import { describe, expect, it } from "vitest";
import { layout } from "./layout";

const row = (hash: string, ...parents: string[]) => ({
  commit: { hash },
  parents: parents.map((p) => ({ hash: p.replace("~", ""), dotted: p.startsWith("~") })),
});

describe("layout", () => {
  it("puts a straight line in one column with one color", () => {
    const r = layout([row("c", "b"), row("b", "a"), row("a")]);
    expect(r.rows.map((x) => x.col)).toEqual([0, 0, 0]);
    expect(new Set(r.rows.map((x) => x.color)).size).toBe(1);
    expect(r.width).toBe(1);
  });

  it("opens a second column for a merged branch and joins it back", () => {
    const r = layout([row("m", "a", "b"), row("b", "a"), row("a")]);
    expect(r.rows.map((x) => x.col)).toEqual([0, 1, 0]);
    expect(r.rows[1].color).not.toBe(r.rows[0].color);
    expect(r.width).toBe(2);
    // Below b, its line bends from column 1 back into column 0.
    expect(r.rows[1].segments).toContainEqual(
      expect.objectContaining({ x1: 1, y1: 0.5, x2: 0, y2: 1 }),
    );
  });

  it("draws a line that passes a row as a straight segment", () => {
    const r = layout([row("m", "a", "b"), row("b", "a"), row("a")]);
    // At row b, column 0 is still waiting for a.
    expect(r.rows[1].segments).toContainEqual(
      expect.objectContaining({ x1: 0, y1: 0, x2: 0, y2: 1 }),
    );
  });

  it("starts a new column for a second branch tip", () => {
    const r = layout([row("x", "a"), row("y", "a"), row("a")]);
    expect(r.rows.map((x) => x.col)).toEqual([0, 1, 0]);
  });

  it("carries dotted edges down to the parent", () => {
    const r = layout([row("m", "a", "~b"), row("z", "q"), row("q"), row("b", "a"), row("a")]);
    const dotted = r.rows.flatMap((x) => x.segments).filter((s) => s.dotted);
    expect(dotted.length).toBeGreaterThan(0);
    expect(r.rows[3].segments.some((s) => s.dotted && s.y2 === 0.5)).toBe(true);
  });
});