// How the CLI's read commands obtain current data.
//
// `collections`, `files --collection`, `get`, and `get-thumb` must answer for
// the account's state at the moment the command runs, not for whatever the
// local cache last happened to hold (owner amendment, issue #36). Each helper
// therefore forces a server round-trip through `Library.fresh()` and only then
// reads — so a collection, file, or metadata change made elsewhere is visible.
//
// `collections` and `files` also list in the library's own enumeration order —
// `listCollections()`/`listFiles()`, the order the pre-library CLI printed —
// rather than the `albums`/`photos` projection's newest-first order, which
// re-sorts the rows. The field values still come from each record's raw
// metadata via `cli-output.ts`.

import type { Collection, EnteFile } from "./model/types.js";
import type { Photo, PhotosAPI } from "./library/index.js";

// The slice of `Library` these helpers read. `Library` satisfies it
// structurally; a test can drive them with a stand-in that records the
// `fresh()` call and serves records in a known enumeration order.
export interface FreshReadLibrary {
    fresh(): Promise<unknown>;
    listCollections(): Collection[];
    getCollection(id: number): Collection | undefined;
    listFiles(collectionID: number): EnteFile[];
    getFileByID(fileID: number): EnteFile | undefined;
    photos: Pick<PhotosAPI, "byID">;
}

// Every live collection, current as of a forced refresh, in enumeration order.
export const freshCollections = async (
    lib: FreshReadLibrary,
): Promise<Collection[]> => {
    await lib.fresh();
    return lib.listCollections();
};

// The files of one collection, current as of a forced refresh, in enumeration
// order. `undefined` (not an empty list) when the collection does not exist, so
// the caller can tell "no such collection" from "an empty collection".
export const freshFiles = async (
    lib: FreshReadLibrary,
    collectionID: number,
): Promise<EnteFile[] | undefined> => {
    await lib.fresh();
    if (!lib.getCollection(collectionID)) return undefined;
    return lib.listFiles(collectionID);
};

// One file, current as of a forced refresh, resolved to both its content
// handle (`Photo`, for fetching bytes) and its raw record (`EnteFile`, for the
// default output name and field values). `undefined` when the file is unknown.
export const freshFile = async (
    lib: FreshReadLibrary,
    fileID: number,
): Promise<{ photo: Photo; file: EnteFile } | undefined> => {
    await lib.fresh();
    const photo = lib.photos.byID({ fileID });
    const file = lib.getFileByID(fileID);
    if (!photo || !file) return undefined;
    return { photo, file };
};