// =======================================================================
// Notes Application - UI & Utilities Module (Native ES Module)
// =======================================================================

export function escapeHtml(str) {
    if (!str) return '';
    return String(str)
        .replace(/&/g, '&')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/"/g, '&quot;')
        .replace(/'/g, '&#039;');
}

export function escapeRegex(string) {
    return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

export function slugify(text) {
    if (!text) return 'book';
    return text.toString().toLowerCase().trim()
        .replace(/[^\w\s-]/g, '')
        .replace(/[\s_-]+/g, '-')
        .replace(/^-+|-+$/g, '');
}

export function shuffleArray(array) {
    const arr = [...array];
    for (let i = arr.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [arr[i], arr[j]] = [arr[j], arr[i]];
    }
    return arr;
}

// -----------------------------------------------------------------------
// Toast Notifications
// -----------------------------------------------------------------------
export function showToast(message, type = 'info') {
    let toastContainer = document.getElementById('notes-toast-container');
    if (!toastContainer) {
        toastContainer = document.createElement('div');
        toastContainer.id = 'notes-toast-container';
        toastContainer.style.cssText = `
            position: fixed;
            bottom: 24px;
            right: 24px;
            z-index: 10000;
            display: flex;
            flex-direction: column;
            gap: 8px;
            pointer-events: none;
        `;
        document.body.appendChild(toastContainer);
    }

    const toast = document.createElement('div');
    const colors = {
        success: '#10b981',
        error: '#ef4444',
        warning: '#f59e0b',
        info: '#3b82f6'
    };
    const bg = colors[type] || colors.info;

    toast.style.cssText = `
        background: ${bg};
        color: #ffffff;
        padding: 10px 18px;
        border-radius: 8px;
        font-size: 14px;
        font-weight: 500;
        box-shadow: 0 4px 14px rgba(0,0,0,0.25);
        opacity: 0;
        transform: translateY(12px);
        transition: all 0.25s ease;
        pointer-events: auto;
        max-width: 340px;
    `;
    toast.textContent = message;
    toastContainer.appendChild(toast);

    requestAnimationFrame(() => {
        toast.style.opacity = '1';
        toast.style.transform = 'translateY(0)';
    });

    setTimeout(() => {
        toast.style.opacity = '0';
        toast.style.transform = 'translateY(12px)';
        setTimeout(() => toast.remove(), 250);
    }, 3500);
}

// -----------------------------------------------------------------------
// Theme Management
// -----------------------------------------------------------------------
export function initTheme() {
    const themeToggle = document.getElementById('theme-toggle');
    const mobileThemeBtn = document.getElementById('mobile-theme-btn');
    const savedTheme = localStorage.getItem('notes_theme') || 'dark';
    document.documentElement.setAttribute('data-theme', savedTheme);

    function toggle() {
        const current = document.documentElement.getAttribute('data-theme');
        const next = current === 'dark' ? 'light' : 'dark';
        document.documentElement.setAttribute('data-theme', next);
        localStorage.setItem('notes_theme', next);
    }

    if (themeToggle) {
        themeToggle.addEventListener('click', toggle);
    }
    if (mobileThemeBtn) {
        mobileThemeBtn.addEventListener('click', () => {
            toggle();
            showToast(`Тема переключена`, 'info');
        });
    }
}

// -----------------------------------------------------------------------
// Modal Open / Close Helpers
// -----------------------------------------------------------------------
export function openModal(modalElem) {
    if (!modalElem) return;
    modalElem.classList.remove('hidden');
}

export function closeModal(modalElem) {
    if (!modalElem) return;
    modalElem.classList.add('hidden');
}

// -----------------------------------------------------------------------
// Header Stat Counters
// -----------------------------------------------------------------------
export function updateHeaderStats(total = 0, today = 0, srsCount = 0) {
    const statTotal = document.getElementById('stat-total');
    const statToday = document.getElementById('stat-today');
    const srsBadge = document.getElementById('srs-badge');
    const tabSrsBadge = document.getElementById('tab-srs-badge');
    const drawerSrsBadge = document.getElementById('drawer-srs-badge');
    const drawerStatTotal = document.getElementById('drawer-stat-total');
    const drawerStatToday = document.getElementById('drawer-stat-today');
    const drawerStatDue = document.getElementById('drawer-stat-due');

    const formattedToday = today > 0 ? `+${today}` : today;

    if (statTotal) statTotal.textContent = total;
    if (statToday) statToday.textContent = formattedToday;
    if (drawerStatTotal) drawerStatTotal.textContent = total;
    if (drawerStatToday) drawerStatToday.textContent = formattedToday;
    if (drawerStatDue) drawerStatDue.textContent = srsCount;

    if (srsBadge) {
        srsBadge.textContent = srsCount;
        srsBadge.style.display = srsCount > 0 ? 'inline-block' : 'none';
    }
    if (tabSrsBadge) {
        tabSrsBadge.textContent = srsCount;
        tabSrsBadge.classList.toggle('hidden', srsCount === 0);
    }
    if (drawerSrsBadge) {
        drawerSrsBadge.textContent = srsCount;
        drawerSrsBadge.classList.toggle('hidden', srsCount === 0);
    }
}

// -----------------------------------------------------------------------
// Audio Player Helper (Safe stub / audio stream)
// -----------------------------------------------------------------------
export function playAudio(url) {
    if (!url) return;
    try {
        const audio = new Audio(url);
        audio.play().catch(e => console.warn('Audio playback not supported or blocked:', e));
    } catch (e) {
        console.warn('Audio play error:', e);
    }
}