// QR Code Generator Application
class QRGenerator {
    constructor() {
        this.currentType = 'url';
        this.currentQRUrl = null;
        this.init();
    }

    init() {
        this.bindEvents();
        this.updateSizeDisplay();
        this.setActiveTab('url');
    }

    bindEvents() {
        // Tab switching
        document.querySelectorAll('.tab-btn').forEach(btn => {
            btn.addEventListener('click', (e) => {
                const type = e.currentTarget.dataset.type;
                this.setActiveTab(type);
            });
        });

        // Size slider
        const sizeSlider = document.getElementById('qr-size');
        sizeSlider.addEventListener('input', () => {
            this.updateSizeDisplay();
        });

        // Generate button
        document.getElementById('generate-btn').addEventListener('click', () => {
            this.generateQRCode();
        });

        // Download button
        document.getElementById('download-btn').addEventListener('click', () => {
            this.downloadQRCode();
        });



        // Real-time input changes
        this.bindInputEvents();

        // Color changes - removed auto-generation
        // Users need to click "Generate QR Code" to apply color changes
    }

    bindInputEvents() {
        // Clear QR code when input changes, but don't auto-generate
        // URL input
        document.getElementById('url-input').addEventListener('input', () => {
            this.clearPreview();
        });

        // Text input
        document.getElementById('text-input').addEventListener('input', () => {
            this.clearPreview();
        });

        // Email inputs
        document.getElementById('email-input').addEventListener('input', () => {
            this.clearPreview();
        });
        document.getElementById('email-subject').addEventListener('input', () => {
            this.clearPreview();
        });
        document.getElementById('email-body').addEventListener('input', () => {
            this.clearPreview();
        });

        // Phone input
        document.getElementById('phone-input').addEventListener('input', () => {
            this.clearPreview();
        });

        // WiFi inputs
        document.getElementById('wifi-ssid').addEventListener('input', () => {
            this.clearPreview();
        });
        document.getElementById('wifi-password').addEventListener('input', () => {
            this.clearPreview();
        });
        document.getElementById('wifi-security').addEventListener('change', () => {
            this.clearPreview();
        });
        document.getElementById('wifi-hidden').addEventListener('change', () => {
            this.clearPreview();
        });

        // SMS inputs
        document.getElementById('sms-number').addEventListener('input', () => {
            this.clearPreview();
        });
        document.getElementById('sms-message').addEventListener('input', () => {
            this.clearPreview();
        });
    }

    setActiveTab(type) {
        this.currentType = type;

        // Update tab buttons
        document.querySelectorAll('.tab-btn').forEach(btn => {
            btn.classList.remove('active');
        });
        document.querySelector(`[data-type="${type}"]`).classList.add('active');

        // Update content forms
        document.querySelectorAll('.content-form').forEach(form => {
            form.classList.remove('active');
        });
        document.getElementById(`${type}-form`).classList.add('active');

        // Clear current QR code
        this.clearPreview();
    }

    updateSizeDisplay() {
        const size = document.getElementById('qr-size').value;
        document.querySelector('.size-value').textContent = `${size}px`;
    }

    autoGenerate() {
        const content = this.getContentData();
        if (content && content.trim()) {
            this.generateQRCode();
        } else {
            this.clearPreview();
        }
    }

    getContentData() {
        switch (this.currentType) {
            case 'url':
                return document.getElementById('url-input').value;

            case 'text':
                return document.getElementById('text-input').value;

            case 'email':
                const email = document.getElementById('email-input').value;
                const subject = document.getElementById('email-subject').value;
                const body = document.getElementById('email-body').value;
                
                if (!email) return '';
                
                let mailto = `mailto:${email}`;
                const params = [];
                if (subject) params.push(`subject=${encodeURIComponent(subject)}`);
                if (body) params.push(`body=${encodeURIComponent(body)}`);
                if (params.length > 0) mailto += `?${params.join('&')}`;
                
                return mailto;

            case 'phone':
                const phone = document.getElementById('phone-input').value;
                return phone ? `tel:${phone}` : '';

            case 'wifi':
                const ssid = document.getElementById('wifi-ssid').value;
                const password = document.getElementById('wifi-password').value;
                const security = document.getElementById('wifi-security').value;
                const hidden = document.getElementById('wifi-hidden').checked;
                
                if (!ssid) return '';
                
                return `WIFI:T:${security};S:${ssid};P:${password};H:${hidden ? 'true' : 'false'};;`;

            case 'sms':
                const smsNumber = document.getElementById('sms-number').value;
                const smsMessage = document.getElementById('sms-message').value;
                
                if (!smsNumber) return '';
                
                let sms = `sms:${smsNumber}`;
                if (smsMessage) sms += `?body=${encodeURIComponent(smsMessage)}`;
                
                return sms;

            default:
                return '';
        }
    }

    async generateQRCode() {
        const content = this.getContentData();
        
        if (!content || !content.trim()) {
            this.showToast('Please enter content to generate QR code', 'error');
            return;
        }

        this.showLoading(true);

        try {
            const qrUrl = this.buildQRUrl(content);
            await this.displayQRCode(qrUrl);
            this.currentQRUrl = qrUrl;
            
            // Enable download button
            document.getElementById('download-btn').disabled = false;
            
            this.showToast('QR code generated successfully!', 'success');
        } catch (error) {
            console.error('Error generating QR code:', error);
            this.showToast('Failed to generate QR code. Please try again.', 'error');
        } finally {
            this.showLoading(false);
        }
    }

    buildQRUrl(content) {
        const size = document.getElementById('qr-size').value;
        const fgColor = document.getElementById('fg-color').value.replace('#', '');
        const bgColor = document.getElementById('bg-color').value.replace('#', '');
        const errorCorrection = document.getElementById('error-correction').value;
        const format = document.getElementById('output-format').value;

        const params = new URLSearchParams({
            cht: 'qr',
            chs: `${size}x${size}`,
            chl: content,
            choe: 'UTF-8',
            chld: `${errorCorrection}|2`,
            icqrf: fgColor,
            icqrb: bgColor
        });

        if (format === 'svg') {
            params.append('chof', '.svg');
        }

        return `https://image-charts.com/chart?${params.toString()}`;
    }

    async displayQRCode(url) {
        return new Promise((resolve, reject) => {
            const img = new Image();
            img.onload = () => {
                const preview = document.getElementById('qr-preview');
                preview.innerHTML = '';
                preview.appendChild(img);
                preview.classList.add('has-qr');
                resolve();
            };
            img.onerror = () => {
                reject(new Error('Failed to load QR code image'));
            };
            img.src = url;
            img.alt = 'Generated QR Code';
            img.style.maxWidth = '100%';
            img.style.height = 'auto';
        });
    }

    clearPreview() {
        const preview = document.getElementById('qr-preview');
        preview.innerHTML = `
            <div class="placeholder">
                <i class="fas fa-qrcode"></i>
                <p>Enter content to generate QR code</p>
            </div>
        `;
        preview.classList.remove('has-qr');
        
        // Disable download button
        document.getElementById('download-btn').disabled = true;
        
        this.currentQRUrl = null;
    }

    async downloadQRCode() {
        if (!this.currentQRUrl) {
            this.showToast('No QR code to download', 'error');
            return;
        }

        try {
            const format = document.getElementById('output-format').value;
            const response = await fetch(this.currentQRUrl);
            const blob = await response.blob();
            
            const url = window.URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            a.download = `qrcode.${format}`;
            document.body.appendChild(a);
            a.click();
            document.body.removeChild(a);
            window.URL.revokeObjectURL(url);
            
            this.showToast('QR code downloaded successfully!', 'success');
        } catch (error) {
            console.error('Error downloading QR code:', error);
            this.showToast('Failed to download QR code', 'error');
        }
    }



    showLoading(show) {
        const overlay = document.getElementById('loading-overlay');
        if (show) {
            overlay.classList.add('show');
        } else {
            overlay.classList.remove('show');
        }
    }

    showToast(message, type = 'info') {
        const container = document.getElementById('toast-container');
        const toast = document.createElement('div');
        toast.className = `toast ${type}`;
        
        const icon = type === 'success' ? 'fas fa-check-circle' : 
                    type === 'error' ? 'fas fa-exclamation-circle' : 
                    'fas fa-info-circle';
        
        toast.innerHTML = `
            <i class="${icon}"></i>
            <span>${message}</span>
        `;
        
        container.appendChild(toast);
        
        // Auto remove after 3 seconds
        setTimeout(() => {
            if (toast.parentNode) {
                toast.parentNode.removeChild(toast);
            }
        }, 3000);
    }

    debounce(func, wait) {
        let timeout;
        return function executedFunction(...args) {
            const later = () => {
                clearTimeout(timeout);
                func(...args);
            };
            clearTimeout(timeout);
            timeout = setTimeout(later, wait);
        };
    }

    // Validation methods
    isValidUrl(string) {
        try {
            new URL(string);
            return true;
        } catch (_) {
            return false;
        }
    }

    isValidEmail(email) {
        const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
        return emailRegex.test(email);
    }

    isValidPhone(phone) {
        const phoneRegex = /^[\+]?[1-9][\d]{0,15}$/;
        return phoneRegex.test(phone.replace(/[\s\-\(\)]/g, ''));
    }

    // Enhanced validation for different content types
    validateContent() {
        const content = this.getContentData();
        
        switch (this.currentType) {
            case 'url':
                if (content && !this.isValidUrl(content)) {
                    this.showToast('Please enter a valid URL', 'error');
                    return false;
                }
                break;
                
            case 'email':
                const email = document.getElementById('email-input').value;
                if (email && !this.isValidEmail(email)) {
                    this.showToast('Please enter a valid email address', 'error');
                    return false;
                }
                break;
                
            case 'phone':
                const phone = document.getElementById('phone-input').value;
                if (phone && !this.isValidPhone(phone)) {
                    this.showToast('Please enter a valid phone number', 'error');
                    return false;
                }
                break;
                
            case 'sms':
                const smsPhone = document.getElementById('sms-number').value;
                if (smsPhone && !this.isValidPhone(smsPhone)) {
                    this.showToast('Please enter a valid phone number', 'error');
                    return false;
                }
                break;
        }
        
        return true;
    }
}

// Utility functions
function formatPhoneNumber(phone) {
    // Remove all non-digit characters except +
    const cleaned = phone.replace(/[^\d\+]/g, '');
    return cleaned;
}

function escapeHtml(text) {
    const map = {
        '&': '&amp;',
        '<': '&lt;',
        '>': '&gt;',
        '"': '&quot;',
        "'": '&#039;'
    };
    return text.replace(/[&<>"']/g, m => map[m]);
}

// Initialize the application when DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
    const qrGenerator = new QRGenerator();
    
    // Add some sample data for demonstration
    const urlInput = document.getElementById('url-input');
    if (urlInput) {
        urlInput.placeholder = 'https://example.com';
    }
    
    // Add keyboard shortcuts
    document.addEventListener('keydown', (e) => {
        // Ctrl/Cmd + Enter to generate
        if ((e.ctrlKey || e.metaKey) && e.key === 'Enter') {
            e.preventDefault();
            qrGenerator.generateQRCode();
        }
        
        // Ctrl/Cmd + D to download
        if ((e.ctrlKey || e.metaKey) && e.key === 'd') {
            e.preventDefault();
            if (!document.getElementById('download-btn').disabled) {
                qrGenerator.downloadQRCode();
            }
        }
    });
    
    // Add focus management for better accessibility
    document.querySelectorAll('.tab-btn').forEach(btn => {
        btn.addEventListener('keydown', (e) => {
            if (e.key === 'Enter' || e.key === ' ') {
                e.preventDefault();
                btn.click();
            }
        });
    });
    
    // Add form validation on submit
    document.querySelectorAll('.form-input, .form-textarea').forEach(input => {
        input.addEventListener('blur', () => {
            qrGenerator.validateContent();
        });
    });
    

    
    // Add drag and drop functionality for future logo upload feature
    const previewArea = document.getElementById('qr-preview');
    previewArea.addEventListener('dragover', (e) => {
        e.preventDefault();
        previewArea.style.borderColor = 'var(--primary-color)';
    });
    
    previewArea.addEventListener('dragleave', (e) => {
        e.preventDefault();
        previewArea.style.borderColor = '';
    });
    
    // Add print functionality
    window.addEventListener('beforeprint', () => {
        document.body.classList.add('printing');
    });
    
    window.addEventListener('afterprint', () => {
        document.body.classList.remove('printing');
    });
    
    // Add service worker for offline functionality (future enhancement)
    if ('serviceWorker' in navigator) {
        navigator.serviceWorker.register('/sw.js').catch(err => {
            console.log('Service worker registration failed:', err);
        });
    }
    
    console.log('QR Generator initialized successfully!');
});