solution

src/App.tsx

@@ -1,156 +1,40 @@
 /* eslint-disable jsx-a11y/control-has-associated-label */
-import React from 'react';
+// #region imports
+import React, { useContext, useState } from 'react';
+import { Footer } from './components/Footer';
+import { Header } from './components/Header';
+import { TodoList } from './components/TodoList';
+import { TodosContext } from './components/TodosContext';
+import { getFilteredTodos } from './services/getFilteredTodos';
+import { FilterStatus } from './types/FilterStatus';
+// #endregion
 
 export const App: React.FC = () => {
+  const { todos } = useContext(TodosContext);
+  const sortedTodos = {
+    active: todos.filter(({ completed }) => !completed),
+    completed: todos.filter(({ completed }) => completed),
+  };
+  const [filterStatus, setFilterStatus] = useState(FilterStatus.All);
+
+  const filteredTodos = getFilteredTodos(todos, sortedTodos, filterStatus);
+
   return (
     <div className="todoapp">
       <h1 className="todoapp__title">todos</h1>
 
       <div className="todoapp__content">
-        <header className="todoapp__header">
-          {/* this button should have `active` class only if all todos are completed */}
-          <button
-            type="button"
-            className="todoapp__toggle-all active"
-            data-cy="ToggleAllButton"
-          />
-
-          {/* Add a todo on form submit */}
-          <form>
-            <input
-              data-cy="NewTodoField"
-              type="text"
-              className="todoapp__new-todo"
-              placeholder="What needs to be done?"
-            />
-          </form>
-        </header>
-
-        <section className="todoapp__main" data-cy="TodoList">
-          {/* This is a completed todo */}
-          <div data-cy="Todo" className="todo completed">
-            <label className="todo__status-label">
-              <input
-                data-cy="TodoStatus"
-                type="checkbox"
-                className="todo__status"
-                checked
-              />
-            </label>
-
-            <span data-cy="TodoTitle" className="todo__title">
-              Completed Todo
-            </span>
-
-            {/* Remove button appears only on hover */}
-            <button type="button" className="todo__remove" data-cy="TodoDelete">
-              ×
-            </button>
-          </div>
-
-          {/* This todo is an active todo */}
-          <div data-cy="Todo" className="todo">
-            <label className="todo__status-label">
-              <input
-                data-cy="TodoStatus"
-                type="checkbox"
-                className="todo__status"
-              />
-            </label>
-
-            <span data-cy="TodoTitle" className="todo__title">
-              Not Completed Todo
-            </span>
-
-            <button type="button" className="todo__remove" data-cy="TodoDelete">
-              ×
-            </button>
-          </div>
+        <Header />
 
-          {/* This todo is being edited */}
-          <div data-cy="Todo" className="todo">
-            <label className="todo__status-label">
-              <input
-                data-cy="TodoStatus"
-                type="checkbox"
-                className="todo__status"
-              />
-            </label>
+        <TodoList todos={filteredTodos} />
 
-            {/* This form is shown instead of the title and remove button */}
-            <form>
-              <input
-                data-cy="TodoTitleField"
-                type="text"
-                className="todo__title-field"
-                placeholder="Empty todo will be deleted"
-                value="Todo is being edited now"
-              />
-            </form>
-          </div>
-
-          {/* This todo is in loadind state */}
-          <div data-cy="Todo" className="todo">
-            <label className="todo__status-label">
-              <input
-                data-cy="TodoStatus"
-                type="checkbox"
-                className="todo__status"
-              />
-            </label>
-
-            <span data-cy="TodoTitle" className="todo__title">
-              Todo is being saved now
-            </span>
-
-            <button type="button" className="todo__remove" data-cy="TodoDelete">
-              ×
-            </button>
-          </div>
-        </section>
-
-        {/* Hide the footer if there are no todos */}
-        <footer className="todoapp__footer" data-cy="Footer">
-          <span className="todo-count" data-cy="TodosCounter">
-            3 items left
-          </span>
-
-          {/* Active link should have the 'selected' class */}
-          <nav className="filter" data-cy="Filter">
-            <a
-              href="#/"
-              className="filter__link selected"
-              data-cy="FilterLinkAll"
-            >
-              All
-            </a>
-
-            <a
-              href="#/active"
-              className="filter__link"
-              data-cy="FilterLinkActive"
-            >
-              Active
-            </a>
-
-            <a
-              href="#/completed"
-              className="filter__link"
-              data-cy="FilterLinkCompleted"
-            >
-              Completed
-            </a>
-          </nav>
-
-          {/* this button should be disabled if there are no completed todos */}
-          <button
-            type="button"
-            className="todoapp__clear-completed"
-            data-cy="ClearCompletedButton"
-          >
-            Clear completed
-          </button>
-        </footer>
+        {todos.length > 0 && (
+          <Footer
+            sortedTodos={sortedTodos}
+            filterStatus={filterStatus}
+            onStatusChange={setFilterStatus}
+          />
+        )}
       </div>
     </div>
   );

src/components/Footer.tsx

@@ -0,0 +1,66 @@
+// #region imports
+import cn from 'classnames';
+import { useContext } from 'react';
+import { FilterStatus } from '../types/FilterStatus';
+import { Todo } from '../types/Todo';
+import { TodosContext } from './TodosContext';
+// #endregion
+
+type Props = {
+  sortedTodos: {
+    active: Todo[];
+    completed: Todo[];
+  };
+  filterStatus: FilterStatus;
+  onStatusChange: (status: FilterStatus) => void;
+};
+
+export const Footer: React.FC<Props> = ({
+  sortedTodos,
+  filterStatus,
+  onStatusChange,
+}) => {
+  const { changeTodos } = useContext(TodosContext);
+  const { active, completed } = sortedTodos;
+  const filterLinks: {
+    [key: string]: string;
+  } = {
+    All: '#/',
+    Active: '#/active',
+    Completed: '#/completed',
+  };
+
+  return (
+    <footer className="todoapp__footer" data-cy="Footer">
+      <span className="todo-count" data-cy="TodosCounter">
+        {`${active.length} items left`}
+      </span>
+
+      <nav className="filter" data-cy="Filter">
+        {Object.values(FilterStatus).map(status => (
+          <a
+            key={status}
+            href={filterLinks[status]}
+            className={cn('filter__link', {
+              selected: status === filterStatus,
+            })}
+            data-cy={`FilterLink${status}`}
+            onClick={() => onStatusChange(status)}
+          >
+            {status}
+          </a>
+        ))}
+      </nav>
+
+      <button
+        type="button"
+        className="todoapp__clear-completed"
+        data-cy="ClearCompletedButton"
+        disabled={!completed.length}
+        onClick={() => changeTodos(active)}
+      >
+        Clear completed
+      </button>
+    </footer>
+  );
+};

src/components/Header.tsx

@@ -0,0 +1,84 @@
+// #region imports
+import classNames from 'classnames';
+import {
+  FormEvent,
+  memo,
+  useContext,
+  useEffect,
+  useRef,
+  useState,
+} from 'react';
+import { TodosContext } from './TodosContext';
+// #endregion
+
+export const Header = memo(function Header() {
+  // #region hooks
+  const { todos, changeTodos } = useContext(TodosContext);
+  const [newTitle, setNewTitle] = useState('');
+  const titleInput = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    titleInput.current?.focus();
+  });
+  // #endregion
+
+  const areTodosCompleted = todos.every(todo => todo.completed);
+
+  // #region handlings
+  const handleTodosToggle = () => {
+    changeTodos(
+      todos.map(todo => ({
+        ...todo,
+        completed: !areTodosCompleted,
+      })),
+    );
+  };
+
+  const handleSubmit = (e: FormEvent) => {
+    e.preventDefault();
+
+    const trimmedTitle = newTitle.trim();
+
+    if (!trimmedTitle) {
+      return;
+    }
+
+    changeTodos([
+      ...todos,
+      {
+        id: +new Date(),
+        title: trimmedTitle,
+        completed: false,
+      },
+    ]);
+    setNewTitle('');
+  };
+  // #endregion
+
+  return (
+    <header className="todoapp__header">
+      {todos.length > 0 && (
+        <button
+          type="button"
+          className={classNames('todoapp__toggle-all', {
+            active: areTodosCompleted,
+          })}
+          onClick={handleTodosToggle}
+          data-cy="ToggleAllButton"
+        />
+      )}
+
+      <form onSubmit={handleSubmit}>
+        <input
+          ref={titleInput}
+          data-cy="NewTodoField"
+          type="text"
+          className="todoapp__new-todo"
+          placeholder="What needs to be done?"
+          value={newTitle}
+          onChange={e => setNewTitle(e.target.value)}
+        />
+      </form>
+    </header>
+  );
+});