"""
To-Do Widget fuer das Lehrer-Dashboard.

Zeigt eine interaktive To-Do-Liste mit localStorage-Persistierung.
"""


class TodosWidget:
    widget_id = 'todos'
    widget_name = 'To-Dos'
    widget_icon = '✓'  # Checkmark
    widget_color = '#10b981'  # Green
    default_width = 'half'
    has_settings = True

    @staticmethod
    def get_css() -> str:
        return """
/* ===== To-Do Widget Styles ===== */
.widget-todos {
    background: var(--bp-surface, #1e293b);
    border: 1px solid var(--bp-border, #475569);
    border-radius: 12px;
    padding: 16px;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.widget-todos .widget-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--bp-border-subtle, rgba(255,255,255,0.1));
}

.widget-todos .widget-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--bp-text, #e5e7eb);
}

.widget-todos .widget-icon {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(16, 185, 129, 0.15);
    color: #10b981;
    border-radius: 8px;
    font-size: 14px;
}

.widget-todos .todo-list {
    flex: 1;
    overflow-y: auto;
    margin-bottom: 12px;
}

.widget-todos .todo-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    border-bottom: 1px solid var(--bp-border-subtle, rgba(255,255,255,0.05));
    transition: background 0.2s;
}

.widget-todos .todo-item:last-child {
    border-bottom: none;
}

.widget-todos .todo-item:hover {
    background: var(--bp-surface-elevated, #334155);
    margin: 0 -8px;
    padding: 10px 8px;
    border-radius: 6px;
}

.widget-todos .todo-checkbox {
    width: 18px;
    height: 18px;
    border: 2px solid var(--bp-border, #475569);
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    flex-shrink: 0;
}

.widget-todos .todo-checkbox:hover {
    border-color: #10b981;
}

.widget-todos .todo-checkbox.checked {
    background: #10b981;
    border-color: #10b981;
}

.widget-todos .todo-checkbox.checked::after {
    content: '\\2713';
    color: white;
    font-size: 12px;
    font-weight: bold;
}

.widget-todos .todo-text {
    flex: 1;
    font-size: 13px;
    color: var(--bp-text, #e5e7eb);
    line-height: 1.4;
}

.widget-todos .todo-item.completed .todo-text {
    text-decoration: line-through;
    color: var(--bp-text-muted, #9ca3af);
}

.widget-todos .todo-delete {
    opacity: 0;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 14px;
}

.widget-todos .todo-item:hover .todo-delete {
    opacity: 1;
}

.widget-todos .todo-delete:hover {
    background: rgba(239, 68, 68, 0.2);
}

.widget-todos .todo-add {
    display: flex;
    gap: 8px;
}

.widget-todos .todo-input {
    flex: 1;
    background: var(--bp-bg, #0f172a);
    border: 1px solid var(--bp-border, #475569);
    border-radius: 6px;
    padding: 8px 12px;
    font-size: 13px;
    color: var(--bp-text, #e5e7eb);
    outline: none;
    transition: border-color 0.2s;
}

.widget-todos .todo-input:focus {
    border-color: #10b981;
}

.widget-todos .todo-input::placeholder {
    color: var(--bp-text-muted, #9ca3af);
}

.widget-todos .todo-add-btn {
    background: #10b981;
    color: white;
    border: none;
    border-radius: 6px;
    padding: 8px 14px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

.widget-todos .todo-add-btn:hover {
    background: #059669;
}

.widget-todos .todo-empty {
    text-align: center;
    padding: 24px;
    color: var(--bp-text-muted, #9ca3af);
    font-size: 13px;
}

.widget-todos .todo-empty-icon {
    font-size: 32px;
    margin-bottom: 8px;
    opacity: 0.5;
}
"""

    @staticmethod
    def get_html() -> str:
        return """
<div class="widget-todos" data-widget-id="todos">
    <div class="widget-header">
        <div class="widget-title">
            <span class="widget-icon">&#10003;</span>
            <span>Meine To-Dos</span>
        </div>
        <button class="widget-settings-btn" onclick="openWidgetSettings('todos')" title="Einstellungen">&#9881;</button>
    </div>
    <div class="todo-list" id="todo-list">
        <div class="todo-empty">
            <div class="todo-empty-icon">&#128221;</div>
            <div>Keine Aufgaben vorhanden</div>
        </div>
    </div>
    <div class="todo-add">
        <input type="text" class="todo-input" id="todo-input" placeholder="Neue Aufgabe..." onkeypress="if(event.key==='Enter')addTodo()">
        <button class="todo-add-btn" onclick="addTodo()">+ Hinzufuegen</button>
    </div>
</div>
"""

    @staticmethod
    def get_js() -> str:
        return """
// ===== To-Do Widget JavaScript =====
const TODOS_STORAGE_KEY = 'bp-lehrer-todos';

function loadTodos() {
    const stored = localStorage.getItem(TODOS_STORAGE_KEY);
    return stored ? JSON.parse(stored) : [];
}

function saveTodos(todos) {
    localStorage.setItem(TODOS_STORAGE_KEY, JSON.stringify(todos));
}

function renderTodos() {
    const todoList = document.getElementById('todo-list');
    if (!todoList) return;

    const todos = loadTodos();

    if (todos.length === 0) {
        todoList.innerHTML = `
            <div class="todo-empty">
                <div class="todo-empty-icon">&#128221;</div>
                <div>Keine Aufgaben vorhanden</div>
            </div>
        `;
        return;
    }

    todoList.innerHTML = todos.map((todo, index) => `
        <div class="todo-item ${todo.completed ? 'completed' : ''}" data-index="${index}">
            <div class="todo-checkbox ${todo.completed ? 'checked' : ''}" onclick="toggleTodo(${index})"></div>
            <span class="todo-text">${escapeHtml(todo.text)}</span>
            <button class="todo-delete" onclick="deleteTodo(${index})" title="Loeschen">&#10005;</button>
        </div>
    `).join('');
}

function addTodo() {
    const input = document.getElementById('todo-input');
    if (!input) return;

    const text = input.value.trim();
    if (!text) return;

    const todos = loadTodos();
    todos.unshift({
        id: Date.now(),
        text: text,
        completed: false,
        createdAt: new Date().toISOString()
    });

    saveTodos(todos);
    renderTodos();
    input.value = '';
}

function toggleTodo(index) {
    const todos = loadTodos();
    if (todos[index]) {
        todos[index].completed = !todos[index].completed;
        saveTodos(todos);
        renderTodos();
    }
}

function deleteTodo(index) {
    const todos = loadTodos();
    todos.splice(index, 1);
    saveTodos(todos);
    renderTodos();
}

function escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

// Initialize todos when widget is rendered
function initTodosWidget() {
    renderTodos();
}
"""