import { describe, it, expect } from "vitest";
import { splitBlocks, diffBlocks } from "../src/trackChangesModel";

describe("splitBlocks", () => {
  it("splits prose paragraphs on blank lines, dropping empties", () => {
    const blocks = splitBlocks("# Heading\n\nFirst para.\n\nSecond para.\n");
    expect(blocks.map((b) => b.type)).toEqual(["prose", "prose", "prose"]);
    expect(blocks[0].raw).toBe("# Heading");
    expect(blocks[2].raw).toBe("Second para.");
  });

  it("keeps a fenced code block whole and tags it `code`", () => {
    const text = "Intro.\n\n```ts\nconst a = 1;\n\nconst b = 2;\n```\n\nOutro.\n";
    const blocks = splitBlocks(text);
    expect(blocks.map((b) => b.type)).toEqual(["prose", "code", "prose"]);
    expect(blocks[1].raw).toBe("```ts\nconst a = 1;\n\nconst b = 2;\n```");
  });

  it("tags a mermaid fence `mermaid`", () => {
    const blocks = splitBlocks("```mermaid\nflowchart LR\n  a-->b\n```\n");
    expect(blocks).toHaveLength(1);
    expect(blocks[0].type).toBe("mermaid");
  });

  it("normalizes the key (whitespace-collapsed) for matching", () => {
    const blocks = splitBlocks("Hello    world\n");
    expect(blocks[0].key).toBe("hello world");
  });
});

describe("diffBlocks", () => {
  const kinds = (base: string, cur: string) => diffBlocks(base, cur).map((o) => o.kind);

  it("unchanged doc → all unchanged", () => {
    const doc = "Alpha.\n\nBravo.\n";
    expect(kinds(doc, doc)).toEqual(["unchanged", "unchanged"]);
  });

  it("a pure addition → an added op", () => {
    const ops = diffBlocks("Alpha.\n", "Alpha.\n\nBravo.\n");
    expect(ops.map((o) => o.kind)).toEqual(["unchanged", "added"]);
  });

  it("a pure deletion → a removed op", () => {
    const ops = diffBlocks("Alpha.\n\nBravo.\n", "Alpha.\n");
    expect(ops.map((o) => o.kind)).toEqual(["unchanged", "removed"]);
  });

  it("a prose modification → a non-atomic changed op", () => {
    const ops = diffBlocks("The quick fox.\n", "The slow fox.\n");
    expect(ops).toHaveLength(1);
    expect(ops[0].kind).toBe("changed");
    expect(ops[0].kind === "changed" && ops[0].atomic).toBe(false);
  });

  it("a code-fence change → an ATOMIC changed op (INV-23)", () => {
    const base = "```ts\nconst a = 1;\n```\n";
    const cur = "```ts\nconst a = 2;\n```\n";
    const ops = diffBlocks(base, cur);
    expect(ops).toHaveLength(1);
    expect(ops[0].kind).toBe("changed");
    expect(ops[0].kind === "changed" && ops[0].atomic).toBe(true);
  });

  it("a mermaid-fence change → an ATOMIC changed op", () => {
    const base = "```mermaid\nflowchart LR\n a-->b\n```\n";
    const cur = "```mermaid\nflowchart LR\n a-->c\n```\n";
    const ops = diffBlocks(base, cur);
    expect(ops[0].kind).toBe("changed");
    expect(ops[0].kind === "changed" && ops[0].atomic).toBe(true);
  });

  it("a reorder → keeps a matched block unchanged", () => {
    const ops = diffBlocks("One.\n\nTwo.\n", "Two.\n\nOne.\n");
    const k = ops.map((o) => o.kind);
    expect(k).toContain("unchanged");
  });
});