/**
 * fleet.js — Fleet Management module for Nexus POS
 *
 * Handles vehicle CRUD, maintenance schedules, logs, and alerts.
 */
var Fleet = (function() {
    'use strict';

    var API = '/pos/api/fleet';
    var token = localStorage.getItem('pos_token');
    var vehicles = [];
    var currentPage = 1;
    var searchTimeout = null;

    // ─── Helpers ───

    function headers() {
        return {
            'Content-Type': 'application/json',
            'Authorization': 'Bearer ' + token
        };
    }

    function fmt(n) {
        if (n == null) return '0';
        return parseFloat(n).toLocaleString('es-MX');
    }

    function fmtMoney(n) {
        if (n == null) return '$0.00';
        return '$' + parseFloat(n).toLocaleString('es-MX', {minimumFractionDigits: 2, maximumFractionDigits: 2});
    }

    function fmtDate(d) {
        if (!d) return '—';
        var dt = new Date(d);
        return dt.toLocaleDateString('es-MX', {day: '2-digit', month: 'short', year: 'numeric'});
    }

    function esc(s) {
        if (!s) return '';
        var d = document.createElement('div');
        d.textContent = s;
        return d.innerHTML;
    }

    // ─── Init ───

    function init() {
        // Tab switching
        document.querySelectorAll('.tab-btn').forEach(function(btn) {
            btn.addEventListener('click', function() {
                var tab = this.getAttribute('data-tab');
                document.querySelectorAll('.tab-btn').forEach(function(b) { b.classList.remove('is-active'); });
                document.querySelectorAll('.tab-panel').forEach(function(p) { p.classList.remove('is-active'); });
                this.classList.add('is-active');
                document.getElementById('tab-' + tab).classList.add('is-active');

                if (tab === 'maintenance') loadMaintenance();
                if (tab === 'history') loadHistory();
                if (tab === 'alerts') loadAlerts();
            });
        });

        // Search
        var searchInput = document.getElementById('searchInput');
        if (searchInput) {
            searchInput.addEventListener('input', function() {
                clearTimeout(searchTimeout);
                searchTimeout = setTimeout(function() {
                    currentPage = 1;
                    loadVehicles();
                }, 300);
            });
        }

        // New vehicle button
        document.getElementById('btnNewVehicle').addEventListener('click', function() {
            openVehicleModal();
        });

        // Load initial data
        loadStats();
        loadVehicles();
    }

    // ─── Stats ───

    function loadStats() {
        fetch(API + '/stats', {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                document.getElementById('statTotal').textContent = fmt(d.total_vehicles);
                document.getElementById('statOverdue').textContent = fmt(d.overdue_count);
                document.getElementById('statUpcoming').textContent = fmt(d.upcoming_this_month);
                document.getElementById('statCost').textContent = fmtMoney(d.total_cost_month);
            })
            .catch(function() {});
    }

    // ─── Vehicles Tab ───

    function loadVehicles() {
        var q = (document.getElementById('searchInput') || {}).value || '';
        var url = API + '/vehicles?page=' + currentPage + '&per_page=50';
        if (q) url += '&q=' + encodeURIComponent(q);

        fetch(url, {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                vehicles = d.data || [];
                renderVehicleGrid(vehicles);
                renderPagination(d.pagination);
                populateVehicleSelects(vehicles);
            })
            .catch(function() {
                document.getElementById('vehicleGrid').innerHTML =
                    '<div class="empty-state"><div class="empty-state__text">Error al cargar vehiculos</div></div>';
            });
    }

    function renderVehicleGrid(list) {
        var grid = document.getElementById('vehicleGrid');
        if (!list.length) {
            grid.innerHTML = '<div class="empty-state">' +
                '<div class="empty-state__icon">&#x1F69A;</div>' +
                '<div class="empty-state__text">No hay vehiculos registrados</div>' +
                '<button class="btn btn--primary" onclick="Fleet.openVehicleModal()">+ Agregar Vehiculo</button>' +
                '</div>';
            return;
        }

        var html = '';
        list.forEach(function(v) {
            var label = (v.make || '') + ' ' + (v.model || '');
            if (v.year) label += ' ' + v.year;

            html += '<div class="vehicle-card" onclick="Fleet.viewVehicle(' + v.id + ')">' +
                '<div class="vehicle-card__header">' +
                    '<span class="vehicle-card__plate">' + esc(v.plate || 'SIN PLACA') + '</span>' +
                    '<span class="badge ' + (v.is_active ? 'badge--active' : 'badge--inactive') + '">' +
                        (v.is_active ? 'Activo' : 'Inactivo') + '</span>' +
                '</div>' +
                '<div class="vehicle-card__info">' +
                    '<div><strong>' + esc(label.trim()) + '</strong></div>' +
                    (v.owner_name ? '<div>' + esc(v.owner_name) + '</div>' : '') +
                    (v.color ? '<div>Color: ' + esc(v.color) + '</div>' : '') +
                '</div>' +
                '<div class="vehicle-card__footer">' +
                    '<span>' + fmt(v.current_mileage) + ' km</span>' +
                    '<span>' + esc(v.fuel_type || '') + '</span>' +
                '</div>' +
            '</div>';
        });
        grid.innerHTML = html;
    }

    function renderPagination(p) {
        var el = document.getElementById('vehiclePagination');
        if (!p || p.total_pages <= 1) { el.innerHTML = ''; return; }

        el.innerHTML = '<button class="pagination__btn" ' + (p.page <= 1 ? 'disabled' : '') +
            ' onclick="Fleet.goPage(' + (p.page - 1) + ')">&laquo; Anterior</button>' +
            '<span class="pagination__info">Pagina ' + p.page + ' de ' + p.total_pages +
            ' (' + p.total + ' vehiculos)</span>' +
            '<button class="pagination__btn" ' + (p.page >= p.total_pages ? 'disabled' : '') +
            ' onclick="Fleet.goPage(' + (p.page + 1) + ')">Siguiente &raquo;</button>';
    }

    function goPage(n) {
        currentPage = n;
        loadVehicles();
    }

    function populateVehicleSelects(list) {
        var opts = '<option value="">-- Seleccionar vehiculo --</option>';
        list.forEach(function(v) {
            var label = (v.plate || 'S/P') + ' - ' + (v.make || '') + ' ' + (v.model || '');
            opts += '<option value="' + v.id + '">' + esc(label.trim()) + '</option>';
        });
        var selects = ['schedVehicleSelect', 'logVehicleSelect'];
        selects.forEach(function(id) {
            var el = document.getElementById(id);
            if (el) el.innerHTML = opts;
        });
    }

    // ─── Vehicle Detail (view in edit modal) ───

    function viewVehicle(id) {
        fetch(API + '/vehicles/' + id, {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(v) {
                openVehicleModal(v);
            });
    }

    // ─── Vehicle Modal ───

    function openVehicleModal(data) {
        var modal = document.getElementById('vehicleModal');
        var title = document.getElementById('vehicleModalTitle');

        if (data && data.id) {
            title.textContent = 'Editar Vehiculo';
            document.getElementById('vehEditId').value = data.id;
            document.getElementById('vehPlate').value = data.plate || '';
            document.getElementById('vehVin').value = data.vin || '';
            document.getElementById('vehMake').value = data.make || '';
            document.getElementById('vehModel').value = data.model || '';
            document.getElementById('vehYear').value = data.year || '';
            document.getElementById('vehMileage').value = data.current_mileage || 0;
            document.getElementById('vehFuel').value = data.fuel_type || 'gasolina';
            document.getElementById('vehColor').value = data.color || '';
            document.getElementById('vehOwner').value = data.owner_name || '';
            document.getElementById('vehNotes').value = data.notes || '';
        } else {
            title.textContent = 'Nuevo Vehiculo';
            document.getElementById('vehEditId').value = '';
            ['vehPlate','vehVin','vehMake','vehModel','vehYear','vehColor','vehOwner','vehNotes']
                .forEach(function(id) { document.getElementById(id).value = ''; });
            document.getElementById('vehMileage').value = '0';
            document.getElementById('vehFuel').value = 'gasolina';
        }

        modal.classList.add('is-open');
    }

    function closeVehicleModal() {
        document.getElementById('vehicleModal').classList.remove('is-open');
    }

    function saveVehicle() {
        var editId = document.getElementById('vehEditId').value;
        var payload = {
            plate: document.getElementById('vehPlate').value.trim(),
            vin: document.getElementById('vehVin').value.trim(),
            make: document.getElementById('vehMake').value.trim(),
            model: document.getElementById('vehModel').value.trim(),
            year: parseInt(document.getElementById('vehYear').value) || null,
            current_mileage: parseInt(document.getElementById('vehMileage').value) || 0,
            fuel_type: document.getElementById('vehFuel').value,
            color: document.getElementById('vehColor').value.trim(),
            owner_name: document.getElementById('vehOwner').value.trim(),
            notes: document.getElementById('vehNotes').value.trim(),
        };

        if (!payload.plate && !payload.vin) {
            alert('Se requiere placa o VIN');
            return;
        }

        var url = API + '/vehicles';
        var method = 'POST';
        if (editId) {
            url += '/' + editId;
            method = 'PUT';
        }

        fetch(url, {
            method: method,
            headers: headers(),
            body: JSON.stringify(payload)
        })
        .then(function(r) { return r.json(); })
        .then(function(d) {
            if (d.error) { alert(d.error); return; }
            closeVehicleModal();
            loadVehicles();
            loadStats();
        })
        .catch(function(e) { alert('Error: ' + e.message); });
    }

    // ─── Maintenance Tab ───

    function loadMaintenance() {
        // Load all vehicles with their schedules
        fetch(API + '/vehicles?per_page=200', {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                var allVehicles = d.data || [];
                var promises = allVehicles.map(function(v) {
                    return fetch(API + '/vehicles/' + v.id + '/schedules', {headers: headers()})
                        .then(function(r) { return r.json(); })
                        .then(function(s) {
                            return {vehicle: v, schedules: s.data || []};
                        });
                });
                return Promise.all(promises);
            })
            .then(function(results) {
                renderMaintenance(results);
            })
            .catch(function() {
                document.getElementById('maintBody').innerHTML =
                    '<tr><td colspan="7" style="text-align:center;color:var(--color-text-muted);">Error al cargar</td></tr>';
            });
    }

    function renderMaintRow(item) {
        var v = item.vehicle;
        var s = item.schedule;
        var now = new Date();
        var isOverdue = false;
        if (s.next_due_at && new Date(s.next_due_at) < now) isOverdue = true;
        if (s.next_due_km && s.next_due_km <= v.current_mileage) isOverdue = true;

        var interval = '';
        if (s.interval_km) interval += fmt(s.interval_km) + ' km';
        if (s.interval_km && s.interval_months) interval += ' / ';
        if (s.interval_months) interval += s.interval_months + ' meses';

        var next = '';
        if (s.next_due_at) next += fmtDate(s.next_due_at);
        if (s.next_due_at && s.next_due_km) next += ' / ';
        if (s.next_due_km) next += fmt(s.next_due_km) + ' km';

        return '<tr>' +
            '<td><strong>' + esc(v.plate || 'S/P') + '</strong><br>' +
                '<span style="font-size:var(--text-caption);color:var(--color-text-muted);">' +
                esc((v.make || '') + ' ' + (v.model || '')) + '</span></td>' +
            '<td>' + esc(s.maintenance_type) + '</td>' +
            '<td class="mono">' + (interval || '—') + '</td>' +
            '<td>' + fmtDate(s.last_done_at) + (s.last_done_km ? '<br><span class="mono" style="font-size:var(--text-caption);">' + fmt(s.last_done_km) + ' km</span>' : '') + '</td>' +
            '<td>' + (next || '—') + '</td>' +
            '<td><span class="badge ' + (isOverdue ? 'badge--overdue' : 'badge--active') + '">' +
                (isOverdue ? 'Vencido' : 'Al dia') + '</span></td>' +
            '<td><button class="btn btn--sm btn--ghost" onclick="Fleet.openLogModalFor(' + v.id + ',' + s.id + ',\'' + esc(s.maintenance_type) + '\')">Registrar</button></td>' +
            '</tr>';
    }

    var maintVS = null;

    function renderMaintenance(results) {
        var body = document.getElementById('maintBody');
        var items = [];

        results.forEach(function(r) {
            r.schedules.forEach(function(s) {
                items.push({vehicle: r.vehicle, schedule: s});
            });
        });

        if (!items.length) {
            body.innerHTML = '<tr><td colspan="7" style="text-align:center;padding:var(--space-6);color:var(--color-text-muted);">' +
                'No hay programas de mantenimiento.<br><button class="btn btn--primary btn--sm" style="margin-top:var(--space-3);" onclick="Fleet.openScheduleModal()">+ Crear Programa</button></td></tr>';
            return;
        }

        if (!maintVS) {
            maintVS = new VirtualScroll({
                container: body,
                rowHeight: 64,
                buffer: 3,
                renderRow: renderMaintRow,
                emptyHtml: '<tr><td colspan="7" style="text-align:center;padding:var(--space-6);color:var(--color-text-muted);">No hay programas de mantenimiento.</td></tr>'
            });
        }
        maintVS.setData(items);
    }

    // ─── History Tab ───

    function loadHistory() {
        fetch(API + '/vehicles?per_page=200', {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                var allVehicles = d.data || [];
                var promises = allVehicles.map(function(v) {
                    return fetch(API + '/vehicles/' + v.id, {headers: headers()})
                        .then(function(r) { return r.json(); })
                        .then(function(detail) {
                            return {vehicle: v, logs: detail.recent_logs || []};
                        });
                });
                return Promise.all(promises);
            })
            .then(function(results) {
                renderHistory(results);
            })
            .catch(function() {
                document.getElementById('historyBody').innerHTML =
                    '<tr><td colspan="7" style="text-align:center;color:var(--color-text-muted);">Error al cargar</td></tr>';
            });
    }

    function renderHistoryRow(l) {
        return '<tr>' +
            '<td>' + fmtDate(l.created_at) + '</td>' +
            '<td><strong>' + esc(l._plate) + '</strong><br>' +
                '<span style="font-size:var(--text-caption);color:var(--color-text-muted);">' + esc(l._make) + '</span></td>' +
            '<td>' + esc(l.maintenance_type) + '</td>' +
            '<td class="mono">' + fmt(l.mileage_at) + '</td>' +
            '<td class="mono">' + fmtMoney(l.cost) + '</td>' +
            '<td>' + esc(l.employee_name || '—') + '</td>' +
            '<td style="max-width:200px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;">' + esc(l.notes || '—') + '</td>' +
            '</tr>';
    }

    var historyVS = null;

    function renderHistory(results) {
        var body = document.getElementById('historyBody');
        var allLogs = [];

        results.forEach(function(r) {
            r.logs.forEach(function(l) {
                l._plate = r.vehicle.plate || 'S/P';
                l._make = (r.vehicle.make || '') + ' ' + (r.vehicle.model || '');
                allLogs.push(l);
            });
        });

        // Sort by date desc
        allLogs.sort(function(a, b) {
            return new Date(b.created_at) - new Date(a.created_at);
        });

        if (!allLogs.length) {
            body.innerHTML = '<tr><td colspan="7" style="text-align:center;padding:var(--space-6);color:var(--color-text-muted);">No hay registros de mantenimiento</td></tr>';
            return;
        }

        if (!historyVS) {
            historyVS = new VirtualScroll({
                container: body,
                rowHeight: 48,
                buffer: 3,
                renderRow: renderHistoryRow,
                emptyHtml: '<tr><td colspan="7" style="text-align:center;padding:var(--space-6);color:var(--color-text-muted);">No hay registros de mantenimiento</td></tr>'
            });
        }
        historyVS.setData(allLogs);
    }

    // ─── Alerts Tab ───

    function loadAlerts() {
        fetch(API + '/alerts', {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                renderAlerts(d.data || []);
            })
            .catch(function() {
                document.getElementById('alertsList').innerHTML =
                    '<div class="empty-state"><div class="empty-state__text">Error al cargar alertas</div></div>';
            });
    }

    function renderAlerts(list) {
        var el = document.getElementById('alertsList');
        if (!list.length) {
            el.innerHTML = '<div class="empty-state">' +
                '<div class="empty-state__icon" style="color:#3FB950;">&#10003;</div>' +
                '<div class="empty-state__text">No hay mantenimientos vencidos</div>' +
                '</div>';
            return;
        }

        var html = '';
        list.forEach(function(a) {
            var detail = '';
            if (a.next_due_at) detail += 'Vencio: ' + fmtDate(a.next_due_at);
            if (a.next_due_km) detail += (detail ? ' | ' : '') + 'Limite: ' + fmt(a.next_due_km) + ' km (actual: ' + fmt(a.current_mileage) + ' km)';

            html += '<div class="alert-card">' +
                '<div class="alert-card__info">' +
                    '<div class="alert-card__vehicle">' +
                        esc(a.plate || 'S/P') + ' — ' + esc((a.make || '') + ' ' + (a.model || '')) +
                        (a.year ? ' ' + a.year : '') +
                    '</div>' +
                    '<div class="alert-card__detail">' +
                        '<span class="badge badge--overdue">' + esc(a.maintenance_type) + '</span>' +
                        ' &nbsp; ' + detail +
                    '</div>' +
                '</div>' +
                '<button class="btn btn--sm btn--primary" onclick="Fleet.openLogModalFor(' + a.vehicle_id + ',' + a.schedule_id + ',\'' + esc(a.maintenance_type) + '\')">Registrar Mant.</button>' +
                '</div>';
        });
        el.innerHTML = html;
    }

    // ─── Schedule Modal ───

    function openScheduleModal(vehicleId) {
        var modal = document.getElementById('scheduleModal');
        document.getElementById('schedType').value = '';
        document.getElementById('schedIntervalKm').value = '';
        document.getElementById('schedIntervalMonths').value = '';
        document.getElementById('schedNextDate').value = '';
        document.getElementById('schedNextKm').value = '';
        document.getElementById('schedNotes').value = '';

        if (vehicleId) {
            document.getElementById('schedVehicleSelect').value = vehicleId;
        }

        modal.classList.add('is-open');
    }

    function closeScheduleModal() {
        document.getElementById('scheduleModal').classList.remove('is-open');
    }

    function saveSchedule() {
        var vehicleId = document.getElementById('schedVehicleSelect').value;
        if (!vehicleId) { alert('Seleccione un vehiculo'); return; }

        var mType = document.getElementById('schedType').value.trim();
        if (!mType) { alert('Ingrese el tipo de mantenimiento'); return; }

        var payload = {
            maintenance_type: mType,
            interval_km: parseInt(document.getElementById('schedIntervalKm').value) || null,
            interval_months: parseInt(document.getElementById('schedIntervalMonths').value) || null,
            next_due_at: document.getElementById('schedNextDate').value || null,
            next_due_km: parseInt(document.getElementById('schedNextKm').value) || null,
            notes: document.getElementById('schedNotes').value.trim(),
        };

        fetch(API + '/vehicles/' + vehicleId + '/schedules', {
            method: 'POST',
            headers: headers(),
            body: JSON.stringify(payload)
        })
        .then(function(r) { return r.json(); })
        .then(function(d) {
            if (d.error) { alert(d.error); return; }
            closeScheduleModal();
            loadMaintenance();
            loadStats();
        })
        .catch(function(e) { alert('Error: ' + e.message); });
    }

    // ─── Log Modal ───

    function openLogModal() {
        var modal = document.getElementById('logModal');
        document.getElementById('logScheduleSelect').innerHTML = '<option value="">-- Sin programa --</option>';
        document.getElementById('logType').value = '';
        document.getElementById('logMileage').value = '';
        document.getElementById('logCost').value = '';
        document.getElementById('logParts').value = '';
        document.getElementById('logNotes').value = '';
        modal.classList.add('is-open');
    }

    function openLogModalFor(vehicleId, scheduleId, maintType) {
        openLogModal();
        document.getElementById('logVehicleSelect').value = vehicleId;
        if (maintType) document.getElementById('logType').value = maintType;

        // Load schedules for this vehicle
        fetch(API + '/vehicles/' + vehicleId + '/schedules', {headers: headers()})
            .then(function(r) { return r.json(); })
            .then(function(d) {
                var opts = '<option value="">-- Sin programa --</option>';
                (d.data || []).forEach(function(s) {
                    var sel = (s.id == scheduleId) ? ' selected' : '';
                    opts += '<option value="' + s.id + '"' + sel + '>' + esc(s.maintenance_type) + '</option>';
                });
                document.getElementById('logScheduleSelect').innerHTML = opts;
            });

        // Pre-fill mileage
        var veh = vehicles.find(function(v) { return v.id == vehicleId; });
        if (veh) document.getElementById('logMileage').value = veh.current_mileage || '';
    }

    function closeLogModal() {
        document.getElementById('logModal').classList.remove('is-open');
    }

    function saveLog() {
        var vehicleId = document.getElementById('logVehicleSelect').value;
        if (!vehicleId) { alert('Seleccione un vehiculo'); return; }

        var mType = document.getElementById('logType').value.trim();
        if (!mType) { alert('Ingrese el tipo de mantenimiento'); return; }

        var payload = {
            schedule_id: parseInt(document.getElementById('logScheduleSelect').value) || null,
            maintenance_type: mType,
            mileage_at: parseInt(document.getElementById('logMileage').value) || null,
            cost: parseFloat(document.getElementById('logCost').value) || 0,
            parts_used: document.getElementById('logParts').value.trim(),
            notes: document.getElementById('logNotes').value.trim(),
        };

        fetch(API + '/vehicles/' + vehicleId + '/log', {
            method: 'POST',
            headers: headers(),
            body: JSON.stringify(payload)
        })
        .then(function(r) { return r.json(); })
        .then(function(d) {
            if (d.error) { alert(d.error); return; }
            closeLogModal();
            loadStats();
            // Refresh current tab
            var activeTab = document.querySelector('.tab-btn.is-active');
            if (activeTab) {
                var tab = activeTab.getAttribute('data-tab');
                if (tab === 'maintenance') loadMaintenance();
                if (tab === 'history') loadHistory();
                if (tab === 'alerts') loadAlerts();
                if (tab === 'vehicles') loadVehicles();
            }
        })
        .catch(function(e) { alert('Error: ' + e.message); });
    }

    // ─── Public API ───

    document.addEventListener('DOMContentLoaded', init);

    return {
        openVehicleModal: openVehicleModal,
        closeVehicleModal: closeVehicleModal,
        saveVehicle: saveVehicle,
        viewVehicle: viewVehicle,
        goPage: goPage,
        openScheduleModal: openScheduleModal,
        closeScheduleModal: closeScheduleModal,
        saveSchedule: saveSchedule,
        openLogModal: openLogModal,
        openLogModalFor: openLogModalFor,
        closeLogModal: closeLogModal,
        saveLog: saveLog,
    };

})();