# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# 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 collections
import sys
import typing
import unittest

sys.path.insert(0, '.')

import config
import numpy as np
import utils
from utils import matmul, mul, nested, o2, reduce, reduce_dim

import paddle
import paddle.nn.functional as F
from paddle.incubate.autograd.utils import as_tensors


def make_v(f, inputs):
    outputs = as_tensors(f(*inputs))
    return [paddle.ones_like(x) for x in outputs]


class TestAutogradFunctional(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls.RAW_INPUTS = {
            'a': [1.0],
            'b': [1.0, 2.0],
            'c': [3.0, 4.0],
            'd': [[2.0], [3.0]],
            'A': [[1.0, 2.0], [2.0, 3.0], [3.0, 4.0]],
            'B': [[1.0, 2.0, 3.0], [2.0, 3.0, 4.0]],
        }

    def setUp(self):
        pass

    def gen_input(self, inp, stop_gradient=False):
        if isinstance(inp, paddle.Tensor):
            return inp
        return paddle.to_tensor(
            self.RAW_INPUTS[inp], stop_gradient=stop_gradient
        )

    def gen_inputs(self, inputs):
        if isinstance(inputs, list):
            inputs = [self.gen_input(x) for x in inputs]
        else:
            inputs = [self.gen_input(inputs)]
        return inputs

    def gen_test_pairs(
        self, func, inputs, v=None, create_graph=False, allow_unused=False
    ):
        def vjp_test():
            nonlocal v
            xs = self.gen_inputs(inputs)
            if v is not None:
                v = self.gen_inputs(v)
                outputs, inputs_grad = paddle.incubate.autograd.vjp(func, xs, v)
            else:
                outputs, inputs_grad = paddle.incubate.autograd.vjp(func, xs)
            return outputs, inputs_grad

        def grad_test():
            nonlocal v
            xs = self.gen_inputs(inputs)
            if v is not None:
                v = self.gen_inputs(v)
            outputs = func(*xs)
            if v is not None:
                inputs_grad = paddle.grad(
                    outputs,
                    xs,
                    v,
                    create_graph=create_graph,
                    allow_unused=allow_unused,
                )
            else:
                inputs_grad = paddle.grad(
                    outputs,
                    xs,
                    create_graph=create_graph,
                    allow_unused=allow_unused,
                )
            return outputs, inputs_grad

        return vjp_test, grad_test

    def gen_jvp_tests(
        self, func, inputs, v=None, create_graph=False, allow_unused=False
    ):
        def jvp_test():
            nonlocal v
            xs = self.gen_inputs(inputs)
            if v is not None:
                v = self.gen_inputs(v)
                outputs, outputs_grad = paddle.incubate.autograd.jvp(
                    func,
                    xs,
                    v,
                    create_graph=create_graph,
                    allow_unused=allow_unused,
                )
            else:
                outputs, outputs_grad = paddle.incubate.autograd.jvp(
                    func,
                    xs,
                    create_graph=create_graph,
                    allow_unused=allow_unused,
                )
            return outputs, outputs_grad

        return jvp_test

    def check_results(self, ref, res):
        type_error = 'Result is different than expected in shape or type'
        value_error = 'Result is different than expected values'
        if ref is None:
            self.assertTrue(res is None, type_error)
        elif isinstance(ref, paddle.Tensor):
            self.assertTrue(isinstance(res, paddle.Tensor), type_error)
            np.testing.assert_allclose(res, ref)
        else:
            self.assertTrue(len(res) == len(ref), type_error)
            for i in range(len(ref)):
                self.check_results(ref[i], res[i])
        return True


class TestVJP(TestAutogradFunctional):
    def func_vjp_i1o1(self):
        test_cases = [
            [reduce, 'A'],  # noqa
            [reduce_dim, 'A'],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            vjp, grad = self.gen_test_pairs(f, inputs)
            vjp_result, grad_result = vjp(), grad()
            self.check_results(grad_result, vjp_result)

    def func_vjp_i2o1(self):
        test_cases = [
            [matmul, ['A', 'B']],  # noqa
            [mul, ['b', 'c']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            vjp, grad = self.gen_test_pairs(f, inputs)
            vjp_result, grad_result = vjp(), grad()
            self.check_results(grad_result, vjp_result)

    def func_vjp_i2o2(self):
        test_cases = [
            [o2, ['A', 'A']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            v = make_v(f, inputs)
            vjp, grad = self.gen_test_pairs(f, inputs, v=v)
            vjp_result, grad_result = vjp(), grad()
            self.check_results(grad_result, vjp_result)

    def func_vjp_i2o2_omitting_v(self):
        test_cases = [
            [o2, ['A', 'A']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            vjp, grad = self.gen_test_pairs(f, inputs)
            vjp_result, grad_result = vjp(), grad()
            self.check_results(grad_result, vjp_result)

    def func_vjp_nested(self):
        x = self.gen_input('a')
        test_cases = [
            [nested(x), 'a'],  # noqa
        ]
        for f, inputs in test_cases:
            vjp, grad = self.gen_test_pairs(f, inputs)
            vjp_result, grad_result = vjp(), grad()
            self.check_results(grad_result, vjp_result)

    def func_vjp_aliased_input(self):
        x = self.gen_input('a')
        ref = self.gen_test_pairs(nested(x), 'a')[0]
        aliased = self.gen_test_pairs(nested(x), x)[0]
        ref_result, aliased_result = ref(), aliased()
        self.check_results(ref_result, aliased_result)

    def test_all_cases(self):
        self.func_vjp_i1o1()
        self.func_vjp_i2o1()
        self.func_vjp_i2o2()
        self.func_vjp_i2o2_omitting_v()
        self.func_vjp_nested()
        self.func_vjp_aliased_input()

    def test_input_single_tensor(self):
        self.assertIsInstance(
            paddle.incubate.autograd.vjp(paddle.tanh, paddle.rand((3, 4)))[1],
            paddle.fluid.framework.Variable,
        )


@utils.place(config.DEVICES)
@utils.parameterize(
    (utils.TEST_CASE_NAME, 'fun', 'xs', 'v', 'expected_exception'),
    (
        (
            'v_shape_not_equal_ys',
            utils.square,
            np.random.rand(3),
            np.random.rand(1),
            RuntimeError,
        ),
    ),
)
class TestVJPException(unittest.TestCase):
    def test_vjp(self):
        with self.assertRaises(self.expected_exception):
            paddle.incubate.autograd.vjp(
                self.fun, paddle.to_tensor(self.xs), paddle.to_tensor(self.v)
            )


def jac(grad_fn, f, inputs):
    assert grad_fn in [
        paddle.incubate.autograd.vjp,
        paddle.incubate.autograd.jvp,
    ]
    if grad_fn is paddle.incubate.autograd.jvp:
        vs = [paddle.zeros_like(x) for x in inputs]
    else:
        outputs = f(*inputs)
        if isinstance(outputs, paddle.Tensor):
            outputs = [outputs]
        vs = [paddle.zeros_like(y) for y in outputs]
    JJ_cols = []
    for i, v in enumerate(vs):
        v = v.flatten()
        for j in range(len(v)):
            _v = paddle.zeros_like(v).detach()
            _v[j] = 1.0
            _v = _v.reshape(vs[i].shape)
            _vs = vs.copy()
            _vs[i] = _v
            _, grads = grad_fn(f, inputs, _vs)
            if isinstance(grads, typing.Sequence):
                d_outs = paddle.concat([d_out.flatten() for d_out in grads])
            else:
                d_outs = grads.flatten()
            JJ_cols.append(d_outs)
    # JJ is the fully unrolled jacobian
    JJ = paddle.stack(JJ_cols)
    if grad_fn is paddle.incubate.autograd.vjp:
        JJ = JJ.t()
    return JJ


class TestJVP(TestAutogradFunctional):
    def func_jvp_i1o1(self):
        test_cases = [
            [reduce, 'A'],  # noqa
            [reduce_dim, 'A'],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            forward_jac = jac(paddle.incubate.autograd.jvp, f, inputs)
            reverse_jac = jac(paddle.incubate.autograd.vjp, f, inputs)
            self.check_results(forward_jac, reverse_jac)

    def func_jvp_i2o1(self):
        test_cases = [  # noqa
            [matmul, ['A', 'B']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            forward_jac = jac(paddle.incubate.autograd.jvp, f, inputs)
            reverse_jac = jac(paddle.incubate.autograd.vjp, f, inputs)
            self.check_results(forward_jac, reverse_jac)

    def func_jvp_i2o2(self):
        test_cases = [  # noqa
            [o2, ['A', 'A']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            forward_jac = jac(paddle.incubate.autograd.jvp, f, inputs)
            reverse_jac = jac(paddle.incubate.autograd.vjp, f, inputs)
            self.check_results(forward_jac, reverse_jac)

    def func_jvp_i2o2_omitting_v(self):
        test_cases = [  # noqa
            [o2, ['A', 'A']],  # noqa
        ]  # noqa
        for f, inputs in test_cases:
            inputs = self.gen_inputs(inputs)
            results_omitting_v = paddle.incubate.autograd.jvp(f, inputs)
            v = [paddle.ones_like(x) for x in inputs]
            results_with_v = paddle.incubate.autograd.jvp(f, inputs, v)
            self.check_results(results_omitting_v, results_with_v)

    def test_all_cases(self):
        self.func_jvp_i1o1()
        self.func_jvp_i2o1()
        self.func_jvp_i2o2()
        self.func_jvp_i2o2_omitting_v()


@utils.place(config.DEVICES)
@utils.parameterize(
    (utils.TEST_CASE_NAME, 'func', 'xs'),
    (
        ('1d_in_1d_out', utils.square, np.array([2.0, 3.0])),
        ('3d_in_3d_out', utils.square, np.random.rand(2, 3, 4)),
        ('single_in_single_out', utils.square, np.random.rand(2, 3)),
        (
            'multi_in_single_out',
            paddle.matmul,
            (np.random.rand(2, 2), np.random.rand(2, 2)),
        ),
    ),
)
class TestJacobianNoBatch(unittest.TestCase):
    def setUp(self):
        self._dtype = (
            self.xs[0].dtype
            if isinstance(self.xs, typing.Sequence)
            else self.xs.dtype
        )
        self._eps = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("eps")
        )
        self._rtol = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("rtol")
        )
        self._atol = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("atol")
        )

    def test_jacobian(self):
        xs = (
            [paddle.to_tensor(x) for x in self.xs]
            if isinstance(self.xs, typing.Sequence)
            else paddle.to_tensor(self.xs)
        )
        self._actual = paddle.incubate.autograd.Jacobian(self.func, xs, False)
        self._expected = self._get_expected()

        Index = collections.namedtuple('Index', ('type', 'value'))
        indexes = (
            Index('all', (slice(0, None, None), slice(0, None, None))),
            Index('row', (0, slice(0, None, None))),
            Index('col', (slice(0, None, None), 0)),
            Index('multi-row', (slice(0, 2, 1), slice(0, None, None))),
        )
        self.assertEqual(self._actual[:].numpy().dtype, self._expected.dtype)
        for index in indexes:
            np.testing.assert_allclose(
                self._actual.__getitem__(index.value),
                self._expected.__getitem__(index.value),
                rtol=self._rtol,
                atol=self._atol,
                err_msg=f'Testcase {index.type} index not passed, value is {index.value}',
            )

    def _get_expected(self):
        xs = (
            [paddle.to_tensor(x) for x in self.xs]
            if isinstance(self.xs, typing.Sequence)
            else paddle.to_tensor(self.xs)
        )
        jac = utils._compute_numerical_jacobian(
            self.func, xs, self._eps, self._dtype
        )
        return utils._np_concat_matrix_sequence(jac, utils.MatrixFormat.NM)


@utils.place(config.DEVICES)
@utils.parameterize(
    (utils.TEST_CASE_NAME, 'func', 'xs'),
    (
        (
            '1d_in_1d_out',
            utils.square,
            np.array([[1.0, 2.0, 3.0], [3.0, 4.0, 3.0]]),
        ),
        ('3d_in_3d_out', utils.square, np.random.rand(2, 3, 4)),
        ('multi_in_single_out', utils.square, np.random.rand(2, 3)),
    ),
)
class TestJacobianBatchFirst(unittest.TestCase):
    def setUp(self):
        self._dtype = (
            self.xs[0].dtype
            if isinstance(self.xs, typing.Sequence)
            else self.xs.dtype
        )
        self._eps = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("eps")
        )
        self._rtol = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("rtol")
        )
        self._atol = (
            config.TOLERANCE.get(str(self._dtype))
            .get("first_order_grad")
            .get("atol")
        )

    def test_jacobian(self):
        xs = (
            [paddle.to_tensor(x) for x in self.xs]
            if isinstance(self.xs, typing.Sequence)
            else paddle.to_tensor(self.xs)
        )
        self._actual = paddle.incubate.autograd.Jacobian(self.func, xs, True)
        self._expected = self._get_expected()

        Index = collections.namedtuple('Index', ('type', 'value'))
        indexes = (
            Index(
                'all',
                (
                    slice(0, None, None),
                    slice(0, None, None),
                    slice(0, None, None),
                ),
            ),
            Index('row', (slice(0, None, None), 0, slice(0, None, None))),
            Index('col', (slice(0, None, None), slice(0, None, None), 0)),
            Index(
                'batch',
                (slice(0, 2, None), slice(0, None, None), slice(0, None, None)),
            ),
            Index(
                'multi_row',
                (slice(0, 1, None), slice(0, 2, 1), slice(0, None, None)),
            ),
        )
        self.assertEqual(self._actual[:].numpy().dtype, self._expected.dtype)
        for index in indexes:
            np.testing.assert_allclose(
                self._actual.__getitem__(index.value),
                self._expected.__getitem__(index.value),
                rtol=self._rtol,
                atol=self._atol,
                err_msg=f'Testcase {index.type} index not passed, value is {index.value}',
            )

    def _get_expected(self):
        xs = (
            [paddle.to_tensor(x) for x in self.xs]
            if isinstance(self.xs, typing.Sequence)
            else paddle.to_tensor(self.xs)
        )
        jac = utils._compute_numerical_batch_jacobian(
            self.func, xs, self._eps, self._dtype, False
        )
        jac = utils._np_concat_matrix_sequence(jac, utils.MatrixFormat.NBM)
        return utils._np_transpose_matrix_format(
            jac, utils.MatrixFormat.NBM, utils.MatrixFormat.BNM
        )


class TestHessianNoBatch(unittest.TestCase):
    @classmethod
    def setUpClass(self):
        self.shape = (2, 2)
        self.dtype = 'float32'
        self.np_dtype = np.float32
        self.numerical_delta = (
            config.TOLERANCE.get(self.dtype).get("second_order_grad").get("eps")
        )
        self.rtol = (
            config.TOLERANCE.get(self.dtype)
            .get("second_order_grad")
            .get("rtol")
        )
        self.atol = (
            config.TOLERANCE.get(self.dtype)
            .get("second_order_grad")
            .get("atol")
        )
        self.x = paddle.rand(shape=self.shape, dtype=self.dtype)
        self.y = paddle.rand(shape=self.shape, dtype=self.dtype)

    def func_single_input(self):
        def func(x):
            return paddle.sum(paddle.matmul(x, x))

        numerical_hessian = utils._compute_numerical_hessian(
            func, self.x, self.numerical_delta, self.np_dtype
        )
        numerical_hessian = utils._np_concat_matrix_sequence(numerical_hessian)

        self.x.stop_gradient = False
        hessian = paddle.incubate.autograd.Hessian(func, self.x)
        np.testing.assert_allclose(
            hessian[:].numpy(), numerical_hessian, self.rtol, self.atol
        )

    def func_multi_input(self):
        def func(x, y):
            return paddle.sum(paddle.matmul(x, y))

        numerical_hessian = utils._compute_numerical_hessian(
            func, [self.x, self.y], self.numerical_delta, self.np_dtype
        )
        numerical_hessian = utils._np_concat_matrix_sequence(numerical_hessian)
        self.x.stop_gradient = False
        self.y.stop_gradient = False
        hessian = paddle.incubate.autograd.Hessian(func, [self.x, self.y])
        np.testing.assert_allclose(
            hessian[:].numpy(),
            numerical_hessian,
            rtol=self.rtol,
            atol=self.atol,
        )

    def func_allow_unused_true(self):
        def func(x, y):
            return paddle.sum(paddle.matmul(x, x))

        numerical_hessian = utils._compute_numerical_hessian(
            func, [self.x, self.y], self.numerical_delta, self.np_dtype
        )
        numerical_hessian = utils._np_concat_matrix_sequence(numerical_hessian)
        self.x.stop_gradient = False
        self.y.stop_gradient = False
        hessian = paddle.incubate.autograd.Hessian(func, [self.x, self.y])
        np.testing.assert_allclose(
            hessian[:].numpy(), numerical_hessian, self.rtol, self.atol
        )

    def func_create_graph_true(self):
        def func(x):
            return paddle.sum(F.sigmoid(x))

        numerical_hessian = utils._compute_numerical_hessian(
            func, self.x, self.numerical_delta, self.np_dtype
        )
        numerical_hessian = utils._np_concat_matrix_sequence(numerical_hessian)
        self.x.stop_gradient = False
        hessian = paddle.incubate.autograd.Hessian(func, self.x)
        assert not hessian[:].stop_gradient
        np.testing.assert_allclose(
            hessian[:].numpy(), numerical_hessian, self.rtol, self.atol
        )

    def func_out_not_single(self):
        def func(x):
            return x * x

        with self.assertRaises(RuntimeError):
            paddle.incubate.autograd.Hessian(func, paddle.ones([3]))

    def test_all_cases(self):
        self.setUpClass()
        self.func_single_input()
        self.func_multi_input()
        self.func_allow_unused_true()
        self.func_create_graph_true()
        self.func_out_not_single()


class TestHessianBatchFirst(unittest.TestCase):
    @classmethod
    def setUpClass(self):
        self.x_shape = (5, 2)
        self.weight_shape = (2, 4)
        self.y_shape = (5, 2)
        self.nbatch, self.nrow = 5, 2
        self.dtype = 'float32'
        self.np_dtype = np.float32
        self.numerical_delta = (
            config.TOLERANCE.get(self.dtype).get('second_order_grad').get('eps')
        )
        self.rtol = (
            config.TOLERANCE.get(self.dtype)
            .get('second_order_grad')
            .get('rtol')
        )
        self.atol = (
            config.TOLERANCE.get(self.dtype)
            .get('second_order_grad')
            .get('atol')
        )
        self.x = paddle.rand(shape=self.x_shape, dtype=self.dtype)
        self.weight = paddle.rand(shape=self.weight_shape, dtype=self.dtype)
        self.y = paddle.rand(shape=self.y_shape, dtype=self.dtype)

    def func_single_input(self):
        def func(x):
            return paddle.matmul(x * x, self.weight)[:, 0:1]

        expected = utils._compute_numerical_batch_hessian(
            func, self.x, self.numerical_delta, self.np_dtype
        )

        H = paddle.incubate.autograd.Hessian(func, self.x, is_batched=True)
        actual = utils._np_transpose_matrix_format(
            H[:].numpy(), utils.MatrixFormat.BNM, utils.MatrixFormat.NBM
        )
        actual = actual.reshape((H.shape[1], -1))

        np.testing.assert_allclose(actual, expected, self.rtol, self.atol)

    def func_multi_input(self):
        def func(x, y):
            return paddle.matmul(x * x * y * y, self.weight)[:, 0:1]

        xs_len = 2
        expected = utils._compute_numerical_batch_hessian(
            func, [self.x, self.y], self.numerical_delta, self.np_dtype
        )
        expected = np.reshape(
            np.array(expected),
            (xs_len, xs_len, self.nrow, self.nbatch, self.nrow),
        )
        expected = [list(row) for row in expected]
        expected = utils._np_concat_matrix_sequence(expected)

        self.x.stop_gradient = False
        self.y.stop_gradient = False
        H = paddle.incubate.autograd.Hessian(
            func, [self.x, self.y], is_batched=True
        )
        actual = utils._np_transpose_matrix_format(
            H[:].numpy(), utils.MatrixFormat.BNM, utils.MatrixFormat.NBM
        )

        np.testing.assert_allclose(actual, expected, self.rtol, self.atol)

    def func_allow_unused(self):
        def func(x, y):
            return paddle.matmul(x * x, self.weight)[:, 0:1]

        xs_len = 2
        expected = utils._compute_numerical_batch_hessian(
            func, [self.x, self.y], self.numerical_delta, self.np_dtype
        )
        expected = np.reshape(
            np.array(expected),
            (xs_len, xs_len, self.nrow, self.nbatch, self.nrow),
        )
        expected = [list(row) for row in expected]
        expected = utils._np_concat_matrix_sequence(expected)
        expected = utils._np_transpose_matrix_format(
            expected, utils.MatrixFormat.NBM, utils.MatrixFormat.BNM
        )

        actual = paddle.incubate.autograd.Hessian(
            func, [self.x, self.y], is_batched=True
        )[:]

        np.testing.assert_allclose(
            actual, expected, rtol=self.rtol, atol=self.atol
        )

    def func_stop_gradient(self):
        def func(x):
            return paddle.matmul(x * x, self.weight)[:, 0:1]

        expected = utils._compute_numerical_batch_hessian(
            func, self.x, self.numerical_delta, self.np_dtype
        )

        x = self.x.clone()
        x.stop_gradient = True
        H = paddle.incubate.autograd.Hessian(func, self.x, is_batched=True)[:]
        actual = utils._np_transpose_matrix_format(
            H[:].numpy(), utils.MatrixFormat.BNM, utils.MatrixFormat.NBM
        )
        actual = actual.reshape((H.shape[1], -1))

        np.testing.assert_allclose(actual, expected, self.rtol, self.atol)

    def func_out_not_single(self):
        def func(x):
            return x * x

        with self.assertRaises(RuntimeError):
            paddle.incubate.autograd.Hessian(
                func, paddle.ones((3, 3)), is_batched=True
            )

    def test_all_cases(self):
        self.setUpClass()
        self.func_single_input()
        self.func_multi_input()
        self.func_allow_unused()
        self.func_stop_gradient()
        self.func_out_not_single()


if __name__ == "__main__":
    np.random.seed(2022)
    unittest.main()
