import sys
import os
from datetime import datetime, timedelta
import pytz
import logging
import shutil
import pandas as pd
from models import TazDownloader, TazConfiguration
from exceptions import TazConfigurationError, TazDownloadError, TazDownloadFormatException

# Get directory
dir_path = os.path.dirname(os.path.realpath(__file__)) + '/'


def main(config: dict):

    # Get german date for tomorrow
    tomorrow = (datetime.now(pytz.timezone('Europe/Berlin')) + timedelta(1)).strftime('%Y_%m_%d')

    # Set log level
    try:
        logging.getLogger().setLevel(config['log_level'].upper())
    except ValueError as e:
        logging.error(f"Could not set log level.\n{e}", exc_info=True)

    # If 'use_lock_file' configuration is set, check if lockfile exists for tomorrow's newspaper
    if config['use_lock_file']:
        try:
            lock_files = [entry for entry in os.listdir(dir_path) if os.path.isfile(entry) and entry.endswith('.lock')]
            # Delete all lock files that do not refer to tomorrow's date
            for file in lock_files:
                if not file.startswith('.' + tomorrow):
                    os.remove(dir_path + file)
            # If there is a lock file for tomorrow, exit the program
            for file in lock_files:
                if file.startswith('.' + tomorrow):
                    logging.info('Tomorrow\'s newspaper was already downloaded. Execution canceled.')
                    sys.exit(0)
        except Exception as e:
            logging.error(f"Could not check for lock files.\n{e}", exc_info=True)

    # Read download history from csv file
    try:
        df = pd.read_csv(dir_path + 'download_history.csv', header=0)
    except FileNotFoundError:
        # In case, there isn't yet a csv file, create data frame with headers
        df = pd.DataFrame(
            columns=[
                'file',
                'download_timestamp',
            ]
        )

    # Instantiate downloader object
    try:
        taz_dl = TazDownloader(config['id'], config['password'], config['download_format'])
    except TazDownloadFormatException as e:
        logging.error(e, exc_info=True)
        sys.exit(1)

    try:
        # Get newspapers available for download
        newspaper_available = taz_dl.scrape_newspaper()

        # Remove outdated newspaper from download_history.csv
        df.drop([index for index, row in df.iterrows() if row.file not in newspaper_available], inplace=True)

        # Find newspaper which are not already downloaded
        newspaper_to_download = [n for n in newspaper_available if n not in df.file.values]
    except TazDownloadError as e:
        logging.error(e, exc_info=True)
        sys.exit(1)

    # Download newspaper
    newspaper_downloaded = []
    for n in newspaper_to_download:
        try:
            if taz_dl.download_newspaper(n):
                newspaper_downloaded.append(n)
        except Exception as e:
            logging.error(f"Could not download {n}\n{e}", exc_info=True)

    # Create lock file for tomorrow
    if config['use_lock_file']:
        try:
            lock_file = '.' + tomorrow + '.lock'
            for n in newspaper_downloaded:
                if n.startswith('taz_' + tomorrow):
                    os.mknod(dir_path + lock_file)
        except Exception as e:
            logging.error(f"Could not download create lock file \"{lock_file}\"\n{e}", exc_info=True)

    # Add downloaded newspaper to download_history.csv
    try:
        for n in newspaper_downloaded:
            df_tmp = pd.DataFrame(
                {
                    'file': [n],
                    'download_timestamp': [datetime.strftime(datetime.now(), '%Y-%m-%d %H:%M:%S')],
                }
            )
            df = df.append(df_tmp, ignore_index=True)
        df.sort_values(by='file', ascending=False, inplace=True)
        df.to_csv(dir_path + 'download_history.csv', index=False)
    except Exception as e:
        logging.error(f"Could not update download_history.csv\n{e}", exc_info=True)

    # Move downloaded file to download folder
    if os.path.isdir(config['download_folder']):
        download_folder = \
            config['download_folder'] if config['download_folder'].endswith('/') else config['download_folder'] + "/"
        for n in newspaper_downloaded:
            try:
                shutil.move(dir_path + 'tmp/' + n, download_folder)
            except Exception as e:
                logging.error(f"Could not move file to download folder \"{download_folder}\"\n{e}", exc_info=True)


if __name__ == '__main__':

    # Set up logging
    logging.basicConfig(
        filename=dir_path + 'tazPlease.log',
        level=logging.ERROR,
        format='%(asctime)s - %(message)s'
    )

    # Load configuration
    try:
        configuration = TazConfiguration().get_config()
    except TazConfigurationError as tce:
        print(tce)
        sys.exit(1)
    except Exception as exception:
        print(exception)
        sys.exit(1)

    # Execute main function
    if configuration:
        main(configuration)