/**
 * Admin Panel - Payments Queue Logic
 */

let allTransactions = [];
let currentPaymentTab = 'pending';
let filteredTransactions = [];
let currentRejectionTxId = null;

async function loadTransactions() {
    const tableBody = document.getElementById('tx-table-body');
    if (!tableBody) return;

    try {
        const res = await fetch('/api/admin/transactions');
        allTransactions = await res.json();
        
        if (allTransactions.length === 0) {
            tableBody.innerHTML = '<tr><td colspan="7" class="text-center padding-30">No transactions found.</td></tr>';
            updatePaymentCounts();
            return;
        }
        
        filterAndDisplayTransactions();
        
    } catch (err) {
        console.error('Failed to load transactions:', err);
        tableBody.innerHTML = '<tr><td colspan="7" class="error-state">Failed to fetch transactions.</td></tr>';
    }
}

function refreshPayments() {
    loadTransactions();
    if(typeof showToast === 'function') {
        showToast('success', 'Payments Refreshed', 'Payment queue has been updated');
    }
}

function switchPaymentTab(tabName) {
    currentPaymentTab = tabName;
    
    // Update tab buttons
    document.querySelectorAll('.payment-tab-btn').forEach(btn => btn.classList.remove('active'));
    document.getElementById(`tab-${tabName}`).classList.add('active');
    
    // Filter and display transactions
    filterAndDisplayTransactions();
}

function filterAndDisplayTransactions() {
    // Apply tab filter
    filteredTransactions = allTransactions.filter(tx => {
        if (currentPaymentTab === 'pending') return tx.status === 'pending';
        if (currentPaymentTab === 'approved') return tx.status === 'approved';
        if (currentPaymentTab === 'rejected') return tx.status === 'rejected';
        return true;
    });
    
    // Apply search filter
    const searchInput = document.getElementById('payment-search');
    const searchTerm = searchInput ? searchInput.value.toLowerCase() : '';
    if (searchTerm) {
        filteredTransactions = filteredTransactions.filter(tx => 
            (tx.user || '').toLowerCase().includes(searchTerm) ||
            (tx.phone || '').toLowerCase().includes(searchTerm) ||
            (tx.utr || '').toLowerCase().includes(searchTerm)
        );
    }
    
    // Apply amount filter
    const filterSelect = document.getElementById('payment-filter');
    const amountFilter = filterSelect ? filterSelect.value : 'all';
    if (amountFilter !== 'all') {
        filteredTransactions = filteredTransactions.filter(tx => {
            const amount = parseFloat(tx.amount) || 0;
            switch (amountFilter) {
                case '0-500': return amount <= 500;
                case '500-1000': return amount > 500 && amount <= 1000;
                case '1000-5000': return amount > 1000 && amount <= 5000;
                case '5000+': return amount > 5000;
                default: return true;
            }
        });
    }
    
    // Apply sorting
    const sortSelect = document.getElementById('payment-sort');
    const sortBy = sortSelect ? sortSelect.value : 'recent';
    filteredTransactions.sort((a, b) => {
        switch (sortBy) {
            case 'newest': 
            case 'recent': return new Date(b.date) - new Date(a.date);
            case 'oldest': return new Date(a.date) - new Date(b.date);
            case 'amount-high': return parseFloat(b.amount) - parseFloat(a.amount);
            case 'amount-low': return parseFloat(a.amount) - parseFloat(b.amount);
            default: return 0;
        }
    });
    
    // Update counts
    updatePaymentCounts();
    
    // Display transactions
    renderTransactions(filteredTransactions);
}

function updatePaymentCounts() {
    const pendingCount = allTransactions.filter(t => t.status === 'pending').length;
    const approvedCount = allTransactions.filter(t => t.status === 'approved').length;
    const rejectedCount = allTransactions.filter(t => t.status === 'rejected').length;
    
    const pendingEl = document.getElementById('pending-count');
    const approvedEl = document.getElementById('approved-count');
    const rejectedEl = document.getElementById('rejected-count');

    if (pendingEl) {
        pendingEl.textContent = pendingCount;
        pendingEl.style.display = pendingCount > 0 ? 'inline-block' : 'none';
    }
    if (approvedEl) {
        approvedEl.textContent = approvedCount;
        approvedEl.style.display = approvedCount > 0 ? 'inline-block' : 'none';
    }
    if (rejectedEl) {
        rejectedEl.textContent = rejectedCount;
        rejectedEl.style.display = rejectedCount > 0 ? 'inline-block' : 'none';
    }
}

function renderTransactions(transactions) {
    const tableBody = document.getElementById('tx-table-body');
    if (!tableBody) return;

    if (transactions.length === 0) {
        tableBody.innerHTML = `
            <tr>
                <td colspan="7" class="text-center padding-30">
                    <i class="fa-solid fa-inbox" style="font-size:2rem; color:var(--text-muted); margin-bottom:10px;"></i>
                    <p style="color:var(--text-muted);">No ${currentPaymentTab} transactions found</p>
                </td>
            </tr>
        `;
        return;
    }

    tableBody.innerHTML = transactions.map(t => {
        const statusClass = `status-${t.status.toLowerCase()}`;
        const actions = t.status === 'pending' ? `
            <div class="admin-actions">
                <button onclick="verifyTransaction('${t.tx_id}', 'approve')" class="btn-verify btn-approve">
                    <i class="fa-solid fa-check"></i> Approve
                </button>
                <button onclick="verifyTransaction('${t.tx_id}', 'reject')" class="btn-verify btn-reject">
                    <i class="fa-solid fa-xmark"></i> Reject
                </button>
                <button onclick="showPaymentDetails('${t.tx_id}')" class="btn-verify btn-details">
                    <i class="fa-solid fa-eye"></i> Details
                </button>
            </div>
        ` : `
            <div class="admin-actions">
                <span class="text-muted-small"><i class="fa-solid fa-circle-check"></i> Complete</span>
                <button onclick="showPaymentDetails('${t.tx_id}')" class="btn-verify btn-details">
                    <i class="fa-solid fa-eye"></i> View
                </button>
            </div>
        `;

        return `
            <tr>
                <td class="text-muted-small">${t.date}</td>
                <td>
                    <div class="user-cell">
                        <strong>${t.user}</strong>
                        <small>${t.phone}</small>
                    </div>
                </td>
                <td class="balance-amount">₹${t.amount}</td>
                <td><code>${t.utr}</code></td>
                <td>
                    ${t.screenshot ? `
                        <a href="${t.screenshot}" target="_blank" class="proof-link" onclick="event.stopPropagation();">
                            <i class="fa-solid fa-image"></i> View Proof
                        </a>
                    ` : '<span class="text-muted-small">N/A</span>'}
                </td>
                <td>
                    <span class="status-pill ${statusClass}">${t.status.toUpperCase()}</span>
                </td>
                <td>${actions}</td>
            </tr>
        `;
    }).join('');
}

async function showPaymentDetails(txId) {
    const transaction = allTransactions.find(t => t.tx_id === txId);
    if (!transaction) return;

    const modal = document.getElementById('payment-details-modal');
    const modalTitle = document.getElementById('modal-title');
    const modalBody = document.getElementById('modal-body');
    const modalActions = document.getElementById('modal-actions');

    if(!modal || !modalTitle || !modalBody || !modalActions) return;

    modalTitle.textContent = `Payment Details - ${transaction.utr}`;

    let rejectionCommentHtml = '';
    if (transaction.status === 'rejected' && transaction.rejection_comment) {
        rejectionCommentHtml = `
            <div style="margin-bottom:20px; padding:15px; background:rgba(255, 118, 117, 0.1); border-radius:8px; border-left:4px solid #ff7675;">
                <strong style="color:#ff7675;">Rejection Reason:</strong><br>
                <p style="margin:8px 0 0 0; color:var(--text-color);">${transaction.rejection_comment}</p>
            </div>
        `;
    }
    
    modalBody.innerHTML = `
        <div style="display:grid; grid-template-columns:1fr 1fr; gap:16px; margin-bottom:20px;">
            <div>
                <strong>User:</strong><br>
                ${transaction.user}<br>
                <small style="color:var(--text-muted);">${transaction.phone}</small>
            </div>
            <div>
                <strong>Amount:</strong><br>
                <span style="font-weight:700; color:var(--primary-color);">₹${transaction.amount}</span>
            </div>
            <div>
                <strong>Status:</strong><br>
                <span class="status-pill status-${transaction.status.toLowerCase()}">${transaction.status.toUpperCase()}</span>
            </div>
            <div>
                <strong>Date:</strong><br>
                ${transaction.date}
            </div>
        </div>
        ${rejectionCommentHtml}
        <div style="margin-bottom:20px;">
            <strong>UTR Number:</strong><br>
            <code style="background:var(--code-bg); padding:8px 12px; border-radius:6px; display:inline-block; margin-top:4px;">${transaction.utr}</code>
        </div>
        <div style="margin-bottom:20px;">
            <strong>Screenshot Proof:</strong><br>
            ${transaction.screenshot ? `
                <a href="${transaction.screenshot}" target="_blank" style="color:var(--primary-color); text-decoration:underline; margin-top:4px; display:inline-block;">
                    <i class="fa-solid fa-image"></i> View Payment Proof
                </a>
            ` : '<span style="color:var(--text-muted);">No screenshot provided</span>'}
        </div>
    `;

    if (transaction.status === 'pending') {
        modalActions.innerHTML = `
            <button onclick="verifyTransaction('${transaction.tx_id}', 'approve')" class="btn-verify btn-approve" style="padding:8px 16px;">
                <i class="fa-solid fa-check"></i> Approve
            </button>
            <button onclick="verifyTransaction('${transaction.tx_id}', 'reject')" class="btn-verify btn-reject" style="padding:8px 16px;">
                <i class="fa-solid fa-xmark"></i> Reject
            </button>
        `;
    } else {
        modalActions.innerHTML = '';
    }

    modal.style.display = 'flex';
}

function closePaymentModal() {
    const modal = document.getElementById('payment-details-modal');
    if (modal) modal.style.display = 'none';
}

function showConfirmModal(action) {
    return new Promise((resolve) => {
        const modal = document.getElementById('custom-confirm-modal');
        const title = document.getElementById('modal-title');
        const message = document.getElementById('modal-message');
        const confirmBtn = document.getElementById('modal-confirm-btn');
        const cancelBtn = document.getElementById('modal-cancel-btn');
        const icon = document.getElementById('modal-icon');
        const iconContainer = document.getElementById('modal-icon-container');

        if (!modal) {
            resolve(confirm(`Are you sure you want to ${action} this transaction?`));
            return;
        }

        if (action === 'approve') {
            title.innerText = 'Approve Payment?';
            message.innerHTML = 'This will securely add the <br>requested funds to the user profile.';
            icon.className = 'fa-solid fa-check-circle';
            iconContainer.style.color = '#00b894';
            confirmBtn.style.background = '#00b894';
            confirmBtn.style.boxShadow = '0 10px 25px rgba(0, 184, 148, 0.3)';
            confirmBtn.innerText = 'Yes, Approve';
        } else {
            title.innerText = 'Reject Payment?';
            message.innerHTML = 'This request will be permanently<br> declined and user will not get funds.';
            icon.className = 'fa-solid fa-triangle-exclamation';
            iconContainer.style.color = '#ff7675';
            confirmBtn.style.background = '#ff7675';
            confirmBtn.style.boxShadow = '0 10px 25px rgba(255, 118, 117, 0.3)';
            confirmBtn.innerText = 'Yes, Reject';
        }

        modal.style.display = 'flex';

        const cleanup = () => {
            confirmBtn.onclick = null;
            cancelBtn.onclick = null;
            modal.style.display = 'none';
        };

        confirmBtn.onclick = () => { cleanup(); resolve(true); };
        cancelBtn.onclick = () => { cleanup(); resolve(false); };
    });
}

function showRejectionCommentModal(txId) {
    currentRejectionTxId = txId;
    const modal = document.getElementById('rejection-comment-modal');
    const commentInput = document.getElementById('rejection-comment');
    if(modal) modal.style.display = 'flex';
    if(commentInput) {
        commentInput.value = '';
        commentInput.focus();
    }
}

function closeRejectionModal() {
    const modal = document.getElementById('rejection-comment-modal');
    if (modal) modal.style.display = 'none';
    currentRejectionTxId = null;
}

async function confirmRejectionWithComment() {
    const commentInput = document.getElementById('rejection-comment');
    const errorElement = document.getElementById('rejection-error');
    if(!commentInput || !errorElement) return;

    const comment = commentInput.value.trim();
    
    if (!comment) {
        errorElement.style.display = 'block';
        commentInput.style.borderColor = '#ff7675';
        commentInput.style.boxShadow = '0 0 0 3px rgba(255, 118, 117, 0.1)';
        
        commentInput.classList.add('shake-animation');
        setTimeout(() => commentInput.classList.remove('shake-animation'), 500);
        
        commentInput.focus();
        return;
    }
    
    if (!currentRejectionTxId) {
        alert('No transaction selected for rejection.');
        return;
    }
    
    errorElement.style.display = 'none';
    commentInput.style.borderColor = 'var(--border-color)';
    commentInput.style.boxShadow = 'none';
    
    try {
        const res = await fetch('/api/admin/verify-payment', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ 
                tx_id: currentRejectionTxId, 
                action: 'reject',
                comment: comment
            })
        });
        
        const data = await res.json();
        
        if (data.success) {
            closeRejectionModal();
            loadTransactions();
            if(typeof showToast === 'function') {
                showToast('success', 'Payment Rejected', 'Payment has been rejected with your comment.');
            }
        } else {
            alert(data.error || 'Rejection failed');
        }
    } catch (err) {
        console.error('Rejection error:', err);
        alert('A network error occurred.');
    }
}

async function verifyTransaction(tx_id, action) {
    if (action === 'reject') {
        showRejectionCommentModal(tx_id);
        return;
    }
    
    const isConfirmed = await showConfirmModal(action);
    if (!isConfirmed) return;

    try {
        const res = await fetch('/api/admin/verify-payment', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ tx_id, action })
        });
        const data = await res.json();
        
        if (data.success) {
            loadTransactions();
        } else {
            alert(data.error || 'Verification failed');
        }
    } catch (err) {
        console.error('Verification error:', err);
        alert('A network error occurred.');
    }
}

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

document.addEventListener('DOMContentLoaded', function() {
    const searchInput = document.getElementById('payment-search');
    const filterSelect = document.getElementById('payment-filter');
    const sortSelect = document.getElementById('payment-sort');
    
    if (searchInput) searchInput.addEventListener('input', debounce(filterAndDisplayTransactions, 300));
    if (filterSelect) filterSelect.addEventListener('change', filterAndDisplayTransactions);
    if (sortSelect) sortSelect.addEventListener('change', filterAndDisplayTransactions);
});