Refactored command logic

cmd/utils.go

@@ -0,0 +1,63 @@
+package cmd
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/mikefarah/yq/v4/pkg/yqlib"
+	"github.com/spf13/cobra"
+)
+
+func initCommand(cmd *cobra.Command, args []string) (firstFileIndex int, err error) {
+	cmd.SilenceUsage = true
+
+	fileInfo, _ := os.Stdout.Stat()
+
+	if forceColor || (!forceNoColor && (fileInfo.Mode()&os.ModeCharDevice) != 0) {
+		colorsEnabled = true
+	}
+
+	firstFileIndex = -1
+	if !nullInput && len(args) == 1 {
+		firstFileIndex = 0
+	} else if len(args) > 1 {
+		firstFileIndex = 1
+	}
+
+	// backwards compatibilty
+	if outputToJSON {
+		outputFormat = "json"
+	}
+
+	if writeInplace && (firstFileIndex == -1) {
+		return 0, fmt.Errorf("write inplace flag only applicable when giving an expression and at least one file")
+	}
+
+	if writeInplace && splitFileExp != "" {
+		return 0, fmt.Errorf("write inplace cannot be used with split file")
+	}
+
+	if nullInput && len(args) > 1 {
+		return 0, fmt.Errorf("cannot pass files in when using null-input flag")
+	}
+
+	return firstFileIndex, nil
+}
+
+func configurePrinterWriter(format yqlib.PrinterOutputFormat, out io.Writer) yqlib.PrinterWriter {
+
+	var printerWriter yqlib.PrinterWriter
+
+	if splitFileExp != "" {
+		colorsEnabled = forceColor
+		splitExp, err := yqlib.NewExpressionParser().ParseExpression(splitFileExp)
+		if err != nil {
+			return nil
+		}
+		printerWriter = yqlib.NewMultiPrinterWriter(splitExp, format)
+	} else {
+		printerWriter = yqlib.NewSinglePrinterWriter(out)
+	}
+	return printerWriter
+}