"""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 import cli_argument_parser


def make_progress_indicator(
        redis_connection: Redis, job_id: 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=job_id, 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

    if not os.path.exists(args.strainsfile):
        print(f"The file '{args.strainsfile}' does not exist.", file=sys.stderr)
        return None

    try:
        conn = Redis.from_url(args.redisurl) # pylint: disable=[unused-variable]
    except ConnectionError as conn_err: # pylint: disable=[unused-variable]
        print(traceback.format_exc(), file=sys.stderr)
        return None

    return args

def process_cli_arguments():
    """Setup command-line parser"""
    parser = cli_argument_parser()
    parser.prog = "worker"
    parser.add_argument(
        "redisurl", default="redis:///", help="URL to the redis server")
    parser.add_argument("job_id", help="The id of the job being processed")

    return cli_args_valid(parser.parse_args())

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

def make_user_aborted(redis_conn, job_id):
    """Mkae function that checks whether the user aborted the process"""
    def __aborted__():
        user_aborted = bool(int(
            redis_conn.hget(name=job_id, key="user_aborted") or "0"))
        if user_aborted:
            redis_conn.hset(name=job_id, 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.redisurl) as redis_conn:
        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.job_id, progress_calculator)
        count = args.count
        filepath = args.filepath
        filetype = (
            FileType.AVERAGE if args.filetype == "average"
            else FileType.STANDARD_ERROR)
        strains = strain_names(args.strainsfile)

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

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

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

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

    return 0

if __name__ == "__main__":
    main()