import shallowEqual from 'shallowequal';
import omit from 'omit.js';
import { getOptionProps, getListeners } from '../props-util';
import PropTypes from '../vue-types';
import proxyComponent from '../proxyComponent';

function getDisplayName(WrappedComponent) {
  return WrappedComponent.name || 'Component';
}

const defaultMapStateToProps = () => ({});
export default function connect(mapStateToProps) {
  const shouldSubscribe = !!mapStateToProps;
  const finalMapStateToProps = mapStateToProps || defaultMapStateToProps;
  return function wrapWithConnect(WrappedComponent) {
    const tempProps = omit(WrappedComponent.props || {}, ['store']);
    const props = {
      __propsSymbol__: PropTypes.any,
    };
    Object.keys(tempProps).forEach(k => {
      props[k] = { ...tempProps[k], required: false };
    });
    const Connect = {
      name: `Connect_${getDisplayName(WrappedComponent)}`,
      props,
      inject: {
        storeContext: { default: () => ({}) },
      },
      data() {
        this.store = this.storeContext.store;
        this.preProps = omit(getOptionProps(this), ['__propsSymbol__']);
        return {
          subscribed: finalMapStateToProps(this.store.getState(), this.$props),
        };
      },
      watch: {
        __propsSymbol__() {
          if (mapStateToProps && mapStateToProps.length === 2) {
            this.subscribed = finalMapStateToProps(this.store.getState(), this.$props);
          }
        },
      },
      mounted() {
        this.trySubscribe();
      },

      beforeDestroy() {
        this.tryUnsubscribe();
      },
      methods: {
        handleChange() {
          if (!this.unsubscribe) {
            return;
          }
          const props = omit(getOptionProps(this), ['__propsSymbol__']);
          const nextSubscribed = finalMapStateToProps(this.store.getState(), props);
          if (
            !shallowEqual(this.preProps, props) ||
            !shallowEqual(this.subscribed, nextSubscribed)
          ) {
            this.subscribed = nextSubscribed;
          }
        },

        trySubscribe() {
          if (shouldSubscribe) {
            this.unsubscribe = this.store.subscribe(this.handleChange);
            this.handleChange();
          }
        },

        tryUnsubscribe() {
          if (this.unsubscribe) {
            this.unsubscribe();
            this.unsubscribe = null;
          }
        },
        getWrappedInstance() {
          return this.$refs.wrappedInstance;
        },
      },
      render() {
        const { $slots = {}, $scopedSlots, subscribed, store } = this;
        const props = getOptionProps(this);
        this.preProps = { ...omit(props, ['__propsSymbol__']) };
        const wrapProps = {
          props: {
            ...props,
            ...subscribed,
            store,
          },
          on: getListeners(this),
          scopedSlots: $scopedSlots,
        };
        return (
          <WrappedComponent {...wrapProps} ref="wrappedInstance">
            {Object.keys($slots).map(name => {
              return <template slot={name}>{$slots[name]}</template>;
            })}
          </WrappedComponent>
        );
      },
    };
    return proxyComponent(Connect);
  };
}