#!/usr/bin/env python3

import json
from selenium import webdriver
from selenium.webdriver.support.wait import WebDriverWait
from flask import Flask, make_response, request, jsonify
from time import sleep
from io import BytesIO
from itertools import product
from PIL import Image
from threading import Semaphore

app = Flask(__name__)

# Sends an internal request to the browser
def send(cmd, params={}):
    resource = "/session/%s/chromium/send_command_and_get_result" % driver.session_id
    url = driver.command_executor._url + resource
    body = json.dumps({'cmd':cmd, 'params': params})
    response = driver.command_executor._request('POST', url, body)
    if response['status']: raise Exception(response.get('value'))
    return response.get('value')

def clear_cache(driver, timeout=60):
    """Clear the cookies and cache for the ChromeDriver instance."""
    # navigate to the settings page
    driver.get('chrome://settings/clearBrowserData')

    # wait for the button to appear
    wait = WebDriverWait(driver, timeout)
    wait.until(get_clear_browsing_button)

    # click the button to clear the cache
    get_clear_browsing_button(driver).click()

    # wait for the button to be gone before returning
    wait.until_not(get_clear_browsing_button)

@app.route("/clearcaches")
def clear():
    global cache

    # There are two caches to clear (this script's cache variable and the browser's
    cache = {}
    clear_cache(driver)

_last_url = None

SEMAPHORE = Semaphore()

@app.route("/prime")
def prime():
    global _last_url
    url = request.args.get('url')
    if _last_url == url:
        return 'ok'

    _last_url = url

    with SEMAPHORE:
        driver.get(url)

        # Send transparency request to browser
        send("Emulation.setDefaultBackgroundColorOverride", \
                {'color': {'r': 0, 'g': 0, 'b': 0, 'a': 0}})

        # Wait until a div element with the id of "done" appears in the DOM
        WebDriverWait(driver, 200).until(lambda x: x.find_element_by_id("done"))

    return 'ok'

#COUNTER = 1
#CACHE = {}  # (x, y, z) => bytes (image data)

@app.route("/tile/<x>/<y>/<z>.png")
def tile(x, y, z):
    rx, ry, rz = map(int, (x, y, z))
    round = 1
    x = rx - rx % round
    y = ry - ry % round
    z = rz
    size = 256
    scale = 2 ** z

    with SEMAPHORE:
        element = driver.find_element_by_tag_name('svg')
        location = element.location

        width = int(element.get_attribute('width'))
        height = int(element.get_attribute('height'))

        tx = -x * size
        ty = -y * size
        transform = "translate(%dpx, %dpx) scale(%f)" % (tx, ty, scale)

        driver.execute_script('document.documentElement.style.setProperty("--transform", arguments[0])', transform)

        screenshot = driver.get_screenshot_as_png()

    data = screenshot

    response = make_response(data)
    response.headers.set('Content-Type', 'image/png')
    return response

@app.route("/event/", methods=["POST"])
def post_event():
    body = request.get_json(force=True)
    assert body['type'] in ('click', 'mousedown', 'mouseup', 'mousemove')
    x, y, z = body['tile']['x'], body['tile']['y'], body['tile']['z']
    rx, ry, rz = map(int, (x, y, z))
    x = rx
    y = ry
    z = rz
    size = 256
    scale = 2 ** z
    ox, oy = body['offset']['x'], body['offset']['y']

    element = driver.find_element_by_tag_name('svg')

    width = int(element.get_attribute('width'))
    height = int(element.get_attribute('height'))
    location = element.location

    tx = -x * size
    ty = -y * size
    transform = "translate(%dpx, %dpx) scale(%f)" % (tx, ty, scale)

    if body['type'] == 'mousedown':
        driver.execute_script('document.documentElement.style.setProperty("--transform", arguments[0])', transform)
        ActionChains(driver) \
            .move_to_element_with_offset(element, ox, oy) \
            .click_and_hold() \
            .perform()

    elif body['type'] == 'click':
        driver.execute_script('document.documentElement.style.setProperty("--transform", arguments[0])', transform)
        ActionChains(driver) \
            .move_to_element_with_offset(element, ox, oy) \
            .click() \
            .perform()

    elif body['type'] == 'mousemove':
        ActionChains(driver) \
            .move_to_element_with_offset(element, ox, oy) \
            .perform()

    elif body['type'] == 'mouseup':
        ActionChains(driver) \
            .move_to_element_with_offset(element, ox, oy) \
            .release() \
            .perform()

    return jsonify({
        'status': 'success',
    })

@app.route("/")
def index():
	return 'ok'

if __name__ == '__main__':
    options = webdriver.ChromeOptions()
    options.add_argument('--no-sandbox')
    options.add_argument('--headless')
    options.add_argument('--disable-web-security')
    options.add_argument('--hide-scrollbars')
    options.binary_location = '/usr/bin/chromium-browser'

    cache = {}

    driver = webdriver.Chrome('/resources/chromedriver', chrome_options=options, desired_capabilities={"acceptInsecureCerts": True})
    driver.set_window_size(256, 256)
    app.run(host='0.0.0.0', port=8030, threaded=True, debug=True)