StoryPlugin.ts

import { jsonParse } from "@dataplan/json";
import { access, context, lambda, listen } from "grafast";
import { gql, makeExtendSchemaPlugin } from "graphile-utils";

import { SCHEMA_NAME } from "../config.js";

/* The JSON object that `tg__graphql_subscription()` delivers via NOTIFY */
interface TgGraphQLSubscriptionPayload {
  event: string;
  subject: string | null;
  [key: string]: string | null;
}

const StorySubscriptionPlugin = makeExtendSchemaPlugin((build) => {
  const { sql } = build;
  if (!sql) {
    throw new Error("sql not found");
  }

  const currentUserIdSource = build.input.pgSources.find((s) => s.name === "current_user_id");
  if (!currentUserIdSource) {
    throw new Error("Couldn't find current_user_id source");
  }

  const storySource = build.input.pgSources.find(
    (s) => !s.parameters && s.extensions?.pg?.schemaName === SCHEMA_NAME && s.extensions.pg.name === "stories"
  );
  if (!storySource) {
    throw new Error("Couldn't find source for app_public.stories");
  }

  const seasonSource = build.input.pgSources.find(
    (s) => !s.parameters && s.extensions?.pg?.schemaName === SCHEMA_NAME && s.extensions.pg.name === "seasons"
  );
  if (!seasonSource) {
    throw new Error("Couldn't find source for app_public.seasons");
  }

  const episodeSource = build.input.pgSources.find(
    (s) => !s.parameters && s.extensions?.pg?.schemaName === SCHEMA_NAME && s.extensions.pg.name === "episodes"
  );
  if (!episodeSource) {
    throw new Error("Couldn't find source for app_public.episodes");
  }

  return {
    typeDefs: gql`
      type StorySubscriptionPayload {
        story: Story!
        season: Season
        episode: Episode
        # This is returned directly from the PostgreSQL subscription payload (JSON object)
        event: String
      }

      input StorySubscriptionInput {
        storyId: String!
      }

      extend type Subscription {
        """
        Triggered when the episode data changes:

        - direct modifications to the user
        - when their organization membership changes
        """
        storyUpdated(input: StorySubscriptionInput): StorySubscriptionPayload
      }
    `,

    plans: {
      Subscription: {
        storyUpdated: {
          subscribePlan(_root, $args) {
            const $input = $args.get("input");
            const $pgSubscriber = context().get("pgSubscriber");
            const $decodedToken = context().get("decodedToken");
            const $topic = lambda([$input, $decodedToken], ([input, decodedToken]) => {
              debugger;
              return `graphql:story:${input.storyId}`;
            });
            return listen($pgSubscriber, $topic, (e) => {
              return e;
            });
          },
          plan($e) {
            return jsonParse<TgGraphQLSubscriptionPayload>($e);
          },
        },
        StorySubscriptionPayload: {
          story($obj) {
            debugger;
            const $id = access($obj, "storyId");
            return storySource.get({ id: $id });
          },

          season($obj) {
            debugger;
            const $id = access($obj, "seasonId");
            return storySource.get({ id: $id });
          },

          episode($obj) {
            debugger;
            const $id = access($obj, "episodeId");
            return storySource.get({ id: $id });
          },
        },
      },
    },
  };
});

const StoryPlugin: GraphileConfig.Preset = {
  plugins: [StorySubscriptionPlugin],
};

export default StoryPlugin;