test creating excel report from inventory table

internal/report/create.go

@@ -0,0 +1,58 @@
+package report
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log/slog"
+	"reflect"
+	"strconv"
+	"vctp/db"
+
+	"github.com/xuri/excelize/v2"
+)
+
+func CreateReport(logger *slog.Logger, Database db.Database, ctx context.Context) ([]byte, error) {
+	var xlsx *excelize.File
+	sheetName := "Inventory Report"
+	var buffer bytes.Buffer
+
+	logger.Debug("Querying inventory table")
+	results, err := Database.Queries().ListInventory(ctx)
+	if err != nil {
+		logger.Error("Unable to query inventory table", "error", err)
+		return nil, err
+	}
+
+	if len(results) == 0 {
+		logger.Error("Empty inventory results")
+		return nil, fmt.Errorf("Empty inventory results")
+	}
+
+	// Use reflection to determine column headings from the first item
+	firstItem := results[0]
+	v := reflect.ValueOf(firstItem)
+	typeOfItem := v.Type()
+
+	// Create column headers dynamically
+	for i := 0; i < v.NumField(); i++ {
+		column := string(rune('A'+i)) + "1" // A1, B1, C1, etc.
+		xlsx.SetCellValue(sheetName, column, typeOfItem.Field(i).Name)
+	}
+
+	// Populate the Excel file with data from the Inventory table
+	for i, item := range results {
+		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())
+		}
+	}
+
+	// Save the Excel file into a byte buffer
+	if err := xlsx.Write(&buffer); err != nil {
+		return nil, err
+	}
+
+	return buffer.Bytes(), nil
+}