# Copyright 2024 Bytedance Ltd. and/or its affiliates
# Copyright 2023-2024 SGLang Team
# Copyright 2025 ModelBest Inc. and/or its affiliates
#
# 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.
"""
PPO Trainer with Ray-based single controller.
This trainer supports model-agonistic model initialization with huggingface
"""

import uuid
from copy import deepcopy
from pprint import pprint

import numpy as np
import ray
import torch
from omegaconf import OmegaConf
from tqdm import tqdm

from verl import DataProto
from verl.experimental.dataset.sampler import AbstractCurriculumSampler
from verl.single_controller.ray import RayClassWithInitArgs
from verl.single_controller.ray.base import create_colocated_worker_cls
from verl.trainer.ppo.core_algos import AdvantageEstimator, agg_loss
from verl.trainer.ppo.metric_utils import (
    compute_data_metrics,
    compute_throughout_metrics,
    compute_timing_metrics,
)
from verl.trainer.ppo.ray_trainer import RayPPOTrainer, apply_kl_penalty, compute_advantage, compute_response_mask
from verl.trainer.ppo.reward import compute_reward, compute_reward_async
from verl.trainer.ppo.utils import Role
from verl.utils.checkpoint.checkpoint_manager import should_save_ckpt_esi
from verl.utils.config import omega_conf_to_dataclass
from verl.utils.debug import marked_timer
from verl.utils.metric import (
    reduce_metrics,
)
from verl.utils.rollout_skip import RolloutSkip


class FullyAsyncRayPPOTrainer(RayPPOTrainer):
    def init_workers(self):
        """Initialize distributed training workers using Ray backend.

        Creates:
        1. Ray resource pools from configuration
        2. Worker groups for each role (actor, critic, etc.)
        """
        self._init_resource_pools()
        self._create_worker_classes()
        self._init_worker_groups()
        self._init_models()
        self._init_async_rollout_manager()

    def _init_resource_pools(self):
        self.resource_pool_manager.create_resource_pool()

        self.resource_pool_to_cls = {pool: {} for pool in self.resource_pool_manager.resource_pool_dict.values()}

    def _create_worker_classes(self):
        self._create_actor_rollout_classes()
        self._create_critic_class()
        self._create_reference_policy_class()
        self._create_reward_model_class()

    def _create_actor_rollout_classes(self):
        raise NotImplementedError

    def _create_critic_class(self):
        # create critic
        if self.use_critic:
            resource_pool = self.resource_pool_manager.get_resource_pool(Role.Critic)
            critic_cfg = omega_conf_to_dataclass(self.config.critic)
            critic_cls = RayClassWithInitArgs(cls=self.role_worker_mapping[Role.Critic], config=critic_cfg)
            self.resource_pool_to_cls[resource_pool][str(Role.Critic)] = critic_cls

    def _create_reference_policy_class(self):
        # create reference policy if needed
        if self.use_reference_policy:
            resource_pool = self.resource_pool_manager.get_resource_pool(Role.RefPolicy)
            ref_policy_cls = RayClassWithInitArgs(
                self.role_worker_mapping[Role.RefPolicy],
                config=self.config.actor_rollout_ref,
                role=str(Role.RefPolicy),
                profile_option=self.config.trainer.npu_profile.options,
            )
            self.resource_pool_to_cls[resource_pool][str(Role.RefPolicy)] = ref_policy_cls

    def _create_reward_model_class(self):
        # create a reward model if reward_fn is None
        if self.use_rm:
            # we create a RM here
            resource_pool = self.resource_pool_manager.get_resource_pool(Role.RewardModel)
            rm_cls = RayClassWithInitArgs(self.role_worker_mapping[Role.RewardModel], config=self.config.reward_model)
            self.resource_pool_to_cls[resource_pool][str(Role.RewardModel)] = rm_cls

    def _init_worker_groups(self):
        # initialize WorkerGroup
        # NOTE: if you want to use a different resource pool for each role, which can support different parallel size,
        # you should not use `create_colocated_worker_cls`.
        # Instead, directly pass different resource pool to different worker groups.
        # See https://github.com/volcengine/verl/blob/master/examples/ray/tutorial.ipynb for more information.
        all_wg = {}
        wg_kwargs = {}  # Setting up kwargs for RayWorkerGroup
        if OmegaConf.select(self.config.trainer, "ray_wait_register_center_timeout") is not None:
            wg_kwargs["ray_wait_register_center_timeout"] = self.config.trainer.ray_wait_register_center_timeout
        if OmegaConf.select(self.config.global_profiler, "steps") is not None:
            wg_kwargs["profile_steps"] = OmegaConf.select(self.config.global_profiler, "steps")
            # Only require nsight worker options when tool is nsys
            if OmegaConf.select(self.config.global_profiler, "tool") == "nsys":
                assert (
                    OmegaConf.select(self.config.global_profiler.global_tool_config.nsys, "worker_nsight_options")
                    is not None
                ), "worker_nsight_options must be set when using nsys with profile_steps"
                wg_kwargs["worker_nsight_options"] = OmegaConf.to_container(
                    OmegaConf.select(self.config.global_profiler.global_tool_config.nsys, "worker_nsight_options")
                )
        wg_kwargs["device_name"] = self.device_name

        for resource_pool, class_dict in self.resource_pool_to_cls.items():
            worker_dict_cls = create_colocated_worker_cls(class_dict=class_dict)
            wg_dict = self.ray_worker_group_cls(
                resource_pool=resource_pool,
                ray_cls_with_init=worker_dict_cls,
                **wg_kwargs,
            )
            spawn_wg = wg_dict.spawn(prefix_set=class_dict.keys())
            all_wg.update(spawn_wg)
        self.all_wg = all_wg

    def _init_models(self):
        if self.use_critic:
            self.critic_wg = self.all_wg[str(Role.Critic)]
            self.critic_wg.init_model()

        if self.use_reference_policy and not self.ref_in_actor:
            self.ref_policy_wg = self.all_wg[str(Role.RefPolicy)]
            self.ref_policy_wg.init_model()

        if self.use_rm:
            self.rm_wg = self.all_wg[str(Role.RewardModel)]
            self.rm_wg.init_model()

        # we should create rollout at the end so that vllm can have a better estimation of kv cache memory
        self.actor_rollout_wg = self.all_wg[str(Role.ActorRollout)]
        self.actor_rollout_wg.init_model()

    def _init_async_rollout_manager(self):
        pass

    def fit(self):
        """
        The training loop of PPO.
        The driver process only need to call the compute functions of the worker group through RPC
        to construct the PPO dataflow.
        The light-weight advantage computation is done on the driver process.
        """
        from omegaconf import OmegaConf

        from verl.utils.tracking import Tracking

        logger = Tracking(
            project_name=self.config.trainer.project_name,
            experiment_name=self.config.trainer.experiment_name,
            default_backend=self.config.trainer.logger,
            config=OmegaConf.to_container(self.config, resolve=True),
        )

        self.global_steps = 0

        # load checkpoint before doing anything
        self._load_checkpoint()

        # perform validation before training
        # currently, we only support validation using the reward_function.
        if self.val_reward_fn is not None and self.config.trainer.get("val_before_train", True):
            val_metrics = self._validate()
            assert val_metrics, f"{val_metrics=}"
            pprint(f"Initial validation metrics: {val_metrics}")
            logger.log(data=val_metrics, step=self.global_steps)
            if self.config.trainer.get("val_only", False):
                return

        if self.config.actor_rollout_ref.rollout.get("skip_rollout", False):
            rollout_skip = RolloutSkip(self.config, self.actor_rollout_wg)
            rollout_skip.wrap_generate_sequences()

        # add tqdm
        progress_bar = tqdm(total=self.total_training_steps, initial=self.global_steps, desc="Training Progress")

        # we start from step 1
        self.global_steps += 1
        last_val_metrics = None
        self.max_steps_duration = 0

        prev_step_profile = False
        curr_step_profile = (
            self.global_steps in self.config.global_profiler.steps
            if self.config.global_profiler.steps is not None
            else False
        )
        next_step_profile = False

        for epoch in range(self.config.trainer.total_epochs):
            for batch_dict in self.train_dataloader:
                metrics = {}
                timing_raw = {}

                with marked_timer("start_profile", timing_raw):
                    self._start_profiling(
                        not prev_step_profile and curr_step_profile
                        if self.config.global_profiler.profile_continuous_steps
                        else curr_step_profile
                    )

                batch, gen_batch = self._prepare_generate_batch(batch_dict)

                is_last_step = self.global_steps >= self.total_training_steps

                with marked_timer("step", timing_raw):
                    # generate a batch
                    with marked_timer("gen", timing_raw, color="red"):
                        if not self.async_rollout_mode:
                            gen_batch_output = self.actor_rollout_wg.generate_sequences(gen_batch)
                        else:
                            gen_batch_output = self.async_rollout_manager.generate_sequences(gen_batch)
                        timing_raw.update(gen_batch_output.meta_info["timing"])
                        gen_batch_output.meta_info.pop("timing", None)

                    if self.config.algorithm.adv_estimator == AdvantageEstimator.REMAX:
                        if self.reward_fn is None:
                            raise ValueError("A reward_fn is required for REMAX advantage estimation.")

                        with marked_timer("gen_max", timing_raw, color="purple"):
                            gen_baseline_batch = deepcopy(gen_batch)
                            gen_baseline_batch.meta_info["do_sample"] = False
                            if not self.async_rollout_mode:
                                gen_baseline_output = self.actor_rollout_wg.generate_sequences(gen_baseline_batch)
                            else:
                                gen_baseline_output = self.async_rollout_manager.generate_sequences(gen_baseline_batch)
                            batch = batch.union(gen_baseline_output)
                            reward_baseline_tensor = self.reward_fn(batch)
                            reward_baseline_tensor = reward_baseline_tensor.sum(dim=-1)

                            batch.pop(batch_keys=list(gen_baseline_output.batch.keys()))

                            batch.batch["reward_baselines"] = reward_baseline_tensor

                            del gen_baseline_batch, gen_baseline_output

                    batch = self._post_generate_batch(batch, gen_batch_output, metrics)
                    batch, reward_extra_infos_dict = self._process_batch_common(batch, metrics, timing_raw)
                    self._log_rollout(batch, reward_extra_infos_dict, timing_raw)

                last_val_metrics = self._validate_metrics(is_last_step, last_val_metrics, metrics, timing_raw)
                self._check_save_checkpoint(is_last_step, timing_raw)

                with marked_timer("stop_profile", timing_raw):
                    next_step_profile = (
                        self.global_steps + 1 in self.config.global_profiler.steps
                        if self.config.global_profiler.steps is not None
                        else False
                    )
                    self._stop_profiling(
                        curr_step_profile and not next_step_profile
                        if self.config.global_profiler.profile_continuous_steps
                        else curr_step_profile
                    )
                    prev_step_profile = curr_step_profile
                    curr_step_profile = next_step_profile

                self._collect_metrics(batch, epoch, metrics, timing_raw)
                self._post_batch_processing(batch)

                # TODO: make a canonical logger that supports various backend
                logger.log(data=metrics, step=self.global_steps)

                progress_bar.update(1)
                self.global_steps += 1

                if (
                    hasattr(self.config.actor_rollout_ref.actor, "profiler")
                    and self.config.actor_rollout_ref.actor.profiler.tool == "torch_memory"
                ):
                    self.actor_rollout_wg.dump_memory_snapshot(
                        tag=f"post_update_step{self.global_steps}", sub_dir=f"step{self.global_steps}"
                    )

                if is_last_step:
                    pprint(f"Final validation metrics: {last_val_metrics}")
                    progress_bar.close()
                    return

    def _prepare_generate_batch(self, batch_dict):
        batch: DataProto = DataProto.from_single_dict(batch_dict)

        # add uid to batch
        batch.non_tensor_batch["uid"] = np.array([str(uuid.uuid4()) for _ in range(len(batch.batch))], dtype=object)

        gen_batch = self._get_gen_batch(batch)

        # pass global_steps to trace
        gen_batch.meta_info["global_steps"] = self.global_steps
        gen_batch = gen_batch.repeat(repeat_times=self.config.actor_rollout_ref.rollout.n, interleave=True)
        return batch, gen_batch

    def _post_generate_batch(self, batch, gen_batch_output, metrics):
        # repeat to align with repeated responses in rollout
        batch = batch.repeat(repeat_times=self.config.actor_rollout_ref.rollout.n, interleave=True)
        batch = batch.union(gen_batch_output)

        if "response_mask" not in batch.batch.keys():
            batch.batch["response_mask"] = compute_response_mask(batch)
        # Balance the number of valid tokens across DP ranks.
        # NOTE: This usually changes the order of data in the `batch`,
        # which won't affect the advantage calculation (since it's based on uid),
        # but might affect the loss calculation (due to the change of mini-batching).
        # TODO: Decouple the DP balancing and mini-batching.
        if self.config.trainer.balance_batch:
            self._balance_batch(batch, metrics=metrics)

        # compute global_valid tokens
        batch.meta_info["global_token_num"] = torch.sum(batch.batch["attention_mask"], dim=-1).tolist()

        return batch

    def _process_batch_common(self, batch, metrics, timing_raw):
        with marked_timer("reward", timing_raw, color="yellow"):
            # compute reward model score
            if self.use_rm:
                reward_tensor = self.rm_wg.compute_rm_score(batch)
                batch = batch.union(reward_tensor)

            if self.config.reward_model.launch_reward_fn_async:
                future_reward = compute_reward_async.remote(data=batch, reward_fn=self.reward_fn)
            else:
                reward_tensor, reward_extra_infos_dict = compute_reward(batch, self.reward_fn)

        # recompute old_log_probs
        with marked_timer("old_log_prob", timing_raw, color="blue"):
            async_training = self.config.get("async_training", None)
            if async_training and async_training.use_rollout_log_probs:
                batch.batch["old_log_probs"] = batch.batch["rollout_log_probs"]
                batch.meta_info["temperature"] = self.config.actor_rollout_ref.rollout.temperature

            else:
                old_log_prob = self.actor_rollout_wg.compute_log_prob(batch)
                entropys = old_log_prob.batch["entropys"]
                response_masks = batch.batch["response_mask"]
                loss_agg_mode = self.config.actor_rollout_ref.actor.loss_agg_mode
                entropy_agg = agg_loss(loss_mat=entropys, loss_mask=response_masks, loss_agg_mode=loss_agg_mode)
                old_log_prob_metrics = {"actor/entropy": entropy_agg.detach().item()}
                metrics.update(old_log_prob_metrics)
                old_log_prob.batch.pop("entropys")
                batch = batch.union(old_log_prob)

                if "rollout_log_probs" in batch.batch.keys():
                    # TODO: we may want to add diff of probs too.
                    from verl.utils.debug.metrics import calculate_debug_metrics

                    metrics.update(calculate_debug_metrics(batch))

        if self.use_reference_policy:
            # compute reference log_prob
            with marked_timer("ref", timing_raw, color="olive"):
                if not self.ref_in_actor:
                    ref_log_prob = self.ref_policy_wg.compute_ref_log_prob(batch)
                else:
                    ref_log_prob = self.actor_rollout_wg.compute_ref_log_prob(batch)
                batch = batch.union(ref_log_prob)

        # compute values
        if self.use_critic:
            with marked_timer("values", timing_raw, color="cyan"):
                values = self.critic_wg.compute_values(batch)
                batch = batch.union(values)

        with marked_timer("adv", timing_raw, color="brown"):
            # we combine with rule-based rm
            reward_extra_infos_dict: dict[str, list]
            if self.config.reward_model.launch_reward_fn_async:
                reward_tensor, reward_extra_infos_dict = ray.get(future_reward)
            batch.batch["token_level_scores"] = reward_tensor

            if reward_extra_infos_dict:
                batch.non_tensor_batch.update({k: np.array(v) for k, v in reward_extra_infos_dict.items()})

            # compute rewards. apply_kl_penalty if available
            if self.config.algorithm.use_kl_in_reward:
                batch, kl_metrics = apply_kl_penalty(
                    batch, kl_ctrl=self.kl_ctrl_in_reward, kl_penalty=self.config.algorithm.kl_penalty
                )
                metrics.update(kl_metrics)
            else:
                batch.batch["token_level_rewards"] = batch.batch["token_level_scores"]

            # compute advantages, executed on the driver process

            norm_adv_by_std_in_grpo = self.config.algorithm.get(
                "norm_adv_by_std_in_grpo", True
            )  # GRPO adv normalization factor

            batch = compute_advantage(
                batch,
                adv_estimator=self.config.algorithm.adv_estimator,
                gamma=self.config.algorithm.gamma,
                lam=self.config.algorithm.lam,
                num_repeat=self.config.actor_rollout_ref.rollout.n,
                norm_adv_by_std_in_grpo=norm_adv_by_std_in_grpo,
                config=self.config.algorithm,
            )

        # update critic
        if self.use_critic:
            with marked_timer("update_critic", timing_raw, color="pink"):
                critic_output = self.critic_wg.update_critic(batch)
            critic_output_metrics = reduce_metrics(critic_output.meta_info["metrics"])
            metrics.update(critic_output_metrics)

        # implement critic warmup
        if self.config.trainer.critic_warmup <= self.global_steps:
            # update actor
            with marked_timer("update_actor", timing_raw, color="red"):
                batch.meta_info["multi_turn"] = self.config.actor_rollout_ref.rollout.multi_turn.enable
                actor_output = self.actor_rollout_wg.update_actor(batch)
            actor_output_metrics = reduce_metrics(actor_output.meta_info["metrics"])
            metrics.update(actor_output_metrics)
        return batch, reward_extra_infos_dict

    def _log_rollout(self, batch, reward_extra_infos_dict, timing_raw):
        # Log rollout generations if enabled
        rollout_data_dir = self.config.trainer.get("rollout_data_dir", None)
        if rollout_data_dir:
            with marked_timer("dump_rollout_generations", timing_raw, color="green"):
                inputs = self.tokenizer.batch_decode(batch.batch["prompts"], skip_special_tokens=True)
                outputs = self.tokenizer.batch_decode(batch.batch["responses"], skip_special_tokens=True)
                scores = batch.batch["token_level_scores"].sum(-1).cpu().tolist()
                sample_gts = [item.non_tensor_batch.get("reward_model", {}).get("ground_truth", None) for item in batch]

                if "request_id" in batch.non_tensor_batch:
                    reward_extra_infos_dict.setdefault(
                        "request_id",
                        batch.non_tensor_batch["request_id"].tolist(),
                    )

                self._dump_generations(
                    inputs=inputs,
                    outputs=outputs,
                    gts=sample_gts,
                    scores=scores,
                    reward_extra_infos_dict=reward_extra_infos_dict,
                    dump_path=rollout_data_dir,
                )

    def _validate_metrics(self, is_last_step, last_val_metrics, metrics, timing_raw):
        if (
            self.val_reward_fn is not None
            and self.config.trainer.test_freq > 0
            and (is_last_step or self.global_steps % self.config.trainer.test_freq == 0)
        ):
            with marked_timer("testing", timing_raw, color="green"):
                val_metrics: dict = self._validate()
                if is_last_step:
                    last_val_metrics = val_metrics
            metrics.update(val_metrics)
            return last_val_metrics

    def _check_save_checkpoint(self, is_last_step, timing_raw):
        # Check if the ESI (Elastic Server Instance)/training plan is close to expiration.
        esi_close_to_expiration = should_save_ckpt_esi(
            max_steps_duration=self.max_steps_duration,
            redundant_time=self.config.trainer.esi_redundant_time,
        )
        # Check if the conditions for saving a checkpoint are met.
        # The conditions include a mandatory condition (1) and
        # one of the following optional conditions (2/3/4):
        # 1. The save frequency is set to a positive value.
        # 2. It's the last training step.
        # 3. The current step number is a multiple of the save frequency.
        # 4. The ESI(Elastic Server Instance)/training plan is close to expiration.
        if self.config.trainer.save_freq > 0 and (
            is_last_step or self.global_steps % self.config.trainer.save_freq == 0 or esi_close_to_expiration
        ):
            if esi_close_to_expiration:
                print("Force saving checkpoint: ESI instance expiration approaching.")
            with marked_timer("save_checkpoint", timing_raw, color="green"):
                self._save_checkpoint()

    def _collect_metrics(self, batch, epoch, metrics, timing_raw):
        steps_duration = timing_raw["step"]
        self.max_steps_duration = max(self.max_steps_duration, steps_duration)

        # training metrics
        metrics.update(
            {
                "training/global_step": self.global_steps,
                "training/epoch": epoch,
            }
        )
        # collect metrics
        metrics.update(compute_data_metrics(batch=batch, use_critic=self.use_critic))
        metrics.update(compute_timing_metrics(batch=batch, timing_raw=timing_raw))
        # TODO: implement actual tflpo and theoretical tflpo
        n_gpus = self.resource_pool_manager.get_n_gpus()
        metrics.update(compute_throughout_metrics(batch=batch, timing_raw=timing_raw, n_gpus=n_gpus))

    def _post_batch_processing(self, batch: DataProto):
        # this is experimental and may be changed/removed in the future in favor of a general-purpose one
        if isinstance(self.train_dataloader.sampler, AbstractCurriculumSampler):
            self.train_dataloader.sampler.update(batch=batch)

        # this is experimental and may be changed/removed in the future
        # in favor of a general-purpose data buffer pool
        if hasattr(self.train_dataset, "on_batch_end"):
            # The dataset may be changed after each training batch
            self.train_dataset.on_batch_end(batch=batch)
