add sheets with chain

parallelSheets.go

package main

import (
	"context"
	"fmt"
	"log"
	"os"

  "github.com/xuri/excelize/v2"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

type Loan struct {
	ID      uint
	Name    string
	Company string
}

func main() {
	dsn := os.Getenv("POSTGRES_CONNECTION_STRING")
	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatal("Failed to connect to database: ", err)
	}
	defer db.Close()

	var loans []Loan
	if err := db.Find(&loans).Error; err != nil {
		log.Fatal("Failed to query database: ", err)
	}

	if err := generateReport(loans); err != nil {
		log.Fatal("Failed to generate report: ", err)
	}
}

func generateReport(loans []Loan) error {
	file := excelize.NewFile()
	sheetName := "Sheet1"

	file.SetCellValue(sheetName, "A1", "ID")
	file.SetCellValue(sheetName, "B1", "Name")
	file.SetCellValue(sheetName, "C1", "Company")

	loanCh := make(chan Loan)

	for i := 0; i < len(loans); i++ {
		go func(l Loan) {
			addLoanToSheet(file, sheetName, l)
			loanCh <- l
		}(loans[i])
	}

	for i := 0; i < len(loans); i++ {
		<-loanCh
	}

	if err := file.SaveAs("report.xlsx"); err != nil {
		return err
	}

	return nil
}

func addLoanToSheet(file *excelize.File, sheetName string, loan Loan) {
	row := len(file.GetRows(sheetName)) + 1
	cell := fmt.Sprintf("A%d", row)
	file.SetCellValue(sheetName, cell, loan.ID)

	cell = fmt.Sprintf("B%d", row)
	file.SetCellValue(sheetName, cell, loan.Name)

	cell = fmt.Sprintf("C%d", row)
	file.SetCellValue(sheetName, cell, loan.Company)
}