# /// script
# dependencies = [
#     "trl",
#     "peft",
#     "datasets",
#     "transformers",
#     "accelerate",
#     "torch",
#     "deepspeed",
#     "mpi4py"
# ]
# ///
import time
from transformers import TrainerCallback

class SpeedCallback(TrainerCallback):
    def __init__(self):
        self.last_time = None

    def on_step_begin(self, args, state, control, **kwargs):
        self.last_time = time.time()

    def on_step_end(self, args, state, control, **kwargs):
        if self.last_time is None:
            return

        elapsed = time.time() - self.last_time
        remaining = max(0, state.max_steps - state.global_step)
        eta_min = remaining * elapsed / 60

        print(
            f"[speed] step {state.global_step}/{state.max_steps} | "
            f"{elapsed:.2f}s/step | ETA {eta_min:.1f} min",
            flush=True,
        )
import inspect

import datasets
import trl.experimental.gold as gold
from transformers import AutoTokenizer


# -----------------------------
# Models
# -----------------------------

STUDENT_MODEL = "Qwen/Qwen2.5-0.5B-Instruct"
TEACHER_MODEL = "Qwen/Qwen2.5-Coder-1.5B-Instruct"

OUTPUT_DIR = "gold-code-deepspeed-test"


# -----------------------------
#
# If ZeRO-3 is painfully slow, try this instead:

DS_CONFIG = {
     "zero_optimization": {
         "stage": 2,
         "overlap_comm": True,
         "contiguous_gradients": True,
     },
     "bf16": {
         "enabled": True,
     },
     "train_micro_batch_size_per_gpu": "auto",
     "gradient_accumulation_steps": "auto",
     "gradient_clipping": "auto",
}


# -----------------------------
# Dataset
# -----------------------------

def to_messages(example):
    description = str(example.get("description", "")).strip()

    if not description:
        description = str(example)

    # Keep prompts short at first. code_contests descriptions can be long.
    description = description[:1500]

    return {
        "messages": [
            {
                "role": "system",
                "content": (
                    "You are a careful competitive programming assistant. "
                    "Return only the final correct solution code. "
                    "Do not include markdown or explanations."
                ),
            },
            {
                "role": "user",
                "content": (
                    "Solve this programming problem:\n\n"
                    f"{description}"
                ),
            },
        ]
    }


def main():
    print("Loading tokenizer...")
    tokenizer = AutoTokenizer.from_pretrained(
        STUDENT_MODEL,
        trust_remote_code=True,
    )

    if tokenizer.pad_token is None:
        tokenizer.pad_token = tokenizer.eos_token

    if tokenizer.pad_token_id is None:
        tokenizer.pad_token_id = tokenizer.eos_token_id

    print("Loading dataset...")
    raw = datasets.load_dataset(
        "deepmind/code_contests",
        split="train[:10000]",
    )

    print("Raw columns:", raw.column_names)

    train_dataset = raw.map(
        to_messages,
        remove_columns=raw.column_names,
    )

    print("Processed example:")
    print(train_dataset[0])

    config = gold.GOLDConfig(
        output_dir=OUTPUT_DIR,

        # GOLD generation settings
        temperature=0.8,
        top_p=0.95,
        max_length=512,
        disable_tqdm=True,
        # Training settings
        max_steps=1000,
        per_device_train_batch_size=1,
        gradient_accumulation_steps=4,
        learning_rate=5e-6,
        model_init_kwargs={
            "torch_dtype": "bfloat16",
            "attn_implementation": "sdpa",
        },

        # Logging/saving
        logging_steps=10,
        save_steps=100,
        report_to="none",
        
        # Precision
        bf16=True,
        hub_model_id="moos124/gold-code-deepspeed-testV2",
        push_to_hub=True,
        # DeepSpeed
        deepspeed=DS_CONFIG,
    )

    # TRL versions differ: some use processing_class, some older ones use tokenizer.
    trainer_kwargs = {
        "model": STUDENT_MODEL,
        "teacher_model": TEACHER_MODEL,
        "args": config,
        "train_dataset": train_dataset,
    }

    signature = inspect.signature(gold.GOLDTrainer)

    if "processing_class" in signature.parameters:
        trainer_kwargs["processing_class"] = tokenizer
    elif "tokenizer" in signature.parameters:
        trainer_kwargs["tokenizer"] = tokenizer
    else:
        print("Warning: GOLDTrainer signature has no processing_class/tokenizer parameter.")

    print("Building GOLDTrainer...")
    trainer = gold.GOLDTrainer(**trainer_kwargs)
    trainer.add_callback(SpeedCallback())
    print("Training...")
    trainer.train()

    print("Saving...")
    trainer.save_model(OUTPUT_DIR)
    # Optional push
    trainer.push_to_hub()


if __name__ == "__main__":
    main()