document.addEventListener('DOMContentLoaded', function() {
    // DOM Elements
    const amountButtons = document.querySelectorAll('.amount-btn');
    const currencyButtons = document.querySelectorAll('.currency-btn');
    const walletInput = document.getElementById('walletAddress');
    const addressError = document.getElementById('addressError');
    const proceedBtn = document.getElementById('proceedBtn');
    const paymentForm = document.getElementById('paymentForm');
    const simulatedReturnBox = document.getElementById('simulatedReturnBox');
    const returnAmountEl = document.getElementById('returnAmount');
    const returnRateEl = document.getElementById('returnRate');
    
    // Summary elements
    const summaryAmount = document.getElementById('summaryAmount');
    const summaryCurrency = document.getElementById('summaryCurrency');
    
    // Selected values
    let selectedAmount = null;
    let selectedCurrency = null;
    
    // Amount selection
    amountButtons.forEach(button => {
        button.addEventListener('click', function() {
            // Remove selected class from all buttons
            amountButtons.forEach(btn => btn.classList.remove('selected'));
            
            // Add selected class to clicked button
            this.classList.add('selected');
            
            // Update selected amount
            selectedAmount = parseInt(this.dataset.value);
            document.getElementById('selectedAmount').value = selectedAmount;
            
            // Update summary
            summaryAmount.textContent = `$${selectedAmount}`;
            
            // Handle $50 special rule
            if (selectedAmount === 50) {
                const rate = (Math.random() * 20 + 20).toFixed(2); // 20-40%
                const returnAmount = (selectedAmount * rate / 100).toFixed(2);
                
                returnRateEl.textContent = `${rate}%`;
                returnAmountEl.textContent = `+$${returnAmount}`;
                simulatedReturnBox.classList.remove('hidden');
            } else {
                simulatedReturnBox.classList.add('hidden');
            }
            
            validateForm();
        });
    });
    
    // Currency selection
    currencyButtons.forEach(button => {
        button.addEventListener('click', function() {
            // Remove selected class from all buttons
            currencyButtons.forEach(btn => btn.classList.remove('selected'));
            
            // Add selected class to clicked button
            this.classList.add('selected');
            
            // Update selected currency
            selectedCurrency = this.dataset.value;
            document.getElementById('selectedCurrency').value = selectedCurrency;
            
            // Update summary
            summaryCurrency.textContent = selectedCurrency;
            
            // Clear previous validation
            addressError.classList.add('hidden');
            walletInput.classList.remove('border-red-500');
            
            validateForm();
        });
    });
    
    // Wallet address validation
    walletInput.addEventListener('input', function() {
        validateWalletAddress();
        validateForm();
    });
    
    // Validate wallet address based on currency
    function validateWalletAddress() {
        const address = walletInput.value.trim();
        
        if (!selectedCurrency) {
            addressError.classList.add('hidden');
            return true;
        }
        
        let isValid = false;
        
        switch(selectedCurrency) {
            case 'USDT':
            case 'BNB':
                // BEP20 addresses: start with 0x and 42 characters
                isValid = /^0x[a-fA-F0-9]{40}$/.test(address);
                break;
            case 'BTC':
                // Bitcoin addresses: start with 1, 3, or bc1
                isValid = /^(1|3)[a-km-zA-HJ-NP-Z1-9]{25,34}$|^bc1[a-z0-9]{39,59}$/.test(address);
                break;
            case 'SOL':
                // Solana addresses: Base58, 32-44 characters
                isValid = /^[1-9A-HJ-NP-Za-km-z]{32,44}$/.test(address);
                break;
            default:
                isValid = false;
        }
        
        if (address && !isValid) {
            addressError.classList.remove('hidden');
            walletInput.classList.add('border-red-500');
            return false;
        } else {
            addressError.classList.add('hidden');
            walletInput.classList.remove('border-red-500');
            return true;
        }
    }
    
    // Form validation
    function validateForm() {
        const name = document.getElementById('userName').value.trim();
        const address = walletInput.value.trim();
        
        const isAmountSelected = selectedAmount !== null;
        const isCurrencySelected = selectedCurrency !== null;
        const isNameValid = name.length > 0;
        const isAddressValid = address.length > 0 && validateWalletAddress();
        
        if (isAmountSelected && isCurrencySelected && isNameValid && isAddressValid) {
            proceedBtn.disabled = false;
            proceedBtn.classList.remove('opacity-50', 'cursor-not-allowed');
            proceedBtn.classList.add('hover:opacity-90');
        } else {
            proceedBtn.disabled = true;
            proceedBtn.classList.add('opacity-50', 'cursor-not-allowed');
            proceedBtn.classList.remove('hover:opacity-90');
        }
    }
    
    // Real-time validation for name field
    document.getElementById('userName').addEventListener('input', validateForm);
    
    // Form submission
    paymentForm.addEventListener('submit', function(e) {
        e.preventDefault();
        
        // Show success message
        proceedBtn.innerHTML = '<div class="flex items-center justify-center"><div class="w-5 h-5 border-t-2 border-r-2 border-white rounded-full animate-spin mr-2"></div> Redirecting...</div>';
        proceedBtn.disabled = true;
        
        // Simulate redirect delay
        setTimeout(() => {
            window.location.href = 'https://example.com/next-step';
        }, 2000);
    });
    
    // Initialize form state
    validateForm();
});