import React from 'react';
import get from 'lodash/get';
import uuid from 'uuid/v4';
import { connect } from 'plugin-api/beta/client/hocs';
import { bindActionCreators } from 'redux';
import { getDisplayName } from 'coral-framework/helpers/hoc';
import { compose, gql } from 'react-apollo';
import withFragments from 'coral-framework/hocs/withFragments';
import withMutation from 'coral-framework/hocs/withMutation';
import { notify } from 'coral-framework/actions/notification';
import { capitalize } from 'coral-framework/helpers/strings';
import { getMyActionSummary, getTotalActionCount } from 'coral-framework/utils';
import hoistStatics from 'recompose/hoistStatics';
import * as PropTypes from 'prop-types';
import { getDefinitionName } from '../utils';
import { t, can } from 'plugin-api/beta/client/services';

import { showSignInDialog } from 'coral-embed-stream/src/actions/login';

/*
 * Disable false-positive warning below, as it doesn't work well with how we currently
 * assemble the queries.
 *
 * Warning: fragment with name {fragment name} already exists.
 * graphql-tag enforces all fragment names across your application to be unique; read more about
 * this in the docs: http://dev.apollodata.com/core/fragments.html#unique-names
 */
gql.disableFragmentWarnings();

export default (reaction, options = {}) =>
  hoistStatics(WrappedComponent => {
    if (typeof reaction !== 'string') {
      console.error('Reaction must be a valid string');
      return null;
    }

    // fragments allow the extension of the fragments defined in this HOC.
    const { fragments = {} } = options;

    // Global instance counter for each `reaction` type.
    let instances = 0;

    // Track current subscriptions.
    let createdSubscription = null;
    let deletedSubscription = null;

    reaction = reaction.toLowerCase();
    const Reaction = capitalize(reaction);

    const COMMENT_FRAGMENT = gql`
    fragment ${Reaction}Button_updateFragment on Comment {
        action_summaries {
        ... on ${Reaction}ActionSummary {
          count
          current_user {
            id
          }
        }
      }
    }
  `;

    const isReaction = a => a.__typename === `${Reaction}ActionSummary`;

    const addReactionToStore = (proxy, { action, self }) => {
      const fragmentId = `Comment_${action.item_id}`;

      // Read the data from our cache for this query.
      const data = proxy.readFragment({
        fragment: COMMENT_FRAGMENT,
        id: fragmentId,
      });

      if (!data) {
        if (self) {
          throw new Error(`Comment ${action.item_id} was not found`);
        }
        return;
      }

      // Add our comment from the mutation to the end.
      let idx = data.action_summaries.findIndex(isReaction);

      // Check whether we already reactioned this comment.
      if (self && idx >= 0 && data.action_summaries[idx].current_user) {
        return;
      }

      if (idx < 0) {
        // Add initial action when it doesn't exist.
        data.action_summaries.push({
          __typename: `${Reaction}ActionSummary`,
          count: 0,
          current_user: null,
        });
        idx = data.action_summaries.length - 1;
      }

      data.action_summaries[idx] = {
        ...data.action_summaries[idx],
        count: data.action_summaries[idx].count + 1,
        current_user: self ? action : data.action_summaries[idx].current_user,
      };

      // Write our data back to the cache.
      proxy.writeFragment({
        fragment: COMMENT_FRAGMENT,
        id: fragmentId,
        data,
      });
    };

    const deleteReactionFromStore = (proxy, { action, self }) => {
      const fragmentId = `Comment_${action.item_id}`;

      // Read the data from our cache for this query.
      const data = proxy.readFragment({
        fragment: COMMENT_FRAGMENT,
        id: fragmentId,
      });

      if (!data) {
        if (self) {
          throw new Error(`Comment ${action.item_id} was not found`);
        }
        return;
      }

      // Check whether we liked this comment.
      const idx = data.action_summaries.findIndex(isReaction);

      if (
        self &&
        (idx < 0 ||
          get(data.action_summaries[idx], 'current_user.id') !== action.id)
      ) {
        return;
      }

      data.action_summaries[idx] = {
        ...data.action_summaries[idx],
        count: data.action_summaries[idx].count - 1,
        current_user: self ? null : data.action_summaries[idx].current_user,
      };

      // Write our data back to the cache.
      proxy.writeFragment({
        fragment: COMMENT_FRAGMENT,
        id: fragmentId,
        data,
      });
    };

    const REACTION_CREATED_SUBSCRIPTION = gql`
    subscription ${Reaction}ActionCreated($assetId: ID!) {
      ${reaction}ActionCreated(asset_id: $assetId) {
        id
        user {
          id
        }
        item_id
      }
    }
  `;

    const REACTION_DELETED_SUBSCRIPTION = gql`
    subscription ${Reaction}ActionDeleted($assetId: ID!) {
      ${reaction}ActionDeleted(asset_id: $assetId) {
        id
        user {
          id
        }
        item_id
      }
    }
  `;

    class WithReactions extends React.Component {
      static contextTypes = {
        client: PropTypes.object.isRequired,
      };

      // Whether or not a mutation is currently active.
      duringMutation = false;

      constructor(props, context) {
        super(props, context);

        // Start subscriptions when it is first needed.
        if (instances === 0) {
          createdSubscription = context.client
            .subscribe({
              query: REACTION_CREATED_SUBSCRIPTION,
              variables: {
                assetId: this.props.asset.id,
              },
            })
            .subscribe({
              next: this.onReactionCreated,
              error(err) {
                console.error('err', err);
              },
            });

          deletedSubscription = context.client
            .subscribe({
              query: REACTION_DELETED_SUBSCRIPTION,
              variables: {
                assetId: this.props.asset.id,
              },
            })
            .subscribe({
              next: this.onReactionDeleted,
              error(err) {
                console.error('err', err);
              },
            });
        }
        instances++;
      }

      // onReactionCreated handles live updates through the subscriptions.
      onReactionCreated = ({ [`${reaction}ActionCreated`]: action }) => {
        if (
          this.props.user &&
          action.user &&
          this.props.user.id === action.user.id
        ) {
          return;
        }
        addReactionToStore(this.context.client, { action, self: false });
      };

      // onReactionDeleted handles live updates through the subscriptions.
      onReactionDeleted = ({ [`${reaction}ActionDeleted`]: action }) => {
        if (
          this.props.user &&
          action.user &&
          this.props.user.id === action.user.id
        ) {
          return;
        }
        deleteReactionFromStore(this.context.client, { action, self: false });
      };

      componentWillUnmount() {
        instances--;

        // End subscriptions when last component will be unmounted.
        if (instances === 0) {
          try {
            createdSubscription.unsubscribe();
            deletedSubscription.unsubscribe();
          } catch (e) {
            console.warn(e);
          }
        }
      }

      postReaction = () => {
        if (this.duringMutation) {
          return;
        }
        this.duringMutation = true;

        // If the current user is suspended, do nothing.
        if (!can(this.props.user, 'INTERACT_WITH_COMMUNITY')) {
          notify('error', t('error.NOT_AUTHORIZED'));
          return;
        }

        return this.props
          .postReaction(this.props.comment)
          .then(result => {
            this.duringMutation = false;
            return result;
          })
          .catch(err => {
            this.duringMutation = false;
            throw err;
          });
      };

      deleteReaction = () => {
        if (this.duringMutation) {
          return;
        }
        this.duringMutation = true;

        // If the current user is suspended, do nothing.
        if (!can(this.props.user, 'INTERACT_WITH_COMMUNITY')) {
          notify('error', t('error.NOT_AUTHORIZED'));
          return;
        }

        return this.props
          .deleteReaction(this.props.comment)
          .then(result => {
            this.duringMutation = false;
            return result;
          })
          .catch(err => {
            this.duringMutation = false;
            throw err;
          });
      };

      render() {
        const { root, asset, comment } = this.props;

        const reactionSummary = getMyActionSummary(
          `${Reaction}ActionSummary`,
          comment
        );

        const count = getTotalActionCount(`${Reaction}ActionSummary`, comment);

        const alreadyReacted = !!reactionSummary;

        return (
          <WrappedComponent
            root={root}
            asset={asset}
            comment={comment}
            showSignInDialog={this.props.showSignInDialog}
            notify={this.props.notify}
            user={this.props.user}
            reactionSummary={reactionSummary}
            count={count}
            alreadyReacted={alreadyReacted}
            postReaction={this.postReaction}
            deleteReaction={this.deleteReaction}
            config={this.props.config}
          />
        );
      }
    }

    const withDeleteReaction = withMutation(
      gql`
      mutation Delete${Reaction}Action($input: Delete${Reaction}ActionInput!) {
        delete${Reaction}Action(input: $input) {
          errors {
            translation_key
          }
        }
      }
    `,
      {
        props: ({ mutate }) => ({
          deleteReaction: comment => {
            const reactionSummary = getMyActionSummary(
              `${Reaction}ActionSummary`,
              comment
            );

            const id = reactionSummary.current_user.id;
            const item_id = comment.id;

            const input = { id };
            return mutate({
              variables: { input },
              optimisticResponse: {
                [`delete${Reaction}Action`]: {
                  __typename: `Delete${Reaction}ActionResponse`,
                  errors: null,
                },
              },
              update: proxy => {
                deleteReactionFromStore(proxy, {
                  action: { item_id, id },
                  self: true,
                });
              },
            });
          },
        }),
      }
    );

    const withPostReaction = withMutation(
      gql`
        mutation Create${Reaction}Action($input: Create${Reaction}ActionInput!) {
          create${Reaction}Action(input: $input) {
            ${reaction} {
              id
            }
            errors {
              translation_key
            }
          }
        }
    `,
      {
        props: ({ mutate }) => ({
          postReaction: comment => {
            const input = {
              item_id: comment.id,
            };

            return mutate({
              variables: { input },
              optimisticResponse: {
                [`create${Reaction}Action`]: {
                  __typename: `Create${Reaction}ActionResponse`,
                  errors: null,
                  [reaction]: {
                    __typename: `${Reaction}Action`,
                    id: uuid(),
                  },
                },
              },
              update: (
                proxy,
                {
                  data: { [`create${Reaction}Action`]: { [reaction]: action } },
                }
              ) => {
                const a = {
                  ...action,
                  item_id: input.item_id,
                };
                addReactionToStore(proxy, { action: a, self: true });
              },
            });
          },
        }),
      }
    );

    const mapStateToProps = state => ({
      user: state.auth.user,
    });

    const mapDispatchToProps = dispatch =>
      bindActionCreators({ showSignInDialog, notify }, dispatch);

    const enhance = compose(
      withFragments({
        ...fragments,
        asset: gql`
        fragment ${Reaction}Button_asset on Asset {
          id
          ${fragments.asset ? `...${getDefinitionName(fragments.asset)}` : ''}
        }
        ${fragments.asset ? fragments.asset : ''}
      `,
        comment: gql`
        fragment ${Reaction}Button_comment on Comment {
          id
          action_summaries {
            __typename
            ... on ${Reaction}ActionSummary {
              count
              current_user {
                id
              }
            }
          }
          ${
            fragments.comment
              ? `...${getDefinitionName(fragments.comment)}`
              : ''
          }
        }
        ${fragments.comment ? fragments.comment : ''}
      `,
      }),
      connect(mapStateToProps, mapDispatchToProps),
      withDeleteReaction,
      withPostReaction
    );

    WithReactions.displayName = `WithReactions(${getDisplayName(
      WrappedComponent
    )})`;

    return enhance(WithReactions);
  });