#!/usr/bin/env python3
"""Install one reviewed CLI bundle offline into a new owner-controlled prefix."""
import argparse
import hashlib
import json
from pathlib import Path
import platform
import shutil
import subprocess
import sys


def digest(path):
    return hashlib.sha256(path.read_bytes()).hexdigest()


def install(bundle, prefix, expected_manifest, python, uv):
    manifest_path = bundle / "manifest.json"
    if digest(manifest_path) != expected_manifest:
        raise ValueError("bundle manifest differs from reviewed digest")
    manifest = json.loads(manifest_path.read_text())
    if manifest["schema"] != "secrets-engine.cli-bundle.v1":
        raise ValueError("unsupported bundle")
    if manifest['system'] != platform.system() or manifest['machine'] != platform.machine():
        raise ValueError("bundle platform differs from installer host")
    expected_files = set(manifest['artifacts']) | {'manifest.json'}
    actual_files = {str(p.relative_to(bundle)) for p in bundle.rglob('*') if p.is_file()}
    if actual_files != expected_files:
        raise ValueError("bundle file set differs")
    for name, expected in manifest['artifacts'].items():
        relative = Path(name)
        if relative.is_absolute() or '..' in relative.parts:
            raise ValueError("invalid artifact path")
        artifact = bundle / relative
        if any(parent.is_symlink() for parent in (artifact,*artifact.parents)) or digest(artifact) != expected:
            raise ValueError("bundle artifact missing or changed")
    # Reserve once; never replace an installed prefix or follow an existing link.
    prefix.mkdir(mode=0o700, parents=False, exist_ok=False)
    try:
        subprocess.run([uv,'--no-config','venv','--python',python,'--no-python-downloads',str(prefix/'venv')],check=True)
        subprocess.run([uv,'--no-config','pip','install','--python',str(prefix/'venv/bin/python'),
                        '--no-index','--find-links',str(bundle/'wheels'),str(bundle/manifest['wheel'])],check=True)
        (prefix/'libexec').mkdir(mode=0o700)
        helper=prefix/'libexec/secrets-engine-pdp-verify'
        shutil.copyfile(bundle/'bin/secrets-engine-pdp-verify',helper);helper.chmod(0o700)
        (prefix/'bin').mkdir(mode=0o700)
        launcher=prefix/'bin/secrets-engine'
        # An absolute venv interpreter fixes the installed dependency environment.
        launcher.write_text('#!'+str(prefix/'venv/bin/python')+'\n'+(bundle/'release_cli.py').read_text())
        launcher.chmod(0o700)
        receipt={"schema":"secrets-engine.cli-install.v1","manifest_sha256":expected_manifest,
                 "helper_sha256":digest(helper),"launcher_sha256":digest(launcher),"prefix":str(prefix),
                 "admission":"artifact integrity only; trust and keys not admitted"}
        (prefix/'install-receipt.json').write_text(json.dumps(receipt,sort_keys=True,indent=2)+'\n')
        return receipt
    except BaseException:
        # Preserve a failed prefix as evidence; never retry into a partial install.
        (prefix/'INSTALL-FAILED').write_text('Incomplete installation; use a new prefix.\n')
        raise


def main():
    parser=argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--bundle',type=Path,default=Path(__file__).resolve().parent)
    parser.add_argument('--prefix',type=Path,required=True)
    parser.add_argument('--manifest-sha256',required=True)
    parser.add_argument('--python',default=sys.executable)
    parser.add_argument('--uv',default='uv')
    args=parser.parse_args()
    try:
        if not args.prefix.is_absolute() or args.prefix.parent.is_symlink():
            raise ValueError('prefix must be absolute with an admitted parent')
        receipt=install(args.bundle.resolve(),args.prefix,args.manifest_sha256,args.python,args.uv)
        print(json.dumps(receipt,sort_keys=True))
    except (OSError,ValueError,KeyError,subprocess.SubprocessError) as exc:
        print('bundle install refused: '+str(exc),file=sys.stderr)
        return 1
    return 0


if __name__=='__main__':
    raise SystemExit(main())