import type { DomainCollection, SubjectTimeInput } from "@/worker/objects/common/collection-types";

export interface CollectionCrudSpec<TDb, TCollection extends DomainCollection, TRecord, TError> {
  ensureDefaultCollection(db: TDb, subjectId: string, nowMs: number): TCollection;
  listCollections(db: TDb, subjectId: string, nowMs: number): TCollection[];
  collectionById(db: TDb, id: string): TCollection | undefined;
  collectionByName(db: TDb, name: string): TCollection | undefined;
  validName(name: string): boolean;
  deleteCollection(db: TDb, id: string): boolean;
  record(row: TCollection): TRecord;
  invalidName(): TError;
  nameConflict(): TError;
  collectionNotFound(): TError;
  emptyDisplayName(): TError;
  defaultDeleteForbidden(): TError;
}

export function listCollectionRecords<TDb, TCollection extends DomainCollection, TRecord, TError>(
  db: TDb,
  input: SubjectTimeInput,
  spec: Pick<CollectionCrudSpec<TDb, TCollection, TRecord, TError>, "listCollections" | "record">,
): { ok: true; records: TRecord[] } {
  return { ok: true, records: spec.listCollections(db, input.subjectId, input.nowMs).map(spec.record) };
}

export function getCollectionRecord<TDb, TCollection extends DomainCollection, TRecord, TError>(
  db: TDb,
  input: SubjectTimeInput & { id: string },
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    "ensureDefaultCollection" | "collectionById" | "record" | "collectionNotFound"
  >,
): { ok: true; record: TRecord } | TError {
  spec.ensureDefaultCollection(db, input.subjectId, input.nowMs);
  const row = spec.collectionById(db, input.id);
  return row ? { ok: true, record: spec.record(row) } : spec.collectionNotFound();
}

export function createCollectionRecord<
  TDb,
  TCollection extends DomainCollection,
  TRecord,
  TError,
  TInput extends SubjectTimeInput & { name: string; displayName?: string },
>(
  db: TDb,
  input: TInput,
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    "validName" | "invalidName" | "ensureDefaultCollection" | "collectionByName" | "nameConflict" | "record"
  > & {
    createCollection(db: TDb, input: TInput, displayName: string): TCollection;
  },
): { ok: true; record: TRecord } | TError {
  if (!spec.validName(input.name)) return spec.invalidName();
  spec.ensureDefaultCollection(db, input.subjectId, input.nowMs);
  if (spec.collectionByName(db, input.name)) return spec.nameConflict();
  const row = spec.createCollection(db, input, input.displayName ?? input.name);
  return { ok: true, record: spec.record(row) };
}

export function updateCollectionRecord<
  TDb,
  TCollection extends DomainCollection,
  TRecord,
  TError,
  TInput extends SubjectTimeInput & { id: string; displayName?: string },
>(
  db: TDb,
  input: TInput,
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    "ensureDefaultCollection" | "record" | "collectionNotFound" | "emptyDisplayName"
  > & {
    updateCollection(db: TDb, input: TInput, displayName: string | undefined): TCollection | undefined;
  },
): { ok: true; record: TRecord } | TError {
  spec.ensureDefaultCollection(db, input.subjectId, input.nowMs);
  const displayName = input.displayName?.trim();
  if (displayName !== undefined && displayName.length === 0) return spec.emptyDisplayName();
  const row = spec.updateCollection(db, input, displayName);
  return row ? { ok: true, record: spec.record(row) } : spec.collectionNotFound();
}

export function deleteCollectionRecord<TDb, TCollection extends DomainCollection, TRecord, TError>(
  db: TDb,
  input: SubjectTimeInput & { id: string },
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    "ensureDefaultCollection" | "collectionById" | "deleteCollection" | "collectionNotFound" | "defaultDeleteForbidden"
  >,
): { ok: true } | TError {
  spec.ensureDefaultCollection(db, input.subjectId, input.nowMs);
  return deleteExistingCollectionRecord(db, spec.collectionById(db, input.id), spec);
}

export function deleteCollectionRecordByName<TDb, TCollection extends DomainCollection, TRecord, TError>(
  db: TDb,
  input: SubjectTimeInput & { name: string },
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    | "ensureDefaultCollection"
    | "collectionByName"
    | "deleteCollection"
    | "collectionNotFound"
    | "defaultDeleteForbidden"
  >,
): { ok: true } | TError {
  spec.ensureDefaultCollection(db, input.subjectId, input.nowMs);
  return deleteExistingCollectionRecord(db, spec.collectionByName(db, input.name), spec);
}

function deleteExistingCollectionRecord<TDb, TCollection extends DomainCollection, TRecord, TError>(
  db: TDb,
  collection: TCollection | undefined,
  spec: Pick<
    CollectionCrudSpec<TDb, TCollection, TRecord, TError>,
    "deleteCollection" | "collectionNotFound" | "defaultDeleteForbidden"
  >,
): { ok: true } | TError {
  if (!collection) return spec.collectionNotFound();
  if (collection.name === "default") return spec.defaultDeleteForbidden();
  spec.deleteCollection(db, collection.id);
  return { ok: true };
}