class ThemeManager {
    constructor() {
        this.theme = this.getStoredTheme() || this.getSystemTheme();
        this.init();
    }

    init() {
        this.applyTheme(this.theme);
        this.bindEvents();
    }

    getStoredTheme() {
        return localStorage.getItem('theme');
    }

    getSystemTheme() {
        return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
    }

    applyTheme(theme) {
        document.documentElement.setAttribute('data-theme', theme);
        this.updateThemeIcon(theme);
        localStorage.setItem('theme', theme);
    }

    updateThemeIcon(theme) {
        const themeIcon = document.querySelector('.theme-icon');
        if (themeIcon) {
            themeIcon.textContent = theme === 'dark' ? '☀️' : '🌙';
        }
    }

    toggleTheme() {
        this.theme = this.theme === 'light' ? 'dark' : 'light';
        this.applyTheme(this.theme);
        this.setCookie('theme', this.theme, 365);
    }

    setCookie(name, value, days) {
        const expires = new Date();
        expires.setTime(expires.getTime() + (days * 24 * 60 * 60 * 1000));
        document.cookie = `${name}=${value};expires=${expires.toUTCString()};path=/`;
    }

    bindEvents() {
        const themeToggle = document.getElementById('theme-toggle');
        if (themeToggle) {
            themeToggle.addEventListener('click', () => this.toggleTheme());
        }

        window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', (e) => {
            if (!this.getStoredTheme()) {
                this.theme = e.matches ? 'dark' : 'light';
                this.applyTheme(this.theme);
            }
        });
    }
}

document.addEventListener('DOMContentLoaded', () => {
    new ThemeManager();
});