import { describe, expect, it } from "vitest";
import { parseCsvPreview } from "./csv-preview";

describe("parseCsvPreview", () => {
  it("reads quoted fields, doubled quotes and CRLF rows", () => {
    expect(parseCsvPreview('name,note\r\n"Smith, Ann","said ""hi"""\r\nBo,\n')).toEqual({
      rows: [
        ["name", "note"],
        ["Smith, Ann", 'said "hi"'],
        ["Bo", ""],
      ],
      truncated: false,
    });
  });

  it("keeps a final row without a trailing newline and skips blank lines", () => {
    expect(parseCsvPreview("a,b\n\n1,2").rows).toEqual([
      ["a", "b"],
      ["1", "2"],
    ]);
  });

  it("keeps newlines inside quoted fields", () => {
    expect(parseCsvPreview('a\n"line 1\nline 2"').rows).toEqual([["a"], ["line 1\nline 2"]]);
  });

  it("stops after the row limit", () => {
    const result = parseCsvPreview("1\n2\n3\n4\n", 2);
    expect(result).toEqual({ rows: [["1"], ["2"]], truncated: true });
  });
});