feat: update session handling and add session history endpoint

realtime/src/store/influx.js

@@ -15,11 +15,10 @@ const writeApi = client.getWriteApi(org, bucket, 'ms', {
 
 /**
  * Scrive dati generici su InfluxDB senza mapping.
- * I campi vengono scritti con il nome originale.
  * @param {string} measurement - nome della measurement (es. 'logs', 'weather')
  * @param {Object} fields - campi { key: value }
  * @param {string} sensor - nome del sensore
- * @param {string} session - id sessione
+ * @param {string} session - id sessione (tag immutabile)
  * @param {number} timestamp - timestamp unix ms
  */
 function writeGenericData(measurement, fields, sensor, session, timestamp) {
@@ -52,6 +51,24 @@ function writeForecastBatch(points, sensor, session) {
     }
 }
 
+/**
+ * Forza il flush del buffer di scrittura.
+ */
+async function flush() {
+    try {
+        await writeApi.flush();
+    } catch (err) {
+        console.error('[INFLUX] Flush error:', err.message);
+    }
+}
+
+/**
+ * Query storica per una sessione: ritorna righe pivotate con tutti i campi.
+ * @param {string} sensor - nome sensore
+ * @param {string} session - session_id (tag InfluxDB)
+ * @param {string} since - ISO timestamp o duration (es. "-30d")
+ * @returns {Array<Object>}
+ */
 async function queryHistory(sensor, session, since) {
     const queryApi = client.getQueryApi(org);
     const fluxQuery = `
@@ -61,6 +78,7 @@ async function queryHistory(sensor, session, since) {
             |> filter(fn: (r) => r.sensor == "${sensor}")
             |> filter(fn: (r) => r.session == "${session}")
             |> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")
+            |> sort(columns: ["_time"])
     `;
 
     const rows = [];
@@ -75,4 +93,44 @@ async function queryHistory(sensor, session, since) {
     });
 }
 
-module.exports = { writeGenericData, writeForecastBatch, queryHistory };
+/**
+ * Esporta tutti i dati di una sessione come CSV.
+ * @param {string} sensor - nome sensore
+ * @param {string} session - session_id
+ * @param {string} since - ISO timestamp inizio (opzionale, default -30d)
+ * @returns {string} CSV content
+ */
+async function exportSessionCSV(sensor, session, since) {
+    const start = since || '-30d';
+    const rows = await queryHistory(sensor, session, start);
+
+    if (rows.length === 0) return '';
+
+    // Raccogli tutti i field names (esclusi meta InfluxDB)
+    const metaKeys = new Set(['result', 'table', '_start', '_stop', '_measurement', 'sensor', 'session', '']);
+    const fieldNames = new Set();
+    for (const row of rows) {
+        for (const key of Object.keys(row)) {
+            if (!metaKeys.has(key) && key !== '_time') {
+                fieldNames.add(key);
+            }
+        }
+    }
+
+    const fields = Array.from(fieldNames).sort();
+    const header = ['timestamp', ...fields].join(',');
+
+    const csvRows = rows.map(row => {
+        const ts = row._time || '';
+        const values = fields.map(f => {
+            const v = row[f];
+            if (v === null || v === undefined) return '';
+            return v;
+        });
+        return [ts, ...values].join(',');
+    });
+
+    return header + '\n' + csvRows.join('\n') + '\n';
+}
+
+module.exports = { writeGenericData, writeForecastBatch, flush, queryHistory, exportSessionCSV };