# Copyright (c) 2022 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 os
import tempfile
import unittest

import numpy as np

import paddle
import paddle.nn as nn
import paddle.nn.functional as F
from paddle.distributed.fleet import auto

paddle.enable_static()

batch_size = 2
hidden_size = 1024
# sequence_len = 512
image_size = hidden_size
class_num = 10


class MLPLayer(nn.Layer):
    def __init__(
        self,
        hidden_size=1024,
        intermediate_size=4 * 1024,
        dropout_ratio=0.1,
        initializer_range=0.02,
    ):
        super().__init__()
        d_model = hidden_size
        dim_feedforward = intermediate_size
        weight_attr = paddle.ParamAttr(
            initializer=nn.initializer.Normal(mean=0.0, std=initializer_range)
        )
        bias_attr = None

        self.linear0 = nn.Linear(
            d_model, dim_feedforward, weight_attr, bias_attr=bias_attr
        )
        self.linear1 = nn.Linear(
            dim_feedforward, d_model, weight_attr, bias_attr=bias_attr
        )
        self.linear2 = nn.Linear(d_model, 1, weight_attr, bias_attr=bias_attr)
        self.norm = nn.LayerNorm(d_model, epsilon=1e-5)
        self.dropout = nn.Dropout(dropout_ratio, mode="upscale_in_train")

    def forward(self, input):
        auto.shard_tensor(input, auto.ProcessMesh([0]), [None, None])
        out = self.norm(input)
        out = self.linear0(out)
        out = F.gelu(out, approximate=True)
        out = self.linear1(out)
        out = self.dropout(out)
        out = self.linear2(out)
        return out


class TestSaveLoad(unittest.TestCase):
    def test_fp32_save_fp16_load(self):

        mlp = MLPLayer(
            hidden_size=hidden_size,
            intermediate_size=4 * hidden_size,
            dropout_ratio=0.1,
            initializer_range=0.02,
        )
        loss = paddle.nn.CrossEntropyLoss()
        optimizer = paddle.optimizer.Adam(
            learning_rate=0.00001,
            beta1=0.9,
            beta2=0.999,
            epsilon=1e-08,
            grad_clip=None,
        )
        metric = paddle.metric.Accuracy()

        inputs_spec = [
            paddle.static.InputSpec(
                shape=[batch_size, image_size], name="input", dtype="float32"
            )
        ]
        labels_spec = [
            paddle.static.InputSpec(
                shape=[batch_size, 1], name="label", dtype="int64"
            )
        ]

        # build fp32 model
        strategy = auto.Strategy()
        strategy.auto_mode = "semi"
        engine_fp32 = auto.Engine(
            mlp, loss, optimizer, metric, strategy=strategy
        )
        engine_fp32.prepare(inputs_spec, labels_spec, mode="train")
        fp32_state = {
            k: np.array(v)
            for k, v in engine_fp32.main_program.state_dict("param").items()
        }
        # save
        temp_dir = tempfile.TemporaryDirectory()
        model_filename = os.path.join(temp_dir.name, 'mlp')
        engine_fp32.save(model_filename)

        # build fp16 model
        strategy = auto.Strategy()
        strategy.auto_mode = "semi"
        amp = strategy.amp
        amp.enable = True
        amp.dtype = "float16"
        amp.level = "o2"
        engine_fp16 = auto.Engine(
            mlp, loss, optimizer, metric, strategy=strategy
        )
        engine_fp16.load(model_filename)
        engine_fp16.prepare(inputs_spec, labels_spec, mode="train")
        fp16_state = {
            k: np.array(v)
            for k, v in engine_fp16.main_program.state_dict("param").items()
        }

        # check param
        for name, fp32_param in fp32_state.items():
            fp16_param = fp16_state[name]
            if "layer_norm" in name:
                assert fp16_param.dtype == np.float32
            else:
                assert fp16_param.dtype == np.float16
            np.testing.assert_allclose(fp32_param, fp16_param, atol=1e-4)

        temp_dir.cleanup()


if __name__ == "__main__":
    unittest.main()
