import { describe, expect, it } from "vitest";
import { anchorHref, generateToc, headingSlug, type TocBlockInput } from "./toc.js";

const b = (id: string, type: string, text: string, parentId: string | null = null, position = "a0"): TocBlockInput => ({
  id,
  type,
  content: { text },
  parentId,
  position
});

describe("TOC + heading anchors (T-147)", () => {
  it("generates entries in document order with levels 1-3", () => {
    const blocks: TocBlockInput[] = [
      b("p1", "PARAGRAPH", "intro"),
      b("h1", "HEADING_1", "Alpha"),
      b("h2", "HEADING_2", "Beta"),
      b("h3", "HEADING_3", "Gamma"),
      b("h4", "HEADING_4" as string, "nope"), // not a heading level
      b("p2", "PARAGRAPH", "more")
    ];
    const toc = generateToc(blocks);
    expect(toc.map((e) => [e.level, e.text])).toEqual([
      [1, "Alpha"],
      [2, "Beta"],
      [3, "Gamma"]
    ]);
    expect(toc.every((e) => e.blockId)).toBe(true);
  });

  it("includes headings nested in the tree (toggle children) at their own level", () => {
    const blocks: TocBlockInput[] = [
      b("t1", "TOGGLE", "section", null, "a0"),
      b("h2", "HEADING_2", "Nested", "t1", "a0"),
      b("h1", "HEADING_1", "Top", null, "a1")
    ];
    const toc = generateToc(blocks);
    expect(toc.map((e) => e.text)).toEqual(["Nested", "Top"]);
  });

  it("derives stable, de-duplicated slugs", () => {
    expect(headingSlug("Hello, World!")).toBe("hello-world");
    expect(headingSlug("  Mixed Case  ")).toBe("mixed-case");
    expect(headingSlug("")).toBe("");
    // de-dup within a page
    const blocks: TocBlockInput[] = [b("a", "HEADING_1", "Intro", null, "a0"), b("c", "HEADING_1", "Intro", null, "a1")];
    const toc = generateToc(blocks);
    expect(toc.map((e) => e.anchor)).toEqual(["intro", "intro-2"]);
  });

  it("treats blocks with a missing parent as root (defensive)", () => {
    const blocks: TocBlockInput[] = [b("x", "HEADING_1", "Orphan", "ghost", "a0")];
    expect(generateToc(blocks).map((e) => e.text)).toEqual(["Orphan"]);
  });

  it("anchorHref produces a # fragment", () => {
    expect(anchorHref("hello-world")).toBe("#hello-world");
  });
});