1 files changed, 222 insertions, 0 deletions
diff --git a/src/services/graphql/api.ts b/src/services/graphql/api.ts
new file mode 100644
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+++ b/src/services/graphql/api.ts
@@ -0,0 +1,222 @@
+import { settings } from '@utils/config';
+import {
+  articleBySlugQuery,
+  articlesCardQuery,
+  articlesQuery,
+  articlesSlugQuery,
+  totalArticlesQuery,
+} from './articles.query';
+import { commentsQuery } from './comments.query';
+import {
+  thematicBySlugQuery,
+  thematicsListQuery,
+  thematicsSlugQuery,
+} from './thematics.query';
+import {
+  topicBySlugQuery,
+  topicsListQuery,
+  topicsSlugQuery,
+} from './topics.query';
+
+export type Queries =
+  | typeof articlesQuery
+  | typeof articleBySlugQuery
+  | typeof articlesCardQuery
+  | typeof articlesSlugQuery
+  | typeof commentsQuery
+  | typeof thematicBySlugQuery
+  | typeof thematicsListQuery
+  | typeof thematicsSlugQuery
+  | typeof topicBySlugQuery
+  | typeof topicsListQuery
+  | typeof topicsSlugQuery
+  | typeof totalArticlesQuery;
+
+export type ArticleResponse<T> = {
+  post: T;
+};
+
+export type ArticlesResponse<T> = {
+  posts: T;
+};
+
+export type CommentsResponse<T> = {
+  comments: T[];
+};
+
+export type ThematicResponse<T> = {
+  thematic: T;
+};
+
+export type ThematicsResponse<T> = {
+  thematics: T;
+};
+
+export type TopicResponse<T> = {
+  topic: T;
+};
+
+export type TopicsResponse<T> = {
+  topics: T;
+};
+
+export type PageInfo = {
+  endCursor: string;
+  hasNextPage: boolean;
+  total: number;
+};
+
+export type Edges<T> = {
+  cursor: string;
+  node: T;
+};
+
+export type EdgesResponse<T> = {
+  edges: Edges<T>[];
+  pageInfo: PageInfo;
+};
+
+export type NodeResponse<T> = {
+  node: T;
+};
+
+export type NodesResponse<T> = {
+  nodes: T[];
+};
+
+export type ResponseMap<T> = {
+  [articleBySlugQuery]: ArticleResponse<NodesResponse<T>>;
+  [articlesCardQuery]: ArticlesResponse<NodesResponse<T>>;
+  [articlesQuery]: ArticlesResponse<EdgesResponse<T>>;
+  [articlesSlugQuery]: ArticlesResponse<EdgesResponse<T>>;
+  [commentsQuery]: CommentsResponse<NodesResponse<T>>;
+  [thematicBySlugQuery]: ThematicResponse<NodesResponse<T>>;
+  [thematicsListQuery]: ThematicsResponse<EdgesResponse<T>>;
+  [thematicsSlugQuery]: ThematicsResponse<EdgesResponse<T>>;
+  [topicBySlugQuery]: TopicResponse<NodesResponse<T>>;
+  [topicsListQuery]: TopicsResponse<EdgesResponse<T>>;
+  [topicsSlugQuery]: TopicsResponse<EdgesResponse<T>>;
+  [totalArticlesQuery]: ArticlesResponse<T>;
+};
+
+export type GraphQLResponse<
+  T extends keyof ResponseMap<U>,
+  U
+> = ResponseMap<U>[T];
+
+export type BySlugVar = {
+  /**
+   * A slug.
+   */
+  slug: string;
+};
+
+export type EdgesVars = {
+  /**
+   * A cursor.
+   */
+  after?: string;
+  /**
+   * The number of items to return.
+   */
+  first: number;
+  /**
+   * A search query.
+   */
+  search?: string;
+};
+
+export type ByContentIdVar = {
+  /**
+   * An article id.
+   */
+  contentId: number;
+};
+
+export type VariablesMap = {
+  [articleBySlugQuery]: BySlugVar;
+  [articlesCardQuery]: EdgesVars;
+  [articlesQuery]: EdgesVars;
+  [articlesSlugQuery]: EdgesVars;
+  [commentsQuery]: ByContentIdVar;
+  [thematicBySlugQuery]: BySlugVar;
+  [thematicsListQuery]: EdgesVars;
+  [thematicsSlugQuery]: EdgesVars;
+  [topicBySlugQuery]: BySlugVar;
+  [topicsListQuery]: EdgesVars;
+  [topicsSlugQuery]: EdgesVars;
+  [totalArticlesQuery]: null;
+};
+
+export type FetchAPIProps<T extends Queries> = {
+  /**
+   * A GraphQL API URL.
+   */
+  api: string;
+  /**
+   * A GraphQL query.
+   */
+  query: T;
+  /**
+   * (Optional) The query variables.
+   */
+  variables?: VariablesMap[T];
+};
+
+/**
+ * Fetch a GraphQL API.
+ * @param {object} obj - An object.
+ * @param {string} obj.api - A GraphQL API URL.
+ * @param {Queries} obj.query - A GraphQL query.
+ * @param {object} [obj.variables] - The query variables.
+ */
+export async function fetchAPI<T, U extends Queries>({
+  api,
+  query,
+  variables,
+}: FetchAPIProps<U>): Promise<GraphQLResponse<U, T>> {
+  const response = await fetch(api, {
+    method: 'POST',
+    headers: {
+      'content-type': 'application/json;charset=UTF-8',
+    },
+    body: JSON.stringify({
+      query,
+      variables,
+    }),
+  });
+
+  type JSONResponse = {
+    data?: GraphQLResponse<U, T>;
+    errors?: Array<{ message: string }>;
+  };
+
+  const { data, errors }: JSONResponse = await response.json();
+
+  if (response.ok) {
+    if (!data) return Promise.reject(new Error(`No data found"`));
+
+    return data;
+  } else {
+    console.error('Failed to fetch API');
+    const error = new Error(
+      errors?.map((e) => e.message).join('\n') ?? 'unknown'
+    );
+    return Promise.reject(error);
+  }
+}
+
+/**
+ * Retrieve the API url from settings.
+ *
+ * @returns {string} The API url.
+ */
+export const getAPIUrl = (): string => {
+  const { url } = settings.api;
+
+  if (!url) {
+    throw new Error('API url is not defined.');
+  }
+
+  return url;
+};