"""spectur_live_view

Open an automated selenium webdriver, and download images from Live View mode.
"""

import os
import time
import pytz
from io import BytesIO
from datetime import datetime
import requests
import yaml
import numpy as np
from PIL import Image
from selenium import webdriver
from selenium.webdriver.firefox.options import Options
from selenium.common.exceptions import (NoSuchElementException,
                                        StaleElementReferenceException,
                                        WebDriverException)

CAM_ID = 0
URL = 'https://camera.uwatchit.com.au/UWatchitWebV2/User/LiveView#'
OUTPUT_DIR = 'images'
TIMEZONE = 'Australia/Sydney'
WAIT_TIME = 0.1
username = ''
password = ''


def start_session():
    """Start automated browser session.

    Returns:
        selenium webdriver object
    """
    # Start webdriver
    options = Options()
    options.headless = False
    driver = webdriver.Firefox(options=options)

    return driver


def login(driver):
    """Log into Spectur camera portal.

    Args:
        driver:  selenium webdriver object

    Returns:
        cookies from current browser session
    """

    driver.get(URL)

    # Get login fields
    usr = driver.find_element_by_id('UserName')
    pss = driver.find_element_by_id('Password')
    btn = driver.find_element_by_id('submitlogin')

    if (username and password):
        # Login automatically if details provided
        usr.send_keys(username)
        pss.send_keys(password)
        btn.click()
    else:
        # Try to get credientials saved locally
        try:
            credential_path = os.path.join(os.path.expanduser('~'), '.spectur')
            with open(credential_path, 'r') as f:
                credentials = yaml.safe_load(f.read())

            # Input login details
            usr.send_keys(credentials['USERNAME'])
            pss.send_keys(credentials['PASSWORD'])
            btn.click()
        except FileNotFoundError:
            # Wait for user to log in manually
            while True:
                try:
                    driver.find_element_by_id('UserName')
                    time.sleep(1)
                except NoSuchElementException:
                    break

    # Extract cookies
    session = requests.Session()
    for c in driver.get_cookies():
        session.cookies.set(c['name'], c['value'])

    return session.cookies


def return_to_live_view(driver):
    """Return to live camera feed in Spectur portal.
    """

    driver.get(URL)
    driver.execute_script('ChangeCam({})'.format(CAM_ID))


def get_image_timestamp(driver):
    """Get timestamp from image link.

    Args:
        driver:  selenium webdriver object

    Returns:
        UNIX timestamp, in seconds
    """

    im_url = driver.find_element_by_id('camimage').get_property('src')
    timestamp = int(im_url.rsplit('&', 1)[-1]) / 1000

    return timestamp


def get_next_image(driver, cookies):
    """Get next image.

    Args:
        driver:   selenium webdriver object
        cookies:  cookies from current browser session
    """
    # Get timestamp
    t_current = get_image_timestamp(driver)

    # Wait until image timestamp is updated
    while t_current == get_image_timestamp(driver):
        time.sleep(WAIT_TIME)

    # Get image URL
    im_url = driver.find_element_by_id('camimage').get_property('src')

    # Get jpeg data, and convert to image object
    page = requests.get(im_url, cookies=cookies)
    im = Image.open(BytesIO(page.content))

    # Get EXIF timestamp
    datestr = im._getexif()[36867]

    # Convert to local time
    t_naive = datetime.strptime(datestr, '%Y:%m:%d %H:%M:%S')
    t_utc = t_naive.replace(tzinfo=pytz.utc)
    t_local = t_utc.astimezone(pytz.timezone(TIMEZONE))

    # Save image
    ts = t_local.strftime
    jpg_name = os.path.join(OUTPUT_DIR, ts('%Y'), ts('%Y-%m-%d'), ts('%H'),
                            ts('%Y-%m-%d_%H-%M-%S%z') + '.jpg')
    os.makedirs(os.path.dirname(jpg_name), exist_ok=True)
    im.save(jpg_name)

    # Get battery level
    with open(os.path.join(OUTPUT_DIR, 'battery.txt'), 'a') as f:
        battery_str = driver.find_element_by_id('battery').text
        f.write('{}\t{}\n'.format(t_local.isoformat(), battery_str[:-1]))

    # Update time counter
    current_time = float(time.mktime(t_local.timetuple()))
    if current_time not in t:
        t.append(current_time)

    # Count images collected
    n = len(t)

    if n > 2:
        # Get frames per second
        fps = 1 / np.median(np.diff(t))

        # Count dropped frames
        n_expected = fps * (t[-1] - t[0])
        n_dropped = np.max([0, int(n_expected - n + 1)])

        msg = '{}  total images: {}  fps: {}  dropped frames: {}'.format(
            t_local.isoformat(), n, fps, n_dropped)
        print(msg, end='\r', flush=True)


def main():
    # Start browser session
    driver = start_session()
    cookies = login(driver)
    return_to_live_view(driver)

    while True:
        try:
            # Get latest image
            get_next_image(driver, cookies)
        except (NoSuchElementException, StaleElementReferenceException,
                WebDriverException):
            # Navigate to Live View
            return_to_live_view(driver)
        except ConnectionError:
            # Attempt to re-login if server goes down
            time.sleep(5)
            cookies = login(driver)


# Create counter
t = []

# Open browser
main()