import numpy as np
from .space import Space


class Tuple(Space):
    """
    A tuple (i.e., product) of simpler spaces

    Example usage:
    self.observation_space = spaces.Tuple((spaces.Discrete(2), spaces.Discrete(3)))
    """

    def __init__(self, spaces):
        self.spaces = spaces
        for space in spaces:
            assert isinstance(
                space, Space
            ), "Elements of the tuple must be instances of gym.Space"
        super(Tuple, self).__init__(None, None)

    def seed(self, seed=None):
        [space.seed(seed) for space in self.spaces]

    def sample(self):
        return tuple([space.sample() for space in self.spaces])

    def contains(self, x):
        if isinstance(x, list):
            x = tuple(x)  # Promote list to tuple for contains check
        return (
            isinstance(x, tuple)
            and len(x) == len(self.spaces)
            and all(space.contains(part) for (space, part) in zip(self.spaces, x))
        )

    def __repr__(self):
        return "Tuple(" + ", ".join([str(s) for s in self.spaces]) + ")"

    def to_jsonable(self, sample_n):
        # serialize as list-repr of tuple of vectors
        return [
            space.to_jsonable([sample[i] for sample in sample_n])
            for i, space in enumerate(self.spaces)
        ]

    def from_jsonable(self, sample_n):
        return [
            sample
            for sample in zip(
                *[
                    space.from_jsonable(sample_n[i])
                    for i, space in enumerate(self.spaces)
                ]
            )
        ]

    def __getitem__(self, index):
        return self.spaces[index]

    def __len__(self):
        return len(self.spaces)

    def __eq__(self, other):
        return isinstance(other, Tuple) and self.spaces == other.spaces