/**
 * TPU Survey - Core Application Logic
 * API communication, Auth state, Toast notifications, Theme
 */

const getAppBasePath = () => {
    return window.location.pathname.includes('/survey') ? '/survey' : '';
};

const API = {
    base: `${getAppBasePath()}/api`,

    async request(endpoint, options = {}) {
        const url = `${this.base}/${endpoint}`;
        const config = {
            headers: { 'Content-Type': 'application/json' },
            ...options
        };
        if (options.body && typeof options.body === 'object') {
            config.body = JSON.stringify(options.body);
        }
        try {
            const res = await fetch(url, config);
            const data = await res.json();
            if (!res.ok) throw new Error(data.error || 'เกิดข้อผิดพลาด');
            return data;
        } catch (err) {
            if (err.message === 'Failed to fetch') throw new Error('ไม่สามารถเชื่อมต่อเซิร์ฟเวอร์ได้');
            throw err;
        }
    },

    get(endpoint) { return this.request(endpoint); },
    post(endpoint, body) { return this.request(endpoint, { method: 'POST', body }); },
    upload(endpoint, formData) {
        const url = `${this.base}/${endpoint}`;
        return fetch(url, { method: 'POST', body: formData })
            .then(res => res.json())
            .then(data => {
                if (data.error) throw new Error(data.error);
                return data;
            });
    }
};

// ============================================================
// Auth State
// ============================================================
const Auth = {
    user: null,

    async check() {
        try {
            const data = await API.get('auth.php?action=check');
            if (data.loggedIn) {
                this.user = data.user;
                return true;
            }
        } catch (e) {}
        this.user = null;
        return false;
    },

    async login(username, password) {
        const data = await API.post('auth.php?action=login', { username, password });
        this.user = data.user;
        return data;
    },

    async logout() {
        await API.post('auth.php?action=logout', {});
        this.user = null;
        window.location.href = `${getAppBasePath()}/index.html`;
    },

    isAdmin() { return this.user?.role === 'admin'; },
    isTeacher() { return this.user?.role === 'teacher'; }
};

// ============================================================
// Sound Effects (Web Audio API)
// ============================================================
const SoundFX = {
    ctx: null,

    getCtx() {
        if (!this.ctx) {
            this.ctx = new (window.AudioContext || window.webkitAudioContext)();
        }
        return this.ctx;
    },

    // เสียง OK — 2 โน้ตสั้น ไพเราะ
    playSuccess() {
        try {
            const ctx = this.getCtx();
            const now = ctx.currentTime;

            // Note 1: C5 (523 Hz)
            const osc1 = ctx.createOscillator();
            const gain1 = ctx.createGain();
            osc1.type = 'sine';
            osc1.frequency.setValueAtTime(523, now);
            gain1.gain.setValueAtTime(0.3, now);
            gain1.gain.exponentialRampToValueAtTime(0.01, now + 0.15);
            osc1.connect(gain1);
            gain1.connect(ctx.destination);
            osc1.start(now);
            osc1.stop(now + 0.15);

            // Note 2: E5 (659 Hz) — ช้ากว่าเล็กน้อย
            const osc2 = ctx.createOscillator();
            const gain2 = ctx.createGain();
            osc2.type = 'sine';
            osc2.frequency.setValueAtTime(659, now + 0.1);
            gain2.gain.setValueAtTime(0, now);
            gain2.gain.setValueAtTime(0.3, now + 0.1);
            gain2.gain.exponentialRampToValueAtTime(0.01, now + 0.3);
            osc2.connect(gain2);
            gain2.connect(ctx.destination);
            osc2.start(now + 0.1);
            osc2.stop(now + 0.3);

            // Note 3: G5 (784 Hz) — จบด้วยโน้ตสูง
            const osc3 = ctx.createOscillator();
            const gain3 = ctx.createGain();
            osc3.type = 'sine';
            osc3.frequency.setValueAtTime(784, now + 0.2);
            gain3.gain.setValueAtTime(0, now);
            gain3.gain.setValueAtTime(0.25, now + 0.2);
            gain3.gain.exponentialRampToValueAtTime(0.01, now + 0.45);
            osc3.connect(gain3);
            gain3.connect(ctx.destination);
            osc3.start(now + 0.2);
            osc3.stop(now + 0.45);
        } catch (e) {
            // AudioContext not supported
        }
    },

    // เสียง Error — โทนต่ำ
    playError() {
        try {
            const ctx = this.getCtx();
            const now = ctx.currentTime;

            const osc = ctx.createOscillator();
            const gain = ctx.createGain();
            osc.type = 'square';
            osc.frequency.setValueAtTime(200, now);
            osc.frequency.linearRampToValueAtTime(150, now + 0.3);
            gain.gain.setValueAtTime(0.15, now);
            gain.gain.exponentialRampToValueAtTime(0.01, now + 0.3);
            osc.connect(gain);
            gain.connect(ctx.destination);
            osc.start(now);
            osc.stop(now + 0.3);
        } catch (e) {}
    }
};

// ============================================================
// Toast Notifications
// ============================================================
const Toast = {
    container: null,

    init() {
        if (!this.container) {
            this.container = document.createElement('div');
            this.container.className = 'toast-container';
            document.body.appendChild(this.container);
        }
    },

    show(message, type = 'info', duration = 4000) {
        this.init();
        const toast = document.createElement('div');
        toast.className = `toast ${type}`;
        
        const icons = { success: '✅', error: '❌', warning: '⚠️', info: 'ℹ️' };
        toast.innerHTML = `<span>${icons[type] || 'ℹ️'}</span><span>${message}</span>`;
        
        this.container.appendChild(toast);
        
        setTimeout(() => {
            toast.style.animation = 'toastOut 0.3s ease forwards';
            setTimeout(() => toast.remove(), 300);
        }, duration);
    },

    success(msg) { this.show(msg, 'success'); SoundFX.playSuccess(); },
    error(msg) { this.show(msg, 'error'); SoundFX.playError(); },
    warning(msg) { this.show(msg, 'warning'); },
    info(msg) { this.show(msg, 'info'); }
};

// ============================================================
// Theme Management (Light Mode Only — ม.ตาปี)
// ============================================================
const Theme = {
    init() { /* Light mode only */ },
    toggle() { /* Disabled */ }
};

// ============================================================
// Modal Helper
// ============================================================
const Modal = {
    show(id) {
        const el = document.getElementById(id);
        if (el) el.classList.add('active');
    },

    hide(id) {
        const el = document.getElementById(id);
        if (el) el.classList.remove('active');
    },

    create(title, bodyHTML, footerHTML = '', size = '') {
        const id = 'modal-' + Date.now();
        const div = document.createElement('div');
        div.id = id;
        div.className = 'modal-overlay';
        div.innerHTML = `
            <div class="modal ${size}">
                <div class="modal-header">
                    <h3>${title}</h3>
                    <button class="modal-close" onclick="Modal.hide('${id}');this.closest('.modal-overlay').remove();">✕</button>
                </div>
                <div class="modal-body">${bodyHTML}</div>
                ${footerHTML ? `<div class="modal-footer">${footerHTML}</div>` : ''}
            </div>
        `;
        document.body.appendChild(div);
        div.classList.add('active');
        
        div.addEventListener('click', (e) => {
            if (e.target === div) { div.classList.remove('active'); div.remove(); }
        });
        
        return id;
    }
};

// ============================================================
// Utility Functions
// ============================================================
function formatDate(dateStr) {
    if (!dateStr) return '-';
    const d = new Date(dateStr);
    return d.toLocaleDateString('th-TH', { year: 'numeric', month: 'short', day: 'numeric' });
}

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

function debounce(fn, delay = 300) {
    let timer;
    return (...args) => {
        clearTimeout(timer);
        timer = setTimeout(() => fn(...args), delay);
    };
}

// ============================================================
// Sidebar Toggle (Mobile)
// ============================================================
function toggleSidebar() {
    const sidebar = document.querySelector('.sidebar');
    const overlay = document.querySelector('.sidebar-overlay');
    if (sidebar) sidebar.classList.toggle('open');
    if (overlay) overlay.classList.toggle('active');
}

// Close sidebar when clicking overlay
document.addEventListener('click', (e) => {
    if (e.target.classList.contains('sidebar-overlay')) {
        toggleSidebar();
    }
});

// Init
Theme.init();