refactor: Move GitHub service into submodule

Author: vovanbo

src/services.ts

@@ -0,0 +1,4 @@
+export enum GithubRepositoriesServiceError {
+    RequestFailed = "GitHub GraphQL request is failed",
+    DeserializationFailed = "Deserialization of GraphQL response is failed",
+}

src/services/github/errors.ts

@@ -0,0 +1,119 @@
+import { Octokit } from "@octokit/core";
+import { retry } from "@octokit/plugin-retry";
+import { type Result, ResultAsync, ok } from "neverthrow";
+import { GithubRepositoriesServiceError } from "./errors";
+import starredRepositoriesQuery from "./queries/starredRepositories.gql";
+import totalStarredRepositoriesCountQuery from "./queries/totalStarredRepositoriesCount.gql";
+import type { GitHubGraphQl } from "./types";
+
+export interface StarredRepositoriesQueryResult {
+    repositories: GitHubGraphQl.StarredRepositoryEdge[];
+    totalCount: number;
+    hasNextPage: boolean;
+    endCursor?: string;
+}
+
+export interface IGithubRepositoriesService {
+    accessToken: string;
+    client: Octokit;
+
+    getUserStarredRepositories(
+        pageSize: number,
+    ): AsyncGenerator<
+        Result<
+            GitHubGraphQl.StarredRepositoryEdge[],
+            GithubRepositoriesServiceError
+        >,
+        void,
+        unknown
+    >;
+
+    getTotalStarredRepositoriesCount(): Promise<
+        ResultAsync<number, GithubRepositoriesServiceError>
+    >;
+}
+
+export class GithubRepositoriesService implements IGithubRepositoriesService {
+    accessToken: string;
+    client: Octokit;
+
+    constructor(accessToken: string) {
+        this.accessToken = accessToken;
+        const OctokitWithRetries = Octokit.plugin(retry);
+        this.client = new OctokitWithRetries({
+            auth: this.accessToken,
+            request: { retries: 1, retryAfter: 1 },
+        });
+    }
+
+    private async getOnePageOfStarredRepos(
+        after: string,
+        pageSize: number,
+    ): Promise<
+        ResultAsync<
+            StarredRepositoriesQueryResult,
+            GithubRepositoriesServiceError
+        >
+    > {
+        const makeRequest = ResultAsync.fromPromise(
+            this.client.graphql<GitHubGraphQl.StarredRepositoriesResponse>(
+                starredRepositoriesQuery,
+                {
+                    after,
+                    pageSize,
+                },
+            ),
+            () => GithubRepositoriesServiceError.RequestFailed,
+        );
+
+        return makeRequest.andThen((response) => {
+            return ok({
+                repositories: response.viewer.starredRepositories.edges,
+                totalCount: response.viewer.starredRepositories.totalCount,
+                hasNextPage:
+                    response.viewer.starredRepositories.pageInfo.hasNextPage,
+                endCursor:
+                    response.viewer.starredRepositories.pageInfo.endCursor,
+            });
+        });
+    }
+
+    public async *getUserStarredRepositories(
+        pageSize: number,
+    ): AsyncGenerator<
+        Result<
+            GitHubGraphQl.StarredRepositoryEdge[],
+            GithubRepositoriesServiceError
+        >,
+        void,
+        unknown
+    > {
+        let after = "";
+        let hasNextPage = false;
+        let totalFetched = 0;
+        do {
+            const requestResult = await this.getOnePageOfStarredRepos(
+                after,
+                pageSize,
+            );
+            const result = requestResult.andThen((data) => {
+                hasNextPage = data.hasNextPage;
+                after = data.endCursor ? data.endCursor : "";
+                totalFetched += data.repositories.length;
+                return ok(data.repositories);
+            });
+            yield result;
+        } while (hasNextPage);
+    }
+
+    public async getTotalStarredRepositoriesCount(): Promise<
+        ResultAsync<number, GithubRepositoriesServiceError>
+    > {
+        return ResultAsync.fromPromise(
+            this.client.graphql<GitHubGraphQl.StarredRepositoriesResponse>(
+                totalStarredRepositoriesCountQuery,
+            ),
+            () => GithubRepositoriesServiceError.RequestFailed,
+        ).map((response) => response.viewer.starredRepositories.totalCount);
+    }
+}