"""Package the hamori project for Google Colab pre-training or fine-tuning.

pretrain mode (default):
  - src/                               (all Python modules)
  - scripts/pretrain.py
  - requirements.txt
  - data/processed/mcgill/train/*.pt
  - data/processed/mcgill/val/*.pt

finetune mode:
  - src/                               (all Python modules)
  - scripts/train.py
  - requirements.txt
  - data/processed/user/train/*.pt
  - data/processed/user/val/*.pt
  - checkpoints/pretrained.pt          (only with --include-checkpoint)

Usage:
    # Pre-training bundle (default)
    python scripts/make_colab_zip.py
    python scripts/make_colab_zip.py --mode pretrain

    # Fine-tuning bundle (run prepare_data.py locally first)
    python scripts/make_colab_zip.py --mode finetune

    # Fine-tuning bundle with pretrained checkpoint included
    python scripts/make_colab_zip.py --mode finetune --include-checkpoint

    # Exclude data files (code only)
    python scripts/make_colab_zip.py --mode finetune --no-data

    # Custom output path
    python scripts/make_colab_zip.py --mode pretrain --output my_bundle.zip

Outputs:
    output/hamori_colab_pretrain.zip  (pretrain mode)
    output/hamori_colab_finetune.zip  (finetune mode)
"""

from __future__ import annotations

import argparse
import sys
import zipfile
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
SRC_DIR = ROOT / "src"
OUT_DIR = ROOT / "output"

COMMON_VERBATIM: list[str] = ["requirements.txt"]

MODE_SCRIPTS: dict[str, list[str]] = {
    "pretrain": ["scripts/pretrain.py"],
    "finetune": ["scripts/train.py"],
}

# Local dir → arc path inside zip
PRETRAIN_DATA: list[tuple[Path, str]] = [
    (ROOT / "data" / "processed" / "mcgill" / "train", "data/processed/mcgill/train"),
    (ROOT / "data" / "processed" / "mcgill" / "val",   "data/processed/mcgill/val"),
]

FINETUNE_DATA: list[tuple[Path, str]] = [
    (ROOT / "data" / "processed" / "user" / "train", "data/processed/user/train"),
    (ROOT / "data" / "processed" / "user" / "val",   "data/processed/user/val"),
]

PRETRAINED_CKPT = ROOT / "checkpoints" / "pretrained.pt"


def build_zip(out_path: Path, mode: str, include_data: bool,
              include_checkpoint: bool) -> None:
    out_path.parent.mkdir(parents=True, exist_ok=True)
    n_files = 0

    data_map = PRETRAIN_DATA if mode == "pretrain" else FINETUNE_DATA

    with zipfile.ZipFile(out_path, "w", compression=zipfile.ZIP_DEFLATED) as zf:
        # src/ — all .py files
        for py in sorted(SRC_DIR.rglob("*.py")):
            arc = "src/" + py.relative_to(SRC_DIR).as_posix()
            zf.write(py, arc)
            n_files += 1

        # common + mode-specific scripts
        for rel in COMMON_VERBATIM + MODE_SCRIPTS[mode]:
            src = ROOT / rel
            if not src.exists():
                print(f"[warn] missing: {src} — skipped", file=sys.stderr)
                continue
            zf.write(src, rel)
            n_files += 1

        # data
        if include_data:
            for local_dir, arc_prefix in data_map:
                if not local_dir.exists():
                    print(f"[warn] data dir not found: {local_dir} — skipped",
                          file=sys.stderr)
                    continue
                pts = sorted(local_dir.glob("*.pt"))
                for pt in pts:
                    zf.write(pt, f"{arc_prefix}/{pt.name}")
                    n_files += 1
                print(f"[data] {arc_prefix}: {len(pts)} files")
        else:
            print("[data] skipped (--no-data)")

        # pretrained checkpoint (finetune mode only, opt-in)
        if mode == "finetune" and include_checkpoint:
            if not PRETRAINED_CKPT.exists():
                print(f"[warn] checkpoint not found: {PRETRAINED_CKPT} — skipped",
                      file=sys.stderr)
            else:
                zf.write(PRETRAINED_CKPT, "checkpoints/pretrained.pt")
                n_files += 1
                ckpt_mb = PRETRAINED_CKPT.stat().st_size / 1_048_576
                print(f"[ckpt] checkpoints/pretrained.pt ({ckpt_mb:.1f} MB)")

    size_mb = out_path.stat().st_size / 1_048_576
    print(f"[done] {out_path}  ({n_files} files, {size_mb:.1f} MB)")


def main() -> None:
    ap = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    ap.add_argument(
        "--mode", choices=["pretrain", "finetune"], default="pretrain",
        help="Bundle mode: 'pretrain' (default) or 'finetune'.",
    )
    ap.add_argument(
        "--output", type=Path, default=None,
        help="Output zip path. Default: output/hamori_colab_<mode>.zip.",
    )
    ap.add_argument(
        "--no-data", action="store_true",
        help="Exclude data files (code-only bundle).",
    )
    ap.add_argument(
        "--include-checkpoint", action="store_true", dest="include_checkpoint",
        help="(finetune mode) Include checkpoints/pretrained.pt in the zip.",
    )
    args = ap.parse_args()

    out_path = args.output or OUT_DIR / f"hamori_colab_{args.mode}.zip"
    build_zip(
        out_path=out_path,
        mode=args.mode,
        include_data=not args.no_data,
        include_checkpoint=args.include_checkpoint,
    )


if __name__ == "__main__":
    main()