import { describe, expect, it } from "vitest";
import { clearTodos, getTodos, setTodos, type TodoState } from "./pure.js";

describe("getTodos", () => {
	it("getTodos: returns fresh array copy (not the live array)", () => {
		const state: TodoState = new Map();
		setTodos(state, "c1", [{ content: "a", status: "pending" }]);
		const snap = getTodos(state, "c1");
		expect(snap).toHaveLength(1);
		// mutating the snapshot array does not affect live state
		snap.push({ content: "evil", status: "completed" });
		expect(getTodos(state, "c1")).toHaveLength(1);
	});

	it("getTodos: empty array for unknown conversation", () => {
		const state: TodoState = new Map();
		expect(getTodos(state, "nope")).toEqual([]);
	});
});

describe("setTodos", () => {
	it("setTodos: replaces the list and returns a copy", () => {
		const state: TodoState = new Map();
		setTodos(state, "c1", [{ content: "first", status: "pending" }]);
		// replace with a different list
		const snap = setTodos(state, "c1", [{ content: "second", status: "in_progress" }]);
		expect(snap).toHaveLength(1);
		const first = snap[0];
		if (first === undefined) throw new Error("expected an item");
		expect(first.content).toBe("second");
		// the previous list is gone
		expect(getTodos(state, "c1").map((t) => t.content)).toEqual(["second"]);
	});
});

describe("clearTodos", () => {
	it("clearTodos: deletes the conversation's list", () => {
		const state: TodoState = new Map();
		setTodos(state, "c1", [{ content: "x", status: "pending" }]);
		expect(getTodos(state, "c1")).toHaveLength(1);
		clearTodos(state, "c1");
		expect(getTodos(state, "c1")).toEqual([]);
		// a second clear is a no-op
		clearTodos(state, "c1");
		expect(getTodos(state, "c1")).toEqual([]);
	});
});
