DriverKind | None

    current: WebDriver | None
    _drivers: set[WebDriver]

    def __init__(self, *, kind: DriverKind | None = None, reuse: bool = True) -> None:
        self.kind = kind
        self.reuse = reuse
        self.current = None
        self._drivers = set()

    def terminate(self, driver: WebDriver) -> None:
        self._drivers.remove(driver)
        driver.quit()

    def reset(self) -> None:
        if self.current is not None:
            self.terminate(self.current)
            self.current = None

    def get(self, scale_factor: float = 1) -> WebDriver:
        if not self.reuse or self.current is None or not scale_factor_less_than_web_driver_device_pixel_ratio(
                scale_factor, self.current):
            self.reset()
            self.current = self.create(scale_factor=scale_factor)
        return self.current

    def create(self, kind: DriverKind | None = None, scale_factor: float = 1) -> WebDriver:
        driver = self._create(kind, scale_factor=scale_factor)
        self._drivers.add(driver)
        return driver

    def _create(self, kind: DriverKind | None, scale_factor: float = 1) -> WebDriver:
        driver_kind = kind or self.kind

        if driver_kind is None:
            driver = _try_create_chromium_webdriver(scale_factor=scale_factor)
            if driver is not None:
                self.kind = "chromium"
                return driver

            driver = _try_create_firefox_webdriver(scale_factor=scale_factor)
            if driver is not None:
                self.kind = "firefox"
                return driver

            raise RuntimeError("Neither firefox and geckodriver nor a variant of chromium browser and " \
                               "chromedriver are available on system PATH. You can install the former " \
                               "with 'conda install -c conda-forge firefox geckodriver'.")
        elif driver_kind == "chromium":
            return create_chromium_webdriver(scale_factor=scale_factor)
        elif driver_kind == "firefox":
            return create_firefox_webdriver(scale_factor=scale_factor)
        else:
            raise ValueError(f"'{driver_kind}' is not a recognized webdriver kind")

    def cleanup(self) -> None:
        self.reset()
        for driver in list(self._drivers):
            self.terminate(driver)

#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------

webdriver_control = _WebdriverState()

atexit.register(lambda: webdriver_control.cleanup())