import React, { PureComponent } from 'react';
import PropTypes from 'prop-types';

import Decimal from 'decimal.js-light';
import _ from 'underscore';

import ActiveResource from 'active-resource';

import occsn from '../../libs/Occasion'

import { ErrorsFor } from 'mitragyna';
import { Button, Col, Card, FormGroup, InputGroup, InputGroupAddon, Input, FormFeedback } from 'reactstrap';

import Coupon from './Redeemables/Coupon.jsx';
import GiftCard from './Redeemables/GiftCard.jsx';

export default class Redeemables extends PureComponent {
  static propTypes = {
    findRedeemable: PropTypes.func.isRequired,
    onChange: PropTypes.func.isRequired,
    onErrors: PropTypes.func.isRequired,
    order: PropTypes.instanceOf(occsn.Order).isRequired,
  };

  static childContextTypes = {
    removeRedeemable: PropTypes.func,
  };

  constructor() {
    super();

    _.bindAll(this,
      'addErrors',
      'addRedeemable',
      'checkForRedeemable',
      'handleChange',
      'showInput',
      'removeRedeemable',
    );
  }

  componentWillMount() {
    this.setState({ code: '' });
  }

  addErrors(errors) {
    let { onErrors, order } = this.props;

    let newOrder = order.clone();

    // TODO: Remove when there is better way to copy these read-only attributes of order
    ActiveResource.Collection.build([
      'subtotal',
      'couponAmount',
      'tax',
      'taxPercentage',
      'giftCardAmount',
      'price',
      'total',
      'outstandingBalance',
      'quantity',
    ])
    .each((attr) => {
      newOrder[attr] = order[attr];
    });

    newOrder.errors().clear();
    errors.each((e) => {
      e.field = 'redeemables.' + e.parameter.replace('filter/', '');
      newOrder.errors().push(e);
    });
    onErrors(newOrder);
  }

  addRedeemable(redeemable) {
    let { onChange, order } = this.props;

    this.setState({ code: '' });

    if(redeemable.isA(occsn.Coupon)) {
      onChange(order.assignAttributes({ coupon: redeemable }))
    } else if(redeemable.isA(occsn.GiftCard)) {
      var outstandingBalance = order.outstandingBalance;
      var giftCardValue = new Decimal(redeemable.value);

      var transactionAmount;
      if(outstandingBalance.greaterThan(giftCardValue)) {
        transactionAmount = giftCardValue;
      } else {
        transactionAmount = outstandingBalance;
      }

      order = order.clone();

      order.charge(redeemable, transactionAmount.toString());

      onChange(order);
    }
  }

  checkForRedeemable(code) {
    let { findRedeemable, order } = this.props;

    findRedeemable(order.product(), code, this.addRedeemable, this.addErrors);
  }

  getChildContext() {
    return {
      removeRedeemable: this.removeRedeemable,
    }
  }

  handleChange(e) {
    this.setState({ code: e.target.value });
  }

  // If true, display the input to search for more redeemables
  //
  // @note Displays in two cases:
  //   - outstandingBalance is greater than zero (more gift cards can be added)
  //   - outstandingBalance is zero, but a coupon has not been added (coupon can still lower order.price)
  //
  // @return [Boolean] whether or not to show the input to search for more redeemables
  showInput() {
    const { order } = this.props;

    return (order.outstandingBalance && !order.outstandingBalance.isZero()) || _.isNull(order.coupon())
  }

  removeRedeemable(redeemable) {
    let { onChange, order } = this.props;

    if(redeemable.isA(occsn.Coupon)) {
      onChange(order.assignAttributes({ coupon: null }))
    } else if(redeemable.isA(occsn.GiftCard)) {
      order = order.clone();

      order.removeCharge(redeemable);

      onChange(order);
    }
  }

  render() {
    let { order } = this.props;
    let { code } = this.state;

    let currency = order.product().merchant().currency();

    let redeemables = [];
    if(!_.isNull(order.coupon())) {
      redeemables.push(<Coupon currency={currency.name} subject={order.coupon()}></Coupon>);
    }

    let giftCardTransactions =
      order.transactions().target()
      .select((t) => { return t.paymentMethod().isA(occsn.GiftCard) });

    giftCardTransactions.each((giftCardTransaction) => {
      redeemables.push(<GiftCard currency={currency.name} subject={giftCardTransaction}></GiftCard>);
    });

    return <section className="redeemables">
      <section className="redeemables-list">
        { redeemables }
      </section>

      { this.showInput() ? (
        <FormGroup className="redeemable-code">
          <InputGroup className={ order.errors().forField('redeemables.code').empty() ? '' : 'is-invalid' }>
            <Input className="redeemable-code-input" onChange={ this.handleChange } value={ code } />
            <InputGroupAddon addonType="append">
              <Button className="redeemable-code-input-button" onClick={ () => this.checkForRedeemable(code) }>Search</Button>
            </InputGroupAddon>
          </InputGroup>
          <ErrorsFor className="redeemable-code-errors" component={FormFeedback} field='redeemables.code'></ErrorsFor>
        </FormGroup>
        ) : (null)
      }
    </section>;
  }
}