import React from 'react';
import PropTypes from 'prop-types';
import ImmutablePropTypes from 'react-immutable-proptypes';
import styled, { cx, css } from 'react-emotion';
import { List, Map } from 'immutable';
import { partial } from 'lodash';
import { SortableContainer, SortableElement, SortableHandle } from 'react-sortable-hoc';
import { ObjectControl } from 'netlify-cms-widget-object';
import {
  ListItemTopBar,
  ObjectWidgetTopBar,
  colors,
  lengths,
  components,
} from 'netlify-cms-ui-default';

function valueToString(value) {
  return value ? value.join(',').replace(/,([^\s]|$)/g, ', $1') : '';
}

const ListItem = styled.div();

const SortableListItem = SortableElement(ListItem);

const StyledListItemTopBar = styled(ListItemTopBar)`
  background-color: ${colors.textFieldBorder};
`

const NestedObjectLabel = styled.div`
  display: ${props => props.collapsed ? 'block' : 'none'};
  border-top: 0;
  background-color: ${colors.textFieldBorder};
  padding: 13px;
  border-radius: 0 0 ${lengths.borderRadius} ${lengths.borderRadius};
`

const styles = {
  collapsedObjectControl: css`
    display: none;
  `,
  listControlItem: css`
    margin-top: 18px;

    &:first-of-type {
      margin-top: 26px;
    }
  `,
  listControlItemCollapsed: css`
    padding-bottom: 0;
  `,
};

const SortableList = SortableContainer(({ items, renderItem }) => {
  return <div>{items.map(renderItem)}</div>;
});

const valueTypes = {
  SINGLE: 'SINGLE',
  MULTIPLE: 'MULTIPLE',
};

export default class ListControl extends React.Component {
  static propTypes = {
    onChange: PropTypes.func.isRequired,
    onChangeObject: PropTypes.func.isRequired,
    value: ImmutablePropTypes.list,
    field: PropTypes.object,
    forID: PropTypes.string,
    mediaPaths: ImmutablePropTypes.map.isRequired,
    getAsset: PropTypes.func.isRequired,
    onOpenMediaLibrary: PropTypes.func.isRequired,
    onAddAsset: PropTypes.func.isRequired,
    onRemoveInsertedMedia: PropTypes.func.isRequired,
    classNameWrapper: PropTypes.string.isRequired,
    setActiveStyle: PropTypes.func.isRequired,
    setInactiveStyle: PropTypes.func.isRequired,
  };

  static defaultProps = {
    value: List(),
  };

  constructor(props) {
    super(props);
    const { field, value } = props;
    const allItemsCollapsed = field.get('collapsed', true);
    const itemsCollapsed = value && Array(value.size).fill(allItemsCollapsed);

    this.state = {
      itemsCollapsed: List(itemsCollapsed),
      value: valueToString(value),
    };
  }

  getValueType = () => {
    const { field } = this.props;
    if (field.get('fields')) {
      return valueTypes.MULTIPLE;
    } else if (field.get('field')) {
      return valueTypes.SINGLE;
    } else {
      return null;
    }
  }

  /**
   * Always update so that each nested widget has the option to update. This is
   * required because ControlHOC provides a default `shouldComponentUpdate`
   * which only updates if the value changes, but every widget must be allowed
   * to override this.
   */
  shouldComponentUpdate() {
    return true;
  }

  handleChange = (e) => {
    const { onChange } = this.props;
    const oldValue = this.state.value;
    const newValue = e.target.value;
    const listValue = e.target.value.split(',');
    if (newValue.match(/,$/) && oldValue.match(/, $/)) {
      listValue.pop();
    }

    const parsedValue = valueToString(listValue);
    this.setState({ value: parsedValue });
    onChange(listValue.map(val => val.trim()));
  };

  handleFocus = () => {
    this.props.setActiveStyle();
  }

  handleBlur = (e) => {
    const listValue = e.target.value.split(',').map(el => el.trim()).filter(el => el);
    this.setState({ value: valueToString(listValue) });
    this.props.setInactiveStyle();
  }

  handleAdd = (e) => {
    e.preventDefault();
    const { value, onChange } = this.props;
    const parsedValue = (this.getValueType() === valueTypes.SINGLE) ? null : Map();
    this.setState({ itemsCollapsed: this.state.itemsCollapsed.push(false) });
    onChange((value || List()).push(parsedValue));
  }

  /**
   * In case the `onChangeObject` function is frozen by a child widget implementation,
   * e.g. when debounced, always get the latest object value instead of using
   * `this.props.value` directly.
   */
  getObjectValue = idx => this.props.value.get(idx) || Map();

  handleChangeFor(index) {
    return (fieldName, newValue, newMetadata) => {
      const { value, metadata, onChange, field } = this.props;
      const collectionName = field.get('name');
      const newObjectValue = this.getObjectValue(index).set(fieldName, newValue);
      const parsedValue = (this.getValueType() === valueTypes.SINGLE) ? newObjectValue.first() : newObjectValue;
      const parsedMetadata = {
        [collectionName]: Object.assign(metadata ? metadata.toJS() : {}, newMetadata ? newMetadata[collectionName] : {}),
      };
      onChange(value.set(index, parsedValue), parsedMetadata);
    };
  }

  handleRemove = (index, event) => {
    event.preventDefault();
    const { itemsCollapsed } = this.state;
    const { value, metadata, onChange, field } = this.props;
    const collectionName = field.get('name');
    const parsedMetadata = metadata && { [collectionName]: metadata.removeIn(value.get(index).valueSeq()) };

    this.setState({ itemsCollapsed: itemsCollapsed.delete(index) });

    onChange(value.remove(index), parsedMetadata);
  };

  handleItemCollapseToggle = (index, event) => {
    event.preventDefault();
    const { itemsCollapsed } = this.state;
    const collapsed = itemsCollapsed.get(index);
    this.setState({ itemsCollapsed: itemsCollapsed.set(index, !collapsed) });
  };

  handleCollapseAllToggle = (e) => {
    e.preventDefault();
    const { value } = this.props;
    const { itemsCollapsed } = this.state;
    const allItemsCollapsed = itemsCollapsed.every(val => val === true);
    this.setState({ itemsCollapsed: List(Array(value.size).fill(!allItemsCollapsed)) });
  };

  objectLabel(item) {
    const { field } = this.props;
    const multiFields = field.get('fields');
    const singleField = field.get('field');
    const labelField = (multiFields && multiFields.first()) || singleField;
    const value = multiFields ? item.get(multiFields.first().get('name')) : singleField.get('label');
    return (value || `No ${ labelField.get('name') }`).toString();
  }

  onSortEnd = ({ oldIndex, newIndex }) => {
    const { value } = this.props;
    const { itemsCollapsed } = this.state;

    // Update value
    const item = value.get(oldIndex);
    const newValue = value.delete(oldIndex).insert(newIndex, item);
    this.props.onChange(newValue);

    // Update collapsing
    const collapsed = itemsCollapsed.get(oldIndex);
    const updatedItemsCollapsed = itemsCollapsed.delete(oldIndex).insert(newIndex, collapsed);
    this.setState({ itemsCollapsed: updatedItemsCollapsed });
  };

  renderItem = (item, index) => {
    const {
      field,
      classNameWrapper,
      editorControl,
      resolveWidget,
    } = this.props;
    const { itemsCollapsed } = this.state;
    const collapsed = itemsCollapsed.get(index);

    return (
      <SortableListItem
        className={cx(styles.listControlItem, { [styles.listControlItemCollapsed]: collapsed })}
        index={index}
        key={`item-${ index }`}
      >
        <StyledListItemTopBar
          collapsed={collapsed}
          onCollapseToggle={partial(this.handleItemCollapseToggle, index)}
          onRemove={partial(this.handleRemove, index)}
          dragHandleHOC={SortableHandle}
        />
        <NestedObjectLabel collapsed={collapsed}>{this.objectLabel(item)}</NestedObjectLabel>
        <ObjectControl
          classNameWrapper={cx(
            classNameWrapper,
            { [styles.collapsedObjectControl]: collapsed },
          )}
          value={item}
          field={field}
          onChangeObject={this.handleChangeFor(index)}
          editorControl={editorControl}
          resolveWidget={resolveWidget}
          forList
        />
      </SortableListItem>
    );
  };

  renderListControl() {
    const { value, forID, field, classNameWrapper } = this.props;
    const { itemsCollapsed } = this.state;
    const items = value || List();
    const label = field.get('label');
    const labelSingular = field.get('label_singular') || field.get('label');
    const listLabel = items.size === 1 ? labelSingular.toLowerCase() : label.toLowerCase();

    return (
      <div id={forID} className={cx(classNameWrapper, components.objectWidgetTopBarContainer)}>
        <ObjectWidgetTopBar
          allowAdd={field.get('allow_add', true)}
          onAdd={this.handleAdd}
          heading={`${items.size} ${listLabel}`}
          label={listLabel}
          onCollapseToggle={this.handleCollapseAllToggle}
          collapsed={itemsCollapsed.every(val => val === true)}
        />
        <SortableList
          items={items}
          renderItem={this.renderItem}
          onSortEnd={this.onSortEnd}
          useDragHandle
          lockAxis="y"
        />
      </div>
    );
  }

  render() {
    const { field, forID, classNameWrapper } = this.props;
    const { value } = this.state;

    if (field.get('field') || field.get('fields')) {
      return this.renderListControl();
    }

    return (<input
      type="text"
      id={forID}
      value={value}
      onChange={this.handleChange}
      onFocus={this.handleFocus}
      onBlur={this.handleBlur}
      className={classNameWrapper}
    />);
  }
}