#!/usr/bin/env python3
import argparse
import json
from pathlib import Path
from typing import Any, Iterable, List, Set

FILENAME_CANDIDATES = ("info.json", "stats.json")


def replace_in_payload(payload: Any, old: str, new: str) -> Any:
    if isinstance(payload, str):
        return payload.replace(old, new)
    if isinstance(payload, list):
        return [replace_in_payload(item, old, new) for item in payload]
    if isinstance(payload, dict):
        return {
            replace_in_payload(k, old, new) if isinstance(k, str) else k: replace_in_payload(v, old, new)
            for k, v in payload.items()
        }
    return payload


def update_metadata(meta_dir: Path, old_name: str, new_name: str) -> None:
    for filename in FILENAME_CANDIDATES:
        json_path = meta_dir / filename
        if not json_path.is_file():
            continue

        with json_path.open("r", encoding="utf-8") as fh:
            data = json.load(fh)

        updated = replace_in_payload(data, old_name, new_name)

        if updated != data:
            with json_path.open("w", encoding="utf-8") as fh:
                json.dump(updated, fh, ensure_ascii=False, indent=2)
            print(f"Updated metadata: {json_path}")


def resolve_metadata_directories(folder: Path, explicit: Iterable[Path]) -> List[Path]:
    dirs: List[Path] = []
    seen: Set[Path] = set()

    def add_candidate(candidate: Path) -> None:
        resolved = candidate.resolve(strict=False)
        if resolved.is_dir() and resolved not in seen:
            seen.add(resolved)
            dirs.append(resolved)

    for meta_path in explicit:
        add_candidate(meta_path)

    try:
        resolved_folder = folder.resolve(strict=False)
    except Exception:
        resolved_folder = folder

    traversal: List[Path] = [resolved_folder]
    traversal.extend(resolved_folder.parents)

    for current in traversal:
        candidate = current / "meta"
        add_candidate(candidate)

    return dirs


def rename_folder(src: Path, new_name: str, metadata_dirs: Iterable[Path], old_name: str | None = None) -> None:
    if not src.exists():
        raise FileNotFoundError(f"Source folder does not exist: {src}")
    if not src.is_dir():
        raise NotADirectoryError(f"Source path is not a directory: {src}")

    target = src.with_name(new_name)
    if target.exists():
        raise FileExistsError(f"Target already exists: {target}")

    name_to_replace = old_name or src.name

    updated_any = False
    for meta_dir in metadata_dirs:
        update_metadata(meta_dir, name_to_replace, new_name)
        updated_any = True
    if not updated_any:
        print("No metadata directories found; skipping metadata update.")

    src.rename(target)
    print(f"Renamed '{src}' -> '{target}'")


def main() -> None:
    parser = argparse.ArgumentParser(description="Rename a folder and update related metadata.")
    parser.add_argument("folder", type=Path, help="Path to the folder you want to rename")
    parser.add_argument("new_name", help="New name for the folder (no path separators)")
    parser.add_argument(
        "--meta",
        type=Path,
        action="append",
        default=[],
        help="Explicit path to a metadata directory to update (can be provided multiple times).",
    )
    parser.add_argument(
        "--metadata-only",
        action="store_true",
        help="Only update metadata; skip renaming. Requires the target folder path to identify nearby metadata directories.",
    )
    parser.add_argument(
        "--old-name",
        help="Old folder name to replace within metadata. Defaults to the current folder name.",
    )
    args = parser.parse_args()

    metadata_dirs = resolve_metadata_directories(args.folder, args.meta)
    if args.metadata_only:
        name_to_replace = args.old_name or args.folder.name
        if not metadata_dirs:
            print("No metadata directories found; nothing to update.")
            return
        for meta_dir in metadata_dirs:
            update_metadata(meta_dir, name_to_replace, args.new_name)
        print("Metadata update complete.")
        return

    rename_folder(args.folder, args.new_name, metadata_dirs, args.old_name)


if __name__ == "__main__":
    main()