#   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.

from __future__ import print_function

import unittest
import numpy as np
import paddle.fluid as fluid
import paddle.fluid.core as core
from paddle.fluid.op import Operator
from paddle.fluid.tests.unittests.op_test import (
    convert_float_to_uint16, convert_uint16_to_float, OpTest, OpTestTool)
import paddle
import paddle.static.amp as amp
import struct


@unittest.skipIf(not core.supports_bfloat16(),
                 'place does not support BF16 evaluation')
class TestSGDOpBF16(OpTest):
    def setUp(self):
        self.op_type = 'sgd'
        self.dtype = np.uint16
        self.conf()
        w = np.random.random((self.h, self.w)).astype('float32')
        w_bf16 = convert_float_to_uint16(w)
        g = np.random.random((self.h, self.w)).astype('float32')
        g_bf16 = convert_float_to_uint16(g)
        lr = np.array([0.1]).astype('float32')
        lr_bf16 = convert_float_to_uint16(lr)

        self.inputs = {'Param': w_bf16, 'Grad': g_bf16, 'LearningRate': lr_bf16}
        self.outputs = {'ParamOut': w - lr * g}

    def conf(self):
        self.h = 102
        self.w = 105

    def test_check_output(self):
        self.check_output_with_place(core.CPUPlace(), check_dygraph=False)


@unittest.skipIf(not core.supports_bfloat16(),
                 'place does not support BF16 evaluation')
class TestSGDOpCase8XBF16(TestSGDOpBF16):
    def conf(self):
        self.h = 10
        self.w = 64


class TestSparseSGDOpBF16(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        np.random.seed(12345)

    def ref_optimize(self, params, grad_rows, grad_array, lr_value):
        reference = np.copy(params)
        for index, id in enumerate(grad_rows):
            reference[id] = params[id] - lr_value * grad_array[index]
        return reference

    def check_output(self, actual_bf16, reference, atol=0, rtol=0.15e-2):
        actual_fp32 = convert_uint16_to_float(actual_bf16)
        np.testing.assert_allclose(actual_fp32, reference, atol=atol, rtol=rtol)

    def create_sparse_grad_var(self, scope, place, height, rows, row_numel):
        grad_selected_rows = scope.var('Grad').get_selected_rows()
        grad_selected_rows.set_height(height)
        grad_selected_rows.set_rows(rows)
        grad_array = np.random.random((len(rows), row_numel)).astype('float32')
        np_array_bf16 = convert_float_to_uint16(grad_array)

        grad_tensor = grad_selected_rows.get_tensor()
        grad_tensor.set(np_array_bf16, place)

        return grad_tensor, grad_array

    def create_dense_param_var(self, scope, place, height, width):
        param_tensor = scope.var('Param').get_tensor()
        param_array = np.random.random((height, width)).astype('float32')
        param_array_bf16 = convert_float_to_uint16(param_array)
        param_tensor.set(param_array_bf16, place)

        return param_tensor, param_array

    def create_sparse_param_var(self, scope, place, height, rows, row_numel):
        param_selected_rows = scope.var('Param').get_selected_rows()
        param_selected_rows.set_height(height)
        param_selected_rows.set_rows(rows)
        param_selected_rows.sync_index()
        param_array = np.random.random((len(rows), row_numel)).astype('float32')
        np_array_bf16 = convert_float_to_uint16(param_array)

        param_tensor = param_selected_rows.get_tensor()
        param_tensor.set(np_array_bf16, place)

        return param_tensor, param_array

    def create_dense_lr_var(self, scope, place):
        lr_tensor = scope.var('LearningRate').get_tensor()
        lr_value = np.random.uniform()
        lr_array = np.full((1), lr_value, np.float32)
        lr_array_bf16 = convert_float_to_uint16(lr_array)
        lr_tensor.set(lr_array_bf16, place)

        return lr_tensor, lr_value


@unittest.skipIf(not core.supports_bfloat16(),
                 'place does not support BF16 evaluation')
class TestSparseGradSGDOpBF16(TestSparseSGDOpBF16):
    def setUp(self):
        self.setup_params()

    def setup_params(self):
        self.grad_height = 10
        self.grad_rows = [0, 4, 7]
        self.grad_row_numel = 12

    def test_sparse_grad_sgd(self):
        scope = core.Scope()
        place = core.CPUPlace()
        _, grad_array = self.create_sparse_grad_var(
            scope, place, self.grad_height, self.grad_rows, self.grad_row_numel)
        param_tensor, param_array = self.create_dense_param_var(
            scope, place, self.grad_height, self.grad_row_numel)
        _, lr_value = self.create_dense_lr_var(scope, place)

        sgd_op = Operator(
            'sgd',
            Param='Param',
            Grad='Grad',
            ParamOut='Param',
            LearningRate='LearningRate')
        sgd_op.run(scope, place)

        reference = self.ref_optimize(param_array, self.grad_rows, grad_array,
                                      lr_value)
        output = np.array(param_tensor)
        self.check_output(output, reference, atol=5e-3, rtol=1e-1)


@unittest.skipIf(not core.supports_bfloat16(),
                 'place does not support BF16 evaluation')
class TestSparseGradSGDOpBF16Case2(TestSparseGradSGDOpBF16):
    def setup_params(self):
        self.grad_height = 14
        self.grad_rows = [1, 4, 12, 7, 8]
        self.grad_row_numel = 16


class TestSparseGradSGDOpBF16Case3(TestSparseGradSGDOpBF16):
    def setup_params(self):
        self.grad_height = 10
        self.grad_rows = [0, 4, 7]
        self.grad_row_numel = 120


@unittest.skipIf(not core.supports_bfloat16(),
                 'place does not support BF16 evaluation')
class TestSparseGradParamSGDOpBF16(TestSparseSGDOpBF16):
    def setUp(self):
        self.setup_params()

    def setup_params(self):
        self.grad_height = 10
        self.grad_rows = [0, 4, 7]
        self.grad_row_numel = 12
        self.param_rows = [a for a in range(self.grad_height)]

    def test_sparse_param_grad_sgd(self):
        scope = core.Scope()
        place = core.CPUPlace()
        _, grad_array = self.create_sparse_grad_var(
            scope, place, self.grad_height, self.grad_rows, self.grad_row_numel)
        param_tensor, param_array = self.create_sparse_param_var(
            scope, place, self.grad_height, self.param_rows,
            self.grad_row_numel)
        _, lr_value = self.create_dense_lr_var(scope, place)

        sgd_op = Operator(
            'sgd',
            Param='Param',
            Grad='Grad',
            ParamOut='Param',
            LearningRate='LearningRate')
        sgd_op.run(scope, place)

        reference = self.ref_optimize(param_array, self.grad_rows, grad_array,
                                      lr_value)
        output = np.array(param_tensor)
        self.check_output(output, reference, atol=5e-3, rtol=1e-1)


class TestSparseGradParamSGDOpBF16Case2(TestSparseGradParamSGDOpBF16):
    def setup_params(self):
        self.grad_height = 14
        self.grad_rows = [1, 4, 12, 7, 8]
        self.grad_row_numel = 16
        self.param_rows = [a for a in range(self.grad_height)]


@OpTestTool.skip_if_not_cpu_bf16()
class TestSGDOpBF16API(unittest.TestCase):
    def setUp(self):
        self.sample_count = 20
        self.value = np.random.random()

        self.ids_shape = (32, 1)
        self.w_shape = (64, 16)
        self.y_shape = (32, 16)
        self.learning_rate = 0.1

        np.random.seed(12345)
        self._set_initializer()
        fluid.set_flags({'FLAGS_use_mkldnn': True})

    def _fp322bf16(self, val: np.float32):
        return np.uint16(struct.unpack('<I', struct.pack('<f', val))[0] >> 16)

    def _bf162fp32(self, val: np.uint16):
        return np.float32(struct.unpack('<f', struct.pack('<I', val << 16))[0])

    def _add_bf16(self, lhs: np.uint16, rhs: np.uint16):
        return self._fp322bf16(self._bf162fp32(lhs) + self._bf162fp32(rhs))

    def _sub_bf16(self, lhs: np.uint16, rhs: np.uint16):
        return self._fp322bf16(self._bf162fp32(lhs) - self._bf162fp32(rhs))

    def _mul_bf16(self, lhs: np.uint16, rhs: np.uint16):
        return self._fp322bf16(self._bf162fp32(lhs) * self._bf162fp32(rhs))

    def _reference(self, data, emb_weight, bf16=False):
        emb_out_shape = np.array(
            [self.ids_shape[0], self.w_shape[1]], dtype=np.int64)
        mean_grad_value = np.float32(1.0) / np.prod(
            emb_out_shape, dtype=np.float32)
        if bf16:
            mean_grad = np.full(
                emb_out_shape,
                self._fp322bf16(mean_grad_value),
                dtype=np.uint16)
        else:
            mean_grad = np.full(
                emb_out_shape, mean_grad_value, dtype=np.float32)
        # add_grad = 1 * mean_grad
        out_dtype = np.uint16 if bf16 else np.float32
        lookup_table_grad = np.zeros(self.w_shape, dtype=out_dtype)

        # indexes may dupplicate
        if bf16:
            for i, idx in enumerate(data):
                idxv = idx[0]
                for j in range(self.w_shape[1]):
                    lookup_table_grad[idxv, j] = self._add_bf16(
                        lookup_table_grad[idxv, j], mean_grad[i, j])

            ref_grad = np.ndarray(shape=emb_weight.shape, dtype=np.uint16)
            lr_bf16 = self._fp322bf16(self.learning_rate)

            for i, row in enumerate(emb_weight):
                for j, val in enumerate(row):
                    ref_grad[i, j] = self._sub_bf16(
                        val, self._mul_bf16(lr_bf16, lookup_table_grad[i, j]))
        else:
            for i, idx in enumerate(data):
                lookup_table_grad[idx, :] += mean_grad[i]
            ref_grad = emb_weight - self.learning_rate * lookup_table_grad
        return ref_grad

    def _check_output(self, actual, reference, bf16=False, atol=0,
                      rtol=0.15e-2):
        output = actual if bf16 else convert_uint16_to_float(actual)
        if bf16:
            np.testing.assert_allclose(output, reference, atol=atol, rtol=rtol)
        else:
            try:
                print('Compare with FP32 values:')
                np.testing.assert_allclose(
                    output, reference, atol=atol, rtol=rtol)
            except AssertionError as e:
                print(e)

    def _set_initializer(self):
        self.initializer = fluid.initializer.Constant(value=self.value)

    def _data_reader(self):
        for sample in range(self.sample_count):
            label = -1 * np.random.random(self.y_shape).astype('float32')
            data = np.random.randint(0, 9, self.ids_shape).astype("int64")
            yield data, label

    def test_sgd(self):
        place = fluid.CPUPlace()
        main = fluid.Program()
        with fluid.program_guard(main):
            x = fluid.layers.data(name='X', shape=self.ids_shape, dtype='int64')
            label = fluid.layers.data(
                name='Y', shape=self.y_shape, dtype='uint16')
            emb = fluid.layers.embedding(
                input=x,
                size=self.w_shape,
                param_attr=fluid.ParamAttr(
                    name="emb_weight", initializer=self.initializer),
                is_sparse=False,
                dtype="uint16")  # bfloat16
            cost = fluid.layers.elementwise_add(emb, label)
            avg_cost = paddle.mean(cost)

            sgd_optimizer = paddle.optimizer.SGD(
                learning_rate=self.learning_rate)
            sgd_optimizer = amp.bf16.decorate_bf16(
                sgd_optimizer,
                amp_lists=amp.bf16.AutoMixedPrecisionListsBF16(
                    custom_bf16_list={'lookup_table', }),
                use_bf16_guard=False,
                use_pure_bf16=True)
            sgd_optimizer.minimize(
                avg_cost, startup_program=fluid.default_startup_program())

            train_reader = paddle.batch(self._data_reader, batch_size=1)
            exe = fluid.Executor(place)
            exe.run(fluid.default_startup_program())
            test_prog = main.clone(for_test=True)
            sgd_optimizer.amp_init(
                place, test_program=test_prog, use_bf16_test=True)

            ref_emb = np.full(self.w_shape, self.value, dtype=np.float32)
            ref_emb_bf16 = np.full(
                self.w_shape, self._fp322bf16(self.value), dtype=np.uint16)
            emb_weight = []

            for sample in train_reader():
                data = sample[0][0]
                label = sample[0][1]
                y_bf16 = convert_float_to_uint16(label)
                emb_weight = exe.run(main,
                                     feed={'X': data,
                                           'Y': y_bf16},
                                     fetch_list=['emb_weight'])

                ref_emb = self._reference(data, ref_emb)
                ref_emb_bf16 = self._reference(data, ref_emb_bf16, True)

            self._check_output(emb_weight[0], ref_emb_bf16, bf16=True)
            self._check_output(emb_weight[0], ref_emb)


if __name__ == '__main__':
    paddle.enable_static()
    unittest.main()
