"""Self-contained loader for DeepSeek-Flash-Mini (HF export).

Usage:
    from load_and_generate import load_model
    model, cfg = load_model(".")            # repo dir containing config.json + model.safetensors
    # or CLI:
    python load_and_generate.py --prompt "Once upon a time" --max-new-tokens 80
"""
import argparse, json
import torch
from safetensors.torch import load_file
from config import ModelConfig
from model import DeepSeekFlashMini
from dataio.tokenizer import load_tokenizer
from generate import Generator


def load_model(repo_dir: str = "."):
    with open(f"{repo_dir}/config.json", encoding="utf-8") as f:
        cfg = ModelConfig(**json.load(f))
    model = DeepSeekFlashMini(cfg)
    sd = load_file(f"{repo_dir}/model.safetensors")
    model.load_state_dict(sd)
    model.eval()
    return model, cfg


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--repo-dir", default=".")
    ap.add_argument("--prompt", default="Once upon a time")
    ap.add_argument("--max-new-tokens", type=int, default=80)
    ap.add_argument("--temperature", type=float, default=0.8)
    ap.add_argument("--top-k", type=int, default=40)
    ap.add_argument("--top-p", type=float, default=0.9)
    ap.add_argument("--device", default="cpu")
    ap.add_argument("--spec", action="store_true", help="use MTP speculative decoding")
    args = ap.parse_args()

    model, cfg = load_model(args.repo_dir)
    tok = load_tokenizer(f"{args.repo_dir}/tokenizer.json")
    gen = Generator(model, tok, device=args.device)
    text = gen.generate(args.prompt, max_new_tokens=args.max_new_tokens,
                        temperature=args.temperature, top_k=args.top_k,
                        top_p=args.top_p, speculative=args.spec)
    print(text)


if __name__ == "__main__":
    main()