/**
 * External dependencies
 */
import { isEqual, keyBy } from 'lodash';
import { EMPTY_OBJECT } from '@nab/utils';
import type { AnyAction } from '@nab/types';

/**
 * Internal dependencies
 */
import { INIT_STATE as IS } from '../config';

import type { State as FullState } from '../types';
type State = FullState[ 'experiment' ][ 'pageViewTriggers' ];

import type { PageViewTriggersAction } from '../actions/page-view-triggers';
import type { SetupEditor } from '../actions/editor';
type Action = PageViewTriggersAction | SetupEditor;

const INIT_STATE = IS.experiment.pageViewTriggers;

export function pageViewTriggers(
	state = INIT_STATE,
	action: AnyAction
): State {
	return actualReducer( state, action as Action ) ?? state;
}

function actualReducer( state: State, action: Action ): State {
	switch ( action.type ) {
		case 'SET_PAGE_VIEW_TRIGGERS':
			return keyBy( action.actions, 'id' );

		case 'SETUP_EDITOR': {
			if ( 'nab/heatmap' === action.experiment.type ) {
				return EMPTY_OBJECT;
			}

			const newActions = keyBy(
				action.experiment.pageViewTriggers,
				'id'
			);
			if ( isEqual( newActions, state.pageViewTriggers ) ) {
				return state;
			}

			return newActions;
		}
	}
}