Solution

src/App.tsx

@@ -1,157 +1,13 @@
-/* eslint-disable jsx-a11y/control-has-associated-label */
 import React from 'react';
+import { Content } from './components/Content';
+import { TodosProvider } from './context/TodosContex';
 
 export const App: React.FC = () => {
   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>
-
-          {/* 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>
-
-            {/* 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>
-      </div>
+      <TodosProvider>
+        <Content />
+      </TodosProvider>
     </div>
   );
 };

src/components/Content.tsx

@@ -0,0 +1,46 @@
+import React, { useContext, useEffect, useState } from 'react';
+import { Header } from './Header';
+import { TodoList } from './TodoList';
+import { Footer } from './Footer';
+import { TodosContext } from '../context/TodosContex';
+
+export const Content: React.FC = () => {
+  const { todos, setTodos } = useContext(TodosContext);
+
+  const [visibleTodos, setVisibleTodos] = useState(todos);
+
+  useEffect(() => {
+    localStorage.setItem('todos', JSON.stringify(todos));
+  }, [todos]);
+
+  const savedTodos = localStorage.getItem('todos');
+
+  useEffect(() => {
+    if (savedTodos) {
+      setTodos(JSON.parse(savedTodos));
+    }
+  }, []);
+
+  useEffect(() => {
+    setVisibleTodos(todos);
+  }, [todos]);
+
+  return (
+    <>
+      <h1 className="todoapp__title">todos</h1>
+
+      <div className="todoapp__content">
+        <Header />
+
+        <TodoList visibleTodos={visibleTodos} />
+
+        {todos.length > 0 && (
+          <Footer
+            visibleTodos={visibleTodos}
+            setVisibleTodos={setVisibleTodos}
+          />
+        )}
+      </div>
+    </>
+  );
+};

src/components/Footer.tsx

@@ -0,0 +1,100 @@
+import React, { useCallback, useContext, useEffect, useState } from 'react';
+import { Filter } from '../types/Filter';
+import classNames from 'classnames';
+import { TodosContext } from '../context/TodosContex';
+import { Todo } from '../types/Todo';
+
+type Props = {
+  visibleTodos: Todo[];
+  setVisibleTodos: (vilteredTodos: Todo[]) => void;
+};
+
+export const Footer: React.FC<Props> = ({ visibleTodos, setVisibleTodos }) => {
+  const { todos, setTodos } = useContext(TodosContext);
+
+  const [selectedFilter, setSelectedFilter] = useState<Filter>(Filter.All);
+
+  const findFilterKey = (value: string): string | undefined => {
+    return Object.keys(Filter).find(
+      key => Filter[key as keyof typeof Filter] === value,
+    );
+  };
+
+  const todosCount = useCallback(
+    (type: Filter.Active | Filter.Completed) => {
+      const value = type === Filter.Active ? false : true;
+
+      return todos.filter(todo => todo.completed === value).length;
+    },
+    [todos],
+  );
+
+  const filterFunction = (filter: Filter) => {
+    switch (filter) {
+      case Filter.All:
+        setVisibleTodos(todos);
+        break;
+
+      case Filter.Active:
+        setVisibleTodos(todos.filter(todo => !todo.completed));
+        break;
+
+      case Filter.Completed:
+        setVisibleTodos(todos.filter(todo => todo.completed));
+        break;
+
+      default:
+        setTodos(todos);
+    }
+  };
+
+  const clearFunction = () => {
+    setTodos(todos.filter(t => !t.completed));
+  };
+
+  const setFilter = (filter: Filter) => {
+    setSelectedFilter(filter);
+
+    filterFunction(filter);
+  };
+
+  useEffect(() => {
+    if (selectedFilter) {
+      filterFunction(selectedFilter);
+    }
+  }, [visibleTodos]);
+
+  return (
+    <footer className="todoapp__footer" data-cy="Footer">
+      <span className="todo-count" data-cy="TodosCounter">
+        {todosCount(Filter.Active)} items left
+      </span>
+
+      <nav className="filter" data-cy="Filter">
+        {Object.values(Filter).map(filter => (
+          <a
+            key={filter}
+            href={`#/${filter}`}
+            className={classNames('filter__link', {
+              selected: selectedFilter === filter,
+            })}
+            onClick={() => setFilter(filter)}
+            data-cy={`FilterLink${findFilterKey(filter)}`}
+          >
+            {findFilterKey(filter)}
+          </a>
+        ))}
+      </nav>
+
+      <button
+        type="button"
+        className="todoapp__clear-completed"
+        data-cy="ClearCompletedButton"
+        disabled={todosCount(Filter.Completed) === 0}
+        onClick={() => clearFunction()}
+      >
+        Clear completed
+      </button>
+    </footer>
+  );
+};

src/components/Header.tsx

@@ -0,0 +1,83 @@
+import React, { useContext, useEffect, useRef, useState } from 'react';
+import { TodosContext } from '../context/TodosContex';
+import classNames from 'classnames';
+import { Todo } from '../types/Todo';
+
+export const Header: React.FC = () => {
+  const { todos, setTodos } = useContext(TodosContext);
+
+  const [title, setTitle] = useState('');
+
+  const inputRef = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    if (inputRef.current) {
+      inputRef.current.focus();
+    }
+  }, [todos]);
+
+  const checkActiveTodos = (): boolean => {
+    if (todos.length > 0) {
+      return todos.every(todo => todo.completed);
+    }
+
+    return false;
+  };
+
+  const onSubmit = (event: React.FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+
+    const normalizedTitle = title.trim();
+
+    if (!normalizedTitle) {
+      return;
+    }
+
+    const newTodo: Todo = {
+      id: +new Date(),
+      title: normalizedTitle,
+      completed: false,
+    };
+
+    setTodos([...todos, newTodo]);
+    setTitle('');
+  };
+
+  const toggleAll = () => {
+    const allCompleted = checkActiveTodos();
+
+    const toggledTodos = todos.map(todo => ({
+      ...todo,
+      completed: allCompleted ? false : true,
+    }));
+
+    setTodos(toggledTodos);
+  };
+
+  return (
+    <header className="todoapp__header">
+      {todos.length > 0 && (
+        <button
+          type="button"
+          className={classNames('todoapp__toggle-all', {
+            active: checkActiveTodos(),
+          })}
+          onClick={toggleAll}
+          data-cy="ToggleAllButton"
+        />
+      )}
+
+      <form onSubmit={event => onSubmit(event)}>
+        <input
+          data-cy="NewTodoField"
+          ref={inputRef}
+          value={title}
+          onChange={event => setTitle(event.target.value)}
+          type="text"
+          className="todoapp__new-todo"
+          placeholder="What needs to be done?"
+        />
+      </form>
+    </header>
+  );
+};