Improved financial chart

go-financial/main.go

@@ -6,6 +6,7 @@ import "io"
 import "log"
 import "os"
 import "strconv"
+import "strings"
 
 var COLUMNS []string
 
@@ -59,48 +60,100 @@ func printHTML(data []FinancialData, out io.Writer) {
         text: 'Source: yahoo.com'
     },
 
+		xAxis: {
+			type: 'datetime'
+		},
     yAxis: {
         title: {
             text: 'Value'
         }
     },
+		 plotOptions: {
+            area: {
+                fillColor: {
+                    linearGradient: {
+                        x1: 0,
+                        y1: 0,
+                        x2: 0,
+                        y2: 1
+                    },
+                    stops: [
+                        [0, Highcharts.getOptions().colors[0]],
+                        [1, Highcharts.Color(Highcharts.getOptions().colors[0]).setOpacity(0).get('rgba')]
+                    ]
+                },
+                marker: {
+                    radius: 2
+                },
+                lineWidth: 1,
+                states: {
+                    hover: {
+                        lineWidth: 1
+                    }
+                },
+                threshold: null
+            }
+        },
     legend: {
         layout: 'vertical',
         align: 'right',
         verticalAlign: 'middle'
     },
 
-    series: [{
-        name: 'Open',
-        data: [`+getDataOpen(data)+`]
-    }, {
-        name: 'Close',
-        data: [`+getDataClose(data)+`]
-    }]
+		series: [{
+            type: 'area',
+            name: 'Open',
+            data: `+getChartDataOpen(data)+`
+        },{
+            type: 'area',
+            name: 'Close',
+            data: `+getChartDataClose(data)+`
+        }]
 	});
 		</script>
   </body>
 </html>`)
 }
 
-func getDataOpen(data []FinancialData) string {
-	str := ""
-	for i, v := range data {
-		str += fmt.Sprintf("%.4f", v.Open)
-		if i < len(data)-1 {
+func toJSDate(date string) string {
+	str := "Date.UTC("
+	parts := strings.Split(date, "-")
+	for i, part := range parts {
+		str += strings.TrimLeft(part, "0")
+		if i < len(parts)-1 {
 			str += ","
 		}
 	}
+	str += ")"
 	return str
 }
-func getDataClose(data []FinancialData) string {
-	str := ""
+
+func getChartDataOpen(data []FinancialData) string {
+	str := "["
 	for i, v := range data {
-		str += fmt.Sprintf("%.4f", v.Close)
+		str += "["
+		str += toJSDate(v.Date)
+		str += fmt.Sprintf(", %.4f", v.Open)
+		str += "]"
 		if i < len(data)-1 {
 			str += ","
 		}
 	}
+	str += "]"
+	return str
+}
+func getChartDataClose(data []FinancialData) string {
+	str := "["
+	for i, v := range data {
+		str += "["
+		str += toJSDate(v.Date)
+		str += fmt.Sprintf(", %.4f", v.Close)
+		str += "]"
+		if i < len(data)-1 {
+			str += ","
+		}
+	}
+	str += "]"
 	return str
 }