add chart data purge when deleting chart, TODO is when changing chart sensor

include/CanGrow_Core.h

@@ -741,7 +741,7 @@ unsigned long Timescale(byte unit) {
  * 
  */
 
-String Str_Chart_Json() {
+String Str_Chart_Json(bool escapeUnit = false) {
   JsonDocument doc;
   for(byte i = 0 ; i < Max_Dashboard_Chart ; i++) {
     if(config.grow.dashboard.chartConfigured[i] == true) {
@@ -752,14 +752,19 @@ String Str_Chart_Json() {
       
       objChart["name"] = config.system.sensor.name[config.grow.dashboard.chartSensor[i]];
       /* when for a RAW reading rawConvert is set, return the converted description and unit */
+      String unit;
       if((SensorIndex[config.system.sensor.type[config.grow.dashboard.chartSensor[i]]].read[config.grow.dashboard.chartRead[i]] == SENSOR_READ_TYPE_RAW) && (config.system.sensor.rawConvert[config.grow.dashboard.chartSensor[i]][config.grow.dashboard.chartRead[i]] > 0)) {
         objChart["descr"] = FPSTR(Sensor_Convert_Raw_descr[config.system.sensor.rawConvert[config.grow.dashboard.chartSensor[i]][config.grow.dashboard.chartRead[i]]]);
-        objChart["unit"] = FPSTR(Sensor_Convert_Raw_unit[config.system.sensor.rawConvert[config.grow.dashboard.chartSensor[i]][config.grow.dashboard.chartRead[i]]]);
+        unit = FPSTR(Sensor_Convert_Raw_unit[config.system.sensor.rawConvert[config.grow.dashboard.chartSensor[i]][config.grow.dashboard.chartRead[i]]]);
       } else {
         objChart["descr"] = FPSTR(Sensor_Read_descr[SensorIndex[config.system.sensor.type[config.grow.dashboard.chartSensor[i]]].read[config.grow.dashboard.chartRead[i]]]);
-        objChart["unit"] = FPSTR(Sensor_Read_unit[SensorIndex[config.system.sensor.type[config.grow.dashboard.chartSensor[i]]].read[config.grow.dashboard.chartRead[i]]]);
+        unit = FPSTR(Sensor_Read_unit[SensorIndex[config.system.sensor.type[config.grow.dashboard.chartSensor[i]]].read[config.grow.dashboard.chartRead[i]]]);
       }
       
+      /* if used within the template processor, it would interprate % as template variable */
+      if(escapeUnit == true)
+        unit.replace(F("%"), F("%%"));
+      objChart["unit"] = unit;
       /* build path to chart data dir */
       char chartDirPath[10];
       snprintf(chartDirPath, sizeof(chartDirPath), "%s%d", CHART_BASE_PATH, i);

include/CanGrow_LittleFS.h

@@ -861,6 +861,37 @@ void LFS_Chart_Rotate_Data(const byte chartId) {
 }
 
 
+/* Function to remove all Chart files */
+void LFS_Chart_Purge_Data(const byte chartId) {
+  const static char LogLoc[] PROGMEM = "[LittleFS:LFS_Chart_Purge_Data]";
+  char chartDirPath[10];
+  snprintf(chartDirPath, sizeof(chartDirPath), "%s%d", CHART_BASE_PATH, chartId);
+  
+  /* https://github.com/cotestatnt/async-esp-fs-webserver/blob/master/src/AsyncFsWebServer.cpp */
+  File root = LittleFS.open(chartDirPath, "r");
+  File file = root.openNextFile();
+  while (file) {
+    char timestampFile_char[12];
+    //timestampFile_char = file.name();
+    unsigned long timestampFile = strtoul(file.name(), NULL, 0);
+    if (!file.isDirectory()) {
+      char pathDelete[32];
+      snprintf(pathDelete, sizeof(pathDelete), "%s/%s", chartDirPath, file.name());
+      if(LittleFS.remove(pathDelete)) {
+        #ifdef DEBUG
+        Log.verbose(F("%s DELETED chart%d/%u" CR), LogLoc, chartId, timestampFile);
+        #endif
+      } else {
+        #ifdef DEBUG
+        Log.error(F("%s FAILED DELETE chart%d/%u" CR), LogLoc, chartId, timestampFile);
+        #endif
+      }
+    } 
+    file = root.openNextFile();
+  }
+}
+
+
 ///*
  //* ESP8266 functions
  //*/

include/Webserver/Page_grow.h

@@ -1214,6 +1214,8 @@ void WebPage_grow_dashboard(AsyncWebServerRequest *request) {
       config.grow.dashboard.chartRead[chartId] = 0;
       memset(config.grow.dashboard.chartColor[chartId], '\0', sizeof config.grow.dashboard.chartColor[chartId]);
       
+      /* purge all data */
+      LFS_Chart_Purge_Data(chartId);
       SaveConfig();
       Log.notice(F("%s config saved" CR), LogLoc);
     } else if(request->hasParam("delete_data", true)) {

include/Webserver/Page_root.h

@@ -161,7 +161,8 @@ String Proc_WebPage_root(const String& var) {
     if(chartCount > 0) {
       /* FOR TESTING ONLY - INCLUDE EXTERNAL CSSCHARTS*/
       html += F("<script type='application/json' id='chartJson'>");
-      html += Str_Chart_Json();
+      /* get chart json with escaped unit (replace % with %% because of template engine) */
+      html += Str_Chart_Json(true);
       html += F("</script>");
       html += F("<link rel='stylesheet' href='https://cdn.jsdelivr.net/npm/charts.css/dist/charts.min.css'>");
       html += F("<div id='chartDiv'><table id='chartTable' class='charts-css line multiple show-data-on-hover show-heading show-primary-axis'><caption>Linechart</caption>");