import { Action } from '../../mini-ngrx/index';
import {
  canChangeHours,
  canChangeMinutes,
  canChangeSeconds,
  canChangeValue,
  timepickerControls
} from '../timepicker-controls.util';
import { TimepickerConfig } from '../timepicker.config';
import { TimepickerComponentState, TimepickerControls } from '../timepicker.models';
import { changeTime, setTime } from '../timepicker.utils';
import { TimepickerActions } from './timepicker.actions';

export class TimepickerState {
  value: Date;
  config: TimepickerComponentState;
  controls: TimepickerControls;
}

export const initialState: TimepickerState = {
  value: null,
  config: new TimepickerConfig(),
  controls: {
    canIncrementHours: true,
    canIncrementMinutes: true,
    canIncrementSeconds: true,

    canDecrementHours: true,
    canDecrementMinutes: true,
    canDecrementSeconds: true
  }
};

export function timepickerReducer(state = initialState, action: Action) {
  switch (action.type) {
    case(TimepickerActions.WRITE_VALUE): {
      return Object.assign({}, state, {value: action.payload});
    }

    case (TimepickerActions.CHANGE_HOURS): {
      if (!canChangeValue(state.config, action.payload) ||
        !canChangeHours(action.payload, state.controls)) {
        return state;
      }

      const _newTime = changeTime(state.value, {hour: action.payload.step});

      return Object.assign({}, state, {value: _newTime});
    }

    case (TimepickerActions.CHANGE_MINUTES): {
      if (!canChangeValue(state.config, action.payload) ||
        !canChangeMinutes(action.payload, state.controls)) {
        return state;
      }

      const _newTime = changeTime(state.value, {minute: action.payload.step});

      return Object.assign({}, state, {value: _newTime});
    }

    case (TimepickerActions.CHANGE_SECONDS): {
      if (!canChangeValue(state.config, action.payload) ||
        !canChangeSeconds(action.payload, state.controls)) {
        return state;
      }

      const _newTime = changeTime(state.value, {seconds: action.payload.step});

      return Object.assign({}, state, {value: _newTime});
    }

    case (TimepickerActions.SET_TIME_UNIT): {
      if (!canChangeValue(state.config)) {
        return state;
      }

      const _newTime = setTime(state.value, action.payload);

      return Object.assign({}, state, {value: _newTime});
    }

    case (TimepickerActions.UPDATE_CONTROLS): {
      const _newControlsState = timepickerControls(state.value, action.payload);
      const _newState: TimepickerState = {
        value: state.value,
        config: action.payload,
        controls: _newControlsState
      };

      if (state.config.showMeridian !== _newState.config.showMeridian) {
        _newState.value = new Date(state.value);
      }

      return Object.assign({}, state, _newState);
    }

    default:
      return state;
  }
}