# Copyright 2018 the GPflow authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import os
from unittest import mock

import numpy as np
import pytest
import tensorflow as tf
import tensorflow_probability as tfp

import gpflow
from gpflow.config import (
    default_float,
    default_int,
    default_jitter,
    default_positive_bijector,
    default_summary_fmt,
    set_default_float,
    set_default_int,
    set_default_jitter,
    set_default_positive_bijector,
    set_default_summary_fmt,
)
from gpflow.utilities import to_default_float, to_default_int


_env_values = [
    ("int", "int16", np.int16),
    ("int", "int64", np.int64),
    ("float", "float16", np.float16),
    ("float", "float32", np.float32),
    ("positive_bijector", "exp", "exp"),
    ("positive_bijector", "softplus", "softplus"),
    ("summary_fmt", "simple", "simple"),
    ("positive_minimum", "1e-3", 1e-3),
    ("jitter", "1e-2", 1e-2),
]


@pytest.mark.parametrize("attr_name, value, expected_value", _env_values)
def test_env_variables(attr_name, value, expected_value):
    env_name = f"GPFLOW_{attr_name.upper()}"
    with mock.patch.dict("os.environ", {env_name: value}):
        assert os.environ[env_name] == value
        config = gpflow.config.Config()
        assert getattr(config, attr_name) == expected_value


@pytest.mark.parametrize("attr_name", set(list(zip(*_env_values))[0]))
def test_env_variables_failures(attr_name):
    if attr_name == "summary_fmt":
        pytest.skip("The `summary_fmt` validation cannot be performed.")
    env_name = f"GPFLOW_{attr_name.upper()}"
    with mock.patch.dict("os.environ", {env_name: "garbage"}):
        with pytest.raises(TypeError):
            gpflow.config.Config()


@pytest.mark.parametrize('getter, setter, valid_type_1, valid_type_2', [
    (default_int, set_default_int, tf.int64, np.int32),
    (default_float, set_default_float, tf.float32, np.float64),
])
def test_dtype_setting(getter, setter, valid_type_1, valid_type_2):
    if valid_type_1 == valid_type_2:
        raise ValueError("cannot test config setting/getting when both types are equal")
    setter(valid_type_1)
    assert getter() == valid_type_1
    setter(valid_type_2)
    assert getter() == valid_type_2


@pytest.mark.parametrize('setter, invalid_type', [
    (set_default_int, str),
    (set_default_int, np.float64),
    (set_default_float, list),
    (set_default_float, tf.int32),
])
def test_dtype_errorcheck(setter, invalid_type):
    with pytest.raises(TypeError):
        setter(invalid_type)


def test_jitter_setting():
    set_default_jitter(1e-3)
    assert default_jitter() == 1e-3
    set_default_jitter(1e-6)
    assert default_jitter() == 1e-6


def test_jitter_errorcheck():
    with pytest.raises(TypeError):
        set_default_jitter("not a float")
    with pytest.raises(ValueError):
        set_default_jitter(-1e-10)


@pytest.mark.parametrize("value, error_msg", [
    ("Unknown", r"`unknown` not in set of valid bijectors: \['exp', 'softplus'\]"),
    (1.0, r"`1.0` not in set of valid bijectors: \['exp', 'softplus'\]"),
])
def test_positive_bijector_error(value, error_msg):
    with pytest.raises(ValueError, match=error_msg):
        set_default_positive_bijector(value)


@pytest.mark.parametrize("value", ["exp", "SoftPlus"])
def test_positive_bijector_setting(value):
    set_default_positive_bijector(value)
    assert default_positive_bijector() == value.lower()


def test_default_summary_fmt_setting():
    set_default_summary_fmt("html")
    assert default_summary_fmt() == "html"
    set_default_summary_fmt(None)
    assert default_summary_fmt() is None


def test_default_summary_fmt_errorcheck():
    with pytest.raises(ValueError):
        set_default_summary_fmt("this_format_definitely_does_not_exist")


@pytest.mark.parametrize('setter, getter, converter, dtype, value', [
    (set_default_int, default_int, to_default_int, np.int32, 3),
    (set_default_int, default_int, to_default_int, tf.int32, 3),
    (set_default_int, default_int, to_default_int, tf.int64, [3, 1, 4, 1, 5, 9]),
    (set_default_int, default_int, to_default_int, np.int64, [3, 1, 4, 1, 5, 9]),
    (set_default_float, default_float, to_default_float, np.float32, 3.14159),
    (set_default_float, default_float, to_default_float, tf.float32, [3.14159, 3.14159, 3.14159]),
    (set_default_float, default_float, to_default_float, np.float64, [3.14159, 3.14159, 3.14159]),
    (set_default_float, default_float, to_default_float, tf.float64, [3.14159, 3.14159, 3.14159]),
])
def test_native_to_default_dtype(setter, getter, converter, dtype, value):
    with gpflow.config.as_context():
        setter(dtype)
        assert converter(value).dtype == dtype
        assert converter(value).dtype == getter()