import { describe, it, expect } from "bun:test";
import { CsvParser, FileChunkSource } from "../src/index.ts";

describe("CsvParser - string input", () => {
  it("parses simple CSV with headers to objects", async () => {
    const parser = new CsvParser();
    const csv = "name,age\nAlice,30\nBob,40";
    const result = await parser.parseFromString(csv, { hasHeader: true, output: "object" });

    expect(result.headers).toEqual(["name", "age"]);
    expect(result.rows).toEqual([
      { name: "Alice", age: "30" },
      { name: "Bob", age: "40" },
    ]);
  });

  it("handles quoted fields with commas and escaped quotes", async () => {
    const parser = new CsvParser();
    const csv = [
      '"name","note"',
      '"Alice","He said ""hello"", world"',
      '"Bob","x,y,z"',
    ].join("\n");

    const result = await parser.parseFromString(csv, { hasHeader: true, output: "object" });
    expect(result.rows).toEqual([
      { name: "Alice", note: 'He said "hello", world' },
      { name: "Bob", note: "x,y,z" },
    ]);
  });

  it("supports CRLF line endings", async () => {
    const parser = new CsvParser();
    const csv = "a,b\r\n1,2\r\n3,4";
    const result = await parser.parseFromString(csv, { hasHeader: true });
    expect(result.headers).toEqual(["a", "b"]);
    expect(result.rows).toEqual([
      ["1", "2"],
      ["3", "4"],
    ]);
  });

  it("skips empty lines by default", async () => {
    const parser = new CsvParser();
    const csv = "a,b\n\n1,2\n\n";
    const result = await parser.parseFromString(csv, { hasHeader: true });
    expect(result.rows).toEqual([["1", "2"]]);
  });

  it("normalizes row length when validateRowLength is true (default)", async () => {
    const parser = new CsvParser();
    const csv = "a,b,c\n1,2\n3,4,5";
    const result = await parser.parseFromString(csv, { hasHeader: true });
    expect(result.rows).toEqual([
      ["1", "2", ""],
      ["3", "4", "5"],
    ]);
  });
});

describe("CsvParser - file input", () => {
  it("parses a CSV file via FileChunkSource", async () => {
    const parser = new CsvParser();
    const content = "city,temp\nBerlin,12\nMunich,10";
    const tmpPath = `${process.cwd()}/test.__tmp.csv`;
    await Bun.write(tmpPath, content);
    try {
      const source = new FileChunkSource(tmpPath);
      const result = await parser.parseFromSource(source, { hasHeader: true, output: "object" });
      expect(result.rows).toEqual([
        { city: "Berlin", temp: "12" },
        { city: "Munich", temp: "10" },
      ]);
    } finally {
      // best-effort cleanup
      try { await Bun.write(tmpPath, ""); } catch {}
    }
  });
});