from itertools import product
from typing import Any, Callable, Optional, List, Sequence

from approvaltests.core.reporter import Reporter
from approvaltests.approvals import verify, initialize_options
from approvaltests.core.options import Options

from approvaltests.pairwise_combinations import get_best_covering_pairs
from approvaltests.reporters.testing_reporter import ReporterForTesting
from approval_utilities.utilities.logger.simple_logger import SimpleLogger

VariationForEachParameter = Sequence[Sequence[Any]]
CombinationsOfParameters = Sequence[Sequence[Any]]


def calculate_total_size(input_arguments):
    from functools import reduce

    return reduce(
        lambda current_size, arguments: len(arguments) * current_size,
        input_arguments,
        1,
    )


def verify_best_covering_pairs(
    function_under_test: Callable,
    input_arguments: VariationForEachParameter,
    formatter: Optional[Callable] = None,
    reporter: Optional[ReporterForTesting] = None,
    *,  # enforce keyword arguments - https://www.python.org/dev/peps/pep-3102/
    options: Optional[Options] = None,
) -> None:
    combinations = get_best_covering_pairs(input_arguments)
    count = len(combinations)

    text = print_combinations(formatter, function_under_test, combinations)
    options = initialize_options(options, reporter)
    total = calculate_total_size(input_arguments)

    header = f"Testing an optimized {count}/{total} scenarios:\n\n"
    verify(header + text, options=options)


def run_all_combinations(
    function_under_test: Callable,
    input_arguments: VariationForEachParameter,
    *,  # enforce keyword arguments - https://www.python.org/dev/peps/pep-3102/
    exception_handler: Callable[[BaseException], None] = SimpleLogger.warning,
) -> None:
    parameter_combinations = product(*input_arguments)
    for args in parameter_combinations:
        try:
            function_under_test(*args)
        except BaseException as exception:
            exception_handler(exception)


def verify_all_combinations(
    function_under_test: Callable,
    input_arguments: VariationForEachParameter,
    formatter: Optional[Callable] = None,
    reporter: Optional[ReporterForTesting] = None,
    *,  # enforce keyword arguments - https://www.python.org/dev/peps/pep-3102/
    options: Optional[Options] = None,
) -> None:
    """Run func with all possible combinations of args and verify outputs against the recorded approval file.

    Args:
        function_under_test (function): function under test.
        input_arguments: list of values to test for each input argument.  For example, a function f(product, quantity)
            could be tested with the input_arguments [['water', 'cola'], [1, 4]], which would result in outputs for the
            following calls being recorded and verified: f('water', 1), f('water', 4), f('cola', 1), f('cola', 4).
        formatter (function): function for formatting the function inputs/outputs before they are recorded to an
            approval file for comparison.
        reporter (approvaltests.reporter.Reporter): an approval reporter.

    Raises:
        ApprovalException: if the results to not match the approved results.
    """
    options = initialize_options(options, reporter)
    verify_all_combinations_with_namer(
        function_under_test, input_arguments, formatter, None, options=options
    )


def verify_all_combinations_with_namer(
    function_under_test: Callable,
    input_arguments: VariationForEachParameter,
    formatter: Optional[Callable] = None,
    reporter: Optional[Reporter] = None,
    *,  # enforce keyword arguments - https://www.python.org/dev/peps/pep-3102/
    options: Optional[Options] = None,
) -> None:
    """Run func with all possible combinations of args and verify outputs against the recorded approval file.

    Args:
        function_under_test (function): function under test.
        input_arguments: list of values to test for each input argument.  For example, a function f(product, quantity)
            could be tested with the input_arguments [['water', 'cola'], [1, 4]], which would result in outputs for the
            following calls being recorded and verified: f('water', 1), f('water', 4), f('cola', 1), f('cola', 4).
        namer (approvaltests.core.Namer): A namer that defines the name of received and approved files.
        formatter (function): function for formatting the function inputs/outputs before they are recorded to an
            approval file for comparison.
        reporter (approvaltests.reporter.Reporter): an approval reporter.

    Raises:
        ApprovalException: if the results to not match the approved results.
    """
    text = print_combinations(formatter, function_under_test, product(*input_arguments))
    options = initialize_options(options, reporter)
    verify(text, options=options)


def print_combinations(
    formatter: Optional[Callable],
    function_under_test: Callable,
    parameter_combinations: CombinationsOfParameters,
) -> str:
    if formatter is None:
        formatter = args_and_result_formatter
    approval_strings = []
    for args in parameter_combinations:
        try:
            result = function_under_test(*args)
        except BaseException as exception:
            result = exception
        approval_strings.append(formatter(args, result))
    return "".join(approval_strings)


def args_and_result_formatter(args: List[Any], result: int) -> str:
    return f"args: {repr(args)} => {repr(result)}\n"


def verify_logging_for_all_combinations(
    function_to_run,
    input_arguments: VariationForEachParameter,
    *,  # enforce keyword arguments - https://www.python.org/dev/peps/pep-3102/
    options: Optional[Options] = None,
):
    def printer(*args):
        SimpleLogger._wrapper.get().log_line(f"Running inputs {args} => ")
        with SimpleLogger._wrapper.get().indent():
            function_to_run(*args)

    output = SimpleLogger.log_to_string()
    run_all_combinations(printer, input_arguments)
    verify(output, options=options)
