import argparse
from collections import Counter, defaultdict
import shelve
from typing import Counter, Dict, List, Optional

import simfile

from smoketest import SimfileError


def analyze(
    simfile_errors: Dict[str, List[SimfileError]],
    *,
    traceback_substring: str,
    verbose: bool,
    number: Optional[int]
) -> None:
    error_counter = Counter()
    error_occurrences = defaultdict(list)
    for filename, errors in simfile_errors.items():
        for error in errors:
            line = error.traceback.splitlines()[-1]
            if not traceback_substring or traceback_substring in line:
                error_counter[line] += 1
                error_occurrences[line].append((filename, error.context))
    for line, count in error_counter.most_common(number):
        print(f'=== {line} ({count} occurrences) ===')
        if verbose:
            for filename, context in error_occurrences[line]:
                print(f'  * "{filename}" (during {repr(context)})')
            print()


def main():
    argparser = argparse.ArgumentParser()
    argparser.add_argument(
        '-s', '--shelf',
        help='shelf file to use',
        default=f'shelf-{simfile.__version__}',
    )
    argparser.add_argument(
        '-t', '--traceback-substring',
        help='filter tracebacks by substring',
    )
    argparser.add_argument(
        '-n', '--number',
        type=int,
        default=10,
        help='number of most common errors to print',
    )
    argparser.add_argument(
        '-v', '--verbose',
        help='enable verbose output',
        default=False,
        action='store_true',
    )
    args = argparser.parse_args()

    with shelve.open(args.shelf) as simfile_errors:
        analyze(
            simfile_errors,
            traceback_substring=args.traceback_substring,
            verbose=args.verbose,
            number=args.number,
        )


if __name__ == '__main__':
    main()