# Copyright (c) 2020 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 contextlib
import filelock
import os
import tempfile
import numpy as np
import random
from urllib.parse import urlparse, unquote

import paddle

from paddleseg.utils import logger, seg_env
from paddleseg.utils.download import download_file_and_uncompress


@contextlib.contextmanager
def generate_tempdir(directory: str=None, **kwargs):
    '''Generate a temporary directory'''
    directory = seg_env.TMP_HOME if not directory else directory
    with tempfile.TemporaryDirectory(dir=directory, **kwargs) as _dir:
        yield _dir


def load_entire_model(model, pretrained):
    if pretrained is not None:
        load_pretrained_model(model, pretrained)
    else:
        logger.warning('Not all pretrained params of {} are loaded, ' \
                       'training from scratch or a pretrained backbone.'.format(model.__class__.__name__))


def download_pretrained_model(pretrained_model):
    """
    Download pretrained model from url.
    Args:
        pretrained_model (str): the url of pretrained weight
    Returns:
        str: the path of pretrained weight
    """
    assert urlparse(pretrained_model).netloc, "The url is not valid."

    pretrained_model = unquote(pretrained_model)
    savename = pretrained_model.split('/')[-1]
    if not savename.endswith(('tgz', 'tar.gz', 'tar', 'zip')):
        savename = pretrained_model.split('/')[-2]
    else:
        savename = savename.split('.')[0]

    with generate_tempdir() as _dir:
        with filelock.FileLock(os.path.join(seg_env.TMP_HOME, savename)):
            pretrained_model = download_file_and_uncompress(
                pretrained_model,
                savepath=_dir,
                extrapath=seg_env.PRETRAINED_MODEL_HOME,
                extraname=savename)
            pretrained_model = os.path.join(pretrained_model, 'model.pdparams')
    return pretrained_model


def load_pretrained_model(model, pretrained_model):
    if pretrained_model is not None:
        logger.info('Loading pretrained model from {}'.format(pretrained_model))

        if urlparse(pretrained_model).netloc:
            pretrained_model = download_pretrained_model(pretrained_model)

        if os.path.exists(pretrained_model):
            para_state_dict = paddle.load(pretrained_model)

            model_state_dict = model.state_dict()
            keys = model_state_dict.keys()
            num_params_loaded = 0
            for k in keys:
                if k not in para_state_dict:
                    logger.warning("{} is not in pretrained model".format(k))
                elif list(para_state_dict[k].shape) != list(model_state_dict[k]
                                                            .shape):
                    logger.warning(
                        "[SKIP] Shape of pretrained params {} doesn't match.(Pretrained: {}, Actual: {})"
                        .format(k, para_state_dict[k].shape, model_state_dict[k]
                                .shape))
                else:
                    model_state_dict[k] = para_state_dict[k]
                    num_params_loaded += 1
            model.set_dict(model_state_dict)
            logger.info("There are {}/{} variables loaded into {}.".format(
                num_params_loaded,
                len(model_state_dict), model.__class__.__name__))

        else:
            raise ValueError('The pretrained model directory is not Found: {}'.
                             format(pretrained_model))
    else:
        logger.info(
            'No pretrained model to load, {} will be trained from scratch.'.
            format(model.__class__.__name__))


def resume(model, optimizer, resume_model):
    if resume_model is not None:
        logger.info('Resume model from {}'.format(resume_model))
        if os.path.exists(resume_model):
            resume_model = os.path.normpath(resume_model)
            ckpt_path = os.path.join(resume_model, 'model.pdparams')
            para_state_dict = paddle.load(ckpt_path)
            ckpt_path = os.path.join(resume_model, 'model.pdopt')
            opti_state_dict = paddle.load(ckpt_path)
            model.set_state_dict(para_state_dict)
            optimizer.set_state_dict(opti_state_dict)

            iter = resume_model.split('_')[-1]
            iter = int(iter)
            return iter
        else:
            raise ValueError(
                'Directory of the model needed to resume is not Found: {}'.
                format(resume_model))
    else:
        logger.info('No model needed to resume.')


def worker_init_fn(worker_id):
    np.random.seed(random.randint(0, 100000))


def get_image_list(image_path):
    """Get image list"""
    valid_suffix = [
        '.JPEG', '.jpeg', '.JPG', '.jpg', '.BMP', '.bmp', '.PNG', '.png'
    ]
    image_list = []
    image_dir = None
    if os.path.isfile(image_path):
        if os.path.splitext(image_path)[-1] in valid_suffix:
            image_list.append(image_path)
        else:
            image_dir = os.path.dirname(image_path)
            with open(image_path, 'r') as f:
                for line in f:
                    line = line.strip()
                    if len(line.split()) > 1:
                        line = line.split()[0]
                    image_list.append(os.path.join(image_dir, line))
    elif os.path.isdir(image_path):
        image_dir = image_path
        for root, dirs, files in os.walk(image_path):
            for f in files:
                if '.ipynb_checkpoints' in root:
                    continue
                if f.startswith('.'):
                    continue
                if os.path.splitext(f)[-1] in valid_suffix:
                    image_list.append(os.path.join(root, f))
    else:
        raise FileNotFoundError(
            '`--image_path` is not found. it should be a path of image, or a file list containing image paths, or a directory including images.'
        )

    if len(image_list) == 0:
        raise RuntimeError(
            'There are not image file in `--image_path`={}'.format(image_path))

    return image_list, image_dir