diff --git a/src/App.tsx b/src/App.tsx
index 017957182..7916fa029 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,3 +1,4 @@
+/* eslint-disable react-hooks/exhaustive-deps */
 import classNames from 'classnames';
 
 import 'bulma/css/bulma.css';
@@ -8,53 +9,151 @@ import { PostsList } from './components/PostsList';
 import { PostDetails } from './components/PostDetails';
 import { UserSelector } from './components/UserSelector';
 import { Loader } from './components/Loader';
+import { useEffect, useState } from 'react';
+import { User } from './types/User';
+import { getUserPosts } from './api/ClientFunctions';
+import { Post } from './types/Post';
 
-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>
+export const App = () => {
+  // #region states
 
-            <div className="block" data-cy="MainContent">
-              <p data-cy="NoSelectedUser">No user selected</p>
+  const [currUser, setCurrUser] = useState<User | null>(null);
+  const [isDdActive, setIsDdActive] = useState(false);
+  const [userPosts, setUserPosts] = useState<Post[]>([]);
+  const [loadingPostsError, setLoadingPostsError] = useState(false);
+  const [arePostsLoading, setArePostsLoading] = useState(false);
+  const [isNoPosts, setIsNoPosts] = useState(false);
+  const [openedPost, setOpenedPost] = useState<Post | null>(null);
+  const [prevUser, setPrevUser] = useState<User | null>(null);
+  const [doesFormExist, setDoesFormExist] = useState(false);
 
-              <Loader />
+  // #endregion
+  // #region handlers
 
-              <div
-                className="notification is-danger"
-                data-cy="PostsLoadingError"
-              >
-                Something went wrong!
-              </div>
+  const sectionOnClickHandler = () => {
+    if (isDdActive) {
+      setIsDdActive(false);
+    }
+  };
+
+  // #endregion
+  // #region useEffects
+
+  useEffect(() => {
+    if (currUser) {
+      const { id } = currUser;
+
+      setArePostsLoading(true);
+
+      getUserPosts(id)
+        .then(posts => {
+          setUserPosts(posts);
+
+          if (loadingPostsError) {
+            setLoadingPostsError(false);
+          }
+        })
+        .catch(() => setLoadingPostsError(true))
+        .finally(() => setArePostsLoading(false));
+    }
+  }, [currUser]);
+
+  useEffect(() => {
+    if (userPosts.length === 0 && currUser) {
+      setIsNoPosts(true);
+    } else if (userPosts.length > 0 && isNoPosts) {
+      setIsNoPosts(false);
+    }
+  }, [currUser, isNoPosts, userPosts]);
+
+  useEffect(() => {
+    if (prevUser?.id !== currUser?.id) {
+      setOpenedPost(null);
+    }
+  }, [prevUser, currUser]);
+
+  useEffect(() => {
+    if (doesFormExist) {
+      setDoesFormExist(false);
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [openedPost]);
 
-              <div className="notification is-warning" data-cy="NoPostsYet">
-                No posts yet
+  // #endregion
+  // #region markups
+
+  const loadingPostsErrorMarkup = (
+    <div className="notification is-danger" data-cy="PostsLoadingError">
+      Something went wrong!
+    </div>
+  );
+  const noPostsMarkup = (
+    <div className="notification is-warning" data-cy="NoPostsYet">
+      No posts yet
+    </div>
+  );
+  const postsList = (
+    <PostsList
+      userPosts={userPosts}
+      openedPost={openedPost}
+      setOpenedPost={setOpenedPost}
+    />
+  );
+
+  // #endregion
+
+  return (
+    <main className="section" onClick={sectionOnClickHandler}>
+      <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
+                  isDdActive={isDdActive}
+                  currUser={currUser}
+                  setPrevUser={setPrevUser}
+                  setCurrUser={setCurrUser}
+                  setIsDdActive={setIsDdActive}
+                />
               </div>
 
-              <PostsList />
+              <div className="block" data-cy="MainContent">
+                {!currUser && <p data-cy="NoSelectedUser">No user selected</p>}
+
+                {arePostsLoading ? (
+                  <Loader />
+                ) : (
+                  (loadingPostsError && loadingPostsErrorMarkup) ||
+                  (isNoPosts && noPostsMarkup) ||
+                  (userPosts.length > 0 && postsList)
+                )}
+              </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={classNames(
+              'tile',
+              'is-parent',
+              'is-8-desktop',
+              'Sidebar',
+              { 'Sidebar--open': openedPost },
+            )}
+          >
+            <div className="tile is-child box is-success ">
+              {openedPost && (
+                <PostDetails
+                  openedPost={openedPost}
+                  doesFormExist={doesFormExist}
+                  setDoesFormExist={setDoesFormExist}
+                />
+              )}
+            </div>
           </div>
         </div>
       </div>
-    </div>
-  </main>
-);
+    </main>
+  );
+};
diff --git a/src/api/ClientFunctions.ts b/src/api/ClientFunctions.ts
new file mode 100644
index 000000000..9f6ec4250
--- /dev/null
+++ b/src/api/ClientFunctions.ts
@@ -0,0 +1,29 @@
+import { client } from '../utils/fetchClient';
+import { User } from '../types/User';
+import { Post } from '../types/Post';
+import { Comment } from '../types/Comment';
+
+export const getUsers = () => {
+  return client.get<User[]>('/users');
+};
+
+export const getUserPosts = (userId: number) => {
+  return client.get<Post[]>(`/posts?userId=${userId}`);
+};
+
+export const getPostComments = (postId: number) => {
+  return client.get<Comment[]>(`/comments?postId=${postId}`);
+};
+
+export const deleteComment = (id: number) => {
+  return client.delete(`/comments/${id}`);
+};
+
+export const postComment = ({
+  postId,
+  name,
+  email,
+  body,
+}: Omit<Comment, 'id'>) => {
+  return client.post<Comment>('/comments', { postId, name, email, body });
+};
diff --git a/src/components/NewCommentForm.tsx b/src/components/NewCommentForm.tsx
index 73a8a0b45..60f69fe55 100644
--- a/src/components/NewCommentForm.tsx
+++ b/src/components/NewCommentForm.tsx
@@ -1,8 +1,117 @@
-import React from 'react';
+/* eslint-disable react-hooks/exhaustive-deps */
+import classNames from 'classnames';
+import React, { useEffect, useState } from 'react';
+import { postComment } from '../api/ClientFunctions';
+import { Comment } from '../types/Comment';
+
+interface Props {
+  postId: number;
+  commentsError: boolean;
+  setCommentsError: (value: boolean) => void;
+  setDoesFormExist: (value: boolean) => void;
+  setComments: React.Dispatch<React.SetStateAction<Comment[]>>;
+}
+
+export const NewCommentForm: React.FC<Props> = ({
+  postId,
+  commentsError,
+  setCommentsError,
+  setDoesFormExist,
+  setComments,
+}) => {
+  // #region states
+
+  const [isNameValid, setIsNameValid] = useState(true);
+  const [isEmailValid, setIsEmailValid] = useState(true);
+  const [isCommentValid, setIsCommentValid] = useState(true);
+  const [nameValue, setNameValue] = useState('');
+  const [emailValue, setEmailValue] = useState('');
+  const [commentValue, setCommentValue] = useState('');
+  const [isSubmitLoading, setIsSubmitLoading] = useState(false);
+
+  // #endregion
+  // #region handlers
+
+  const clearHandler = () => {
+    setNameValue('');
+    setEmailValue('');
+    setCommentValue('');
+    setIsNameValid(true);
+    setIsEmailValid(true);
+    setIsCommentValid(true);
+  };
+
+  const onSubmit = (event: React.FormEvent) => {
+    event.preventDefault();
+    const IS_VALID =
+      nameValue.length > 0 && emailValue.length > 0 && commentValue.length > 0;
+
+    if (nameValue.length === 0) {
+      setIsNameValid(false);
+    }
+
+    if (emailValue.length === 0) {
+      setIsEmailValid(false);
+    }
+
+    if (commentValue.length === 0) {
+      setIsCommentValid(false);
+    }
+
+    if (!IS_VALID) {
+      return;
+    }
+
+    setIsSubmitLoading(true);
+
+    const comment = {
+      postId: postId,
+      name: nameValue,
+      email: emailValue,
+      body: commentValue,
+    };
+
+    if (commentsError) {
+      setCommentsError(false);
+    }
+
+    postComment(comment)
+      .then(_comment => {
+        setComments(currentComments => [...currentComments, _comment]);
+        setCommentValue('');
+      })
+      .catch(() => {
+        setCommentsError(true);
+        setDoesFormExist(false);
+      })
+      .finally(() => setIsSubmitLoading(false));
+  };
+
+  // #endregion
+  // #region useEffects
+
+  useEffect(() => {
+    if (!isNameValid) {
+      setIsNameValid(true);
+    }
+  }, [nameValue]);
+
+  useEffect(() => {
+    if (!isEmailValid) {
+      setIsEmailValid(true);
+    }
+  }, [emailValue]);
+
+  useEffect(() => {
+    if (!isCommentValid) {
+      setIsCommentValid(true);
+    }
+  }, [commentValue]);
+
+  // #endregion
 
-export const NewCommentForm: React.FC = () => {
   return (
-    <form data-cy="NewCommentForm">
+    <form data-cy="NewCommentForm" onSubmit={onSubmit}>
       <div className="field" data-cy="NameField">
         <label className="label" htmlFor="comment-author-name">
           Author Name
@@ -14,24 +123,32 @@ export const NewCommentForm: React.FC = () => {
             name="name"
             id="comment-author-name"
             placeholder="Name Surname"
-            className="input is-danger"
+            value={nameValue}
+            onChange={event => setNameValue(event.target.value)}
+            className={classNames('input', {
+              'is-danger': !isNameValid,
+            })}
           />
 
           <span className="icon is-small is-left">
             <i className="fas fa-user" />
           </span>
 
-          <span
-            className="icon is-small is-right has-text-danger"
-            data-cy="ErrorIcon"
-          >
-            <i className="fas fa-exclamation-triangle" />
-          </span>
+          {!isNameValid && (
+            <span
+              className="icon is-small is-right has-text-danger"
+              data-cy="ErrorIcon"
+            >
+              <i className="fas fa-exclamation-triangle" />
+            </span>
+          )}
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Name is required
-        </p>
+        {!isNameValid && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            Name is required
+          </p>
+        )}
       </div>
 
       <div className="field" data-cy="EmailField">
@@ -45,24 +162,32 @@ export const NewCommentForm: React.FC = () => {
             name="email"
             id="comment-author-email"
             placeholder="email@test.com"
-            className="input is-danger"
+            value={emailValue}
+            onChange={event => setEmailValue(event.target.value)}
+            className={classNames('input', {
+              'is-danger': !isEmailValid,
+            })}
           />
 
           <span className="icon is-small is-left">
             <i className="fas fa-envelope" />
           </span>
 
-          <span
-            className="icon is-small is-right has-text-danger"
-            data-cy="ErrorIcon"
-          >
-            <i className="fas fa-exclamation-triangle" />
-          </span>
+          {!isEmailValid && (
+            <span
+              className="icon is-small is-right has-text-danger"
+              data-cy="ErrorIcon"
+            >
+              <i className="fas fa-exclamation-triangle" />
+            </span>
+          )}
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Email is required
-        </p>
+        {!isEmailValid && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            Email is required
+          </p>
+        )}
       </div>
 
       <div className="field" data-cy="BodyField">
@@ -75,25 +200,39 @@ export const NewCommentForm: React.FC = () => {
             id="comment-body"
             name="body"
             placeholder="Type comment here"
-            className="textarea is-danger"
+            value={commentValue}
+            onChange={event => setCommentValue(event.target.value)}
+            className={classNames('textarea', {
+              'is-danger': !isCommentValid,
+            })}
           />
         </div>
 
-        <p className="help is-danger" data-cy="ErrorMessage">
-          Enter some text
-        </p>
+        {!isCommentValid && (
+          <p className="help is-danger" data-cy="ErrorMessage">
+            Enter some text
+          </p>
+        )}
       </div>
 
       <div className="field is-grouped">
         <div className="control">
-          <button type="submit" className="button is-link is-loading">
+          <button
+            type="submit"
+            className={classNames('button', 'is-link', {
+              'is-loading': isSubmitLoading,
+            })}
+          >
             Add
           </button>
         </div>
 
         <div className="control">
-          {/* eslint-disable-next-line react/button-has-type */}
-          <button type="reset" className="button is-link is-light">
+          <button
+            type="reset"
+            className="button is-link is-light"
+            onClick={clearHandler}
+          >
             Clear
           </button>
         </div>
diff --git a/src/components/PostDetails.tsx b/src/components/PostDetails.tsx
index 2f82db916..bb03aded0 100644
--- a/src/components/PostDetails.tsx
+++ b/src/components/PostDetails.tsx
@@ -1,107 +1,154 @@
-import React from 'react';
+/* eslint-disable react-hooks/exhaustive-deps */
+import React, { useEffect, useState } from 'react';
 import { Loader } from './Loader';
 import { NewCommentForm } from './NewCommentForm';
+import { Post } from '../types/Post';
+import { Comment } from '../types/Comment';
+import { deleteComment, getPostComments } from '../api/ClientFunctions';
 
-export const PostDetails: React.FC = () => {
-  return (
-    <div className="content" data-cy="PostDetails">
-      <div className="content" data-cy="PostDetails">
-        <div className="block">
-          <h2 data-cy="PostTitle">
-            #18: voluptate et itaque vero tempora molestiae
-          </h2>
-
-          <p data-cy="PostBody">
-            eveniet quo quis laborum totam consequatur non dolor ut et est
-            repudiandae est voluptatem vel debitis et magnam
-          </p>
-        </div>
+interface Props {
+  openedPost: Post;
+  doesFormExist: boolean;
+  setDoesFormExist: (value: boolean) => void;
+}
+
+export const PostDetails: React.FC<Props> = React.memo(
+  ({ openedPost, doesFormExist, setDoesFormExist }) => {
+    // #region states
+
+    const [comments, setComments] = useState<Comment[]>([]);
+    const [commentsError, setCommentsError] = useState(false);
+    const [areCommLoading, setAreCommLoading] = useState(false);
+
+    // #endregion
+    // #region variables
+
+    const { id, title, body } = openedPost;
+    const conditionForButton =
+      !commentsError && !areCommLoading && !doesFormExist;
+
+    // #endregion
+    // #region useEffects
+
+    useEffect(() => {
+      setAreCommLoading(true);
+
+      getPostComments(id)
+        .then(_comments => {
+          setComments(_comments);
+
+          if (commentsError) {
+            setCommentsError(false);
+          }
+        })
+        .catch(() => setCommentsError(true))
+        .finally(() => setAreCommLoading(false));
+    }, [id]);
+
+    // #endregion
+    // #region handlers
+
+    const deleteHandler = (_id: number) => {
+      const updatedComments = comments.filter(comment => comment.id !== _id);
+
+      setComments(updatedComments);
+
+      deleteComment(_id);
+    };
+
+    // #endregion
+    // #region markups
 
-        <div className="block">
-          <Loader />
+    const errorMarkup = (
+      <div className="notification is-danger" data-cy="CommentsError">
+        Something went wrong
+      </div>
+    );
+    const noCommentsMarkup = (
+      <p className="title is-4" data-cy="NoCommentsMessage">
+        No comments yet
+      </p>
+    );
+    const commentsTitleMarkup = <p className="title is-4">Comments:</p>;
+    const commentsMarkup = comments.map(comment => {
+      // eslint-disable-next-line @typescript-eslint/no-shadow
+      const { id, name, body, email } = comment;
 
-          <div className="notification is-danger" data-cy="CommentsError">
-            Something went wrong
+      return (
+        <article
+          key={`comment-${id}`}
+          className="message is-small"
+          data-cy="Comment"
+        >
+          <div className="message-header">
+            <a href={`mailto:${email}`} data-cy="CommentAuthor">
+              {name}
+            </a>
+            <button
+              data-cy="CommentDelete"
+              type="button"
+              className="delete is-small"
+              aria-label="delete"
+              onClick={() => deleteHandler(id)}
+            >
+              delete button
+            </button>
           </div>
 
-          <p className="title is-4" data-cy="NoCommentsMessage">
-            No comments yet
-          </p>
+          <div className="message-body" data-cy="CommentBody">
+            {body}
+          </div>
+        </article>
+      );
+    });
 
-          <p className="title is-4">Comments:</p>
+    // #endregion
 
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
-              <button
-                data-cy="CommentDelete"
-                type="button"
-                className="delete is-small"
-                aria-label="delete"
-              >
-                delete button
-              </button>
-            </div>
+    return (
+      <div className="content" data-cy="PostDetails">
+        <div className="content" data-cy="PostDetails">
+          <div className="block">
+            <h2 data-cy="PostTitle">
+              {`#${id}`}: {title}
+            </h2>
 
-            <div className="message-body" data-cy="CommentBody">
-              Some comment
-            </div>
-          </article>
+            <p data-cy="PostBody">{body}</p>
+          </div>
 
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
+          <div className="block">
+            {areCommLoading ? (
+              <Loader />
+            ) : (
+              (commentsError && errorMarkup) ||
+              (comments.length === 0 && noCommentsMarkup) ||
+              (commentsTitleMarkup && commentsMarkup)
+            )}
 
+            {conditionForButton && (
               <button
-                data-cy="CommentDelete"
+                data-cy="WriteCommentButton"
                 type="button"
-                className="delete is-small"
-                aria-label="delete"
+                className="button is-link"
+                onClick={() => setDoesFormExist(true)}
               >
-                delete button
+                Write a comment
               </button>
-            </div>
-            <div className="message-body" data-cy="CommentBody">
-              One more comment
-            </div>
-          </article>
-
-          <article className="message is-small" data-cy="Comment">
-            <div className="message-header">
-              <a href="mailto:misha@mate.academy" data-cy="CommentAuthor">
-                Misha Hrynko
-              </a>
+            )}
+          </div>
 
-              <button
-                data-cy="CommentDelete"
-                type="button"
-                className="delete is-small"
-                aria-label="delete"
-              >
-                delete button
-              </button>
-            </div>
-
-            <div className="message-body" data-cy="CommentBody">
-              {'Multi\nline\ncomment'}
-            </div>
-          </article>
-
-          <button
-            data-cy="WriteCommentButton"
-            type="button"
-            className="button is-link"
-          >
-            Write a comment
-          </button>
+          {doesFormExist && (
+            <NewCommentForm
+              postId={id}
+              commentsError={commentsError}
+              setCommentsError={setCommentsError}
+              setDoesFormExist={setDoesFormExist}
+              setComments={setComments}
+            />
+          )}
         </div>
-
-        <NewCommentForm />
       </div>
-    </div>
-  );
-};
+    );
+  },
+);
+
+PostDetails.displayName = 'PostDetails';
diff --git a/src/components/PostsList.tsx b/src/components/PostsList.tsx
index cf90f04b0..c885ef834 100644
--- a/src/components/PostsList.tsx
+++ b/src/components/PostsList.tsx
@@ -1,86 +1,69 @@
 import React from 'react';
+import { Post } from '../types/Post';
+import classNames from 'classnames';
 
-export const PostsList: React.FC = () => (
-  <div data-cy="PostsList">
-    <p className="title">Posts:</p>
+interface Props {
+  userPosts: Post[];
+  openedPost: Post | null;
+  setOpenedPost: (post: Post | null) => void;
+}
 
-    <table className="table is-fullwidth is-striped is-hoverable is-narrow">
-      <thead>
-        <tr className="has-background-link-light">
-          <th>#</th>
-          <th>Title</th>
-          {/* eslint-disable-next-line jsx-a11y/control-has-associated-label */}
-          <th> </th>
-        </tr>
-      </thead>
+export const PostsList: React.FC<Props> = ({
+  userPosts,
+  openedPost,
+  setOpenedPost,
+}) => {
+  const clickHandler = (post: Post) => {
+    if (openedPost?.id === post.id) {
+      setOpenedPost(null);
 
-      <tbody>
-        <tr data-cy="Post">
-          <td data-cy="PostId">17</td>
+      return;
+    }
 
-          <td data-cy="PostTitle">
-            fugit voluptas sed molestias voluptatem provident
-          </td>
+    setOpenedPost(post);
+  };
 
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
+  return (
+    <div data-cy="PostsList">
+      <p className="title">Posts:</p>
 
-        <tr data-cy="Post">
-          <td data-cy="PostId">18</td>
+      <table className="table is-fullwidth is-striped is-hoverable is-narrow">
+        <thead>
+          <tr className="has-background-link-light">
+            <th>#</th>
+            <th>Title</th>
+            <th> </th>
+          </tr>
+        </thead>
 
-          <td data-cy="PostTitle">
-            voluptate et itaque vero tempora molestiae
-          </td>
+        <tbody>
+          {userPosts?.map(post => {
+            const { id, title } = post;
+            const isNotOpen = openedPost?.id !== id;
 
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link"
-            >
-              Close
-            </button>
-          </td>
-        </tr>
+            return (
+              <tr data-cy="Post" key={`post-${id}`}>
+                <td data-cy="PostId">{id}</td>
 
-        <tr data-cy="Post">
-          <td data-cy="PostId">19</td>
-          <td data-cy="PostTitle">adipisci placeat illum aut reiciendis qui</td>
+                <td data-cy="PostTitle">{title}</td>
 
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
-
-        <tr data-cy="Post">
-          <td data-cy="PostId">20</td>
-          <td data-cy="PostTitle">doloribus ad provident suscipit at</td>
-
-          <td className="has-text-right is-vcentered">
-            <button
-              type="button"
-              data-cy="PostButton"
-              className="button is-link is-light"
-            >
-              Open
-            </button>
-          </td>
-        </tr>
-      </tbody>
-    </table>
-  </div>
-);
+                <td className="has-text-right is-vcentered">
+                  <button
+                    type="button"
+                    data-cy="PostButton"
+                    className={classNames('button', 'is-link', {
+                      'is-light': isNotOpen,
+                    })}
+                    onClick={() => clickHandler(post)}
+                  >
+                    {isNotOpen ? 'Open' : 'Close'}
+                  </button>
+                </td>
+              </tr>
+            );
+          })}
+        </tbody>
+      </table>
+    </div>
+  );
+};
diff --git a/src/components/UserSelector.tsx b/src/components/UserSelector.tsx
index c89442841..d73b9a0ef 100644
--- a/src/components/UserSelector.tsx
+++ b/src/components/UserSelector.tsx
@@ -1,16 +1,62 @@
-import React from 'react';
+import React, { useEffect, useState } from 'react';
+import { getUsers } from '../api/ClientFunctions';
+import { User } from '../types/User';
+import classNames from 'classnames';
+
+interface Props {
+  currUser: User | null;
+  isDdActive: boolean;
+  setPrevUser: (user: User | null) => void;
+  setCurrUser: (user: User | null) => void;
+  setIsDdActive: (value: boolean) => void;
+}
+
+export const UserSelector: React.FC<Props> = ({
+  currUser,
+  isDdActive,
+  setPrevUser,
+  setCurrUser,
+  setIsDdActive,
+}) => {
+  const [users, setUsers] = useState<User[]>([]);
+
+  // #region handlers
+
+  const buttonOnClickHandler = () => {
+    if (isDdActive) {
+      setIsDdActive(false);
+
+      return;
+    }
+
+    setIsDdActive(true);
+  };
+
+  const selectUserHandler = (user: User) => {
+    setPrevUser(currUser);
+    setCurrUser(user);
+  };
+
+  // #endregion
+
+  useEffect(() => {
+    getUsers().then(_users => setUsers(_users));
+  }, []);
 
-export const UserSelector: React.FC = () => {
   return (
-    <div data-cy="UserSelector" className="dropdown is-active">
+    <div
+      data-cy="UserSelector"
+      className={classNames('dropdown', { 'is-active': isDdActive })}
+    >
       <div className="dropdown-trigger">
         <button
           type="button"
           className="button"
           aria-haspopup="true"
           aria-controls="dropdown-menu"
+          onClick={buttonOnClickHandler}
         >
-          <span>Choose a user</span>
+          <span>{currUser ? currUser.name : 'Choose a user'}</span>
 
           <span className="icon is-small">
             <i className="fas fa-angle-down" aria-hidden="true" />
@@ -20,21 +66,22 @@ export const UserSelector: React.FC = () => {
 
       <div className="dropdown-menu" id="dropdown-menu" role="menu">
         <div className="dropdown-content">
-          <a href="#user-1" className="dropdown-item">
-            Leanne Graham
-          </a>
-          <a href="#user-2" className="dropdown-item is-active">
-            Ervin Howell
-          </a>
-          <a href="#user-3" className="dropdown-item">
-            Clementine Bauch
-          </a>
-          <a href="#user-4" className="dropdown-item">
-            Patricia Lebsack
-          </a>
-          <a href="#user-5" className="dropdown-item">
-            Chelsey Dietrich
-          </a>
+          {users.map(user => {
+            const { name, id } = user;
+
+            return (
+              <a
+                href={`#user-${id}`}
+                key={id}
+                className={classNames('dropdown-item', {
+                  'is-active': currUser?.id === id,
+                })}
+                onClick={() => selectUserHandler(user)}
+              >
+                {name}
+              </a>
+            );
+          })}
         </div>
       </div>
     </div>