"""External worker script that checks file for correctness"""
import os
import sys
import traceback
from typing import Callable
from zipfile import ZipFile, is_zipfile

import jsonpickle
from redis import Redis
from redis.exceptions import ConnectionError # pylint: disable=[redefined-builtin]

from quality_control.utils import make_progress_calculator
from quality_control.parsing import FileType, strain_names, collect_errors

from qc_app.db_utils import database_connection

from .cli_parser import init_cli_parser
from .qc import add_file_validation_arguments


def make_progress_indicator(redis_connection: Redis,
                            jobid: str,
                            progress_calc_fn: Callable) -> Callable:
    """Make function that will compute the progress and update redis"""
    def __indicator__(linenumber, linetext):
        progress = progress_calc_fn(linenumber, linetext)
        redis_connection.hset(name=str(jobid), mapping=progress._asdict())

        return progress

    return __indicator__

def cli_args_valid(args):
    "Check that the command-line arguments are provided and correct"
    if not os.path.exists(args.filepath):
        print(f"The file '{args.filepath}' does not exist.", file=sys.stderr)
        return None

    try:
        _conn = Redis.from_url(args.redisuri)
    except ConnectionError as _conn_err:
        print(traceback.format_exc(), file=sys.stderr)
        return None

    return args

def process_cli_arguments():
    """Setup command-line parser"""
    parser = init_cli_parser(
        "validate-file",
        ("Verify that the file with the expression data conforms to "
         "expectations."))
    parser.add_argument("speciesid",
                        type=int,
                        help="Species for which the data is to be processed.")
    parser = add_file_validation_arguments(parser)

    return cli_args_valid(parser.parse_args())

def stream_error(redis_conn, jobid, error):
    """Update redis with the most current error(s) found"""
    errors = jsonpickle.decode(
        redis_conn.hget(str(jobid), key="errors") or jsonpickle.encode(tuple()))
    redis_conn.hset(
        str(jobid), key="errors", value=jsonpickle.encode(errors + (error,)))

def make_user_aborted(redis_conn, jobid):
    """Mkae function that checks whether the user aborted the process"""
    def __aborted__():
        user_aborted = bool(int(
            redis_conn.hget(name=str(jobid), key="user_aborted") or "0"))
        if user_aborted:
            redis_conn.hset(name=str(jobid), key="status", value="aborted")

        return user_aborted
    return __aborted__

def get_zipfile_size(filepath):
    "Compute size of given zipfile"
    with ZipFile(filepath, "r") as zfile:
        return zfile.infolist()[0].file_size

def main():
    "entry point to the script"
    args = process_cli_arguments()
    if args is None:
        print("Quiting due to errors!", file=sys.stderr)
        return 1

    with (Redis.from_url(args.redisuri) as redis_conn,
          database_connection(args.databaseuri) as dbconn):
        progress_calculator = make_progress_calculator(
            get_zipfile_size(args.filepath) if is_zipfile(args.filepath)
            else os.stat(args.filepath).st_size)
        progress_indicator = make_progress_indicator(
            redis_conn, args.jobid, progress_calculator)
        count = args.count
        filepath = args.filepath
        filetype = (
            FileType.AVERAGE if args.filetype == "average"
            else FileType.STANDARD_ERROR)
        strains = strain_names(dbconn, args.speciesid)

        redis_conn.hset(name=str(args.jobid), key="status", value="Processing")
        redis_conn.hset(
            name=str(args.jobid), key="message", value="Collecting errors")

        error_count = 0
        for error in collect_errors(
                filepath, filetype, strains, progress_indicator,
                make_user_aborted(redis_conn, args.jobid)):
            stream_error(redis_conn, args.jobid, error)

            if count > 0:
                error_count = error_count + 1
                if error_count >= count:
                    break

        redis_conn.hset(name=str(args.jobid), key="status", value="success")

    return 0

if __name__ == "__main__":
    main()