/**
 * @file Tests for the History commit-graph layout: a straight line, a branch
 * merged back, converging lanes and a parent beyond the loaded page.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */
import { describe, it, expect } from "vitest";
import { commitGraph } from "../commitGraph";

const c = (sha: string, ...parents: string[]) => ({ sha, parents });

describe("commitGraph", () => {
  it("draws a linear history in one column", () => {
    const { rows, width } = commitGraph([c("c", "b"), c("b", "a"), c("a")]);
    expect(width).toBe(1);
    expect(rows.map((r) => r.col)).toEqual([0, 0, 0]);
    // The tip has no line from above; the root none below.
    expect(rows[0]?.segs).toEqual([{ x1: 0, y1: 0.5, x2: 0, y2: 1, color: 0 }]);
    expect(rows[2]?.segs).toEqual([{ x1: 0, y1: 0, x2: 0, y2: 0.5, color: 0 }]);
  });

  it("opens a lane for a merged branch and closes it at the fork point", () => {
    //   m        merge of b2 into a2
    //   |\\
    //   a2 b2
    //   |  b1
    //   |/
    //   a1
    const { rows, width } = commitGraph([
      c("m", "a2", "b2"),
      c("a2", "a1"),
      c("b2", "b1"),
      c("b1", "a1"),
      c("a1"),
    ]);
    expect(width).toBe(2);
    expect(rows.map((r) => r.col)).toEqual([0, 0, 1, 1, 0]);
    expect(rows[0]?.segs).toContainEqual({ x1: 0, y1: 0.5, x2: 1, y2: 1, color: 1 });
    // b1's lane converges into a1's column.
    expect(rows[4]?.segs).toContainEqual({ x1: 1, y1: 0, x2: 0, y2: 0.5, color: 1 });
    expect(rows[1]?.color).toBe(rows[0]?.color);
    expect(rows[2]?.color).not.toBe(rows[0]?.color);
  });

  it("keeps a lane running for a parent past the page", () => {
    const { rows } = commitGraph([c("b", "a")]);
    expect(rows[0]?.segs).toEqual([{ x1: 0, y1: 0.5, x2: 0, y2: 1, color: 0 }]);
  });
});