import { truncateFileNameForLine } from "./truncateFileNameForLine";

describe("truncateFileNameForLine", () => {
  it("returns an empty string when the input is undefined", () => {
    expect(truncateFileNameForLine(undefined)).toBe("");
  });

  it("returns the name unchanged when it fits inside the budget", () => {
    expect(truncateFileNameForLine("report.pdf")).toBe("report.pdf");
  });

  it("preserves a short extension and truncates the stem with a middle ellipsis", () => {
    expect(truncateFileNameForLine("file-sample_2_dx.docx")).toBe(
      "file-samp….docx",
    );
  });

  it("preserves an uncommon extension like .fodt", () => {
    expect(truncateFileNameForLine("very-long-name-for-document.fodt")).toBe(
      "very-long….fodt",
    );
  });

  it("preserves longer extensions like .numbers", () => {
    expect(truncateFileNameForLine("quarterly-budget.numbers")).toBe(
      "quarte….numbers",
    );
  });

  it("treats overly long trailing tokens as not-an-extension and tail truncates", () => {
    expect(truncateFileNameForLine("file.verylongextensionname")).toBe(
      "file.verylonge…",
    );
  });

  it("truncates a URL-shaped filename with no detectable extension using a tail ellipsis", () => {
    expect(truncateFileNameForLine("vertopal.com/converter")).toBe(
      "vertopal.com/c…",
    );
  });

  it("falls back to tail truncation when the extension cannot fit", () => {
    const long = "a".repeat(50) + ".verylongextension";
    expect(truncateFileNameForLine(long, 24)).toMatch(/^a+…$/);
  });

  it("respects a caller-supplied maxLength", () => {
    expect(truncateFileNameForLine("report.pdf", 6)).toBe("r….pdf");
  });

  it("returns a name shorter than the budget unchanged regardless of extension", () => {
    expect(truncateFileNameForLine("notes.txt")).toBe("notes.txt");
    expect(truncateFileNameForLine("a/b/c")).toBe("a/b/c");
  });

  it("clamps maxLength to a sensible minimum to preserve the single-line guarantee", () => {
    expect(truncateFileNameForLine("report.pdf", 0)).toBe("r…");
    expect(truncateFileNameForLine("report.pdf", -5)).toBe("r…");
    expect(truncateFileNameForLine("report.pdf", 1)).toBe("r…");
  });
});