import { toDocument } from "./to-document";

import { BLOCKS, type Document } from "@contentful/rich-text-types";

const makeDocument = (text = "Hello"): Document => ({
  nodeType: BLOCKS.DOCUMENT,
  data: {},
  content: [
    {
      nodeType: BLOCKS.PARAGRAPH,
      data: {},
      content: [{ nodeType: "text", value: text, marks: [], data: {} }],
    },
  ],
});

describe("toDocument", () => {
  // ── Falsy inputs ─────────────────────────────────────
  it("returns null for null", () => {
    expect(toDocument(null)).toBeNull();
  });

  it("returns null for undefined", () => {
    expect(toDocument(undefined)).toBeNull();
  });

  it("returns null for empty string", () => {
    expect(toDocument("")).toBeNull();
  });

  it("returns null for 0", () => {
    expect(toDocument(0)).toBeNull();
  });

  it("returns null for false", () => {
    expect(toDocument(false)).toBeNull();
  });

  // ── REST/CDA Document ────────────────────────────────
  it("returns Document directly when given a valid REST Document", () => {
    const doc = makeDocument();
    expect(toDocument(doc)).toBe(doc);
  });

  // ── GraphQL RichText { json: Document } ──────────────
  it("extracts Document from GraphQL format { json, links }", () => {
    const doc = makeDocument("GraphQL");
    const graphql = { json: doc, links: { assets: [] } };
    expect(toDocument(graphql)).toBe(doc);
  });

  it("extracts Document from GraphQL format without links", () => {
    const doc = makeDocument("NoLinks");
    expect(toDocument({ json: doc })).toBe(doc);
  });

  it("returns null when json property is not a valid Document", () => {
    expect(toDocument({ json: "not-a-document" })).toBeNull();
  });

  it("returns null when json property is null", () => {
    expect(toDocument({ json: null })).toBeNull();
  });

  // ── Non-matching objects ─────────────────────────────
  it("returns null for an object without nodeType or json", () => {
    expect(toDocument({ foo: "bar" })).toBeNull();
  });

  it("returns null for an object with nodeType but no content", () => {
    expect(toDocument({ nodeType: BLOCKS.DOCUMENT })).toBeNull();
  });

  it("returns null for an array", () => {
    expect(toDocument([1, 2, 3])).toBeNull();
  });

  it("returns null for a number", () => {
    expect(toDocument(42)).toBeNull();
  });

  it("returns null for a non-empty string", () => {
    expect(toDocument("hello")).toBeNull();
  });
});