feat: support deleting comment reactions

src/core/server/graph/tenant/mutators/comment.ts

@@ -2,11 +2,13 @@ import TenantContext from "talk-server/graph/tenant/context";
 import {
   GQLCreateCommentInput,
   GQLCreateCommentReactionInput,
+  GQLDeleteCommentReactionInput,
   GQLEditCommentInput,
 } from "talk-server/graph/tenant/schema/__generated__/types";
 import {
   create,
-  createCommentReaction,
+  createReaction,
+  deleteReaction,
   edit,
 } from "talk-server/services/comments";
 
@@ -36,7 +38,11 @@ export default (ctx: TenantContext) => ({
       ctx.req
     ),
   createReaction: (input: GQLCreateCommentReactionInput) =>
-    createCommentReaction(ctx.mongo, ctx.tenant, ctx.user!, {
+    createReaction(ctx.mongo, ctx.tenant, ctx.user!, {
+      item_id: input.commentID,
+    }),
+  deleteReaction: (input: GQLDeleteCommentReactionInput) =>
+    deleteReaction(ctx.mongo, ctx.tenant, ctx.user!, {
       item_id: input.commentID,
     }),
 });

src/core/server/graph/tenant/resolvers/mutation.ts

@@ -27,6 +27,10 @@ const Mutation: GQLMutationTypeResolver<void> = {
     comment: await ctx.mutators.Comment.createReaction(input),
     clientMutationId: input.clientMutationId,
   }),
+  deleteCommentReaction: async (source, { input }, ctx) => ({
+    comment: await ctx.mutators.Comment.deleteReaction(input),
+    clientMutationId: input.clientMutationId,
+  }),
 };
 
 export default Mutation;

src/core/server/graph/tenant/schema/schema.graphql

@@ -1475,7 +1475,7 @@ type UpdateSettingsPayload {
 }
 
 ##################
-## Mutation
+## createCommentReaction
 ##################
 
 input CreateCommentReactionInput {
@@ -1502,6 +1502,34 @@ type CreateCommentReactionPayload {
   clientMutationId: String!
 }
 
+##################
+## deleteCommentReaction
+##################
+
+input DeleteCommentReactionInput {
+  """
+  commentID is the Comment's ID that we want to delete a Reaction on.
+  """
+  commentID: ID!
+
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+}
+
+type DeleteCommentReactionPayload {
+  """
+  comment is the Comment that the Reaction was deleted on.
+  """
+  comment: Comment
+
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+}
+
 ##################
 ## Mutation
 ##################
@@ -1531,6 +1559,14 @@ type Mutation {
   createCommentReaction(
     input: CreateCommentReactionInput!
   ): CreateCommentReactionPayload @auth
+
+  """
+  deleteCommentReaction will delete a Reaction authored by the current logged in
+  user on a Comment if it exists.
+  """
+  deleteCommentReaction(
+    input: CreateCommentReactionInput!
+  ): CreateCommentReactionPayload @auth
 }
 
 ################################################################################

src/core/server/models/action.ts

@@ -315,6 +315,27 @@ export function encodeActionCounts(...actions: Action[]): EncodedActionCounts {
   return actionCounts;
 }
 
+/**
+ * invertEncodedActionCounts will allow inverting of the action count object.
+ *
+ * @param actionCounts the encoded action counts to invert
+ */
+export function invertEncodedActionCounts(
+  actionCounts: EncodedActionCounts
+): EncodedActionCounts {
+  for (const key in actionCounts) {
+    if (!actionCounts.hasOwnProperty(key)) {
+      continue;
+    }
+
+    if (actionCounts[key] > 0) {
+      actionCounts[key] = -actionCounts[key];
+    }
+  }
+
+  return actionCounts;
+}
+
 /**
  * encodeActionCountKeys encodes the action into string keys which represents
  * the groupings as seen in `EncodedActionCounts`.

src/core/server/services/comments/index.ts

@@ -6,7 +6,10 @@ import {
   ACTION_TYPE,
   CreateActionInput,
   createActions,
+  deleteAction,
+  DeleteActionInput,
   encodeActionCounts,
+  invertEncodedActionCounts,
 } from "talk-server/models/action";
 import {
   retrieveAsset,
@@ -222,9 +225,50 @@ async function addCommentActions(
   return comment;
 }
 
+async function deleteCommentAction(
+  mongo: Db,
+  tenant: Tenant,
+  comment: Readonly<Comment>,
+  input: DeleteActionInput
+): Promise<Readonly<Comment>> {
+  // Create each of the actions, returning each of the action results.
+  const { wasDeleted, action } = await deleteAction(mongo, tenant.id, input);
+  if (wasDeleted) {
+    // Compute the action counts, and invert them (because we're deleting an
+    // action).
+    const actionCounts = invertEncodedActionCounts(encodeActionCounts(action!));
+
+    // Update the comment action counts here.
+    const updatedComment = await updateCommentActionCounts(
+      mongo,
+      tenant.id,
+      comment.id,
+      actionCounts
+    );
+
+    // Update the Asset with the updated action counts.
+    await updateAssetActionCounts(
+      mongo,
+      tenant.id,
+      comment.asset_id,
+      actionCounts
+    );
+
+    // Check to see if there was an actual comment returned.
+    if (!updatedComment) {
+      // TODO: (wyattjoh) return a better error.
+      throw new Error("could not update comment action counts");
+    }
+
+    return updatedComment;
+  }
+
+  return comment;
+}
+
 export type CreateCommentReaction = Pick<CreateActionInput, "item_id">;
 
-export async function createCommentReaction(
+export async function createReaction(
   mongo: Db,
   tenant: Tenant,
   author: User,
@@ -249,3 +293,29 @@ export async function createCommentReaction(
 
   return comment;
 }
+
+export type DeleteCommentReaction = Pick<DeleteActionInput, "item_id">;
+
+export async function deleteReaction(
+  mongo: Db,
+  tenant: Tenant,
+  author: User,
+  input: DeleteCommentReaction
+) {
+  // Get the Comment that we are leaving the Action on.
+  let comment = await retrieveComment(mongo, tenant.id, input.item_id);
+  if (!comment) {
+    // TODO: replace to match error returned by the models/comments.ts
+    throw new Error("comment not found");
+  }
+
+  // Add the comment actions, and return the Comment that we just updated.
+  comment = await deleteCommentAction(mongo, tenant, comment, {
+    action_type: ACTION_TYPE.REACTION,
+    item_type: ACTION_ITEM_TYPE.COMMENTS,
+    item_id: input.item_id,
+    user_id: author.id,
+  });
+
+  return comment;
+}