import { describe, expect, it } from "vitest";
import { isAlwaysVisible, visibleIdentities } from "@/lib/identityVisibility";

/**
 * Issue #73: a unique address per service, on a server with an alias domain,
 * gives every local part twice and a compose picker nobody can use — while only
 * a handful are ever sent from.
 *
 * The interesting cases are not the hiding. They are the three refusals, all of
 * which exist because a sender picker with nothing usable in it is worse than a
 * cluttered one.
 */

const ids = (n: number) => Array.from({ length: n }, (_, i) => ({ id: `i${i + 1}`, email: `a${i + 1}@example.com` }));

describe("hiding identities from the picker", () => {
  it("removes the hidden ones", () => {
    expect(visibleIdentities(ids(4), ["i2", "i4"]).map((i) => i.id)).toEqual(["i1", "i3"]);
  });

  it("changes nothing when none are hidden", () => {
    const all = ids(3);
    expect(visibleIdentities(all, [])).toBe(all);
  });
});

describe("what it refuses to hide", () => {
  it("keeps the identity the draft is already using", () => {
    // Otherwise the select has no matching option and the From line moves
    // under the writer.
    expect(visibleIdentities(ids(3), ["i2"], ["i2"]).map((i) => i.id)).toEqual(["i1", "i2", "i3"]);
  });

  it("keeps the default, which a new draft starts on", () => {
    expect(visibleIdentities(ids(3), ["i1", "i3"], [null, "i1"]).map((i) => i.id)).toEqual(["i1", "i2"]);
  });

  it("shows everything rather than nothing when all are hidden", () => {
    const all = ids(3);
    expect(visibleIdentities(all, ["i1", "i2", "i3"]).map((i) => i.id)).toEqual(["i1", "i2", "i3"]);
  });

  it("ignores an id for an identity that no longer exists", () => {
    // A deleted identity leaves its id behind in the setting; it must not
    // silently hide anything else or empty the list.
    expect(visibleIdentities(ids(2), ["gone"]).map((i) => i.id)).toEqual(["i1", "i2"]);
  });

  it("tolerates nulls among the ids to keep", () => {
    expect(visibleIdentities(ids(2), ["i1"], [null, undefined]).map((i) => i.id)).toEqual(["i2"]);
  });
});

describe("what the settings row may offer", () => {
  it("refuses to offer hiding for an always-visible identity", () => {
    expect(isAlwaysVisible("i1", ["i1"])).toBe(true);
    expect(isAlwaysVisible("i2", ["i1"])).toBe(false);
    expect(isAlwaysVisible("i2", [null, undefined])).toBe(false);
  });
});