import time

from aalpy.base import SUL, Oracle
from aalpy.learning_algs.stochastic.DifferenceChecker import AdvancedHoeffdingChecker, HoeffdingChecker, \
    ChiSquareChecker, DifferenceChecker
from aalpy.learning_algs.stochastic.SamplingBasedObservationTable import SamplingBasedObservationTable
from aalpy.learning_algs.stochastic.StochasticCexProcessing import stochastic_longest_prefix, stochastic_rs
from aalpy.learning_algs.stochastic.StochasticTeacher import StochasticTeacher
from aalpy.utils.HelperFunctions import print_learning_info, print_observation_table, get_cex_prefixes, \
    get_available_oracles_and_err_msg

from aalpy.utils.ModelChecking import stop_based_on_confidence

strategies = ['classic', 'normal', 'chi2']
cex_sampling_options = [None, 'bfs']
cex_processing_options = [None, 'longest_prefix', 'rs']
print_options = [0, 1, 2, 3]
diff_checker_options = {'classic': HoeffdingChecker(),
                        'chi2': ChiSquareChecker(),
                        'normal': AdvancedHoeffdingChecker()}
available_oracles, available_oracles_error_msg = get_available_oracles_and_err_msg()


def run_stochastic_Lstar(input_alphabet, sul: SUL, eq_oracle: Oracle, n_c=20, n_resample=100, target_unambiguity=0.99,
                         min_rounds=10, max_rounds=200, automaton_type='mdp', strategy='normal',
                         cex_processing=None, samples_cex_strategy=None, custom_oracle=False,
                         return_data=False, property_based_stopping=None, print_level=2):
    """
    Learning of Markov Decision Processes based on 'L*-Based Learning of Markov Decision Processes' by Tappler et al.

    Args:

        input_alphabet: input alphabet

        sul: system under learning

        eq_oracle: equivalence oracle

        n_c: cutoff for a cell to be considered complete (Default value = 20)

        n_resample: resampling size (Default value = 100)

        target_unambiguity: target unambiguity value (default 0.99)

        min_rounds: minimum number of learning rounds (Default value = 10)

        max_rounds: if learning_rounds >= max_rounds, learning will stop (Default value = 200)

        automaton_type: either 'mdp' or 'smm' (Default value = 'mdp')

        strategy: either one of ['classic', 'normal', 'chi2'] or a object implementing DifferenceChecker class,
            default value is 'normal'. Classic strategy is the one presented
            in the seed paper, 'normal' is the updated version and chi2 is based on chi squared.

        cex_processing: cex processing strategy, None , 'longest_prefix' or 'rs' (rs is experimental)

        samples_cex_strategy: strategy for finding counterexamples in the trace tree. None, 'bfs' or
            "random:<#traces to check:int>:<stop probability for single trace in [0,1)>" eg. random:200:0.2

        property_based_stopping: A tuple containing (path to the properties file, correct values of each property,
            allowed error for each property. Recommended one is 0.02 (2%)).

        custom_oracle: if True, warning about oracle type will be removed and custom oracle can be used

        return_data: if True, map containing all information like number of queries... will be returned
            (Default value = False)

        print_level: 0 - None, 1 - just results, 2 - current round and hypothesis size, 3 - educational/debug
            (Default value = 2)


    Returns:

      learned MDP/SMM
    """

    assert samples_cex_strategy in cex_sampling_options or samples_cex_strategy.startswith('random')
    assert cex_processing in cex_processing_options
    assert automaton_type in {'mdp', 'smm'}
    if property_based_stopping:
        assert len(property_based_stopping) == 3

    if strategy in diff_checker_options:
        compatibility_checker = diff_checker_options[strategy]
    else:
        assert isinstance(strategy, DifferenceChecker)
        compatibility_checker = strategy

    if not custom_oracle and type(eq_oracle) not in available_oracles:
        raise SystemExit(available_oracles_error_msg)

    stochastic_teacher = StochasticTeacher(sul, n_c, eq_oracle, automaton_type, compatibility_checker,
                                           samples_cex_strategy=samples_cex_strategy)

    # This way all steps from eq. oracle will be added to the tree
    eq_oracle.sul = stochastic_teacher.sul

    observation_table = SamplingBasedObservationTable(input_alphabet, automaton_type,
                                                      stochastic_teacher, compatibility_checker=compatibility_checker,
                                                      strategy=strategy,
                                                      cex_processing=cex_processing)

    start_time = time.time()
    eq_query_time = 0

    # Ask queries for non-completed cells and update the observation table
    observation_table.refine_not_completed_cells(n_resample, uniform=True)
    observation_table.update_obs_table_with_freq_obs()

    learning_rounds = 0
    while True:
        learning_rounds += 1

        observation_table.make_closed_and_consistent()

        hypothesis = observation_table.generate_hypothesis()

        observation_table.trim(hypothesis)

        # If there is no chaos state is not reachable, remove it from state set
        chaos_cex_present = observation_table.chaos_counterexample(hypothesis)

        if not chaos_cex_present:
            if automaton_type == 'mdp':
                hypothesis.states.remove(next(state for state in hypothesis.states if state.output == 'chaos'))
            else:
                hypothesis.states.remove(next(state for state in hypothesis.states if state.state_id == 'chaos'))

        if print_level > 1:
            print(f'Hypothesis: {learning_rounds}: {len(hypothesis.states)} states.')

        if print_level == 3:
            print_observation_table(observation_table, 'stochastic')

        cex = None
        if not chaos_cex_present:
            eq_query_start = time.time()
            cex = stochastic_teacher.equivalence_query(hypothesis)
            eq_query_time += time.time() - eq_query_start

        if cex:
            if print_level == 3:
                print('Counterexample', cex)
            # get all prefixes and add them to the S set
            if cex_processing is None:
                for pre in get_cex_prefixes(cex, automaton_type):
                    if pre not in observation_table.S:
                        observation_table.S.append(pre)
            else:
                suffixes = None
                if cex_processing == 'longest_prefix':
                    prefixes = observation_table.S + list(observation_table.get_extended_s())
                    suffixes = stochastic_longest_prefix(cex, prefixes)
                elif cex_processing == 'rs':
                    suffixes = stochastic_rs(sul, cex, hypothesis)
                for suf in suffixes:
                    if suf not in observation_table.E:
                        observation_table.E.append(suf)

        # Ask queries for non-completed cells and update the observation table
        refined = observation_table.refine_not_completed_cells(n_resample)
        observation_table.update_obs_table_with_freq_obs()

        if property_based_stopping and learning_rounds >= min_rounds:
            # stop based on maximum allowed error
            if stop_based_on_confidence(hypothesis, property_based_stopping, print_level):
                break
        else:
            # stop based on number of unambiguous rows
            stop_based_on_unambiguity = observation_table.stop(learning_rounds, chaos_cex_present,
                                                               target_unambiguity=target_unambiguity,
                                                               min_rounds=min_rounds, max_rounds=max_rounds,
                                                               print_unambiguity=print_level > 1)
            if stop_based_on_unambiguity:
                break

        if not refined:
            break

    total_time = round(time.time() - start_time, 2)
    eq_query_time = round(eq_query_time, 2)
    learning_time = round(total_time - eq_query_time, 2)

    info = {
        'learning_rounds': learning_rounds,
        'automaton_size': len(hypothesis.states),
        'queries_learning': stochastic_teacher.sul.num_queries - eq_oracle.num_queries,
        'steps_learning': stochastic_teacher.sul.num_steps - eq_oracle.num_queries,
        'queries_eq_oracle': eq_oracle.num_queries,
        'steps_eq_oracle': eq_oracle.num_steps,
        'learning_time': learning_time,
        'eq_oracle_time': eq_query_time,
        'total_time': total_time
    }

    if print_level > 0:
        print_learning_info(info)

    if return_data:
        return hypothesis, info

    return hypothesis
