// @vitest-environment happy-dom
import { cleanup, render, screen } from "@testing-library/react";
import { afterEach, describe, expect, it } from "vitest";

import { DiffView } from "./DiffView.js";
import { toolDiffMeta } from "./model.js";

afterEach(cleanup);

function lines(kind: string): string[] {
  return [...document.querySelectorAll(`.st-ln-${kind}`)].map((el) => el.textContent ?? "");
}

describe("DiffView", () => {
  it("marks insertions and deletions with their column prefixes", () => {
    render(<DiffView diff={{ path: "src/a.ts", oldText: "one\ntwo\n", newText: "one\nTWO\nthree\n" }} />);
    expect(lines("del")).toEqual(["- two"]);
    expect(lines("add")).toEqual(["+ TWO", "+ three"]);
    expect(lines("ctx")).toEqual(["  one"]);
    expect(screen.getByText("src/a.ts")).toBeTruthy();
  });

  it("carries the +added −removed counts the tool head shows", () => {
    render(<DiffView diff={{ path: "a.ts", oldText: "one\ntwo\n", newText: "one\nTWO\nthree\n" }} />);
    const body = document.querySelector<HTMLElement>(".st-diff")!;
    expect(body.dataset.added).toBe("2");
    expect(body.dataset.removed).toBe("1");
    expect(toolDiffMeta([{ type: "diff", path: "a.ts", oldText: "one\ntwo\n", newText: "one\nTWO\nthree\n" }]))
      .toBe("+2 −1");
  });

  it("renders every line of a new file as added", () => {
    render(<DiffView diff={{ path: "new.ts", newText: "alpha\nbeta\n" }} />);
    expect(lines("add")).toEqual(["+ alpha", "+ beta"]);
    expect(lines("del")).toEqual([]);
  });

  it("collapses a long unchanged run to a hunk summary", () => {
    const filler = Array.from({ length: 20 }, (_, i) => `line ${i}`).join("\n");
    render(<DiffView diff={{ path: "a.ts", oldText: `head\n${filler}\n`, newText: `HEAD\n${filler}\n` }} />);
    expect(lines("hunk")).toEqual(["⋯ 17 unchanged lines ⋯"]);
  });

  it("copies the whole diff, prefixes included", () => {
    render(<DiffView diff={{ path: "a.ts", oldText: "one\n", newText: "two\n" }} />);
    const body = document.querySelector<HTMLElement>(".st-diff")!;
    expect(body.getAttribute("aria-label")).toBe("Copy diff");
    expect(body.textContent).toBe("- one+ two");
  });
});