import React from 'react'
import PropTypes from 'prop-types'
import classnames from 'classnames'
import lodash from 'lodash';

import LayerListGroup from './LayerListGroup'
import LayerListItem from './LayerListItem'
import ModalAdd from './ModalAdd'

import {SortableContainer} from 'react-sortable-hoc';

const layerListPropTypes = {
  layers: PropTypes.array.isRequired,
  selectedLayerIndex: PropTypes.number.isRequired,
  onLayersChange: PropTypes.func.isRequired,
  onLayerSelect: PropTypes.func,
  sources: PropTypes.object.isRequired,
}

function layerPrefix(name) {
  return name.replace(' ', '-').replace('_', '-').split('-')[0]
}

function findClosestCommonPrefix(layers, idx) {
  const currentLayerPrefix = layerPrefix(layers[idx].id)
  let closestIdx = idx
  for (let i = idx; i > 0; i--) {
    const previousLayerPrefix = layerPrefix(layers[i-1].id)
    if(previousLayerPrefix === currentLayerPrefix) {
      closestIdx = i - 1
    } else {
      return closestIdx
    }
  }
  return closestIdx
}

let UID = 0;

// List of collapsible layer editors
class LayerListContainer extends React.Component {
  static propTypes = {...layerListPropTypes}
  static defaultProps = {
    onLayerSelect: () => {},
  }

  constructor(props) {
    super(props);
    this.selectedItemRef = React.createRef();
    this.scrollContainerRef = React.createRef();
    this.state = {
      collapsedGroups: {},
      areAllGroupsExpanded: false,
      keys: {
        add: UID++,
      },
      isOpen: {
        add: false,
      }
    }
  }

  toggleModal(modalName) {
    this.setState({
      keys: {
        ...this.state.keys,
        [modalName]: UID++,
      },
      isOpen: {
        ...this.state.isOpen,
        [modalName]: !this.state.isOpen[modalName]
      }
    })
  }

  toggleLayers = () => {
    let idx=0

    let newGroups=[]

    this.groupedLayers().forEach(layers => {
      const groupPrefix = layerPrefix(layers[0].id)
      const lookupKey = [groupPrefix, idx].join('-')


      if (layers.length > 1) {
        newGroups[lookupKey] = this.state.areAllGroupsExpanded
      }

      layers.forEach((layer) => {
        idx += 1
      })
    });

    this.setState({
      collapsedGroups: newGroups,
      areAllGroupsExpanded: !this.state.areAllGroupsExpanded
    })
  }

  groupedLayers() {
    const groups = []
    const layerIdCount = new Map();

    for (let i = 0; i < this.props.layers.length; i++) {
      const origLayer = this.props.layers[i];
      const previousLayer = this.props.layers[i-1]
      layerIdCount.set(origLayer.id,
        layerIdCount.has(origLayer.id) ? layerIdCount.get(origLayer.id) + 1 : 0
      );
      const layer = {
        ...origLayer,
        key: `layers-list-${origLayer.id}-${layerIdCount.get(origLayer.id)}`,
      }
      if(previousLayer && layerPrefix(previousLayer.id) == layerPrefix(layer.id)) {
        const lastGroup = groups[groups.length - 1]
        lastGroup.push(layer)
      } else {
        groups.push([layer])
      }
    }
    return groups
  }

  toggleLayerGroup(groupPrefix, idx) {
    const lookupKey = [groupPrefix, idx].join('-')
    const newGroups = { ...this.state.collapsedGroups }
    if(lookupKey in this.state.collapsedGroups) {
      newGroups[lookupKey] = !this.state.collapsedGroups[lookupKey]
    } else {
      newGroups[lookupKey] = false
    }
    this.setState({
      collapsedGroups: newGroups
    })
  }

  isCollapsed(groupPrefix, idx) {
    const collapsed = this.state.collapsedGroups[[groupPrefix, idx].join('-')]
    return collapsed === undefined ? true : collapsed
  }

  shouldComponentUpdate (nextProps, nextState) {
    // Always update on state change
    if (this.state !== nextState) {
      return true;
    }

    // This component tree only requires id and visibility from the layers
    // objects
    function getRequiredProps (layer) {
      const out = {
        id: layer.id,
      };

      if (layer.layout) {
        out.layout = {
          visibility: layer.layout.visibility
        };
      }
      return out;
    }
    const layersEqual = lodash.isEqual(
      nextProps.layers.map(getRequiredProps),
      this.props.layers.map(getRequiredProps),
    );

    function withoutLayers (props) {
      const out = {
        ...props
      };
      delete out['layers'];
      return out;
    }

    // Compare the props without layers because we've already compared them
    // efficiently above.
    const propsEqual = lodash.isEqual(
      withoutLayers(this.props),
      withoutLayers(nextProps)
    );

    const propsChanged = !(layersEqual && propsEqual);
    return propsChanged;
  }

  componentDidUpdate (prevProps) {
    if (prevProps.selectedLayerIndex !== this.props.selectedLayerIndex) {
      const selectedItemNode = this.selectedItemRef.current;
      if (selectedItemNode && selectedItemNode.node) {
        const target = selectedItemNode.node;
        const options = {
          root: this.scrollContainerRef.current,
          threshold: 1.0
        }
        const observer = new IntersectionObserver(entries => {
          observer.unobserve(target);
          if (entries.length > 0 && entries[0].intersectionRatio < 1) {
            target.scrollIntoView();
          }
        }, options);

        observer.observe(target);
      }
    }
  }

  render() {

    const listItems = []
    let idx = 0
    const layersByGroup = this.groupedLayers();
    layersByGroup.forEach(layers => {
      const groupPrefix = layerPrefix(layers[0].id)
      if(layers.length > 1) {
        const grp = <LayerListGroup
          data-wd-key={[groupPrefix, idx].join('-')}
          aria-controls={layers.map(l => l.key).join(" ")}
          key={`group-${groupPrefix}-${idx}`}
          title={groupPrefix}
          isActive={!this.isCollapsed(groupPrefix, idx) || idx === this.props.selectedLayerIndex}
          onActiveToggle={this.toggleLayerGroup.bind(this, groupPrefix, idx)}
        />
        listItems.push(grp)
      }

      layers.forEach((layer, idxInGroup) => {
        const groupIdx = findClosestCommonPrefix(this.props.layers, idx)

        const layerError = this.props.errors.find(error => {
          return (
            error.parsed &&
            error.parsed.type === "layer" &&
            error.parsed.data.index == idx
          );
        });

        const additionalProps = {};
        if (idx === this.props.selectedLayerIndex) {
          additionalProps.ref = this.selectedItemRef;
        }

        const listItem = <LayerListItem
          className={classnames({
            'maputnik-layer-list-item-collapsed': layers.length > 1 && this.isCollapsed(groupPrefix, groupIdx) && idx !== this.props.selectedLayerIndex,
            'maputnik-layer-list-item-group-last': idxInGroup == layers.length - 1 && layers.length > 1,
            'maputnik-layer-list-item--error': !!layerError
          })}
          index={idx}
          key={layer.key}
          id={layer.key}
          layerId={layer.id}
          layerIndex={idx}
          layerType={layer.type}
          visibility={(layer.layout || {}).visibility}
          isSelected={idx === this.props.selectedLayerIndex}
          onLayerSelect={this.props.onLayerSelect}
          onLayerDestroy={this.props.onLayerDestroy.bind(this)}
          onLayerCopy={this.props.onLayerCopy.bind(this)}
          onLayerVisibilityToggle={this.props.onLayerVisibilityToggle.bind(this)}
          {...additionalProps}
        />
        listItems.push(listItem)
        idx += 1
      })
    })

    return <section
      className="maputnik-layer-list"
      role="complementary"
      aria-label="Layers list"
      ref={this.scrollContainerRef}
    >
      <ModalAdd
          key={this.state.keys.add}
          layers={this.props.layers}
          sources={this.props.sources}
          isOpen={this.state.isOpen.add}
          onOpenToggle={this.toggleModal.bind(this, 'add')}
          onLayersChange={this.props.onLayersChange}
      />
      <header className="maputnik-layer-list-header">
        <span className="maputnik-layer-list-header-title">Layers</span>
        <span className="maputnik-space" />
        <div className="maputnik-default-property">
          <div className="maputnik-multibutton">
            <button
              id="skip-target-layer-list"
              onClick={this.toggleLayers}
              className="maputnik-button">
              {this.state.areAllGroupsExpanded === true ? "Collapse" : "Expand"}
            </button>
          </div>
        </div>
        <div className="maputnik-default-property">
          <div className="maputnik-multibutton">
            <button
              onClick={this.toggleModal.bind(this, 'add')}
              data-wd-key="layer-list:add-layer"
              className="maputnik-button maputnik-button-selected">
             Add Layer
            </button>
          </div>
        </div>
      </header>
      <div
        role="navigation"
        aria-label="Layers list"
      >
        <ul className="maputnik-layer-list-container">
          {listItems}
        </ul>
      </div>
    </section>
  }
}

const LayerListContainerSortable = SortableContainer((props) => <LayerListContainer {...props} />)

export default class LayerList extends React.Component {
  static propTypes = {...layerListPropTypes}

  render() {
    return <LayerListContainerSortable
      {...this.props}
      helperClass='sortableHelper'
      onSortEnd={this.props.onMoveLayer.bind(this)}
      useDragHandle={true}
      shouldCancelStart={() => false}
    />
  }
}