#   copyright (c) 2018 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 unittest
import os
import time
import sys
import random
import math
import functools
import contextlib
import struct
import numpy as np
import paddle
import paddle.fluid as fluid
from paddle.dataset.common import download
from paddle.fluid.contrib.slim.quantization import PostTrainingQuantization

paddle.enable_static()

random.seed(0)
np.random.seed(0)


class TestPostTrainingQuantization(unittest.TestCase):
    def setUp(self):
        self.download_path = 'int8/download'
        self.cache_folder = os.path.expanduser('~/.cache/paddle/dataset/' +
                                               self.download_path)
        self.timestamp = time.strftime('%Y-%m-%d-%H-%M-%S', time.localtime())
        self.int8_model_path = os.path.join(os.getcwd(),
                                            "post_training_" + self.timestamp)
        try:
            os.system("mkdir -p " + self.int8_model_path)
        except Exception as e:
            print("Failed to create {} due to {}".format(self.int8_model_path,
                                                         str(e)))
            sys.exit(-1)

    def tearDown(self):
        try:
            os.system("rm -rf {}".format(self.int8_model_path))
        except Exception as e:
            print("Failed to delete {} due to {}".format(self.int8_model_path,
                                                         str(e)))

    def cache_unzipping(self, target_folder, zip_path):
        if not os.path.exists(target_folder):
            cmd = 'mkdir {0} && tar xf {1} -C {0}'.format(target_folder,
                                                          zip_path)
            os.system(cmd)

    def download_model(self, data_url, data_md5, folder_name):
        download(data_url, self.download_path, data_md5)
        file_name = data_url.split('/')[-1]
        zip_path = os.path.join(self.cache_folder, file_name)
        print('Data is downloaded at {0}'.format(zip_path))

        data_cache_folder = os.path.join(self.cache_folder, folder_name)
        self.cache_unzipping(data_cache_folder, zip_path)
        return data_cache_folder

    def get_batch_reader(self, data_path, place):
        def reader():
            with open(data_path, 'rb') as in_file:
                while True:
                    plen = in_file.read(4)
                    if plen is None or len(plen) != 4:
                        break

                    alllen = struct.unpack('i', plen)[0]
                    label_len = alllen & 0xFFFF
                    seq_len = (alllen >> 16) & 0xFFFF

                    label = in_file.read(4 * label_len)
                    label = np.frombuffer(
                        label, dtype=np.int32).reshape([len(label) // 4])
                    if label.shape[0] != 1 or label[0] > 6350:
                        continue

                    feat = in_file.read(4 * seq_len * 8)
                    feat = np.frombuffer(
                        feat,
                        dtype=np.float32).reshape([len(feat) // 4 // 8, 8])
                    lod_feat = [feat.shape[0]]

                    minputs = fluid.create_lod_tensor(feat, [lod_feat], place)
                    yield [minputs]

        return reader

    def get_simple_reader(self, data_path, place):
        def reader():
            with open(data_path, 'rb') as in_file:
                while True:
                    plen = in_file.read(4)
                    if plen is None or len(plen) != 4:
                        break

                    alllen = struct.unpack('i', plen)[0]
                    label_len = alllen & 0xFFFF
                    seq_len = (alllen >> 16) & 0xFFFF

                    label = in_file.read(4 * label_len)
                    label = np.frombuffer(
                        label, dtype=np.int32).reshape([len(label) // 4])
                    if label.shape[0] != 1 or label[0] > 6350:
                        continue

                    feat = in_file.read(4 * seq_len * 8)
                    feat = np.frombuffer(
                        feat,
                        dtype=np.float32).reshape([len(feat) // 4 // 8, 8])
                    lod_feat = [feat.shape[0]]

                    minputs = fluid.create_lod_tensor(feat, [lod_feat], place)
                    yield minputs, label

        return reader

    def run_program(self, model_path, data_path, infer_iterations):
        print("test model path:" + model_path)
        place = fluid.CPUPlace()
        exe = fluid.Executor(place)
        [infer_program, feed_dict, fetch_targets] = \
            fluid.io.load_inference_model(model_path, exe)

        val_reader = self.get_simple_reader(data_path, place)

        all_num = 0
        right_num = 0
        periods = []
        for batch_id, (data, label) in enumerate(val_reader()):
            t1 = time.time()
            cls_out, ctc_out = exe.run(infer_program,
                                       feed={feed_dict[0]: data},
                                       fetch_list=fetch_targets,
                                       return_numpy=False)
            t2 = time.time()
            periods.append(t2 - t1)

            cls_out = np.array(cls_out).reshape(-1)
            out_cls_label = np.argmax(cls_out)

            all_num += 1
            if out_cls_label == label[0]:
                right_num += 1

            if (batch_id + 1) == infer_iterations:
                break

        latency = np.average(periods)
        acc = right_num / all_num
        return (latency, acc)

    def generate_quantized_model(self,
                                 model_path,
                                 data_path,
                                 algo="KL",
                                 quantizable_op_type=["conv2d"],
                                 is_full_quantize=False,
                                 is_use_cache_file=False,
                                 is_optimize_model=False,
                                 batch_size=10,
                                 batch_nums=10):

        place = fluid.CPUPlace()
        exe = fluid.Executor(place)
        scope = fluid.global_scope()
        batch_generator = self.get_batch_reader(data_path, place)

        ptq = PostTrainingQuantization(
            executor=exe,
            model_dir=model_path,
            batch_generator=batch_generator,
            batch_nums=batch_nums,
            algo=algo,
            quantizable_op_type=quantizable_op_type,
            is_full_quantize=is_full_quantize,
            optimize_model=is_optimize_model,
            is_use_cache_file=is_use_cache_file)
        ptq.quantize()
        ptq.save_quantized_model(self.int8_model_path)

    def run_test(self, model_name, model_url, model_md5, data_name, data_url,
                 data_md5, algo, quantizable_op_type, is_full_quantize,
                 is_use_cache_file, is_optimize_model, diff_threshold,
                 infer_iterations, quant_iterations):
        fp32_model_path = self.download_model(model_url, model_md5, model_name)
        fp32_model_path = os.path.join(fp32_model_path, model_name)

        data_path = self.download_model(data_url, data_md5, data_name)
        data_path = os.path.join(data_path, data_name)

        print("Start FP32 inference for {0} on {1} samples ...".format(
            model_name, infer_iterations))
        (fp32_latency, fp32_acc) = self.run_program(fp32_model_path, data_path,
                                                    infer_iterations)

        print("Start post training quantization for {0} on {1} samples ...".
              format(model_name, quant_iterations))
        self.generate_quantized_model(fp32_model_path, data_path, algo,
                                      quantizable_op_type, is_full_quantize,
                                      is_use_cache_file, is_optimize_model,
                                      quant_iterations)

        print("Start INT8 inference for {0} on {1} samples ...".format(
            model_name, infer_iterations))
        (int8_latency, int8_acc) = self.run_program(self.int8_model_path,
                                                    data_path, infer_iterations)

        print("---Post training quantization of {} method---".format(algo))
        print("FP32 {0}: batch_size {1}, latency {2} s, acc {3}.".format(
            model_name, 1, fp32_latency, fp32_acc))
        print("INT8 {0}: batch_size {1}, latency {2} s, acc1 {3}.\n".format(
            model_name, 1, int8_latency, int8_acc))
        sys.stdout.flush()

        delta_value = fp32_acc - int8_acc
        self.assertLess(delta_value, diff_threshold)


class TestPostTrainingKLForMnist(TestPostTrainingQuantization):
    def test_post_training_kl(self):
        model_name = "nlp_lstm_fp32_model"
        model_url = "https://paddle-inference-dist.cdn.bcebos.com/int8/unittest_model_data/nlp_lstm_fp32_model.tar.gz"
        model_md5 = "519b8eeac756e7b4b7bcb2868e880452"
        data_name = "quant_lstm_input_data"
        data_url = "https://paddle-inference-dist.cdn.bcebos.com/int8/unittest_model_data/quant_lstm_input_data.tar.gz"
        data_md5 = "add84c754e9b792fea1fbd728d134ab7"
        algo = "KL"
        quantizable_op_type = ["mul", "lstm"]
        is_full_quantize = False
        is_use_cache_file = False
        is_optimize_model = False
        diff_threshold = 0.01
        infer_iterations = 100
        quant_iterations = 10
        self.run_test(model_name, model_url, model_md5, data_name, data_url,
                      data_md5, algo, quantizable_op_type, is_full_quantize,
                      is_use_cache_file, is_optimize_model, diff_threshold,
                      infer_iterations, quant_iterations)


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