// @flow
import * as React from 'react';
import { observable } from 'mobx';
import { observer, inject } from 'mobx-react';
import type { Location } from 'react-router-dom';
import Flex from 'shared/components/Flex';
import styled from 'styled-components';
import { color } from 'shared/styles/constants';
import { PlusIcon, CollectionIcon } from 'outline-icons';

import Header from './Header';
import SidebarLink from './SidebarLink';
import DropToImport from 'components/DropToImport';
import CollectionMenu from 'menus/CollectionMenu';

import CollectionsStore from 'stores/CollectionsStore';
import UiStore from 'stores/UiStore';
import Document from 'models/Document';
import Collection from 'models/Collection';
import DocumentsStore from 'stores/DocumentsStore';
import { type NavigationNode } from 'types';

type Props = {
  history: Object,
  location: Location,
  collections: CollectionsStore,
  documents: DocumentsStore,
  onCreateCollection: () => void,
  ui: UiStore,
};

@observer
class Collections extends React.Component<Props> {
  render() {
    const { history, location, collections, ui, documents } = this.props;

    return (
      <Flex column>
        <Header>Collections</Header>
        {collections.orderedData.map(collection => (
          <CollectionLink
            key={collection.id}
            history={history}
            location={location}
            collection={collection}
            activeDocument={documents.active}
            prefetchDocument={documents.prefetchDocument}
            ui={ui}
          />
        ))}

        {collections.isLoaded && (
          <SidebarLink
            onClick={this.props.onCreateCollection}
            icon={<PlusIcon />}
          >
            New collection…
          </SidebarLink>
        )}
      </Flex>
    );
  }
}

type CollectionLinkProps = {
  history: Object,
  collection: Collection,
  ui: UiStore,
  activeDocument: ?Document,
  prefetchDocument: (id: string) => Promise<void>,
};

@observer
class CollectionLink extends React.Component<*> {
  props: CollectionLinkProps;

  @observable menuOpen = false;

  renderDocuments() {
    const {
      history,
      collection,
      activeDocument,
      prefetchDocument,
    } = this.props;

    return (
      <CollectionChildren column>
        {collection.documents.map(document => (
          <DocumentLink
            key={document.id}
            history={history}
            document={document}
            activeDocument={activeDocument}
            prefetchDocument={prefetchDocument}
            depth={0}
          />
        ))}
      </CollectionChildren>
    );
  }

  render() {
    const { history, collection, ui } = this.props;
    const expanded = collection.id === ui.activeCollectionId;

    return (
      <StyledDropToImport
        key={collection.id}
        history={history}
        collectionId={collection.id}
        activeClassName="activeDropZone"
        menuOpen={this.menuOpen}
      >
        <SidebarLink
          key={collection.id}
          to={collection.url}
          icon={<CollectionIcon expanded={expanded} color={collection.color} />}
          iconColor={collection.color}
          expandedContent={this.renderDocuments()}
          hideExpandToggle
          expand={expanded}
        >
          <CollectionName justify="space-between">
            {collection.name}
          </CollectionName>
        </SidebarLink>
        <CollectionAction>
          <CollectionMenu
            history={history}
            collection={collection}
            onOpen={() => (this.menuOpen = true)}
            onClose={() => (this.menuOpen = false)}
          />
        </CollectionAction>
      </StyledDropToImport>
    );
  }
}

type DocumentLinkProps = {
  document: NavigationNode,
  history: Object,
  activeDocument: ?Document,
  activeDocumentRef: HTMLElement => void,
  prefetchDocument: (documentId: string) => void,
  depth: number,
};

const DocumentLink = observer(
  ({
    document,
    activeDocument,
    activeDocumentRef,
    prefetchDocument,
    depth,
    history,
  }: DocumentLinkProps) => {
    const isActiveDocument =
      activeDocument && activeDocument.id === document.id;
    const showChildren = !!(
      activeDocument &&
      (activeDocument.pathToDocument
        .map(entry => entry.id)
        .includes(document.id) ||
        isActiveDocument)
    );

    const handleMouseEnter = (event: SyntheticEvent<*>) => {
      event.stopPropagation();
      event.preventDefault();
      prefetchDocument(document.id);
    };

    return (
      <Flex
        column
        key={document.id}
        innerRef={isActiveDocument ? activeDocumentRef : undefined}
        onMouseEnter={handleMouseEnter}
      >
        <DropToImport
          history={history}
          documentId={document.id}
          activeClassName="activeDropZone"
        >
          <SidebarLink
            to={document.url}
            expand={showChildren}
            expandedContent={
              document.children.length ? (
                <DocumentChildren column>
                  {document.children.map(childDocument => (
                    <DocumentLink
                      key={childDocument.id}
                      history={history}
                      document={childDocument}
                      activeDocument={activeDocument}
                      prefetchDocument={prefetchDocument}
                      depth={depth + 1}
                    />
                  ))}
                </DocumentChildren>
              ) : (
                undefined
              )
            }
          >
            {document.title}
          </SidebarLink>
        </DropToImport>
      </Flex>
    );
  }
);

const CollectionName = styled(Flex)`
  padding: 0 0 4px;
`;

const CollectionAction = styled.span`
  position: absolute;
  right: 0;
  top: 0;
  color: ${color.slate};
  svg {
    opacity: 0.75;
  }

  &:hover {
    svg {
      opacity: 1;
    }
  }
`;

const StyledDropToImport = styled(DropToImport)`
  position: relative;

  ${CollectionAction} {
    display: ${props => (props.menuOpen ? 'inline' : 'none')};
  }

  &:hover {
    ${CollectionAction} {
      display: inline;
    }
  }
`;

const CollectionChildren = styled(Flex)`
  margin-top: -4px;
  margin-left: 36px;
  padding-bottom: 4px;
`;

const DocumentChildren = styled(Flex)`
  margin-top: -4px;
  margin-left: 12px;
`;

export default inject('collections', 'ui', 'documents')(Collections);