from random import Random
from typing import Iterable
from importlib import reload
from inspect import getmembers, isclass

from eth2spec.gen_helpers.gen_base import gen_runner, gen_typing

from eth2spec.debug import random_value, encode
from eth2spec.config import config_util
from eth2spec.phase0 import spec as spec_phase0
from eth2spec.phase1 import spec as spec_phase1
from eth2spec.test.context import PHASE0, PHASE1
from eth2spec.utils.ssz.ssz_typing import Container
from eth2spec.utils.ssz.ssz_impl import (
    hash_tree_root,
    serialize,
)


MAX_BYTES_LENGTH = 1000
MAX_LIST_LENGTH = 10


def create_test_case(rng: Random, typ,
                     mode: random_value.RandomizationMode, chaos: bool) -> Iterable[gen_typing.TestCasePart]:
    value = random_value.get_random_ssz_object(rng, typ, MAX_BYTES_LENGTH, MAX_LIST_LENGTH, mode, chaos)
    yield "value", "data", encode.encode(value)
    yield "serialized", "ssz", serialize(value)
    roots_data = {
        "root": '0x' + hash_tree_root(value).hex()
    }
    yield "roots", "data", roots_data


def get_spec_ssz_types(spec):
    return [
        (name, value) for (name, value) in getmembers(spec, isclass)
        if issubclass(value, Container) and value != Container  # only the subclasses, not the imported base class
    ]


def ssz_static_cases(fork_name: str, seed: int, name, ssz_type,
                     mode: random_value.RandomizationMode, chaos: bool, count: int):
    random_mode_name = mode.to_name()

    # Reproducible RNG
    rng = Random(seed)

    for i in range(count):
        yield gen_typing.TestCase(
            fork_name=fork_name,
            runner_name='ssz_static',
            handler_name=name,
            suite_name=f"ssz_{random_mode_name}{'_chaos' if chaos else ''}",
            case_name=f"case_{i}",
            case_fn=lambda: create_test_case(rng, ssz_type, mode, chaos)
        )


def create_provider(fork_name, config_name: str, seed: int, mode: random_value.RandomizationMode, chaos: bool,
                    cases_if_random: int) -> gen_typing.TestProvider:
    def prepare_fn(configs_path: str) -> str:
        # Apply changes to presets, this affects some of the vector types.
        config_util.prepare_config(configs_path, config_name)
        reload(spec_phase0)
        reload(spec_phase1)
        return config_name

    def cases_fn() -> Iterable[gen_typing.TestCase]:
        count = cases_if_random if chaos or mode.is_changing() else 1
        spec = spec_phase0
        if fork_name == PHASE1:
            spec = spec_phase1

        for (i, (name, ssz_type)) in enumerate(get_spec_ssz_types(spec)):
            yield from ssz_static_cases(fork_name, seed * 1000 + i, name, ssz_type, mode, chaos, count)

    return gen_typing.TestProvider(prepare=prepare_fn, make_cases=cases_fn)


if __name__ == "__main__":
    # [(seed, config name, randomization mode, chaos on/off, cases_if_random)]
    settings = []
    seed = 1
    for mode in random_value.RandomizationMode:
        settings.append((seed, "minimal", mode, False, 30))
        seed += 1
    settings.append((seed, "minimal", random_value.RandomizationMode.mode_random, True, 30))
    seed += 1
    settings.append((seed, "mainnet", random_value.RandomizationMode.mode_random, False, 5))
    seed += 1

    for fork in [PHASE0, PHASE1]:
        gen_runner.run_generator("ssz_static", [
            create_provider(fork, config_name, seed, mode, chaos, cases_if_random)
            for (seed, config_name, mode, chaos, cases_if_random) in settings
        ])