/**
 * Internationalization (i18n) support for the application
 */

// Global translations object
let currentTranslations = {};
let currentLanguage = 'sl';

/**
 * Initialize i18n system
 */
async function initI18n() {
    try {
        const response = await fetch('/api/language');
        if (response.ok) {
            const data = await response.json();
            currentTranslations = data.translations;
            currentLanguage = data.current_language;

            // Update language selector if it exists
            updateLanguageSelector();

            // Translate the page
            translatePage();

            // Signal that translations are ready
            window.dispatchEvent(new Event('i18nReady'));
        }
    } catch (error) {
        console.error('Failed to initialize i18n:', error);
        // Even on error, signal ready so page doesn't get stuck
        window.dispatchEvent(new Event('i18nReady'));
    }
}

/**
 * Get translation for a key with dot notation
 * @param {string} key - Translation key (e.g., 'general.save')
 * @param {object} params - Optional parameters for string interpolation
 * @returns {string} Translated text or key if not found
 */
function t(key, params = {}) {
    const keys = key.split('.');
    let value = currentTranslations;

    for (const k of keys) {
        if (value && typeof value === 'object' && k in value) {
            value = value[k];
        } else {
            console.warn(`Translation key not found: ${key}`);
            return key; // Return key if translation not found
        }
    }

    if (typeof value !== 'string') {
        console.warn(`Translation value is not a string: ${key}`);
        return key;
    }

    // Simple string interpolation
    let result = value;
    for (const [param, replacement] of Object.entries(params)) {
        result = result.replace(new RegExp(`\\{${param}\\}`, 'g'), replacement);
    }

    return result;
}

/**
 * Change application language
 * @param {string} language - Language code (e.g., 'sl', 'en')
 */
async function changeLanguage(language) {
    try {
        const response = await fetch(`/api/language/${language}`, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            }
        });

        if (response.ok) {
            const data = await response.json();
            currentTranslations = data.translations;
            currentLanguage = language;

            // Update UI
            updateLanguageSelector();
            translatePage();
        } else {
            throw new Error('Failed to change language');
        }
    } catch (error) {
        console.error('Error changing language:', error);
        showNotification(t('messages.error'), 'error');
    }
}

/**
 * Update language selector UI
 */
function updateLanguageSelector() {
    const selector = document.getElementById('languageSelector');
    if (selector) {
        selector.value = currentLanguage;
    }

    // Update flag if exists
    const flag = document.getElementById('languageFlag');
    if (flag) {
        flag.textContent = currentLanguage === 'sl' ? '🇸🇮' : '🇬🇧';
    }
}

/**
 * Translate all elements with data-i18n attribute
 */
function translatePage() {
    // Translate elements with data-i18n attribute
    const elements = document.querySelectorAll('[data-i18n]');
    elements.forEach(element => {
        const key = element.getAttribute('data-i18n');
        if (key) {
            element.textContent = t(key);
        }
    });

    // Translate placeholders
    const placeholderElements = document.querySelectorAll('[data-i18n-placeholder]');
    placeholderElements.forEach(element => {
        const key = element.getAttribute('data-i18n-placeholder');
        if (key) {
            element.placeholder = t(key);
        }
    });

    // Translate titles/tooltips
    const titleElements = document.querySelectorAll('[data-i18n-title]');
    titleElements.forEach(element => {
        const key = element.getAttribute('data-i18n-title');
        if (key) {
            element.title = t(key);
        }
    });

    // Translate aria-labels
    const ariaElements = document.querySelectorAll('[data-i18n-aria]');
    ariaElements.forEach(element => {
        const key = element.getAttribute('data-i18n-aria');
        if (key) {
            element.setAttribute('aria-label', t(key));
        }
    });

    // Translate tooltips
    const tooltipElements = document.querySelectorAll('[data-i18n-tooltip]');
    tooltipElements.forEach(element => {
        const key = element.getAttribute('data-i18n-tooltip');
        if (key) {
            element.setAttribute('data-tooltip', t(key));
        }
    });
}

/**
 * Show notification message
 */
function showNotification(message, type = 'info') {
    // Create notification element if it doesn't exist
    let notification = document.getElementById('i18nNotification');
    if (!notification) {
        notification = document.createElement('div');
        notification.id = 'i18nNotification';
        notification.style.cssText = `
            position: fixed;
            top: 20px;
            right: 20px;
            padding: 12px 20px;
            border-radius: 8px;
            color: white;
            font-weight: bold;
            z-index: 10000;
            transition: all 0.3s ease;
            transform: translateX(100%);
        `;
        document.body.appendChild(notification);
    }

    // Set color based on type
    const colors = {
        success: '#28a745',
        error: '#dc3545',
        warning: '#ffc107',
        info: '#007bff'
    };

    notification.style.backgroundColor = colors[type] || colors.info;
    notification.textContent = message;
    notification.style.transform = 'translateX(0)';

    // Hide after 3 seconds
    setTimeout(() => {
        notification.style.transform = 'translateX(100%)';
    }, 3000);
}

/**
 * Create language selector dropdown
 */
function createLanguageSelector(containerId) {
    const container = document.getElementById(containerId);
    if (!container) return;

    const selector = document.createElement('select');
    selector.id = 'languageSelector';
    selector.style.cssText = `
        width: 100%;
        padding: 14px 18px;
        border: 2px solid #dee2e6;
        border-radius: 10px;
        background: white;
        color: #495057;
        font-size: 0.95rem;
        font-weight: 500;
        cursor: pointer;
        transition: all 0.3s ease;
        box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1);
        margin-bottom: 12px;
    `;

    // Add options
    const languages = [
        { code: 'sl', name: '🇸🇮 Slovenščina', flag: '🇸🇮' },
        { code: 'en', name: '🇬🇧 English', flag: '🇬🇧' }
    ];

    languages.forEach(lang => {
        const option = document.createElement('option');
        option.value = lang.code;
        option.textContent = lang.name;
        selector.appendChild(option);
    });

    selector.value = currentLanguage;

    // Add event listeners
    selector.addEventListener('change', (e) => {
        changeLanguage(e.target.value);
    });

    // Add hover effects to match nav-link styling
    selector.addEventListener('mouseenter', () => {
        selector.style.background = '#f8f9fa';
        selector.style.borderColor = '#007bff';
        selector.style.color = '#007bff';
        selector.style.transform = 'translateY(-2px)';
        selector.style.boxShadow = '0 5px 12px rgba(0, 123, 255, 0.15)';
    });

    selector.addEventListener('mouseleave', () => {
        selector.style.background = 'white';
        selector.style.borderColor = '#dee2e6';
        selector.style.color = '#495057';
        selector.style.transform = 'translateY(0)';
        selector.style.boxShadow = '0 3px 6px rgba(0, 0, 0, 0.1)';
    });

    container.appendChild(selector);
}

// Initialize when DOM is loaded
document.addEventListener('DOMContentLoaded', initI18n);

// Export functions for global use
window.t = t;
window.changeLanguage = changeLanguage;
window.createLanguageSelector = createLanguageSelector;

// Export i18n object with useful functions
window.i18n = {
    t: t,
    updatePageTranslations: translatePage,
    changeLanguage: changeLanguage
};