#!/usr/bin/env python3
"""Safely move or delete entries inside the knowledge vault."""

from __future__ import annotations

import json
import shutil
import sys
from pathlib import Path

VAULT: Path


def fail(message: str) -> int:
    print(message, file=sys.stderr)
    return 1


def vault_entry(relative: str) -> Path | None:
    if not relative or relative.startswith("/") or "\0" in relative:
        return None
    candidate = VAULT / relative
    parent = candidate.parent.resolve()
    if parent != VAULT and VAULT not in parent.parents:
        return None
    return parent / candidate.name


def move_entry(source_relative: str, destination_relative: str) -> int:
    source = vault_entry(source_relative)
    destination_directory = (VAULT / destination_relative).resolve()
    if source is None or not (source.exists() or source.is_symlink()):
        return fail("selected entry no longer exists")
    if destination_directory != VAULT and VAULT not in destination_directory.parents:
        return fail("destination escaped the vault")
    if not destination_directory.is_dir():
        return fail("destination directory no longer exists")
    if source.is_dir() and (
        destination_directory == source or source in destination_directory.parents
    ):
        return fail("cannot move a directory into itself")

    destination = destination_directory / source.name
    if destination.exists() or destination.is_symlink():
        return fail(f"already exists: {destination.name}")
    try:
        source.rename(destination)
    except OSError as error:
        return fail(f"cannot move {source.name}: {error}")

    json.dump(
        {
            "action": "move",
            "relative": destination.relative_to(VAULT).as_posix(),
            "kind": "directory" if destination.is_dir() else "note",
        },
        sys.stdout,
    )
    return 0


def delete_entry(source_relative: str) -> int:
    source = vault_entry(source_relative)
    if source is None or not (source.exists() or source.is_symlink()):
        return fail("selected entry no longer exists")
    try:
        if source.is_symlink():
            source.unlink()
        elif source.is_dir():
            shutil.rmtree(source)
        else:
            source.unlink()
    except OSError as error:
        return fail(f"cannot delete {source.name}: {error}")
    json.dump({"action": "delete", "relative": source_relative}, sys.stdout)
    return 0


def main() -> int:
    global VAULT
    if len(sys.argv) < 4:
        return fail(
            "usage: manage-entry.py VAULT ACTION SOURCE [DESTINATION_DIRECTORY]"
        )
    VAULT = Path(sys.argv[1]).expanduser().resolve()
    if not VAULT.is_dir():
        return fail(f"vault does not exist: {VAULT}")
    action, source = sys.argv[2:4]
    if action == "move" and len(sys.argv) == 5:
        return move_entry(source, sys.argv[4])
    if action == "delete" and len(sys.argv) == 4:
        return delete_entry(source)
    return fail("invalid file operation")


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