import { Map as $Map, List, fromJS } from 'immutable';
import actions from './input-actions';

function getInitState () {
    return new $Map();
}

function init (state, { id, value }) {
    state = assertId(state, id);
    return state.setIn(id, fromJS(value));
}

function assertId (state, id) {
    if (!state.hasIn(id)) {
        return state.setIn(id, new $Map({ inputId: id }));
    }
    return state;
}

function assertList (state, id, key) {
    if (!state.getIn(id).has(key)) {
        return state.setIn(id.concat([key]), new List());
    }
    return state;
}

function setKeyValue (state, { id, key, value }) {
    state = assertId(state, id);
    return state.setIn(id.concat([key]), value);
}

function increment (state, { id, key }) {
    state = assertId(state, id);
    return state.updateIn(id.concat([key]), (value = 0)  => value + 1);
}

function clear (state, { id }) {
    if (state.hasIn(id)) {
        return state.removeIn(id);
    }
    return state;
}

function addToList (state, { id, key, value }) {
    state = assertId(state, id);
    state = assertList(state, id, key);

    return state.updateIn(id.concat([key]), (list) => list.push(value));
}

function updateInList (state, { id, key, index, newValue }) {
    state = assertId(state, id);
    state = assertList(state, id, key);

    return state.updateIn(id.concat([key]), (list) => list.set(index, newValue));
}

function removeFromList (state, { id, key, index }) {
    state = assertId(state, id);
    state = assertList(state, id, key);

    return state.updateIn(id.concat([key]), (list) => list.remove(index));
}

const inputState = (state = getInitState(), action) => {
    if (!action.id) {
        return state;
    }

    switch (action.type) {
        case actions.INIT:
            return init(state, action);
        case actions.SET_VALUE:
            if (actions.key != null && actions.value != null) {
                throw new Error('Missing required key / value');
            }
            return setKeyValue(state, action);
        case actions.INCREMENT_VALUE:
            return increment(state, action);
        case actions.LIST_PUSH:
            return addToList(state, action);
        case actions.LIST_POP:
            return removeFromList(state, action);
        case actions.LIST_UP:
            return updateInList(state, action);
        case actions.CLEAR:
            return clear(state, action);
        default:
            // console.log('TYPE', action.type, action);
            return state;
    }
};

export default inputState;