export interface EmailSearchFilters {
  query?: string;
  from?: string;
  to?: string;
  subject?: string;
  since?: Date;
  before?: Date;
  unseen?: boolean;
}

export type ImapSearchCriteria = Record<string, unknown>;

export function buildSearchCriteria(filters: EmailSearchFilters): ImapSearchCriteria {
  const criteria: ImapSearchCriteria = {};

  // ImapFlow's `text` criterion searches headers and body. All populated
  // properties in this object are combined with AND semantics.
  if (filters.query) criteria.text = filters.query;
  if (filters.from) criteria.from = filters.from;
  if (filters.to) criteria.to = filters.to;
  if (filters.subject) criteria.subject = filters.subject;
  if (filters.since) criteria.since = filters.since;
  if (filters.before) criteria.before = filters.before;
  if (filters.unseen) criteria.seen = false;

  if (Object.keys(criteria).length === 0) criteria.all = true;
  return criteria;
}

interface ESearchLike {
  all?: unknown;
}

export function normalizeSearchUids(result: unknown): number[] {
  if (result === false || result === null || result === undefined) return [];

  const raw = Array.isArray(result)
    ? result
    : typeof result === "object" && Array.isArray((result as ESearchLike).all)
      ? (result as ESearchLike).all
      : [];

  const valid = (raw as unknown[]).filter(
    (uid): uid is number => typeof uid === "number" && Number.isSafeInteger(uid) && uid > 0,
  );
  return [...new Set(valid)];
}

export interface PaginationResult {
  page: number[];
  total: number;
  offset: number;
  hasMore: boolean;
}

export function paginateNewestFirst(
  uids: number[],
  offset: number,
  limit: number,
): PaginationResult {
  const safeOffset = Math.max(0, offset);
  const safeLimit = Math.max(1, limit);
  const newestFirst = [...uids].reverse();
  const page = newestFirst.slice(safeOffset, safeOffset + safeLimit);
  return {
    page,
    total: newestFirst.length,
    offset: safeOffset,
    hasMore: safeOffset + safeLimit < newestFirst.length,
  };
}

export interface EmailSearchFilters {
  query?: string;
  from?: string;
  to?: string;
  subject?: string;
  since?: Date;
  before?: Date;
  unseen?: boolean;
}

export type ImapSearchCriteria = Record<string, unknown>;

export function buildSearchCriteria(filters: EmailSearchFilters): ImapSearchCriteria {
  const criteria: ImapSearchCriteria = {};

  // ImapFlow's `text` criterion searches headers and body. All populated
  // properties in this object are combined with AND semantics.
  if (filters.query) criteria.text = filters.query;
  if (filters.from) criteria.from = filters.from;
  if (filters.to) criteria.to = filters.to;
  if (filters.subject) criteria.subject = filters.subject;
  if (filters.since) criteria.since = filters.since;
  if (filters.before) criteria.before = filters.before;
  if (filters.unseen) criteria.seen = false;

  if (Object.keys(criteria).length === 0) criteria.all = true;
  return criteria;
}

interface ESearchLike {
  all?: unknown;
}

export function normalizeSearchUids(result: unknown): number[] {
  if (result === false || result === null || result === undefined) return [];

  const raw = Array.isArray(result)
    ? result
    : typeof result === "object" && Array.isArray((result as ESearchLike).all)
      ? (result as ESearchLike).all
      : [];

  const valid = (raw as unknown[]).filter(
    (uid): uid is number => typeof uid === "number" && Number.isSafeInteger(uid) && uid > 0,
  );
  return [...new Set(valid)];
}

export interface PaginationResult {
  page: number[];
  total: number;
  offset: number;
  hasMore: boolean;
}

export function paginateNewestFirst(
  uids: number[],
  offset: number,
  limit: number,
): PaginationResult {
  const safeOffset = Math.max(0, offset);
  const safeLimit = Math.max(1, limit);
  const newestFirst = [...uids].reverse();
  const page = newestFirst.slice(safeOffset, safeOffset + safeLimit);
  return {
    page,
    total: newestFirst.length,
    offset: safeOffset,
    hasMore: safeOffset + safeLimit < newestFirst.length,
  };
}