refactor: move buildCSV() to UsageGraphs_UsageGraphs

The buildCSV() method is shared amongst all usagegraphs classes and can
therefore be added to the abstract UsageGraphs_UsageGraphs class,
provided that it is amended to take in a string as a parameter with the
name of the section (eg. 'Admin')

code/web/services/Admin/AJAX.php

@@ -1614,7 +1614,7 @@ public function copyMenuLinks() {
 	public function exportUsageData() {
 		require_once ROOT_DIR . '/services/Admin/UsageGraphs.php';
 		$aspenUsageGraph = new Admin_UsageGraphs(); 
-		$aspenUsageGraph->buildCSV();
+		$aspenUsageGraph->buildCSV('Admin');
 		// TODO: trigger page refresh
 	}
 }

code/web/services/Admin/AbstractUsageGraphs.php

@@ -40,4 +40,48 @@ public function canView(): bool {
 		]);
 	}
 
+	public function buildCSV(string $section): void {
+		global $interface;
+
+		$stat = $_REQUEST['stat'];
+		if (!empty($_REQUEST['instance'])) {
+			$instanceName = $_REQUEST['instance'];
+		} else {
+			$instanceName = '';
+		}
+		$this->getAndSetInterfaceDataSeries($stat, $instanceName);
+		$dataSeries = $interface->getVariable('dataSeries');
+
+		$filename = "{$section}UsageData_{$stat}.csv";
+		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
+		header("Cache-Control: no-store, no-cache, must-revalidate");
+		header("Cache-Control: post-check=0, pre-check=0", false);
+		header("Pragma: no-cache");
+		header('Content-Type: text/csv; charset=utf-8');
+		header("Content-Disposition: attachment;filename={$filename}");
+		$fp = fopen('php://output', 'w');
+		$graphTitles = array_keys($dataSeries);
+		$numGraphTitles = count($dataSeries);
+
+		// builds the header for each section of the table in the CSV - column headers: Dates, and the title of the graph
+		for($i = 0; $i < $numGraphTitles; $i++) {
+			$dataSerie = $dataSeries[$graphTitles[$i]];
+			$numRows = count($dataSerie['data']);
+			$dates = array_keys($dataSerie['data']);
+			$header = ['Dates', $graphTitles[$i]];
+			fputcsv($fp, $header);
+
+				// builds each subsequent data row - aka the column value
+				if (empty($numRows)) {
+					fputcsv($fp, ['no data found']);
+				}
+				for($j = 0; $j < $numRows; $j++) {
+					$date = $dates[$j];
+					$value = $dataSerie['data'][$date];
+					$row = [$date, $value];
+					fputcsv($fp, $row);
+				}
+		}
+		exit();
+	}
 }

code/web/services/Admin/UsageGraphs.php

@@ -21,48 +21,6 @@ function getActiveAdminSection(): string {
 		return 'system_reports';
 	}
 
-
-	public function buildCSV() {
-		global $interface;
-
-		$stat = $_REQUEST['stat'];
-		if (!empty($_REQUEST['instance'])) {
-			$instanceName = $_REQUEST['instance'];
-		} else {
-			$instanceName = '';
-		}
-		$this->getAndSetInterfaceDataSeries($stat, $instanceName);
-		$dataSeries = $interface->getVariable('dataSeries');
-
-		$filename = "AspenUsageData_{$stat}.csv";
-		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-		header("Cache-Control: no-store, no-cache, must-revalidate");
-		header("Cache-Control: post-check=0, pre-check=0", false);
-		header("Pragma: no-cache");
-		header('Content-Type: text/csv; charset=utf-8');
-		header("Content-Disposition: attachment;filename={$filename}");
-		$fp = fopen('php://output', 'w');
-		$graphTitles = array_keys($dataSeries);
-		$numGraphTitles = count($dataSeries);
-
-		// builds the header for each section of the table in the CSV - column headers: Dates, and the title of the graph
-		for($i = 0; $i < $numGraphTitles; $i++) {
-			$dataSerie = $dataSeries[$graphTitles[$i]];
-			$numRows = count($dataSerie['data']);
-			$dates = array_keys($dataSerie['data']);
-			$header = ['Dates', $graphTitles[$i]];
-			fputcsv($fp, $header);
-
-				// builds each subsequent data row - aka the column value
-				for($j = 0; $j < $numRows; $j++) {
-					$date = $dates[$j];
-					$value = $dataSerie['data'][$date];
-					$row = [$date, $value];
-					fputcsv($fp, $row);
-				}
-		}
-		exit();
-	}
 	private function getAndSetInterfaceDataSeries($stat, $instanceName) {
 		global $interface;
 		global $enabledModules;