fix excel report

internal/report/create.go

@@ -3,17 +3,19 @@ package report
 import (
 	"bytes"
 	"context"
+	"database/sql"
 	"fmt"
 	"log/slog"
 	"reflect"
 	"strconv"
+	"time"
 	"vctp/db"
 
 	"github.com/xuri/excelize/v2"
 )
 
 func CreateReport(logger *slog.Logger, Database db.Database, ctx context.Context) ([]byte, error) {
-	var xlsx *excelize.File
+	//var xlsx *excelize.File
 	sheetName := "Inventory Report"
 	var buffer bytes.Buffer
 
@@ -29,6 +31,23 @@ func CreateReport(logger *slog.Logger, Database db.Database, ctx context.Context
 		return nil, fmt.Errorf("Empty inventory results")
 	}
 
+	// Create excek workbook
+	xlsx := excelize.NewFile()
+	err = xlsx.SetSheetName("Sheet1", sheetName)
+	if err != nil {
+		logger.Error("Error setting sheet name", "error", err, "sheet_name", sheetName)
+		return nil, err
+	}
+
+	// Set the document properties
+	err = xlsx.SetDocProps(&excelize.DocProperties{
+		Creator: "json2excel",
+		Created: time.Now().Format(time.RFC3339),
+	})
+	if err != nil {
+		logger.Error("Error setting document properties", "error", err, "sheet_name", sheetName)
+	}
+
 	// Use reflection to determine column headings from the first item
 	firstItem := results[0]
 	v := reflect.ValueOf(firstItem)
@@ -45,7 +64,8 @@ func CreateReport(logger *slog.Logger, Database db.Database, ctx context.Context
 		v = reflect.ValueOf(item)
 		for j := 0; j < v.NumField(); j++ {
 			column := string(rune('A'+j)) + strconv.Itoa(i+2) // Start from row 2
-			xlsx.SetCellValue(sheetName, column, v.Field(j).Interface())
+			value := getFieldValue(v.Field(j))
+			xlsx.SetCellValue(sheetName, column, value)
 		}
 	}
 
@@ -56,3 +76,38 @@ func CreateReport(logger *slog.Logger, Database db.Database, ctx context.Context
 
 	return buffer.Bytes(), nil
 }
+
+// Helper function to get the actual value of sql.Null types
+func getFieldValue(field reflect.Value) interface{} {
+	switch field.Kind() {
+	case reflect.Struct:
+		// Handle sql.Null types based on their concrete type
+		switch field.Interface().(type) {
+		case sql.NullString:
+			ns := field.Interface().(sql.NullString)
+			if ns.Valid {
+				return ns.String
+			}
+			return ""
+		case sql.NullInt64:
+			ni := field.Interface().(sql.NullInt64)
+			if ni.Valid {
+				return ni.Int64
+			}
+			return 0
+		case sql.NullFloat64:
+			nf := field.Interface().(sql.NullFloat64)
+			if nf.Valid {
+				return nf.Float64
+			}
+			return nil
+		case sql.NullBool:
+			nb := field.Interface().(sql.NullBool)
+			if nb.Valid {
+				return nb.Bool
+			}
+			return false
+		}
+	}
+	return field.Interface() // Return the value as-is for non-sql.Null types
+}