Solution

src/App.scss

@@ -18,6 +18,37 @@
   }
 }
 
+@media print, screen and (min-width: 769px) {
+  .tile:not(.is-child) {
+      display: flex;
+  }
+}
+
+.tile.is-ancestor:last-child {
+  margin-bottom: -.75rem;
+}
+
+.tile.is-ancestor {
+  margin-left: -.75rem;
+  margin-right: -.75rem;
+  margin-top: -.75rem;
+}
+
+.tile {
+  align-items: stretch;
+  min-height: min-content;
+  flex-basis: 0;
+  flex-grow: 1;
+  flex-shrink: 1;
+}
+
 .message-body {
   white-space: pre-line;
 }
+
+.container {
+  flex-grow: 1;
+  margin: 0 auto;
+  position: relative;
+  width: auto;
+}

src/App.tsx

@@ -1,60 +1,108 @@
-import classNames from 'classnames';
-
 import 'bulma/css/bulma.css';
 import '@fortawesome/fontawesome-free/css/all.css';
+import cn from 'classnames';
 import './App.scss';
 
-import { PostsList } from './components/PostsList';
-import { PostDetails } from './components/PostDetails';
-import { UserSelector } from './components/UserSelector';
-import { Loader } from './components/Loader';
-
-export const App = () => (
-  <main className="section">
-    <div className="container">
-      <div className="tile is-ancestor">
-        <div className="tile is-parent">
-          <div className="tile is-child box is-success">
-            <div className="block">
-              <UserSelector />
-            </div>
+import { PostsList, PostDetails, UserSelector, Loader } from './components';
+import { User } from './types';
+import { usePosts, useUsers } from './hooks';
 
-            <div className="block" data-cy="MainContent">
-              <p data-cy="NoSelectedUser">No user selected</p>
+export const App = () => {
+  const {
+    users,
+    errorMessage: usersErrorMessage,
+    selectedUser,
+    setSelectedUser,
+  } = useUsers();
+  const {
+    posts,
+    selectedPost,
+    setSelectedPost,
+    isLoading,
+    setIsLoading,
+    errorMessage: postsErrorMessage,
+  } = usePosts(selectedUser?.id);
 
-              <Loader />
+  const errorMessage = usersErrorMessage || postsErrorMessage;
 
-              <div
-                className="notification is-danger"
-                data-cy="PostsLoadingError"
-              >
-                Something went wrong!
-              </div>
+  const handleSelectUserId = (user: User) => {
+    setIsLoading(true);
+    setSelectedPost(null);
+    setSelectedUser(user);
 
-              <div className="notification is-warning" data-cy="NoPostsYet">
-                No posts yet
+    if (selectedUser === user) {
+      setIsLoading(false);
+    }
+  };
+
+  return (
+    <main className="section">
+      <div className="container">
+        <div className="tile is-ancestor">
+          <div className="tile is-parent">
+            <div className="tile is-child box is-success">
+              <div className="block">
+                <UserSelector
+                  users={users}
+                  selectedUser={selectedUser}
+                  onSelectUser={handleSelectUserId}
+                />
               </div>
 
-              <PostsList />
+              <div className="block" data-cy="MainContent">
+                {!selectedUser && (
+                  <p data-cy="NoSelectedUser">No user selected</p>
+                )}
+
+                {selectedUser && isLoading && <Loader />}
+
+                {selectedUser && !isLoading && errorMessage && (
+                  <div
+                    className="notification is-danger"
+                    data-cy="PostsLoadingError"
+                  >
+                    {errorMessage}
+                  </div>
+                )}
+
+                {selectedUser &&
+                  !isLoading &&
+                  !errorMessage &&
+                  posts.length === 0 && (
+                    <div
+                      className="notification is-warning"
+                      data-cy="NoPostsYet"
+                    >
+                      No posts yet
+                    </div>
+                  )}
+
+                {selectedUser &&
+                  !isLoading &&
+                  !errorMessage &&
+                  posts.length !== 0 && (
+                    <PostsList
+                      posts={posts}
+                      selectedPost={selectedPost}
+                      onSelectPost={setSelectedPost}
+                    />
+                  )}
+              </div>
             </div>
           </div>
-        </div>
 
-        <div
-          data-cy="Sidebar"
-          className={classNames(
-            'tile',
-            'is-parent',
-            'is-8-desktop',
-            'Sidebar',
-            'Sidebar--open',
-          )}
-        >
-          <div className="tile is-child box is-success ">
-            <PostDetails />
+          <div
+            data-cy="Sidebar"
+            className={cn('tile is-parent is-8-desktop Sidebar', {
+              'Sidebar--open': selectedPost,
+            })}
+          >
+            <div className="tile is-child box is-success ">
+              {selectedPost && <PostDetails selectedPost={selectedPost} />}
+            </div>
           </div>
         </div>
       </div>
-    </div>
-  </main>
-);
+    </main>
+  );
+};

src/api/comments.ts

@@ -0,0 +1,14 @@
+import { Comment } from '../types/Comment';
+import { client } from '../utils/fetchClient';
+
+export const getComments = (postId: number) => {
+  return client.get<Comment[]>(`/comments?postId=${postId}`);
+};
+
+export const deleteComment = (commentId: number) => {
+  return client.delete(`/comments/${commentId}`);
+};
+
+export const addComment = (newComment: Omit<Comment, 'id'>) => {
+  return client.post<Comment>('/comments', newComment);
+};

src/api/posts.ts

@@ -0,0 +1,6 @@
+import { Post } from '../types/Post';
+import { client } from '../utils/fetchClient';
+
+export const getUserPosts = (selectedUserId: number) => {
+  return client.get<Post[]>(`/posts?userId=${selectedUserId}`);
+};

src/api/users.ts

@@ -0,0 +1,6 @@
+import { User } from '../types/User';
+import { client } from '../utils/fetchClient';
+
+export const getUsers = () => {
+  return client.get<User[]>('/users');
+};

src/components/CommentItem.tsx

@@ -0,0 +1,33 @@
+import { FC } from 'react';
+
+import { Comment } from '../types';
+
+type Props = {
+  comment: Comment;
+  onDelete: (commentId: number) => Promise<void>;
+};
+
+export const CommentItem: FC<Props> = ({ comment, onDelete }) => {
+  const { id, name, email, body } = comment;
+
+  return (
+    <article className="message is-small" data-cy="Comment">
+      <div className="message-header">
+        <a href={`mailto:${email}`} data-cy="CommentAuthor">
+          {name}
+        </a>
+        <button
+          data-cy="CommentDelete"
+          type="button"
+          className="delete is-small"
+          aria-label="delete"
+          onClick={() => onDelete(id)}
+        ></button>
+      </div>
+
+      <div className="message-body" data-cy="CommentBody">
+        {body}
+      </div>
+    </article>
+  );
+};