import { useEffectHook } from "./useEffectHook";
import { ElementState } from "../ElementState";
import { IElementState } from "../types";

describe("useEffectHook tests", () => {
    describe("when first tick", () => {
        let state: IElementState;
        beforeEach(() => {
            state = new ElementState({
                args: ["arg1", "arg2"],
                func: jest.fn(),
            });
            state.isFirstTick = true;
        });
        it("when isFirstTick true, should call effect and push to effects", () => {
            const dispose = jest.fn();
            const effect = jest.fn().mockReturnValue(dispose);
            const deps = ["dep1", "dep2"];
            useEffectHook(state, effect, deps);
            expect(effect.mock.calls.length).toBe(1);
            expect(state.effects.length).toBe(1);
            expect(state.effects[0]).toEqual({
                deps,
                dispose,
            });
        });
        it("when isFirstTick true and effect throw error, should set state.error to it", () => {
            useEffectHook(
                state,
                () => {
                    throw new Error("error1");
                },
                [],
            );
            expect(state.error).toEqual(new Error("error1"));
        });
    });
    describe("when not first tick", () => {
        let state: IElementState;
        const currentEffectNumber = 15;
        beforeEach(() => {
            state = new ElementState({
                args: ["arg1", "arg2"],
                func: jest.fn(),
            });
            state.isFirstTick = false;
            state.tickState.currentEffectNumber = currentEffectNumber;
        });
        it("when not found effect with currentEffectNumber, should throw error", () => {
            expect(() => useEffectHook(state, jest.fn(), [])).toThrowError(
                "Expected effect with number " + currentEffectNumber,
            );
        });
        it("when existing args.length not equal to new args length, should throw error", () => {
            state.effects[currentEffectNumber] = { deps: ["dep1", "dep2"] };
            expect(() => useEffectHook(state, jest.fn(), ["dep3"])).toThrowError(
                "Dependencies not equal, old version of effect has dependencies and new version not has",
            );
        });
        it("when existing args and new args is equal, should do nothing", () => {
            state.effects[currentEffectNumber] = { deps: ["dep1", "dep2"] };
            const newFunc = jest.fn();
            useEffectHook(state, newFunc, ["dep1", "dep2"]);
            expect(state.effects[currentEffectNumber]);
        });
    });
});