# 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.
"""
Analyze the FLOPs and Params of the model.
Usually, just call paddle.flops to output the model information.
We use this file for output flops clearly.
"""

import argparse
import os
import sys

import numpy as np
import paddle
from paddle.hapi.dynamic_flops import (count_io_info, count_parameters,
                                       register_hooks)
from paddle.hapi.static_flops import Table

from paddleseg.cvlibs import Config, SegBuilder
from paddleseg.utils import get_sys_env, logger, op_flops_funs


def parse_args():
    parser = argparse.ArgumentParser(description='Model training')
    parser.add_argument("--config", help="The path of config file.", type=str)
    parser.add_argument(
        "--input_shape",
        nargs='+',
        type=int,
        help="Set the input shape, such as --input_shape 1 3 1024 1024",
        default=[1, 3, 1024, 1024])
    return parser.parse_args()


# For output flops clearly, modify the dynamic_flops function in paddle/hapi/dynamic_flops.py
def _dynamic_flops(model, inputs, custom_ops=None, print_detail=False):
    handler_collection = []
    types_collection = set()
    if custom_ops is None:
        custom_ops = {}

    def add_hooks(m):
        if len(list(m.children())) > 0:
            return
        m.register_buffer('total_ops', paddle.zeros([1], dtype='int64'))
        m.register_buffer('total_params', paddle.zeros([1], dtype='int64'))
        m_type = type(m)

        flops_fn = None
        if m_type in custom_ops:
            flops_fn = custom_ops[m_type]
            if m_type not in types_collection:
                print("Customize Function has been applied to {}".format(
                    m_type))
        elif m_type in register_hooks:
            flops_fn = register_hooks[m_type]
            if m_type not in types_collection:
                print("{}'s flops has been counted".format(m_type))
        else:
            if m_type not in types_collection:
                print(
                    "Cannot find suitable count function for {}. Treat it as zero FLOPs."
                    .format(m_type))

        if flops_fn is not None:
            flops_handler = m.register_forward_post_hook(flops_fn)
            handler_collection.append(flops_handler)
        params_handler = m.register_forward_post_hook(count_parameters)
        io_handler = m.register_forward_post_hook(count_io_info)
        handler_collection.append(params_handler)
        handler_collection.append(io_handler)
        types_collection.add(m_type)

    training = model.training

    model.eval()
    model.apply(add_hooks)

    with paddle.framework.no_grad():
        model(inputs)

    total_ops = 0
    total_params = 0
    for m in model.sublayers():
        if len(list(m.children())) > 0:
            continue
        if set(['total_ops', 'total_params', 'input_shape',
                'output_shape']).issubset(set(list(m._buffers.keys()))):
            total_ops += m.total_ops
            total_params += m.total_params

    if training:
        model.train()
    for handler in handler_collection:
        handler.remove()

    table = Table(
        ["Layer Name", "Input Shape", "Output Shape", "Params(M)", "Flops(G)"])

    for n, m in model.named_sublayers():
        if len(list(m.children())) > 0:
            continue
        if set(['total_ops', 'total_params', 'input_shape',
                'output_shape']).issubset(set(list(m._buffers.keys()))):
            table.add_row([
                m.full_name(), list(m.input_shape.numpy()),
                list(m.output_shape.numpy()),
                round(float(m.total_params / 1e6), 3),
                round(float(m.total_ops / 1e9), 3)
            ])
            m._buffers.pop("total_ops")
            m._buffers.pop("total_params")
            m._buffers.pop('input_shape')
            m._buffers.pop('output_shape')
    if print_detail:
        table.print_table()
    print('Total Flops: {}G     Total Params: {}M'.format(
        round(float(total_ops / 1e9), 3), round(float(total_params / 1e6), 3)))
    return int(total_ops)


def analyze(args):
    env_info = get_sys_env()
    info = ['{}: {}'.format(k, v) for k, v in env_info.items()]
    info = '\n'.join(['', format('Environment Information', '-^48s')] + info +
                     ['-' * 48])
    logger.info(info)

    paddle.set_device('cpu')

    cfg = Config(args.config)
    builder = SegBuilder(cfg)

    custom_ops = {paddle.nn.SyncBatchNorm: op_flops_funs.count_syncbn}
    inputs = paddle.randn(args.input_shape)
    _dynamic_flops(builder.model, inputs, custom_ops=custom_ops, print_detail=True)


if __name__ == '__main__':
    args = parse_args()
    if not args.config:
        raise RuntimeError('No configuration file specified.')

    logger.info("config:" + args.config)
    logger.info("input_shape:")
    logger.info(args.input_shape)
    analyze(args)
