import { describe, expect, test } from "bun:test";
import { ApiError, request } from "../src/api.ts";

function fakeFetch(res: Response | (() => never)) {
  const calls: { url: string; init: RequestInit }[] = [];
  const fn = (async (url: string, init: RequestInit) => {
    calls.push({ url, init });
    if (typeof res === "function") return res();
    return res.clone();
  }) as unknown as typeof fetch;
  return { fn, calls };
}

describe("request", () => {
  test("throws an ApiError carrying code on a non-2xx JSON error", async () => {
    const { fn } = fakeFetch(
      new Response(JSON.stringify({ error: { code: "validation", message: "title: required" } }), {
        status: 400,
        headers: { "content-type": "application/json" },
      }),
    );
    const err = await request("POST", "entries/quick", { body: { title: "" }, fetchImpl: fn }).catch((e) => e);
    expect(err).toBeInstanceOf(ApiError);
    expect(err.code).toBe("validation");
    expect(err.status).toBe(400);
    expect(err.message).toBe("title: required");
  });

  test("non-GET requests send the CSRF header, JSON and same-origin cookies", async () => {
    const { fn, calls } = fakeFetch(new Response(JSON.stringify({ id: "e1" }), { status: 201 }));
    const out = await request<{ id: string }>("POST", "entries/quick", { body: { title: "Dune" }, fetchImpl: fn });
    expect(out).toEqual({ id: "e1" });
    const { url, init } = calls[0]!;
    expect(url).toBe("/api/v1/entries/quick");
    const h = new Headers(init.headers);
    expect(h.get("x-requested-with")).toBe("sttracker");
    expect(h.get("content-type")).toBe("application/json");
    expect(init.credentials).toBe("same-origin");
    expect(init.body).toBe(JSON.stringify({ title: "Dune" }));
  });

  test("login and register also send the CSRF header and JSON content type", async () => {
    const { fn, calls } = fakeFetch(new Response(JSON.stringify({ id: "u1" })));
    await request("POST", "auth/login", { body: { username: "a", password: "b" }, fetchImpl: fn });
    await request("POST", "history/h1/restore", { fetchImpl: fn });
    for (const c of calls) {
      const h = new Headers(c.init.headers);
      expect(h.get("x-requested-with")).toBe("sttracker");
      expect(h.get("content-type")).toBe("application/json");
    }
  });

  test("multipart uploads send the CSRF header but let fetch set the content type", async () => {
    const { fn, calls } = fakeFetch(new Response(JSON.stringify({ id: "a1" }), { status: 201 }));
    const form = new FormData();
    form.set("entity", "entry");
    await request("POST", "attachments", { form, fetchImpl: fn });
    const h = new Headers(calls[0]!.init.headers);
    expect(h.get("x-requested-with")).toBe("sttracker");
    expect(h.get("content-type")).toBeNull();
    expect(calls[0]!.init.body).toBe(form);
  });

  test("GET builds the query string and skips empty values", async () => {
    const { fn, calls } = fakeFetch(new Response(JSON.stringify({ items: [] })));
    await request("GET", "entries", { query: { q: "dune", status: undefined, draft: true, limit: 50 }, fetchImpl: fn });
    expect(calls[0]!.url).toBe("/api/v1/entries?q=dune&draft=true&limit=50");
  });

  test("204 resolves to undefined", async () => {
    const { fn } = fakeFetch(new Response(null, { status: 204 }));
    expect(await request("DELETE", "engagements/x", { fetchImpl: fn })).toBeUndefined();
  });

  test("a non-JSON error still becomes an ApiError", async () => {
    const { fn } = fakeFetch(new Response("<html>Bad gateway</html>", { status: 502 }));
    const err = await request("GET", "me", { fetchImpl: fn }).catch((e) => e);
    expect(err).toBeInstanceOf(ApiError);
    expect(err.code).toBe("http_502");
    expect(err.status).toBe(502);
  });

  test("a network failure becomes an ApiError with code network", async () => {
    const { fn } = fakeFetch(() => {
      throw new TypeError("fetch failed");
    });
    const err = await request("GET", "me", { fetchImpl: fn }).catch((e) => e);
    expect(err).toBeInstanceOf(ApiError);
    expect(err.code).toBe("network");
    expect(err.status).toBe(0);
  });
});