import type { SavedIdentity } from "../shared/types";

export type IdentityFilterMode = "both" | "email" | "username";
export type IdentityKind = "email" | "username";

function compareSavedIdentity(a: SavedIdentity, b: SavedIdentity): number {
  return (
    b.lastUsed - a.lastUsed ||
    b.useCount - a.useCount ||
    a.value.localeCompare(b.value) ||
    a.type.localeCompare(b.type)
  );
}

function matchesQuery(identity: SavedIdentity, query: string): boolean {
  const q = query.trim().toLowerCase();
  if (!q) return true;
  return [identity.value, identity.exampleDomain ?? "", identity.type]
    .join(" ")
    .toLowerCase()
    .includes(q);
}

export function sortSavedIdentities(identities: SavedIdentity[]): SavedIdentity[] {
  return [...identities].sort(compareSavedIdentity);
}

export function filterSavedIdentities(
  identities: SavedIdentity[],
  query: string,
  mode: IdentityFilterMode,
): SavedIdentity[] {
  const typeFiltered = identities.filter((identity) => {
    if (mode === "email") return identity.type === "email";
    if (mode === "username") return identity.type === "username";
    return true;
  });

  return sortSavedIdentities(typeFiltered).filter((identity) => matchesQuery(identity, query));
}

export function resolveCustomIdentityKind(
  query: string,
  mode: IdentityFilterMode,
  fallback: IdentityKind,
): IdentityKind {
  if (mode === "email") return "email";
  if (mode === "username") return "username";
  const trimmed = query.trim();
  if (!trimmed) return fallback;
  return trimmed.includes("@") ? "email" : fallback;
}

export function identityFilterLabel(mode: IdentityFilterMode): string {
  if (mode === "email") return "Emails";
  if (mode === "username") return "Usernames";
  return "Both";
}