#   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 os
import time
import numpy as np
import argparse
import functools
import shutil
import math
import multiprocessing

import paddle
import paddle.fluid as fluid
import reader
from mobilenet_ssd import mobile_net
from utility import add_arguments, print_arguments
from train import build_program
from train import train_parameters
from infer import draw_bounding_box_on_image

parser = argparse.ArgumentParser(description=__doc__)
add_arg = functools.partial(add_arguments, argparser=parser)
# yapf: disable
add_arg('learning_rate',    float, 0.0001,              "Learning rate.")
add_arg('batch_size',       int,   64,                  "Minibatch size.")
add_arg('epoc_num',         int,   20,                  "Epoch number.")
add_arg('use_gpu',          bool,  True,                "Whether use GPU.")
add_arg('parallel',         bool,  True,                "Whether train in parallel on multi-devices.")
add_arg('model_save_dir',   str,   'quant_model',       "The path to save model.")
add_arg('init_model',       str,   'ssd_mobilenet_v1_pascalvoc', "The init model path.")
add_arg('ap_version',       str,   '11point',           "mAP version can be integral or 11point.")
add_arg('image_shape',      str,   '3,300,300',         "Input image shape.")
add_arg('mean_BGR',         str,   '127.5,127.5,127.5', "Mean value for B,G,R channel which will be subtracted.")
add_arg('lr_epochs',        str,   '30,60',             "The learning decay steps.")
add_arg('lr_decay_rates',   str,   '1,0.1,0.01',        "The learning decay rates for each step.")
add_arg('data_dir',         str,   'data/pascalvoc',    "Data directory")
add_arg('act_quant_type',   str,   'abs_max',           "Quantize type of activation, whicn can be abs_max or range_abs_max")
add_arg('image_path',       str,   '',                  "The image used to inference and visualize.")
add_arg('confs_threshold',  float, 0.5,                 "Confidence threshold to draw bbox.")
add_arg('mode',             str,   'train',             "Job mode can be one of ['train', 'test', 'infer'].")
#yapf: enable

def test(exe, test_prog, map_eval, test_py_reader):
    _, accum_map = map_eval.get_map_var()
    map_eval.reset(exe)
    test_py_reader.start()
    try:
        batch = 0
        while True:
            test_map, = exe.run(test_prog, fetch_list=[accum_map])
            if batch % 10 == 0:
                print("Batch {0}, map {1}".format(batch, test_map))
            batch += 1
    except fluid.core.EOFException:
        test_py_reader.reset()
    finally:
        test_py_reader.reset()
    print("Test map {0}".format(test_map))
    return test_map


def save_model(exe, main_prog, model_save_dir, postfix):
    model_path = os.path.join(model_save_dir, postfix)
    if os.path.isdir(model_path):
        shutil.rmtree(model_path)
    fluid.io.save_persistables(exe, model_path, main_program=main_prog)


def train(args,
          data_args,
          train_params,
          train_file_list,
          val_file_list):

    model_save_dir = args.model_save_dir
    init_model = args.init_model
    epoc_num = args.epoc_num
    use_gpu = args.use_gpu
    parallel = args.parallel
    is_shuffle = True
    act_quant_type = args.act_quant_type

    if use_gpu:
        devices_num = fluid.core.get_cuda_device_count()
    else:
        devices_num = int(os.environ.get('CPU_NUM', multiprocessing.cpu_count()))

    batch_size = train_params['batch_size']
    batch_size_per_device = batch_size // devices_num
    num_workers = 4

    startup_prog = fluid.Program()
    train_prog = fluid.Program()
    test_prog = fluid.Program()

    train_py_reader, loss = build_program(
        main_prog=train_prog,
        startup_prog=startup_prog,
        train_params=train_params,
        is_train=True)
    test_py_reader, map_eval, _, _ = build_program(
        main_prog=test_prog,
        startup_prog=startup_prog,
        train_params=train_params,
        is_train=False)

    test_prog = test_prog.clone(for_test=True)

    transpiler = fluid.contrib.QuantizeTranspiler(weight_bits=8,
        activation_bits=8,
        activation_quantize_type=act_quant_type,
        weight_quantize_type='abs_max')

    transpiler.training_transpile(train_prog, startup_prog)
    transpiler.training_transpile(test_prog, startup_prog)

    place = fluid.CUDAPlace(0) if use_gpu else fluid.CPUPlace()
    exe = fluid.Executor(place)
    exe.run(startup_prog)

    if init_model:
        print('Load init model %s.' % init_model)
        def if_exist(var):
            return os.path.exists(os.path.join(init_model, var.name))
        fluid.io.load_vars(exe, init_model, main_program=train_prog,
                           predicate=if_exist)
    else:
        print('There is no init model.')

    if parallel:
        train_exe = fluid.ParallelExecutor(main_program=train_prog,
            use_cuda=True if use_gpu else False, loss_name=loss.name)

    train_reader = reader.train(data_args,
                                train_file_list,
                                batch_size_per_device,
                                shuffle=is_shuffle,
                                num_workers=num_workers)
    test_reader = reader.test(data_args, val_file_list, batch_size)
    train_py_reader.decorate_paddle_reader(train_reader)
    test_py_reader.decorate_paddle_reader(test_reader)

    train_py_reader.start()
    best_map = 0.
    for epoc in range(epoc_num):
        if epoc == 0:
            # test quantized model without quantization-aware training.
            test_map = test(exe, test_prog, map_eval, test_py_reader)
        batch = 0
        train_py_reader.start()
        while True:
            try:
                # train
                start_time = time.time()
                if parallel:
                    outs = train_exe.run(fetch_list=[loss.name])
                else:
                    outs = exe.run(train_prog, fetch_list=[loss])
                end_time = time.time()
                avg_loss = np.mean(np.array(outs[0]))
                if batch % 10 == 0:
                    print("Epoc {:d}, batch {:d}, loss {:.6f}, time {:.5f}".format(
                        epoc , batch, avg_loss, end_time - start_time))
            except (fluid.core.EOFException, StopIteration):
                train_reader().close()
                train_py_reader.reset()
                break
        test_map = test(exe, test_prog, map_eval, test_py_reader)
        save_model(exe, train_prog, model_save_dir, str(epoc))
        if test_map > best_map:
            best_map = test_map
            save_model(exe, train_prog, model_save_dir, 'best_map')
        print("Best test map {0}".format(best_map))


def eval(args, data_args, configs, val_file_list):
    init_model = args.init_model
    use_gpu = args.use_gpu
    act_quant_type = args.act_quant_type
    model_save_dir = args.model_save_dir

    batch_size = configs['batch_size']
    batch_size_per_device = batch_size

    startup_prog = fluid.Program()
    test_prog = fluid.Program()
    test_py_reader, map_eval, nmsed_out, image = build_program(
        main_prog=test_prog,
        startup_prog=startup_prog,
        train_params=configs,
        is_train=False)
    test_prog = test_prog.clone(for_test=True)

    transpiler = fluid.contrib.QuantizeTranspiler(weight_bits=8,
        activation_bits=8,
        activation_quantize_type=act_quant_type,
        weight_quantize_type='abs_max')
    transpiler.training_transpile(test_prog, startup_prog)

    place = fluid.CUDAPlace(0) if use_gpu else fluid.CPUPlace()
    exe = fluid.Executor(place)
    exe.run(startup_prog)

    def if_exist(var):
        return os.path.exists(os.path.join(init_model, var.name))
    fluid.io.load_vars(exe, init_model, main_program=test_prog,
                       predicate=if_exist)

    # freeze after load parameters
    transpiler.freeze_program(test_prog, place)

    test_reader = reader.test(data_args, val_file_list, batch_size)
    test_py_reader.decorate_paddle_reader(test_reader)

    test_map = test(exe, test_prog, map_eval, test_py_reader)
    print("Test model {0}, map {1}".format(init_model, test_map))
    # convert model to 8-bit before saving, but now Paddle can't load
    # the 8-bit model to do inference.
    # transpiler.convert_to_int8(test_prog, place)
    fluid.io.save_inference_model(model_save_dir, [image.name],
                                  [nmsed_out], exe, test_prog)


def infer(args, data_args):
    model_dir = args.init_model
    image_path = args.image_path
    confs_threshold = args.confs_threshold

    place = fluid.CUDAPlace(0) if args.use_gpu else fluid.CPUPlace()
    exe = fluid.Executor(place)
    [inference_program, feed , fetch] = fluid.io.load_inference_model(
        dirname=model_dir,
        executor=exe,
        model_filename='__model__')

    #print(np.array(fluid.global_scope().find_var('conv2d_20.w_0').get_tensor()))
    #print(np.max(np.array(fluid.global_scope().find_var('conv2d_20.w_0').get_tensor())))
    infer_reader = reader.infer(data_args, image_path)
    data = infer_reader()
    data = data.reshape((1,) + data.shape)
    outs = exe.run(inference_program,
                   feed={feed[0]: data},
                   fetch_list=fetch,
                   return_numpy=False)
    out = np.array(outs[0])
    draw_bounding_box_on_image(image_path, out, confs_threshold,
                               data_args.label_list)


if __name__ == '__main__':
    args = parser.parse_args()
    print_arguments(args)

    # for pascalvoc
    label_file = 'label_list'
    train_list = 'trainval.txt'
    val_list = 'test.txt'
    dataset = 'pascalvoc'

    mean_BGR = [float(m) for m in args.mean_BGR.split(",")]
    image_shape = [int(m) for m in args.image_shape.split(",")]
    lr_epochs = [int(m) for m in args.lr_epochs.split(",")]
    lr_rates = [float(m) for m in args.lr_decay_rates.split(",")]
    train_parameters[dataset]['image_shape'] = image_shape
    train_parameters[dataset]['batch_size'] = args.batch_size
    train_parameters[dataset]['lr'] = args.learning_rate
    train_parameters[dataset]['epoc_num'] = args.epoc_num
    train_parameters[dataset]['ap_version'] = args.ap_version
    train_parameters[dataset]['lr_epochs'] = lr_epochs
    train_parameters[dataset]['lr_decay'] = lr_rates

    data_args = reader.Settings(
        dataset=dataset,
        data_dir=args.data_dir,
        label_file=label_file,
        resize_h=image_shape[1],
        resize_w=image_shape[2],
        mean_value=mean_BGR,
        apply_distort=True,
        apply_expand=True,
        ap_version = args.ap_version)
    if args.mode == 'train':
        train(args, data_args, train_parameters[dataset], train_list, val_list)
    elif args.mode == 'test':
        eval(args, data_args, train_parameters[dataset], val_list)
    else:
        infer(args, data_args)
