from __future__ import annotations

import argparse
from pathlib import Path

_ORIGINAL = """    const rootSkip = new Set(['proc', 'dev', 'sys']);
    for (const p of readConfig?.denyOnly || []) {
        if (normalizePathForSandbox(p) === '/') {
            for (const child of fs.readdirSync('/')) {
                if (!rootSkip.has(child))
                    readDenyPaths.push('/' + child);
            }
        }
"""

_REPLACEMENT = """    const rootSkip = new Set(['proc', 'dev', 'sys']);
    const rootChildIsAllowedSymlink = (childPath) => {
        try {
            if (!fs.lstatSync(childPath).isSymbolicLink())
                return false;
            const resolved = fs.realpathSync(childPath);
            return readAllowPaths.some(allowPath => resolved === allowPath || resolved.startsWith(allowPath + '/'));
        }
        catch {
            return false;
        }
    };
    for (const p of readConfig?.denyOnly || []) {
        if (normalizePathForSandbox(p) === '/') {
            for (const child of fs.readdirSync('/')) {
                const childPath = '/' + child;
                if (!rootSkip.has(child) && !rootChildIsAllowedSymlink(childPath))
                    readDenyPaths.push(childPath);
            }
        }
"""

_TMPFS_ORIGINAL = """            args.push('--ro-bind', allowPath, allowPath);
            logForDebugging(`[Sandbox Linux] Re-allowed read access within denied region: ${allowPath}`);
        }
    }
}
"""

_TMPFS_REPLACEMENT = """            args.push('--ro-bind', allowPath, allowPath);
            logForDebugging(`[Sandbox Linux] Re-allowed read access within denied region: ${allowPath}`);
        }
    }
    // A denyRead tmpfs must not become an unlisted writable location. Remount
    // only the parent mount read-only; explicit writable child binds remain rw.
    if (!allowedWritePaths.includes(normalizedPath)) {
        args.push('--remount-ro', normalizedPath);
    }
}
"""


def patch_file(path: Path) -> None:
    source = path.read_text(encoding="utf-8")
    if _REPLACEMENT in source or _TMPFS_REPLACEMENT in source:
        raise RuntimeError("sandbox runtime merged-usr patch is already patched")
    if source.count(_ORIGINAL) != 1:
        raise RuntimeError("sandbox runtime merged-usr patch target does not match pinned source")
    if source.count(_TMPFS_ORIGINAL) != 1:
        raise RuntimeError("sandbox runtime read-only tmpfs patch target does not match pinned source")
    patched = source.replace(_ORIGINAL, _REPLACEMENT)
    patched = patched.replace(_TMPFS_ORIGINAL, _TMPFS_REPLACEMENT)
    path.write_text(patched, encoding="utf-8")


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("path", type=Path)
    args = parser.parse_args()
    patch_file(args.path)


if __name__ == "__main__":
    main()