$(document).ready(function() {
    var currentAdmin = null;
    var users = [];
    var folders = [];
    var assignedFolders = [];
    var selectedUserId = "";

    $.get('/api/auth/me')
        .done(function(user) {
            if (user.role !== 'admin') {
                alert('Kein Zugriff!');
                window.location.href = '/';
                return;
            }

            currentAdmin = user;
            $('#admin-user-label').text(user.username || 'Admin');
            refreshDashboard();
            $('body').removeClass('is-preload');
        })
        .fail(function() { window.location.href = '/'; });

    function showView(name) {
        $('.admin-view').removeClass('active').filter('[data-view="' + name + '"]').addClass('active');
        $('.nav-item').removeClass('active').filter('[data-view="' + name + '"]').addClass('active');
        window.scrollTo({ top: 0, behavior: 'smooth' });
    }

    $('.admin-nav').on('click', '.nav-item', function() {
        showView($(this).data('view'));
    });

    $('#logout-btn').click(function(e) {
        e.preventDefault();
        $.post('/api/auth/logout').done(function() { window.location.href = '/'; });
    });

    $('#refresh-dashboard').click(refreshDashboard);

    function refreshDashboard() {
        $.when(loadUsers(), loadFolders()).done(function() {
            renderStats();
            renderUsers();
            renderUserSelect();
            renderFolders();
            if (selectedUserId) {
                loadAssignments(selectedUserId);
            } else {
                renderSelectedUserSummary(null);
            }
        });
    }

    function loadUsers() {
        return $.get('/api/admin/users').done(function(data) {
            users = data || [];
        }).fail(function(xhr) {
            $('#users-tbody').html(
                '<tr><td colspan="6" style="color:#e44d26;">Fehler beim Laden: HTTP ' +
                xhr.status + '</td></tr>'
            );
        });
    }

    function loadFolders() {
        return $.get('/api/admin/folders').done(function(data) {
            folders = data || [];
        }).fail(function() {
            $('#folders-overview').html('<p style="color:#e44d26;">Ordner konnten nicht geladen werden.</p>');
        });
    }

    function roleCounts() {
        return users.reduce(function(acc, user) {
            var role = user.role || 'client';
            acc[role] = (acc[role] || 0) + 1;
            return acc;
        }, { admin: 0, user: 0, client: 0 });
    }

    function totalAssignments() {
        return users.reduce(function(total, user) {
            return total + ((user.folders && user.folders.length) || 0);
        }, 0);
    }

    function totalImages() {
        return folders.reduce(function(total, folder) {
            return total + (folder.image_count || 0);
        }, 0);
    }

    function renderStats() {
        var roles = roleCounts();
        var expiredClients = users.filter(function(user) { return user.expired; }).length;
        var unassignedUsers = users.filter(function(user) {
            return (user.role || 'client') !== 'admin' && (!user.folders || !user.folders.length);
        }).length;
        var unsharedFolders = folders.filter(function(folder) {
            return !folder.assigned_users || !folder.assigned_users.length;
        }).length;

        $('#stat-users').text(users.length);
        $('#stat-users-sub').text(roles.admin + ' Admins, ' + roles.user + ' User');
        $('#stat-folders').text(folders.length);
        $('#stat-folders-sub').text(totalImages() + ' Bilder in privaten Ordnern');
        $('#stat-access').text(totalAssignments());
        $('#stat-access-sub').text(unassignedUsers + ' Nutzer ohne Ordner');
        $('#stat-clients').text(roles.client);
        $('#stat-clients-sub').text(expiredClients + ' abgelaufen');

        renderAttentionList(unassignedUsers, unsharedFolders, expiredClients);
        renderRoleList(roles);
    }

    function appendSignal($target, label, value, muted) {
        var $item = $('<div></div>').addClass('signal-item');
        $('<strong></strong>').text(label).appendTo($item);
        $('<span></span>').toggleClass('muted', !!muted).text(value).appendTo($item);
        $target.append($item);
    }

    function renderAttentionList(unassignedUsers, unsharedFolders, expiredClients) {
        var $list = $('#attention-list').empty();
        appendSignal($list, 'Nutzer ohne Ordner', unassignedUsers, unassignedUsers === 0);
        appendSignal($list, 'Ordner ohne Freigabe', unsharedFolders, unsharedFolders === 0);
        appendSignal($list, 'Abgelaufene Clients', expiredClients, expiredClients === 0);
        appendSignal($list, 'Gesamtbilder privat', totalImages(), totalImages() === 0);
    }

    function renderRoleList(roles) {
        var $list = $('#role-list').empty();
        appendSignal($list, 'Admins', roles.admin || 0);
        appendSignal($list, 'Permanente User', roles.user || 0);
        appendSignal($list, 'Clients', roles.client || 0);
        appendSignal($list, 'Freigaben', totalAssignments());
    }

    function getRoleBadge(role, expired) {
        if (expired) return $('<span></span>').addClass('badge badge-expired').text('abgelaufen');
        return $('<span></span>').addClass('badge badge-' + (role || 'client')).text(role || 'client');
    }

    function renderUsers() {
        var $tbody = $('#users-tbody').empty();
        if (!users.length) {
            $tbody.html('<tr><td colspan="6" style="text-align:center;">Keine Nutzer gefunden</td></tr>');
            return;
        }

        users.forEach(function(user) {
            var role = user.role || 'client';
            var created = user.created_at ? new Date(user.created_at).toLocaleDateString('de-DE') : '-';
            var status = created;
            if (role === 'client' && user.expires_at) {
                status = (user.expired ? 'Abgelaufen: ' : 'Bis: ') +
                    new Date(user.expires_at).toLocaleDateString('de-DE');
            }

            var $row = $('<tr></tr>');
            var $userCell = $('<td></td>').text(user.username + ' ').append(getRoleBadge(role, user.expired));
            var $foldersCell = $('<td></td>');
            if (user.folders && user.folders.length) {
                user.folders.forEach(function(folder) {
                    $('<span></span>').addClass('badge folder-badge').text(folder).appendTo($foldersCell);
                });
            } else {
                $foldersCell.append($('<span></span>').addClass('muted').text('Keine privaten Ordner'));
            }

            var $actions = $('<td></td>');
            $('<button type="button" class="btn-small user-access">Zugriff</button>')
                .data('user-id', user.id)
                .appendTo($actions);
            $('<button type="button" class="btn-small user-password">PW</button>')
                .data('user-id', user.id)
                .data('username', user.username)
                .appendTo($actions);
            $('<button type="button" class="btn-small btn-danger user-delete">Loeschen</button>')
                .data('user-id', user.id)
                .data('username', user.username)
                .appendTo($actions);

            $row.append($('<td></td>').text(user.id));
            $row.append($userCell);
            $row.append($('<td></td>').text(role));
            $row.append($('<td></td>').text(status));
            $row.append($foldersCell);
            $row.append($actions);
            $tbody.append($row);
        });
    }

    function renderUserSelect() {
        var $select = $('#user-select').html('<option value="">Nutzer waehlen...</option>');
        users.forEach(function(user) {
            if ((user.role || 'client') === 'admin') return;
            $('<option></option>')
                .val(user.id)
                .text(user.username + ' (' + (user.role || 'client') + ')')
                .appendTo($select);
        });
        if (selectedUserId) $select.val(selectedUserId);
    }

    function renderFolders() {
        var $wrap = $('#folders-overview').empty();
        if (!folders.length) {
            $wrap.html('<p class="muted">Keine Unterordner im Bilderpfad gefunden.</p>');
            return;
        }

        folders.forEach(function(folder) {
            var $card = $('<div></div>').addClass('folder-card');
            $('<h3></h3>').text(folder.name).appendTo($card);

            var $meta = $('<div></div>').addClass('folder-meta').appendTo($card);
            $('<span></span>').addClass('folder-pill').text((folder.image_count || 0) + ' Bilder').appendTo($meta);
            $('<span></span>').addClass('folder-pill').text('privat').appendTo($meta);
            $('<span></span>').addClass('folder-pill').text((folder.assigned_users || []).length + ' Freigaben').appendTo($meta);

            var $assigned = $('<div></div>').appendTo($card);
            if (folder.assigned_users && folder.assigned_users.length) {
                folder.assigned_users.forEach(function(user) {
                    $('<span></span>').addClass('badge folder-badge').text(user.username).appendTo($assigned);
                });
            } else {
                $assigned.append($('<span></span>').addClass('muted').text('Noch niemandem freigegeben'));
            }

            var $actions = $('<div></div>').addClass('folder-actions').appendTo($card);
            $('<button type="button" class="btn-small folder-preview-btn">Ansehen</button>')
                .data('folder', folder.name)
                .appendTo($actions);
            $('<button type="button" class="btn-small folder-assign-btn">Freigaben</button>')
                .data('folder', folder.name)
                .appendTo($actions);

            $wrap.append($card);
        });
    }

    function renderAccessList() {
        var $list = $('#folder-access-list').empty();
        if (!folders.length) {
            $list.html('<p class="muted">Keine Unterordner gefunden.</p>');
            return;
        }

        folders.forEach(function(folder) {
            var checked = assignedFolders.indexOf(folder.name) !== -1;
            var $label = $('<label></label>').addClass('access-item');
            $('<input type="checkbox" />')
                .val(folder.name)
                .prop('checked', checked)
                .appendTo($label);
            $('<span></span>').text(folder.name + ' (' + (folder.image_count || 0) + ')').appendTo($label);
            $list.append($label);
        });
    }

    function findUser(userId) {
        var id = String(userId || '');
        return users.find(function(user) { return String(user.id) === id; }) || null;
    }

    function renderSelectedUserSummary(user) {
        var $summary = $('#selected-user-summary').empty();
        if (!user) {
            appendSignal($summary, 'Auswahl', 'Kein Nutzer', true);
            return;
        }
        appendSignal($summary, 'Rolle', user.role || 'client');
        appendSignal($summary, 'Ordner', (assignedFolders.length || 0) + ' freigegeben');
        if (user.expires_at) {
            appendSignal($summary, 'Client bis', new Date(user.expires_at).toLocaleDateString('de-DE'), !!user.expired);
        }
    }

    function loadAssignments(userId) {
        selectedUserId = String(userId || "");
        if (!selectedUserId) {
            $('#folder-table-wrap').hide();
            $('#folder-access-empty').show();
            assignedFolders = [];
            renderSelectedUserSummary(null);
            return;
        }

        $('#user-select').val(selectedUserId);
        $.get('/api/admin/assign?user_id=' + encodeURIComponent(selectedUserId)).done(function(data) {
            assignedFolders = data || [];
            renderAccessList();
            renderSelectedUserSummary(findUser(selectedUserId));
            $('#folder-access-empty').hide();
            $('#folder-table-wrap').show();
        }).fail(function() {
            assignedFolders = [];
            renderAccessList();
            renderSelectedUserSummary(findUser(selectedUserId));
            $('#folder-access-empty').hide();
            $('#folder-table-wrap').show();
        });
    }

    function saveAssignments() {
        if (!selectedUserId) return;
        assignedFolders = [];
        $('#folder-access-list input:checked').each(function() {
            assignedFolders.push($(this).val());
        });
        $.ajax({
            url: '/api/admin/assign',
            type: 'POST',
            contentType: 'application/json',
            data: JSON.stringify({ user_id: selectedUserId, folders: assignedFolders })
        }).done(function() {
            $('#assign-status').text('Gespeichert').show().delay(1200).fadeOut();
            refreshDashboard();
        }).fail(function(xhr) {
            alert((xhr.responseJSON && xhr.responseJSON.error) || 'Speichern fehlgeschlagen');
        });
    }

    $('#users-tbody').on('click', '.user-access', function() {
        loadAssignments($(this).data('user-id'));
        showView('access');
    });

    $('#user-select').change(function() {
        loadAssignments($(this).val());
    });

    $('#folder-access-list').on('change', 'input[type="checkbox"]', saveAssignments);

    $('#folders-overview').on('click', '.folder-assign-btn', function() {
        var folder = $(this).data('folder');
        showView('access');
        if (!selectedUserId) {
            alert('Bitte zuerst einen Nutzer in den Freigaben waehlen.');
            return;
        }
        var $checkbox = $('#folder-access-list input').filter(function() {
            return $(this).val() === folder;
        });
        if ($checkbox.length) {
            $checkbox.prop('checked', !$checkbox.prop('checked')).trigger('change');
        }
    });

    $('#folders-overview').on('click', '.folder-preview-btn', function() {
        var folder = $(this).data('folder');
        showView('preview');
        $('#folder-preview-title').text('Ordnerinhalt: ' + folder);
        $('#folder-preview-note').text('Lade Bilder...');
        $('#folder-preview').empty();
        $.get('/api/admin/folders/' + encodeURIComponent(folder) + '/images').done(function(images) {
            $('#folder-preview-note').text((images || []).length + ' Bilder im Ordner');
            var $preview = $('#folder-preview').empty();
            if (!images || !images.length) {
                $preview.html('<p class="muted">Dieser Ordner ist leer.</p>');
                return;
            }
            images.forEach(function(img) {
                var $link = $('<a></a>').attr({ href: img.full_url, target: '_blank', rel: 'noopener' });
                $('<img />').attr({ src: img.thumb_url, alt: img.name, title: img.name }).appendTo($link);
                $preview.append($link);
            });
        }).fail(function(xhr) {
            $('#folder-preview-note').text((xhr.responseJSON && xhr.responseJSON.error) || 'Ordner konnte nicht geladen werden.');
        });
    });

    $('#create-user-form').submit(function(e) {
        e.preventDefault();
        var username = $('#new-username').val().trim();
        var password = $('#new-password').val();
        var role = $('#new-role').val();
        if (!username || !password) {
            alert('Bitte Username und Passwort eingeben.');
            return;
        }
        $.ajax({
            url: '/api/admin/users',
            type: 'POST',
            contentType: 'application/json',
            data: JSON.stringify({ username: username, password: password, role: role })
        }).done(function() {
            $('#new-username, #new-password').val('');
            refreshDashboard();
        }).fail(function(xhr) {
            var msg = (xhr.responseJSON && xhr.responseJSON.error) || 'Unbekannter Fehler';
            alert('Fehler beim Erstellen: ' + msg);
        });
    });

    $('#users-tbody').on('click', '.user-delete', function() {
        var id = $(this).data('user-id');
        var name = $(this).data('username');
        if (!confirm('Nutzer "' + name + '" wirklich loeschen?')) return;
        $.ajax({ url: '/api/admin/users/' + id, type: 'DELETE' })
            .done(function() {
                if (String(selectedUserId) === String(id)) {
                    selectedUserId = "";
                    assignedFolders = [];
                }
                refreshDashboard();
            })
            .fail(function(err) { alert(err.responseJSON ? err.responseJSON.error : 'Fehler'); });
    });

    $('#users-tbody').on('click', '.user-password', function() {
        var id = $(this).data('user-id');
        var name = $(this).data('username');
        var newPw = prompt('Neues Passwort fuer "' + name + '":');
        if (!newPw) return;
        $.ajax({
            url: '/api/admin/users/' + id + '/password',
            type: 'PUT',
            contentType: 'application/json',
            data: JSON.stringify({ new_password: newPw })
        }).done(function() {
            alert('Passwort geaendert.');
        }).fail(function(err) {
            alert(err.responseJSON ? err.responseJSON.error : 'Fehler');
        });
    });

    $('#admin-pw-form').submit(function(e) {
        e.preventDefault();
        $.post('/api/auth/change-password', {
            old_password: $('#admin-pw-old').val(),
            new_password: $('#admin-pw-new').val()
        }).done(function() {
            alert('Passwort geaendert.');
            $('#admin-pw-old, #admin-pw-new').val('');
        }).fail(function(xhr) {
            alert(xhr.responseJSON ? xhr.responseJSON.error : 'Fehler');
        });
    });
});