package main

import (
	"encoding/csv"
	"fmt"
	"math/rand"
	"os"
)

func generateCSV(outputFile string) error {
	columns, err := fetchTableMetadata()
	if err != nil {
		return fmt.Errorf("error fetching table metadata: %w", err)
	}

	file, err := os.Create(outputFile)
	if err != nil {
		return fmt.Errorf("could not create file: %w", err)
	}
	defer file.Close()

	writer := csv.NewWriter(file)
	defer writer.Flush()

	header := make([]string, len(columns))
	for i, col := range columns {
		header[i] = col.Name
	}

	err = writer.Write(header)
	if err != nil {
		return fmt.Errorf("error writing header: %w", err)
	}

	for i := 0; i < numRows; i++ {
		rowData := make([]string, len(columns))
		for j, col := range columns {
			switch col.TypeName {
			case "integer", "float":
				rowData[j] = fmt.Sprint(rand.Intn(1000))
			case "varchar", "text":
				rowData[j] = fmt.Sprintf("sample text %d", rand.Intn(100))
			default:
				rowData[j] = ""
			}
			if col.MaxCharacterLength != nil && *col.MaxCharacterLength < len(rowData[j]) {
				rowData[j] = rowData[j][:*col.MaxCharacterLength]
			}
		}

		err := writer.Write(rowData)
		if err != nil {
			return fmt.Errorf("error writing row data: %w", err)
		}
	}

	fmt.Printf("CSV file '%s' generated successfully\n", outputFile)
	return nil
}