"""
Stage download (v8b): fetch Qwen3-8B weights into MODEL_PATH.

Downloads MODEL_REPO (default Qwen/Qwen3-8B) into MODEL_PATH
(default ~/jrhu/v8b/data/models/Qwen3-8B) via huggingface_hub.

Resume: snapshot_download is incremental; re-running only fetches
missing/changed files. Skips entirely if the target already looks
complete (config.json + a safetensors index present), unless --force.
"""
import argparse
import glob
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from configs.paths import MODEL_PATH, MODEL_REPO, ensure_dirs
from src.utils import setup_logger
from configs.paths import LOG_DIR


def _looks_complete(path: str) -> bool:
    if not os.path.isdir(path):
        return False
    has_config = os.path.isfile(os.path.join(path, "config.json"))
    has_weights = bool(
        glob.glob(os.path.join(path, "*.safetensors"))
        or glob.glob(os.path.join(path, "*.bin"))
    )
    return has_config and has_weights


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--repo", default=MODEL_REPO)
    ap.add_argument("--dest", default=MODEL_PATH)
    ap.add_argument("--force", action="store_true")
    args = ap.parse_args()

    ensure_dirs("monitoring")
    log = setup_logger("download_model", os.path.join(LOG_DIR, "download_model.log"))
    log.info("=" * 70)
    log.info(f"Download model  repo={args.repo}  dest={args.dest}")
    log.info("=" * 70)

    if _looks_complete(args.dest) and not args.force:
        log.info(f"  [resume] {args.dest} already looks complete — SKIP "
                 f"(use --force to re-fetch).")
        return

    os.makedirs(args.dest, exist_ok=True)
    from huggingface_hub import snapshot_download

    path = snapshot_download(
        repo_id=args.repo,
        local_dir=args.dest,
        local_dir_use_symlinks=False,
        resume_download=True,
        allow_patterns=[
            "*.json", "*.safetensors", "*.txt", "*.model",
            "tokenizer*", "vocab*", "merges*", "*.py",
        ],
    )
    log.info(f"Downloaded snapshot -> {path}")
    log.info(f"Complete? {_looks_complete(args.dest)}")
    log.info("Done.")


if __name__ == "__main__":
    main()