# copyright (c) 2024 PaddlePaddle Authors. All Rights Reserve.
#
# 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.


from pathlib import Path
import lazy_paddle as paddle

from ..base import BaseTrainer, BaseTrainDeamon
from ...utils.config import AttrDict
from ...utils import logging
from .model_list import MODELS


class DetTrainer(BaseTrainer):
    """Object Detection Model Trainer"""

    entities = MODELS

    def build_deamon(self, config: AttrDict) -> "DetTrainDeamon":
        """build deamon thread for saving training outputs timely

        Args:
            config (AttrDict): PaddleX pipeline config, which is loaded from pipeline yaml file.

        Returns:
            DetTrainDeamon: the training deamon thread object for saving training outputs timely.
        """
        return DetTrainDeamon(config)

    def _update_dataset(self):
        """update dataset settings"""
        self.pdx_config.update_dataset(self.global_config.dataset_dir, "COCODetDataset")

    def update_config(self):
        """update training config"""
        if self.train_config.log_interval:
            self.pdx_config.update_log_interval(self.train_config.log_interval)
        if self.train_config.eval_interval:
            self.pdx_config.update_eval_interval(self.train_config.eval_interval)

        self._update_dataset()

        if self.train_config.num_classes is not None:
            self.pdx_config.update_num_class(self.train_config.num_classes)
        if (
            self.train_config.pretrain_weight_path
            and self.train_config.pretrain_weight_path != ""
        ):
            self.pdx_config.update_pretrained_weights(
                self.train_config.pretrain_weight_path
            )
        if self.train_config.batch_size is not None:
            self.pdx_config.update_batch_size(self.train_config.batch_size)
        if self.train_config.learning_rate is not None:
            self.pdx_config.update_learning_rate(self.train_config.learning_rate)
        if self.train_config.epochs_iters is not None:
            self.pdx_config.update_epochs(self.train_config.epochs_iters)
            epochs_iters = self.train_config.epochs_iters
        else:
            epochs_iters = self.pdx_config.get_epochs_iters()
        if self.global_config.output is not None:
            self.pdx_config.update_save_dir(self.global_config.output)

        if "PicoDet" in self.global_config.model:
            assigner_epochs = max(int(epochs_iters / 10), 1)
            try:
                self.pdx_config.update_static_assigner_epochs(assigner_epochs)
            except Exception:
                logging.info(
                    f"The model({self.global_config.model}) don't support to update_static_assigner_epochs!"
                )

    def get_train_kwargs(self) -> dict:
        """get key-value arguments of model training function

        Returns:
            dict: the arguments of training function.
        """
        train_args = {"device": self.get_device()}
        if (
            self.train_config.resume_path is not None
            and self.train_config.resume_path != ""
        ):
            train_args["resume_path"] = self.train_config.resume_path
        train_args["dy2st"] = self.train_config.get("dy2st", False)
        return train_args


class DetTrainDeamon(BaseTrainDeamon):
    """DetTrainResultDemon"""

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def get_the_pdparams_suffix(self):
        """get the suffix of pdparams file"""
        return "pdparams"

    def get_the_pdema_suffix(self):
        """get the suffix of pdema file"""
        return "pdema"

    def get_the_pdopt_suffix(self):
        """get the suffix of pdopt file"""
        return "pdopt"

    def get_the_pdstates_suffix(self):
        """get the suffix of pdstates file"""
        return "pdstates"

    def get_ith_ckp_prefix(self, epoch_id):
        """get the prefix of the epoch_id checkpoint file"""
        return f"{epoch_id}"

    def get_best_ckp_prefix(self):
        """get the prefix of the best checkpoint file"""
        return "best_model"

    def get_score(self, pdstates_path):
        """get the score by pdstates file"""
        if not Path(pdstates_path).exists():
            return 0
        return paddle.load(pdstates_path)["metric"]

    def get_epoch_id_by_pdparams_prefix(self, pdparams_prefix):
        """get the epoch_id by pdparams file"""
        return int(pdparams_prefix)