/**
 * parseErrorDetail extracts structured error details from request.ts
 * formatted errors ("message - {json}") and from raw JSON messages,
 * so the UI can show server-provided details instead of opaque text.
 */
import { describe, it, expect } from "vitest";
import { parseErrorDetail } from "./error";

describe("parseErrorDetail", () => {
  it("returns null for non-Error values", () => {
    expect(parseErrorDetail("just a string")).toBeNull();
    expect(parseErrorDetail(42)).toBeNull();
    expect(parseErrorDetail(null)).toBeNull();
    expect(parseErrorDetail(undefined)).toBeNull();
  });

  it("returns null for a plain-text error message", () => {
    expect(parseErrorDetail(new Error("network is down"))).toBeNull();
  });

  it("parses JSON after the ' - ' separator used by request.ts", () => {
    const error = new Error('Request failed - {"detail": "quota exceeded"}');
    // The detail key is unwrapped so callers get the server message directly
    expect(parseErrorDetail(error)).toBe("quota exceeded");
  });

  it("unwraps the detail key when present", () => {
    const error = new Error('400 Bad Request - {"detail": "invalid key"}');
    expect(parseErrorDetail(error)).toBe("invalid key");
  });

  it("returns the parsed object when there is no detail key", () => {
    const error = new Error('500 - {"code": "internal"}');
    expect(parseErrorDetail(error)).toEqual({ code: "internal" });
  });

  it("falls back to parsing the whole message when no separator", () => {
    const error = new Error('{"detail": "rate limited"}');
    expect(parseErrorDetail(error)).toBe("rate limited");
  });

  it("returns null when the separator payload is not valid JSON", () => {
    const error = new Error("failed - not json at all");
    expect(parseErrorDetail(error)).toBeNull();
  });

  it("returns null when the whole message is not JSON", () => {
    const error = new Error("{broken json");
    expect(parseErrorDetail(error)).toBeNull();
  });

  it("returns null when the whole message parses to a non-object", () => {
    const error = new Error("42");
    expect(parseErrorDetail(error)).toBeNull();
  });
});