#!/usr/bin/env python3
"""Check or regenerate the repository SHA-256 manifest using only the standard library."""
from __future__ import annotations
import argparse,hashlib,json
from pathlib import Path,PurePosixPath
ROOT=Path(__file__).resolve().parents[1]
SKIP_PARTS={"__pycache__",".pytest_cache",".git",".venv",".hf-uploader-venv","node_modules","htmlcov",".cache","build","dist"}
SKIP_NAMES={"SHA256SUMS",".coverage",".DS_Store"}
def inventory(root):
    for p in sorted(root.rglob("*")):
        rel=p.relative_to(root)
        if any(part in SKIP_PARTS or part.endswith((".egg-info",".dist-info")) for part in rel.parts):continue
        if p.name in SKIP_NAMES or p.suffix in {".pyc",".pyo"}:continue
        if p.is_symlink():raise ValueError("Symlinks are not accepted: "+rel.as_posix())
        if p.is_file():yield p
def write_manifest(root=ROOT):
    root=Path(root).resolve()
    lines=[hashlib.sha256(p.read_bytes()).hexdigest()+"  "+p.relative_to(root).as_posix()
           for p in inventory(root)]
    (root/"SHA256SUMS").write_text("\n".join(lines)+"\n",encoding="utf-8")
    return len(lines)
def verify_release(root=ROOT):
    root=Path(root).resolve();manifest=root/"SHA256SUMS"
    if not manifest.is_file():raise ValueError("SHA256SUMS is missing")
    expected={};errors=[]
    for line in manifest.read_text(encoding="utf-8").splitlines():
        if not line.strip():continue
        digest,sep,name=line.partition("  ")
        if not sep or len(digest)!=64 or any(c not in "0123456789abcdef" for c in digest):
            raise ValueError("Malformed checksum entry")
        posix=PurePosixPath(name)
        if posix.is_absolute() or ".." in posix.parts or "\\" in name:
            raise ValueError("Unsafe checksum path")
        if name in expected:raise ValueError("Duplicate checksum entry")
        expected[name]=digest
    for name,digest in expected.items():
        p=root/name
        if not p.resolve().is_relative_to(root):
            errors.append({"path":name,"reason":"outside repository"});continue
        if p.is_symlink() or not p.is_file():
            errors.append({"path":name,"reason":"missing or non-regular file"});continue
        if hashlib.sha256(p.read_bytes()).hexdigest()!=digest:
            errors.append({"path":name,"reason":"hash mismatch"})
    actual={p.relative_to(root).as_posix() for p in inventory(root)}
    errors.extend({"path":name,"reason":"unlisted extra file"} for name in sorted(actual-set(expected)))
    return {"ok":not errors,"manifest_entries":len(expected),"errors":errors,
            "paths":sorted(expected)+["SHA256SUMS"],
            "total_bytes":sum((root/name).stat().st_size for name in expected if (root/name).is_file())+manifest.stat().st_size}
def main():
    parser=argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--write",action="store_true",help="regenerate after intentional edits")
    args=parser.parse_args()
    if args.write:print(json.dumps({"manifest_written":write_manifest()}))
    result=verify_release()
    print(json.dumps({k:v for k,v in result.items() if k!="paths"},indent=2))
    return 0 if result["ok"] else 1
if __name__=="__main__":raise SystemExit(main())