let editingParticipantId = null;
let isAdmin = false;

// Initialize on page load
document.addEventListener('DOMContentLoaded', function() {
    checkAdminStatus();
    loadParticipants();
    // Show today's entries by default
    filterByToday();
    updateLastScanResult();

    // Auto-refresh logs every 5 seconds
    setInterval(refreshLogs, 5000);
    setInterval(loadParticipants, 5000);
    setInterval(updateLastScanResult, 1000);
    setInterval(checkAdminStatus, 10000);
});

// ===== AUTHENTICATION =====
async function checkAdminStatus() {
    try {
        const response = await fetch('/api/check-admin');
        const data = await response.json();
        isAdmin = data.is_admin;
        updateAdminUI();
    } catch (error) {
        console.error('Error checking admin status:', error);
    }
}

function updateAdminUI() {
    const adminBtn = document.getElementById('adminToggleBtn');
    const addBtn = document.querySelector('[onclick="openAddParticipantModal()"]');
    const addUnregisteredBtn = document.getElementById('addUnregisteredBtn');
    const addItemBtn = document.getElementById('addItemBtn');
    const editBalanceBtn = document.getElementById('editBalanceBtn');

    if (!adminBtn) return;

    if (isAdmin) {
        adminBtn.textContent = 'Odjava Admin';
        adminBtn.onclick = adminLogout;
        adminBtn.classList.add('active');
        if (addBtn) addBtn.style.display = 'block';
        if (addItemBtn) addItemBtn.style.display = 'inline-flex';
        if (editBalanceBtn) editBalanceBtn.style.display = 'inline-flex';
    } else {
        adminBtn.textContent = 'Prijava Admin';
        adminBtn.onclick = openLoginModal;
        adminBtn.classList.remove('active');
        if (addBtn) addBtn.style.display = 'none';
        if (addItemBtn) addItemBtn.style.display = 'none';
        if (editBalanceBtn) editBalanceBtn.style.display = 'none';
    }
    if (addUnregisteredBtn) addUnregisteredBtn.style.display = 'block';
    updateUIDVisibility();
}

async function adminLogin() {
    const password = document.getElementById('loginPassword').value;

    if (!password) {
        alert('Prosimo, vnesite geslo');
        return;
    }

    try {
        const response = await fetch('/api/login', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ password })
        });

        const data = await response.json();

        if (data.success) {
            isAdmin = true;
            closeLoginModal();
            updateAdminUI();
            loadParticipants();
            loadStore();
            alert('Uspešna prijava!');
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

async function adminLogout() {
    try {
        const response = await fetch('/api/logout', {
            method: 'POST'
        });

        if (response.ok) {
            isAdmin = false;
            updateAdminUI();
            loadParticipants();
            loadStore();
            alert('Odjavljen');
        }
    } catch (error) {
        console.error('Logout error:', error);
    }
}

function openLoginModal() {
    document.getElementById('loginModal').classList.add('show');
    document.getElementById('loginPassword').focus();
}

function closeLoginModal() {
    document.getElementById('loginModal').classList.remove('show');
    document.getElementById('loginPassword').value = '';
}

function handleLoginKeypress(event) {
    if (event.key === 'Enter') {
        adminLogin();
    }
}

// ===== PARTICIPANT MANAGEMENT =====
async function loadParticipants() {
    try {
        const response = await fetch('/api/participants');
        const participants = await response.json();

        const tbody = document.getElementById('participantsTable');
        tbody.innerHTML = '';

        participants.forEach(p => {
            const row = document.createElement('tr');
            const dateAdded = p.date_added ? p.date_added.split('T')[0] : '-';
            const expiration = p.expiration_date ? p.expiration_date.split('T')[0] : '-';

            // Check if card is expired
            let isExpired = false;
            if (expiration !== '-') {
                const expirationDate = new Date(expiration);
                const today = new Date();
                today.setHours(0, 0, 0, 0);
                isExpired = expirationDate < today;
            }

            const keyUID = p.key_uid ? p.key_uid : '-';

            const actionButtons = isAdmin ? `
                    <button class="action-btn edit-btn" onclick="openEditModal(${p.id}, '${p.name}', '${p.card_uid || ''}', '${p.key_uid || ''}', '${expiration}')">Uredi</button>
                    <button class="action-btn delete-btn" onclick="deleteParticipant(${p.id})">Izbriši</button>
                ` : '';

            row.innerHTML = `
                <td>${p.id}</td>
                <td>${p.name}</td>
                <td>${p.card_uid || '-'}</td>
                <td>${keyUID}</td>
                <td>${expiration}</td>
                <td>${dateAdded}</td>
                <td>${actionButtons || '-'}</td>
            `;

            // Add expired class if card is expired
            if (isExpired) {
                row.classList.add('expired');
            }

            tbody.appendChild(row);
        });

        // Update participant filter dropdown
        updateParticipantFilter(participants);
        updateUIDVisibility();
    } catch (error) {
        console.error('Error loading participants:', error);
    }
}

function updateParticipantFilter(participants) {
    const filterSelect = document.getElementById('participantFilter');
    const currentValue = filterSelect.value;

    // Clear existing options except the first one
    filterSelect.innerHTML = '<option value="">Vsi udeleženci</option>';

    // Sort participants by name and add to dropdown
    participants
        .sort((a, b) => a.name.localeCompare(b.name))
        .forEach(p => {
            const option = document.createElement('option');
            option.value = p.name;
            option.textContent = p.name;
            filterSelect.appendChild(option);
        });

    // Restore previous selection if it still exists
    filterSelect.value = currentValue;
}

async function addParticipant() {
    const name = document.getElementById('inputName').value.trim();
    const cardUID = document.getElementById('inputCardUID').value.trim();
    const keyUID = document.getElementById('inputKeyUID').value.trim();
    const expiration = document.getElementById('inputExpiration').value;

    if (!name) {
        alert('Prosimo, izpolnite polje za ime');
        return;
    }

    if (!cardUID && !keyUID) {
        alert('Prosimo, vnesite vsaj UID kartice ali UID ključa');
        return;
    }

    try {
        const response = await fetch('/api/participants', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                name: name,
                card_uid: cardUID || null,
                key_uid: keyUID || null,
                expiration_date: expiration || null
            })
        });

        if (!response.ok) {
            const errorData = await response.json();
            alert('Napaka: ' + (errorData.message || 'Unknown error'));
            return;
        }

        const data = await response.json();
        if (data.success) {
            alert('Udeleženec je bil uspešno dodan');
            closeAddParticipantModal();
            loadParticipants();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

function openEditModal(id, name, cardUID, keyUID, expiration) {
    editingParticipantId = id;
    document.getElementById('editName').value = name;
    document.getElementById('editCardUID').value = cardUID;
    document.getElementById('editKeyUID').value = keyUID;
    document.getElementById('editExpiration').value = expiration !== '-' ? expiration : '';
    document.getElementById('editModal').classList.add('show');
}

function openAddParticipantModal() {
    document.getElementById('addParticipantModal').classList.add('show');
}

function closeAddParticipantModal() {
    document.getElementById('addParticipantModal').classList.remove('show');
    document.getElementById('inputName').value = '';
    document.getElementById('inputCardUID').value = '';
    document.getElementById('inputKeyUID').value = '';
    document.getElementById('inputExpiration').value = '';
}

function openAddUnregisteredModal() {
    document.getElementById('addUnregisteredModal').classList.add('show');
    document.getElementById('inputUnregisteredName').focus();
}

function closeAddUnregisteredModal() {
    document.getElementById('addUnregisteredModal').classList.remove('show');
    document.getElementById('inputUnregisteredName').value = '';
}

async function addUnregisteredUser() {
    const name = document.getElementById('inputUnregisteredName').value.trim();

    if (!name) {
        alert('Prosimo, izpolnite polje za ime');
        return;
    }

    try {
        const response = await fetch('/api/logs/unregistered', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                name: name
            })
        });

        const data = await response.json();
        if (data.success) {
            alert('Neregistrirani udeleženec je bil uspešno dodan');
            closeAddUnregisteredModal();
            refreshLogs();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

function closeModal() {
    document.getElementById('editModal').classList.remove('show');
    editingParticipantId = null;
}

async function saveChanges() {
    if (!editingParticipantId) return;

    const name = document.getElementById('editName').value.trim();
    const cardUID = document.getElementById('editCardUID').value.trim();
    const keyUID = document.getElementById('editKeyUID').value.trim();
    const expiration = document.getElementById('editExpiration').value;

    if (!name) {
        alert('Prosimo, izpolnite polje za ime');
        return;
    }

    if (!cardUID && !keyUID) {
        alert('Prosimo, vnesite vsaj UID kartice ali UID ključa');
        return;
    }

    try {
        const response = await fetch(`/api/participants/${editingParticipantId}`, {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                name: name,
                card_uid: cardUID,
                key_uid: keyUID,
                expiration_date: expiration || null
            })
        });

        if (!response.ok) {
            const errorData = await response.json();
            alert('Napaka: ' + (errorData.message || 'Unknown error'));
            return;
        }

        const data = await response.json();
        if (data.success) {
            alert('Udeleženec je bil uspešno posodobljen');
            closeModal();
            loadParticipants();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

async function deleteParticipant(id) {
    if (!confirm('Ali ste prepričani, da želite izbrisati tega udeleženca?')) return;

    try {
        const response = await fetch(`/api/participants/${id}`, {
            method: 'DELETE'
        });

        const data = await response.json();
        if (data.success) {
            alert('Udeleženec je bil uspešno izbrisan');
            loadParticipants();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

// ===== LOGS MANAGEMENT =====
async function refreshLogs() {
    try {
        const filter = document.getElementById('filterSelect').value || 'All';
        const response = await fetch(`/api/logs?filter=${filter}`);
        const logs = await response.json();

        // Apply client-side filtering
        const filteredLogs = applyLogFilters(logs);

        const tbody = document.getElementById('logsTable');
        tbody.innerHTML = '';

        if (filteredLogs.length === 0) {
            tbody.innerHTML = `<tr><td colspan="8" style="text-align: center; padding: 20px; color: var(--text-secondary);">Ni najdenih dnevnikov, ki bi ustrezali filtrom</td></tr>`;
            return;
        }

        // Count occurrences of each name to detect duplicates
        const nameCounts = {};
        filteredLogs.forEach(log => {
            nameCounts[log.name] = (nameCounts[log.name] || 0) + 1;
        });

        // Count registered vs unregistered users
        let registeredCount = 0;
        let unregisteredCount = 0;

        filteredLogs.forEach(log => {
            const row = document.createElement('tr');
            const timestamp = log.timestamp;
            const date = timestamp.split('T')[0];
            const time = timestamp.split('T')[1].substring(0, 8);

            // Determine status class
            let statusClass = 'pass';
            if (log.scan_result === 'FAIL') {
                statusClass = 'fail';
            } else if (log.scan_result === 'MANUAL') {
                statusClass = 'manual';
            }

            // Check if this is an unregistered duplicate
            const isDuplicate = nameCounts[log.name] > 1;

            const actionButtons = isAdmin ? `
                <button class="action-btn delete-btn" onclick="deleteLog(${log.id})">Izbriši</button>
            ` : '';

            row.innerHTML = `
                <td>${log.id}</td>
                <td>${log.name}</td>
                <td>${log.card_uid || '-'}</td>
                <td>${log.key_uid || '-'}</td>
                <td><span class="${statusClass}">${log.scan_result}</span></td>
                <td>${date}</td>
                <td>${time}</td>
                <td>${actionButtons}</td>
            `;

            // Add duplicate warning class if this is a duplicate unregistered user
            if (isDuplicate && log.scan_result === 'MANUAL') {
                row.classList.add('duplicate-warning');
            }

            // Count registered vs unregistered
            if (log.scan_result === 'MANUAL') {
                unregisteredCount++;
            } else if (log.scan_result === 'PASS') {
                registeredCount++;
            }

            tbody.appendChild(row);
        });

        // Update stats display
        document.getElementById('statRegistered').textContent = registeredCount;
        document.getElementById('statUnregistered').textContent = unregisteredCount;

        updateUIDVisibility();
    } catch (error) {
        console.error('Error loading logs:', error);
    }
}

function applyLogFilters(logs) {
    const participantFilter = document.getElementById('participantFilter').value;
    const startDateFilter = document.getElementById('startDateFilter').value;
    const endDateFilter = document.getElementById('endDateFilter').value;

    return logs.filter(log => {
        // Filter by participant
        if (participantFilter && log.name !== participantFilter) {
            return false;
        }

        // Filter by date range
        if (startDateFilter || endDateFilter) {
            const logDate = log.timestamp.split('T')[0];

            if (startDateFilter && logDate < startDateFilter) {
                return false;
            }

            if (endDateFilter && logDate > endDateFilter) {
                return false;
            }
        }

        return true;
    });
}

async function deleteLog(logId) {
    if (!confirm('Ali ste prepričani, da želite izbrisati ta dnevnik?')) return;

    try {
        const response = await fetch(`/api/logs/${logId}`, {
            method: 'DELETE'
        });

        const data = await response.json();
        if (data.success) {
            alert('Dnevnik je bil uspešno izbrisan');
            refreshLogs();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

function resetFilters() {
    document.getElementById('filterSelect').value = 'All';
    document.getElementById('participantFilter').value = '';
    document.getElementById('startDateFilter').value = '';
    document.getElementById('endDateFilter').value = '';
    // Remove active class from all quick filter buttons
    document.querySelectorAll('.btn-quick-filter').forEach(btn => {
        btn.classList.remove('active');
    });
    refreshLogs();
}

function getDateString(date) {
    return date.toISOString().split('T')[0];
}

function filterByToday() {
    const today = new Date();
    document.getElementById('startDateFilter').value = getDateString(today);
    document.getElementById('endDateFilter').value = getDateString(today);
    updateQuickFilterButtons('today');
    refreshLogs();
}

function filterByLastWeek() {
    const today = new Date();
    const lastWeek = new Date(today.getTime() - 7 * 24 * 60 * 60 * 1000);
    document.getElementById('startDateFilter').value = getDateString(lastWeek);
    document.getElementById('endDateFilter').value = getDateString(today);
    updateQuickFilterButtons('week');
    refreshLogs();
}

function filterByLastMonth() {
    const today = new Date();
    const lastMonth = new Date(today.getTime() - 30 * 24 * 60 * 60 * 1000);
    document.getElementById('startDateFilter').value = getDateString(lastMonth);
    document.getElementById('endDateFilter').value = getDateString(today);
    updateQuickFilterButtons('month');
    refreshLogs();
}

function filterByLastYear() {
    const today = new Date();
    const lastYear = new Date(today.getTime() - 365 * 24 * 60 * 60 * 1000);
    document.getElementById('startDateFilter').value = getDateString(lastYear);
    document.getElementById('endDateFilter').value = getDateString(today);
    updateQuickFilterButtons('year');
    refreshLogs();
}

function updateQuickFilterButtons(activeFilter) {
    const buttons = document.querySelectorAll('.btn-quick-filter');
    buttons.forEach(btn => btn.classList.remove('active'));

    if (activeFilter === 'today') buttons[0].classList.add('active');
    else if (activeFilter === 'week') buttons[1].classList.add('active');
    else if (activeFilter === 'month') buttons[2].classList.add('active');
    else if (activeFilter === 'year') buttons[3].classList.add('active');
}

async function exportLogs() {
    try {
        // Get current filter values
        const filter = document.getElementById('filterSelect').value;
        const participant = document.getElementById('participantFilter').value;
        const startDate = document.getElementById('startDateFilter').value;
        const endDate = document.getElementById('endDateFilter').value;

        // Build query string with filters
        const params = new URLSearchParams({
            filter: filter,
            participant: participant,
            startDate: startDate,
            endDate: endDate
        });

        const response = await fetch('/api/export?' + params.toString());
        const result = await response.json();

        if (!result.success) {
            alert('Napaka pri izvozу: ' + result.message);
            return;
        }

        // Decode base64 file data
        const binaryString = atob(result.data);
        const bytes = new Uint8Array(binaryString.length);
        for (let i = 0; i < binaryString.length; i++) {
            bytes[i] = binaryString.charCodeAt(i);
        }

        // Create blob and trigger download with file dialog
        const blob = new Blob([bytes], { type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' });

        // Try to use pywebview if available (for desktop app)
        if (window.pywebview && window.pywebview.api) {
            try {
                const success = await window.pywebview.api.save_file(result.filename, result.data);
                if (success) {
                    alert('Datoteka je bila uspešno izvožena');
                    return;
                } else {
                    console.log('PyWebView save was cancelled, falling back to browser download');
                }
            } catch (error) {
                console.log('PyWebView save failed, falling back to browser download', error);
            }
        }

        // Fallback to browser download
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = result.filename;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(url);

        alert('Datoteka je bila uspešno izvožena');
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

// ===== PRINT LOGS =====
function printLogs() {
    const start = document.getElementById('startDateFilter').value;
    const end = document.getElementById('endDateFilter').value;
    const dateRange = document.getElementById('print-date-range');

    if (start && end) {
        dateRange.textContent = `Obdobje: ${start} – ${end}`;
    } else if (start) {
        dateRange.textContent = `Od: ${start}`;
    } else if (end) {
        dateRange.textContent = `Do: ${end}`;
    } else {
        dateRange.textContent = `Natisnjeno: ${new Date().toLocaleDateString('sl-SI')}`;
    }

    window.print();
}

// ===== DOCUMENTS =====
async function loadDocuments() {
    try {
        const response = await fetch('/api/documents');
        const files = await response.json();
        const grid = document.getElementById('documentsGrid');

        if (files.length === 0) {
            grid.innerHTML = `<p style="color: var(--text-secondary);">Ni dokumentov. Dodajte PDF datoteke v mapo static/PDF.</p>`;
            return;
        }

        grid.innerHTML = '';
        files.forEach(filename => {
            const card = document.createElement('div');
            card.className = 'document-card';
            const displayName = filename.replace(/\.pdf$/i, '').replace(/_/g, ' ');
            card.innerHTML = `
                <div class="document-icon">
                    <svg width="40" height="40" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round">
                        <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z"></path>
                        <polyline points="14 2 14 8 20 8"></polyline>
                        <line x1="9" y1="13" x2="15" y2="13"></line>
                        <line x1="9" y1="17" x2="15" y2="17"></line>
                    </svg>
                </div>
                <div class="document-name">${displayName}</div>
                <button class="btn btn-primary document-print-btn" onclick="printDocument('${filename}')">Natisni</button>
            `;
            grid.appendChild(card);
        });
    } catch (error) {
        console.error('Error loading documents:', error);
    }
}

function printDocument(filename) {
    const url = `/static/PDF/${encodeURIComponent(filename)}`;
    let iframe = document.getElementById('print-iframe');
    if (!iframe) {
        iframe = document.createElement('iframe');
        iframe.id = 'print-iframe';
        iframe.style.cssText = 'display:none;position:fixed;top:0;left:0;width:0;height:0;';
        document.body.appendChild(iframe);
    }
    iframe.onload = () => iframe.contentWindow.print();
    iframe.src = url;
}

// ===== TAB SWITCHING =====
function switchTab(tabName, event) {
    // Hide all tabs
    document.querySelectorAll('.tab-panel').forEach(tab => {
        tab.classList.remove('active');
    });

    // Remove active class from all buttons
    document.querySelectorAll('.tab-nav-btn').forEach(btn => {
        btn.classList.remove('active');
    });

    // Show selected tab
    document.getElementById(tabName + '-tab').classList.add('active');

    // Add active class to clicked button
    event.target.classList.add('active');

    // Load tab-specific data
    if (tabName === 'documents') loadDocuments();
    if (tabName === 'store') loadStore();
}

// Close modal when clicking outside
window.onclick = function(event) {
    const editModal = document.getElementById('editModal');
    const addModal = document.getElementById('addParticipantModal');
    const loginModal = document.getElementById('loginModal');
    const addUnregisteredModal = document.getElementById('addUnregisteredModal');
    const addItemModal = document.getElementById('addItemModal');
    const editBalanceModal = document.getElementById('editBalanceModal');

    if (event.target === editModal) closeModal();
    if (event.target === addModal) closeAddParticipantModal();
    if (event.target === loginModal) closeLoginModal();
    if (event.target === addUnregisteredModal) closeAddUnregisteredModal();
    if (event.target === addItemModal) closeAddItemModal();
    if (event.target === editBalanceModal) closeEditBalanceModal();
}

// ===== LAST SCAN RESULT =====
let lastScannedUID = '-';
let lastScanTimestamp = null;

async function updateLastScanResult() {
    try {
        const response = await fetch('/api/last-scan');
        const result = await response.json();

        const resultCard = document.getElementById('resultCard');
        const uidDiv = resultCard.querySelector('.result-uid');
        const nameDiv = resultCard.querySelector('.result-name');
        const statusDiv = resultCard.querySelector('.result-status');

        uidDiv.textContent = result.uid;
        nameDiv.textContent = result.name;
        statusDiv.textContent = result.status;
        lastScannedUID = result.uid;

        // If a new scan just happened, immediately refresh the logs table
        if (result.timestamp && result.timestamp !== lastScanTimestamp) {
            lastScanTimestamp = result.timestamp;
            refreshLogs();
        }

        // Update card styling based on result
        resultCard.className = 'result-card';
        if (result.status === 'PASS') {
            resultCard.classList.add('pass');
        } else if (result.status === 'FAIL') {
            resultCard.classList.add('fail');
        }
    } catch (error) {
        console.error('Error updating last scan result:', error);
    }
}

function copyUID(evt) {
    if (lastScannedUID === '-') {
        alert('Ni skeniranega UID-ja za kopiranje');
        return;
    }

    const copyBtn = evt.currentTarget;

    // Try using clipboard API first
    if (navigator.clipboard && navigator.clipboard.writeText) {
        navigator.clipboard.writeText(lastScannedUID).then(() => {
            showCopySuccess(copyBtn);
        }).catch(err => {
            console.error('Clipboard API failed:', err);
            fallbackCopy(lastScannedUID, copyBtn);
        });
    } else {
        // Fallback for older browsers
        fallbackCopy(lastScannedUID, copyBtn);
    }
}

function fallbackCopy(text, copyBtn) {
    const textarea = document.createElement('textarea');
    textarea.value = text;
    textarea.style.position = 'fixed';
    textarea.style.opacity = '0';
    document.body.appendChild(textarea);
    textarea.select();
    try {
        document.execCommand('copy');
        showCopySuccess(copyBtn);
    } catch (err) {
        console.error('Fallback copy failed:', err);
        alert('Napaka pri kopiranju UID-ja');
    }
    document.body.removeChild(textarea);
}

function showCopySuccess(copyBtn) {
    copyBtn.style.color = 'var(--accent-green)';
    setTimeout(() => {
        copyBtn.style.color = '';
    }, 1500);
}

// ===== UID VISIBILITY MANAGEMENT =====
function updateUIDVisibility() {
    const display = isAdmin ? '' : 'none';

    // Participants table columns
    const cardUIDHeader = document.getElementById('card-uid-header');
    const keyUIDHeader = document.getElementById('key-uid-header');
    if (cardUIDHeader) cardUIDHeader.style.display = display;
    if (keyUIDHeader) keyUIDHeader.style.display = display;

    // Logs table columns
    const logsCardUIDHeader = document.getElementById('logs-card-uid-header');
    const logsKeyUIDHeader = document.getElementById('logs-key-uid-header');
    const logsActionsHeader = document.getElementById('logs-actions-header');
    if (logsCardUIDHeader) logsCardUIDHeader.style.display = display;
    if (logsKeyUIDHeader) logsKeyUIDHeader.style.display = display;
    if (logsActionsHeader) logsActionsHeader.style.display = display;

    // Hide/show corresponding cells in all table rows
    hideTableColumn('participantsTable', 2, !isAdmin); // Card UID column
    hideTableColumn('participantsTable', 3, !isAdmin); // Key UID column
    hideTableColumn('logsTable', 2, !isAdmin); // Card UID column
    hideTableColumn('logsTable', 3, !isAdmin); // Key UID column
    hideTableColumn('logsTable', 7, !isAdmin); // Actions column

    // Last scan result UID
    const scanUIDContainer = document.getElementById('scan-result-uid-container');
    if (scanUIDContainer) scanUIDContainer.style.display = display;
}

// ===== STORE =====
let cart = [];
let storeItems = [];
let currentBalance = 0;
let editingItemId = null;

async function loadStore() {
    await Promise.all([loadStoreItems(), loadBalance()]);
}

async function loadStoreItems() {
    try {
        const response = await fetch('/api/store/items');
        storeItems = await response.json();
        renderInventory();
        renderCart();
    } catch (error) {
        console.error('Error loading store items:', error);
    }
}

async function loadBalance() {
    try {
        const response = await fetch('/api/store/balance');
        const data = await response.json();
        currentBalance = data.balance;
        document.getElementById('storeBalanceDisplay').textContent = '€' + currentBalance.toFixed(2);
        updateCartTotals();
    } catch (error) {
        console.error('Error loading balance:', error);
    }
}

const ITEM_FALLBACK_SVG = `<svg width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.2" stroke-linecap="round" stroke-linejoin="round" style="color:var(--text-secondary)"><path d="M6 2L3 6v14a2 2 0 002 2h14a2 2 0 002-2V6l-3-4z"/><line x1="3" y1="6" x2="21" y2="6"/><path d="M16 10a4 4 0 01-8 0"/></svg>`;

function renderInventory() {
    const grid = document.getElementById('inventoryGrid');
    if (!grid) return;

    if (storeItems.length === 0) {
        grid.innerHTML = '<p style="color: var(--text-secondary); grid-column: 1/-1;">Ni artiklov v zalogi.</p>';
        return;
    }

    grid.innerHTML = '';
    storeItems.forEach(item => {
        const card = document.createElement('div');
        card.className = 'inventory-card' + (item.stock === 0 ? ' out-of-stock' : '');
        const imgHtml = item.image
            ? `<img src="${item.image}" alt="${item.name}" class="inventory-card-img">`
            : `<div class="inventory-card-img-placeholder">${ITEM_FALLBACK_SVG}</div>`;
        card.innerHTML = `
            ${imgHtml}
            <div class="inventory-card-body">
                <div class="inventory-card-name">${item.name}</div>
                <div class="inventory-card-price">€${item.price.toFixed(2)}</div>
                <div class="inventory-card-stock ${item.stock === 0 ? 'stock-empty' : ''}">Zaloga: ${item.stock}</div>
            </div>
            <div class="inventory-card-actions">
                <button class="btn btn-primary inventory-add-btn" onclick="addToCart(${item.id})" ${item.stock === 0 ? 'disabled' : ''}>+ Dodaj</button>
                ${isAdmin ? `<button class="action-btn edit-btn" onclick="openEditItemModal(${item.id})">Uredi</button>
                <button class="action-btn delete-btn" onclick="deleteStoreItem(${item.id})">Izbriši</button>` : ''}
            </div>
        `;
        grid.appendChild(card);
    });
}

function addToCart(itemId) {
    const item = storeItems.find(i => i.id === itemId);
    if (!item || item.stock === 0) return;

    const existing = cart.find(c => c.id === itemId);
    const currentQty = existing ? existing.qty : 0;

    if (currentQty >= item.stock) {
        alert('Ni dovolj zaloge');
        return;
    }

    if (existing) {
        existing.qty++;
    } else {
        cart.push({ id: item.id, name: item.name, price: item.price, qty: 1 });
    }
    renderCart();
}

function removeFromCart(itemId) {
    const idx = cart.findIndex(c => c.id === itemId);
    if (idx === -1) return;
    if (cart[idx].qty > 1) {
        cart[idx].qty--;
    } else {
        cart.splice(idx, 1);
    }
    renderCart();
}

function clearCart() {
    cart = [];
    renderCart();
}

function renderCart() {
    const container = document.getElementById('cartItems');
    if (!container) return;

    if (cart.length === 0) {
        container.innerHTML = '<p style="color: var(--text-secondary); text-align: center; padding: 20px;">Košarica je prazna</p>';
        updateCartTotals();
        return;
    }

    container.innerHTML = '';
    cart.forEach(item => {
        const row = document.createElement('div');
        row.className = 'cart-item';
        row.innerHTML = `
            <div class="cart-item-name">${item.name}</div>
            <div class="cart-item-controls">
                <button class="cart-qty-btn" onclick="removeFromCart(${item.id})">−</button>
                <span class="cart-qty">${item.qty}</span>
                <button class="cart-qty-btn" onclick="addToCart(${item.id})">+</button>
            </div>
            <div class="cart-item-subtotal">€${(item.price * item.qty).toFixed(2)}</div>
        `;
        container.appendChild(row);
    });

    updateCartTotals();
}

function updateCartTotals() {
    const total = cart.reduce((sum, i) => sum + i.price * i.qty, 0);
    const balanceAfter = currentBalance + total;

    const totalEl = document.getElementById('cartTotal');
    const balanceAfterEl = document.getElementById('cartBalanceAfter');

    if (totalEl) totalEl.textContent = '€' + total.toFixed(2);
    if (balanceAfterEl) {
        balanceAfterEl.textContent = '€' + balanceAfter.toFixed(2);
        balanceAfterEl.className = 'cart-balance-after';
    }
}

async function processPayment() {
    if (cart.length === 0) {
        alert('Košarica je prazna');
        return;
    }

    const total = cart.reduce((sum, i) => sum + i.price * i.qty, 0);
    const balanceAfter = currentBalance + total;

    if (!confirm(`Skupaj: €${total.toFixed(2)}\nStanje po plačilu: €${balanceAfter.toFixed(2)}\n\nPotrdite plačilo?`)) return;

    try {
        const cartItems = cart.map(cartItem => {
            const storeItem = storeItems.find(i => i.id === cartItem.id);
            return {
                id: cartItem.id,
                name: cartItem.name,
                price: cartItem.price,
                qty: cartItem.qty,
                new_stock: storeItem ? storeItem.stock - cartItem.qty : 0,
                image: storeItem ? storeItem.image : null
            };
        });

        const response = await fetch('/api/store/payments', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                items: cart.map(i => ({ name: i.name, qty: i.qty, price: i.price })),
                cart_items: cartItems,
                total,
                balance_before: currentBalance,
                balance_after: balanceAfter
            })
        });

        const data = await response.json();
        if (!data.success) { alert('Napaka: ' + data.message); return; }

        cart = [];
        await loadStore();
        alert('Plačilo uspešno!');
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

let currentItemImage = null;

function openAddItemModal() {
    editingItemId = null;
    currentItemImage = null;
    document.getElementById('addItemModalTitle').textContent = 'Dodaj artikel';
    document.getElementById('addItemSubmitBtn').textContent = 'Dodaj';
    document.getElementById('itemName').value = '';
    document.getElementById('itemPrice').value = '';
    document.getElementById('itemStock').value = '';
    document.getElementById('itemImageInput').value = '';
    setImagePreview(null);
    document.getElementById('addItemModal').classList.add('show');
    document.getElementById('itemName').focus();
}

function openEditItemModal(itemId) {
    const item = storeItems.find(i => i.id === itemId);
    if (!item) return;
    editingItemId = itemId;
    currentItemImage = item.image || null;
    document.getElementById('addItemModalTitle').textContent = 'Uredi artikel';
    document.getElementById('addItemSubmitBtn').textContent = 'Shrani';
    document.getElementById('itemName').value = item.name;
    document.getElementById('itemPrice').value = item.price;
    document.getElementById('itemStock').value = item.stock;
    document.getElementById('itemImageInput').value = '';
    setImagePreview(item.image || null);
    document.getElementById('addItemModal').classList.add('show');
}

function closeAddItemModal() {
    document.getElementById('addItemModal').classList.remove('show');
    editingItemId = null;
    currentItemImage = null;
}

function handleImageUpload(event) {
    const file = event.target.files[0];
    if (!file) return;
    const reader = new FileReader();
    reader.onload = (e) => {
        currentItemImage = e.target.result;
        setImagePreview(currentItemImage);
    };
    reader.readAsDataURL(file);
}

function setImagePreview(src) {
    const preview = document.getElementById('imagePreview');
    const placeholder = document.getElementById('imageUploadPlaceholder');
    const removeBtn = document.getElementById('removeImageBtn');
    if (src) {
        preview.src = src;
        preview.style.display = 'block';
        placeholder.style.display = 'none';
        removeBtn.style.display = 'inline-block';
    } else {
        preview.src = '';
        preview.style.display = 'none';
        placeholder.style.display = 'flex';
        removeBtn.style.display = 'none';
    }
}

function removeItemImage() {
    currentItemImage = null;
    document.getElementById('itemImageInput').value = '';
    setImagePreview(null);
}

async function submitItem() {
    const name = document.getElementById('itemName').value.trim();
    const price = parseFloat(document.getElementById('itemPrice').value);
    const stock = parseInt(document.getElementById('itemStock').value, 10);

    if (!name) { alert('Vnesite ime artikla'); return; }
    if (isNaN(price) || price < 0) { alert('Vnesite veljavno ceno'); return; }
    if (isNaN(stock) || stock < 0) { alert('Vnesite veljavno zalogo'); return; }

    try {
        let response;
        if (editingItemId) {
            response = await fetch(`/api/store/items/${editingItemId}`, {
                method: 'PUT',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ name, price, stock, image: currentItemImage })
            });
        } else {
            response = await fetch('/api/store/items', {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ name, price, stock, image: currentItemImage })
            });
        }

        const data = await response.json();
        if (data.success) {
            closeAddItemModal();
            await loadStoreItems();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

async function deleteStoreItem(itemId) {
    if (!confirm('Izbriši artikel?')) return;
    try {
        const response = await fetch(`/api/store/items/${itemId}`, { method: 'DELETE' });
        const data = await response.json();
        if (data.success) {
            cart = cart.filter(c => c.id !== itemId);
            await loadStoreItems();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

function openEditBalanceModal() {
    document.getElementById('balanceInput').value = currentBalance.toFixed(2);
    document.getElementById('editBalanceModal').classList.add('show');
    document.getElementById('balanceInput').focus();
}

function closeEditBalanceModal() {
    document.getElementById('editBalanceModal').classList.remove('show');
}

async function saveBalance() {
    const amount = parseFloat(document.getElementById('balanceInput').value);
    if (isNaN(amount)) { alert('Vnesite veljavno vrednost'); return; }

    try {
        const response = await fetch('/api/store/balance', {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ balance: amount })
        });
        const data = await response.json();
        if (data.success) {
            closeEditBalanceModal();
            await loadBalance();
        } else {
            alert('Napaka: ' + data.message);
        }
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

// ===== PAYMENT HISTORY =====
let paymentHistoryVisible = false;

function togglePaymentHistory() {
    paymentHistoryVisible = !paymentHistoryVisible;
    const panel = document.getElementById('paymentHistoryPanel');
    panel.style.display = paymentHistoryVisible ? 'block' : 'none';
    if (paymentHistoryVisible) loadPaymentHistory();
}

async function loadPaymentHistory() {
    try {
        const response = await fetch('/api/store/payments');
        const payments = await response.json();
        const tbody = document.getElementById('paymentHistoryTable');
        if (!tbody) return;

        const clearBtn = document.getElementById('clearHistoryBtn');
        if (clearBtn) clearBtn.style.display = isAdmin ? 'inline-block' : 'none';

        if (payments.length === 0) {
            tbody.innerHTML = `<tr><td colspan="7" style="text-align:center;padding:20px;color:var(--text-secondary);">Ni zabeleženih plačil</td></tr>`;
            return;
        }

        tbody.innerHTML = '';
        [...payments].reverse().forEach(p => {
            const ts = p.timestamp;
            const date = ts.split('T')[0];
            const time = ts.split('T')[1].substring(0, 8);
            const itemsSummary = p.items.map(i => `${i.name} ×${i.qty}`).join(', ');
            const row = document.createElement('tr');
            row.innerHTML = `
                <td>${p.id}</td>
                <td>${date}</td>
                <td>${time}</td>
                <td style="max-width:220px;word-break:break-word;">${itemsSummary}</td>
                <td style="font-weight:700;color:var(--accent-blue);">€${p.total.toFixed(2)}</td>
                <td>€${p.balance_before.toFixed(2)}</td>
                <td>€${p.balance_after.toFixed(2)}</td>
            `;
            tbody.appendChild(row);
        });
    } catch (error) {
        console.error('Error loading payment history:', error);
    }
}

async function clearPaymentHistory() {
    if (!confirm('Izbriši celotno zgodovino plačil?')) return;
    try {
        const response = await fetch('/api/store/payments', { method: 'DELETE' });
        const data = await response.json();
        if (data.success) loadPaymentHistory();
        else alert('Napaka: ' + data.message);
    } catch (error) {
        alert('Napaka: ' + error.message);
    }
}

function hideTableColumn(tableId, columnIndex, hide) {
    const table = document.getElementById(tableId);
    if (!table) return;

    const rows = table.getElementsByTagName('tr');
    for (let row of rows) {
        const cell = row.cells[columnIndex];
        if (cell) {
            cell.style.display = hide ? 'none' : '';
        }
    }
}