/* @vitest-environment node */

import { describe, it, expect, vi, beforeEach } from "vitest";
import {
	apiFetch,
	ApiClientError,
	getFiles,
	login,
	getMe,
} from "./apiClient.js";

beforeEach(() => {
	// Restore mocks between tests to avoid cross-test pollution.
	vi.restoreAllMocks();

	// In these unit tests we stub the global fetch implementation.
	// This allows us to validate:
	// - request defaults (credentials/cache)
	// - URL building
	// - error mapping
	global.fetch = vi.fn();
});

describe("lib/frontend/apiClient", () => {
	it("apiFetch uses credentials=include and cache=no-store", async () => {
		fetch.mockResolvedValue(
			new Response(JSON.stringify({ ok: true }), {
				status: 200,
				headers: { "Content-Type": "application/json" },
			})
		);

		await apiFetch("/api/health");

		expect(fetch).toHaveBeenCalledTimes(1);
		const [url, init] = fetch.mock.calls[0];

		expect(url).toBe("/api/health");
		expect(init.credentials).toBe("include");
		expect(init.cache).toBe("no-store");
	});

	it("apiFetch serializes JSON bodies and sets Content-Type", async () => {
		fetch.mockResolvedValue(
			new Response(JSON.stringify({ ok: true }), {
				status: 200,
				headers: { "Content-Type": "application/json" },
			})
		);

		await login({ username: "u", password: "p" });

		const [, init] = fetch.mock.calls[0];
		expect(init.method).toBe("POST");
		expect(init.headers.Accept).toBe("application/json");
		expect(init.headers["Content-Type"]).toBe("application/json");
		expect(init.body).toBe(JSON.stringify({ username: "u", password: "p" }));
	});

	it("apiFetch throws ApiClientError for standardized backend error payloads", async () => {
		fetch.mockResolvedValue(
			new Response(
				JSON.stringify({
					error: { message: "Unauthorized", code: "AUTH_UNAUTHENTICATED" },
				}),
				{ status: 401, headers: { "Content-Type": "application/json" } }
			)
		);

		await expect(apiFetch("/api/branches")).rejects.toMatchObject({
			name: "ApiClientError",
			status: 401,
			code: "AUTH_UNAUTHENTICATED",
			message: "Unauthorized",
		});
	});

	it("apiFetch maps network failures to CLIENT_NETWORK_ERROR", async () => {
		fetch.mockRejectedValue(new Error("connection refused"));

		try {
			await apiFetch("/api/branches");
			throw new Error("Expected apiFetch to throw");
		} catch (err) {
			expect(err).toBeInstanceOf(ApiClientError);
			expect(err.code).toBe("CLIENT_NETWORK_ERROR");
			expect(err.status).toBe(0);
		}
	});

	it("getFiles builds the expected query string", async () => {
		fetch.mockResolvedValue(
			new Response(
				JSON.stringify({
					branch: "NL01",
					year: "2024",
					month: "10",
					day: "23",
					files: [],
				}),
				{ status: 200, headers: { "Content-Type": "application/json" } }
			)
		);

		await getFiles("NL01", "2024", "10", "23");

		const [url] = fetch.mock.calls[0];
		// We do not rely on param ordering beyond URLSearchParams defaults.
		expect(url).toContain("/api/files?");
		expect(url).toContain("branch=NL01");
		expect(url).toContain("year=2024");
		expect(url).toContain("month=10");
		expect(url).toContain("day=23");
	});

	it("getMe calls /api/auth/me and returns the parsed payload", async () => {
		// /api/auth/me returns 200 with { user: null } or { user: {...} }.
		// For this unit test we only need to ensure:
		// - correct endpoint
		// - correct method
		// - response is returned as parsed JSON
		fetch.mockResolvedValue(
			new Response(JSON.stringify({ user: null }), {
				status: 200,
				headers: { "Content-Type": "application/json" },
			})
		);

		const res = await getMe();

		expect(res).toEqual({ user: null });

		expect(fetch).toHaveBeenCalledTimes(1);
		const [url, init] = fetch.mock.calls[0];
		expect(url).toBe("/api/auth/me");
		expect(init.method).toBe("GET");

		// Ensure our global defaults are still enforced for session-based calls.
		expect(init.credentials).toBe("include");
		expect(init.cache).toBe("no-store");
	});
});