"""Stage a full-Hub update or lightweight metadata archive; never upload."""

from __future__ import annotations

import argparse
import gzip
import json
import shutil
import tarfile
from pathlib import Path

from kitti_c2l.release import (
    DATA_FILES,
    RELEASE_VERSION,
    sha256,
    validate_hub_manifest,
    validate_release,
)

RELEASE_FILES = (
    "README.md",
    "LICENSE",
    "LICENSE-DATA",
    "CITATION.cff",
    "configs/sequence_mapping.yaml",
    "docs/PROTOCOL.md",
    "docs/BASELINES.md",
    "docs/ASSESSMENT.md",
    "docs/RELEASING.md",
    "docs/THIRD_PARTY.md",
    "release/v1/APPLE-MOBILEVIT-LICENSE.txt",
    "release/v1/UNICAL-LICENSE.txt",
    "release/v1/protocol.json",
    "release/v1/provenance.json",
    "release/v1/baselines_manifest.json",
    "release/v1/verification.json",
    "release/v1/manifest.json",
    "release/v1/CITATION.cff",
    "release/v1/assessment_results.json",
    "release/v1/HF_DATASET_CARD.md",
    "release/v1/hub_manifest.json",
    "release/v1/hub_payload_verification.json",
    "release/v1/hub_loading_verification.json",
    "release/v1/full_release_verification.json",
    *(f"data/{name}" for name in DATA_FILES),
)


def write_checksums(directory: Path) -> None:
    files = sorted(
        path for path in directory.rglob("*") if path.is_file() and path.name != "SHA256SUMS"
    )
    (directory / "SHA256SUMS").write_text(
        "".join(f"{sha256(path)}  {path.relative_to(directory).as_posix()}\n" for path in files)
    )


def archive_directory(directory: Path) -> Path:
    archive = directory.with_name(directory.name + ".tar.gz")
    with (
        archive.open("xb") as raw,
        gzip.GzipFile(filename="", fileobj=raw, mode="wb", mtime=0) as compressed,
    ):
        with tarfile.open(fileobj=compressed, mode="w") as tar:
            for path in sorted(directory.rglob("*")):
                if not path.is_file():
                    continue
                info = tar.gettarinfo(
                    str(path), arcname=f"{directory.name}/{path.relative_to(directory).as_posix()}"
                )
                info.uid = info.gid = info.mtime = 0
                info.uname = info.gname = ""
                info.mode = 0o644
                with path.open("rb") as stream:
                    tar.addfile(info, stream)
    return archive


def prepare(
    root: Path, output: Path, kitti_calib_root: Path | None = None, *, profile: str = "metadata"
) -> Path:
    if profile not in {"metadata", "full-update"}:
        raise ValueError(f"Unknown release profile: {profile}")
    validate_release(root, kitti_calib_root=kitti_calib_root)
    hub = validate_hub_manifest(root) if profile == "full-update" else None
    if output.exists() or output.with_name(output.name + ".tar.gz").exists():
        raise FileExistsError(f"Refusing to overwrite release output: {output}")
    # Resolve every source before creating output: no recursive working-directory upload.
    for relative in RELEASE_FILES:
        source = root / relative
        if not source.is_file() or source.is_symlink():
            raise ValueError(f"Missing or symlinked release source: {relative}")
    output.mkdir(parents=True)
    for relative in RELEASE_FILES:
        destination = output / relative
        destination.parent.mkdir(parents=True, exist_ok=True)
        shutil.copyfile(root / relative, destination)
    # This command stages the frozen v1.0 profile, even when the source
    # repository's current citation advances to an additive dataset release.
    shutil.copyfile(root / "release/v1/CITATION.cff", output / "CITATION.cff")
    if hub is not None:
        shutil.copyfile(root / "release/v1/HF_DATASET_CARD.md", output / "README.md")
        (output / "release-profile.json").write_text(
            json.dumps(
                {
                    "profile": profile,
                    "target_repo": hub["repo_id"],
                    "base_revision": hub["revision"],
                    "requires_existing_frame_shards": True,
                    "delete_remote_files": False,
                    "note": "Update package only; the 50 existing frame shards stay on the Hub. No upload is performed.",
                },
                indent=2,
            )
            + "\n"
        )
    write_checksums(output)
    return archive_directory(output)


def main() -> None:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--root", type=Path, default=Path(__file__).resolve().parents[1])
    parser.add_argument("--profile", choices=["full-update", "metadata"], default="full-update")
    parser.add_argument("--output", type=Path)
    parser.add_argument("--kitti-calib-root", type=Path)
    args = parser.parse_args()
    output = args.output or Path(f"dist/kitti-c2l-{args.profile}-v{RELEASE_VERSION}")
    archive = prepare(
        args.root.resolve(), output.resolve(), args.kitti_calib_root, profile=args.profile
    )
    print(f"Prepared {args.profile}: {output}\nArchive: {archive}\nSHA-256: {sha256(archive)}")


if __name__ == "__main__":
    main()