import type { Store } from './createStore'
import { createStore } from './createStore'
import reducer from './reducer'
import { INITIAL_STATE } from '.'

jest.mock('./reducer')

describe('createStore', () => {
    let store: Store

    beforeEach(() => {
        store = createStore()
    })

    it('should notify when state changes', () => {
        const listener = jest.fn()
        store.subscribe(listener)
        jest.mocked(reducer).mockReturnValue({ ...INITIAL_STATE })
        store.dispatch({
            type: 'updateSelection',
            payload: new Set(['1', '2']),
        })
        expect(listener).toHaveBeenCalledTimes(1)
    })

    it('should not notify when state changes if unsubscribed', () => {
        const listener = jest.fn()
        const unsubscribe = store.subscribe(listener)
        unsubscribe()
        jest.mocked(reducer).mockReturnValue({ ...INITIAL_STATE })
        store.dispatch({
            type: 'updateSelection',
            payload: new Set(['1', '2']),
        })
        expect(listener).not.toHaveBeenCalled()
    })

    it('should not notify if state does not change', () => {
        const listener = jest.fn()
        store.subscribe(listener)
        jest.mocked(reducer).mockReturnValue(store.getState())
        store.dispatch({
            type: 'updateSelection',
            payload: new Set(['1', '2']),
        })
        expect(listener).not.toHaveBeenCalled()
    })

    it('should return state when getState is called', () => {
        expect(store.getState()).toEqual(INITIAL_STATE)
    })
})