Initial.html

<!DOCTYPE html>
<html lang="ru">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Электронный журнал студентов</title>
    <style>
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body {
            font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
            background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
            color: #e8e8e8;
            min-height: 100vh;
            padding: 20px;
        }

        .container {
            max-width: 900px;
            margin: 0 auto;
        }

        h1 {
            text-align: center;
            margin-bottom: 10px;
            color: #e94560;
            font-size: 1.8rem;
        }

        .subtitle {
            text-align: center;
            color: #a0a0a0;
            margin-bottom: 30px;
            font-size: 0.95rem;
        }

        .card {
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.1);
            border-radius: 12px;
            padding: 20px;
            margin-bottom: 20px;
            backdrop-filter: blur(10px);
        }

        .card h2 {
            font-size: 1.2rem;
            margin-bottom: 15px;
            color: #e94560;
            border-bottom: 1px solid rgba(233, 69, 96, 0.3);
            padding-bottom: 8px;
        }

        .form-row {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
            margin-bottom: 12px;
            align-items: center;
        }

        input[type="text"],
        input[type="number"] {
            padding: 10px 14px;
            border: 1px solid rgba(255, 255, 255, 0.2);
            border-radius: 8px;
            background: rgba(0, 0, 0, 0.3);
            color: #fff;
            font-size: 0.95rem;
            outline: none;
            transition: border-color 0.2s;
        }

        input:focus {
            border-color: #e94560;
        }

        button {
            padding: 10px 18px;
            border: none;
            border-radius: 8px;
            background: #e94560;
            color: white;
            font-size: 0.95rem;
            cursor: pointer;
            transition: background 0.2s, transform 0.1s;
        }

        button:hover {
            background: #ff6b81;
        }

        button:active {
            transform: scale(0.97);
        }

        button.secondary {
            background: #0f3460;
        }

        button.secondary:hover {
            background: #1a4a7a;
        }

        button.danger {
            background: #c0392b;
        }

        button.danger:hover {
            background: #e74c3c;
        }

        table {
            width: 100%;
            border-collapse: collapse;
            margin-top: 10px;
        }

        th, td {
            padding: 12px 10px;
            text-align: left;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }

        th {
            color: #e94560;
            font-weight: 600;
            font-size: 0.9rem;
        }

        tr:hover {
            background: rgba(255, 255, 255, 0.03);
        }

        .stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
            gap: 15px;
        }

        .stat-box {
            background: rgba(0, 0, 0, 0.25);
            border-radius: 10px;
            padding: 15px;
            text-align: center;
        }

        .stat-box .value {
            font-size: 1.5rem;
            font-weight: 700;
            color: #e94560;
            margin: 5px 0;
        }

        .stat-box .label {
            font-size: 0.85rem;
            color: #a0a0a0;
        }

        .empty {
            text-align: center;
            color: #888;
            padding: 30px;
        }

        .message {
            margin-top: 10px;
            padding: 10px 14px;
            border-radius: 8px;
            font-size: 0.9rem;
            display: none;
        }

        .message.success {
            background: rgba(46, 204, 113, 0.15);
            border: 1px solid rgba(46, 204, 113, 0.4);
            color: #2ecc71;
            display: block;
        }

        .message.error {
            background: rgba(231, 76, 60, 0.15);
            border: 1px solid rgba(231, 76, 60, 0.4);
            color: #e74c3c;
            display: block;
        }

        .actions {
            display: flex;
            gap: 8px;
        }

        .actions button {
            padding: 6px 12px;
            font-size: 0.85rem;
        }

        @media (max-width: 600px) {
            .form-row {
                flex-direction: column;
                align-items: stretch;
            }
            input, button {
                width: 100%;
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <h1>Электронный журнал студентов</h1>
        <p class="subtitle">Простой веб-вариант программы</p>

        <!-- Добавление студента -->
        <div class="card">
            <h2>Добавить студента</h2>
            <div class="form-row">
                <input type="text" id="studentName" placeholder="Имя студента" style="flex: 1;">
                <button onclick="addStudent()">Добавить</button>
            </div>
            <div id="msgAdd" class="message"></div>
        </div>

        <!-- Добавление оценки -->
        <div class="card">
            <h2>Добавить оценку</h2>
            <div class="form-row">
                <input type="number" id="gradeId" placeholder="ID студента" style="width: 140px;">
                <input type="number" id="gradeValue" placeholder="Оценка (0-100)" min="0" max="100" step="0.1" style="width: 160px;">
                <button onclick="addGrade()">Выставить</button>
            </div>
            <div id="msgGrade" class="message"></div>
        </div>

        <!-- Статистика -->
        <div class="card">
            <h2>Статистика</h2>
            <div class="stats" id="stats">
                <div class="stat-box">
                    <div class="label">Всего студентов</div>
                    <div class="value" id="statTotal">0</div>
                </div>
                <div class="stat-box">
                    <div class="label">Средний балл группы</div>
                    <div class="value" id="statAvg">—</div>
                </div>
                <div class="stat-box">
                    <div class="label">Лучший студент</div>
                    <div class="value" id="statTop" style="font-size: 1.1rem;">—</div>
                </div>
                <div class="stat-box">
                    <div class="label">Самый низкий балл</div>
                    <div class="value" id="statBottom" style="font-size: 1.1rem;">—</div>
                </div>
            </div>
        </div>

        <!-- Список студентов -->
        <div class="card">
            <h2>Список студентов</h2>
            <div id="studentList">
                <div class="empty">Список пуст</div>
            </div>
        </div>
    </div>

    <script>
        class Student {
            constructor(name, id) {
                this.name = name;
                this.id = id;
                this.grades = [];
            }

            addGrade(grade) {
                if (grade >= 0 && grade <= 100) {
                    this.grades.push(grade);
                    return true;
                }
                return false;
            }

            getAverage() {
                if (this.grades.length === 0) return 0;
                return this.grades.reduce((a, b) => a + b, 0) / this.grades.length;
            }
        }

        class GradeBook {
            constructor() {
                this.students = [];
                this.nextId = 1001;
            }

            addStudent(name) {
                const student = new Student(name, this.nextId);
                this.students.push(student);
                this.nextId++;
                return student;
            }

            findStudent(id) {
                return this.students.find(s => s.id === id) || null;
            }

            removeStudent(id) {
                const index = this.students.findIndex(s => s.id === id);
                if (index !== -1) {
                    this.students.splice(index, 1);
                    return true;
                }
                return false;
            }

            getStatistics() {
                const withGrades = this.students.filter(s => s.grades.length > 0);
                if (withGrades.length === 0) {
                    return {
                        total: this.students.length,
                        avg: null,
                        top: null,
                        bottom: null
                    };
                }

                let totalAvg = 0;
                let maxAvg = -1;
                let minAvg = 101;
                let topStudent = null;
                let bottomStudent = null;

                for (const s of withGrades) {
                    const avg = s.getAverage();
                    totalAvg += avg;
                    if (avg > maxAvg) {
                        maxAvg = avg;
                        topStudent = s;
                    }
                    if (avg < minAvg) {
                        minAvg = avg;
                        bottomStudent = s;
                    }
                }

                return {
                    total: this.students.length,
                    avg: totalAvg / withGrades.length,
                    top: topStudent,
                    bottom: bottomStudent
                };
            }
        }

        const book = new GradeBook();

        // Тестовые данные
        book.addStudent("Иван Петров");
        book.addStudent("Анна Сидорова");
        book.addStudent("Алексей Козлов");
        book.findStudent(1001).addGrade(85.5);
        book.findStudent(1001).addGrade(90.0);
        book.findStudent(1002).addGrade(78.0);
        book.findStudent(1002).addGrade(82.5);
        book.findStudent(1002).addGrade(91.0);
        book.findStudent(1003).addGrade(95.0);

        function showMessage(elementId, text, isError = false) {
            const el = document.getElementById(elementId);
            el.textContent = text;
            el.className = 'message ' + (isError ? 'error' : 'success');
            setTimeout(() => {
                el.className = 'message';
                el.textContent = '';
            }, 3000);
        }

        function addStudent() {
            const input = document.getElementById('studentName');
            const name = input.value.trim();
            if (!name) {
                showMessage('msgAdd', 'Имя не может быть пустым', true);
                return;
            }
            const s = book.addStudent(name);
            showMessage('msgAdd', `Студент "${name}" добавлен с ID ${s.id}`);
            input.value = '';
            render();
        }

        function addGrade() {
            const id = parseInt(document.getElementById('gradeId').value);
            const grade = parseFloat(document.getElementById('gradeValue').value);

            if (isNaN(id) || isNaN(grade)) {
                showMessage('msgGrade', 'Неверный ввод', true);
                return;
            }

            const s = book.findStudent(id);
            if (!s) {
                showMessage('msgGrade', `Студент с ID ${id} не найден`, true);
                return;
            }

            if (s.addGrade(grade)) {
                showMessage('msgGrade', `Оценка ${grade} добавлена студенту ${s.name}`);
                document.getElementById('gradeId').value = '';
                document.getElementById('gradeValue').value = '';
                render();
            } else {
                showMessage('msgGrade', 'Оценка должна быть от 0 до 100', true);
            }
        }

        function removeStudent(id) {
            if (book.removeStudent(id)) {
                render();
            }
        }

        function render() {
            // Список студентов
            const list = document.getElementById('studentList');
            if (book.students.length === 0) {
                list.innerHTML = '<div class="empty">Список пуст</div>';
            } else {
                let html = `
                    <table>
                        <thead>
                            <tr>
                                <th>ID</th>
                                <th>Имя</th>
                                <th>Средний балл</th>
                                <th>Оценок</th>
                                <th>Оценки</th>
                                <th>Действия</th>
                            </tr>
                        </thead>
                        <tbody>
                `;
                for (const s of book.students) {
                    const avg = s.grades.length ? s.getAverage().toFixed(2) : '—';
                    const gradesStr = s.grades.length ? s.grades.join(', ') : 'нет';
                    html += `
                        <tr>
                            <td>${s.id}</td>
                            <td>${s.name}</td>
                            <td>${avg}</td>
                            <td>${s.grades.length}</td>
                            <td style="font-size: 0.85rem; color: #aaa;">${gradesStr}</td>
                            <td class="actions">
                                <button class="danger" onclick="removeStudent(${s.id})">Удалить</button>
                            </td>
                        </tr>
                    `;
                }
                html += '</tbody></table>';
                list.innerHTML = html;
            }

            // Статистика
            const stats = book.getStatistics();
            document.getElementById('statTotal').textContent = stats.total;
            document.getElementById('statAvg').textContent = stats.avg !== null ? stats.avg.toFixed(2) : '—';
            document.getElementById('statTop').textContent = stats.top 
                ? `${stats.top.name} (${stats.top.getAverage().toFixed(2)})` 
                : '—';
            document.getElementById('statBottom').textContent = stats.bottom 
                ? `${stats.bottom.name} (${stats.bottom.getAverage().toFixed(2)})` 
                : '—';
        }

        // Enter для удобства
        document.getElementById('studentName').addEventListener('keydown', e => {
            if (e.key === 'Enter') addStudent();
        });
        document.getElementById('gradeValue').addEventListener('keydown', e => {
            if (e.key === 'Enter') addGrade();
        });

        // Первоначальный рендер
        render();
    </script>
</body>
</html>