package flags

import (

"fmt"

"os"

"strings"

"github.com/spf13/pflag"

)

type readFromFileFlag struct {

// Used to read file.

// Set to os.ReadFile, except during tests

reader func(filename string) ([]byte, error)

value string

}

// Ensure the implementation satisfies the expected interface

var _ pflag.Value = &readFromFileFlag{}

// ReadFromFileFlag returns a string flag.

// If it starts with "@", it is assumed to be a file path and content is read from file instead

func ReadFromFileFlag() *readFromFileFlag {

return &readFromFileFlag{

reader: os.ReadFile,

}

}

func (f *readFromFileFlag) String() string {

return f.value

}

func (f *readFromFileFlag) Set(value string) error {

if !strings.HasPrefix(value, "@") {

f.value = value

} else {

valuePath := strings.Trim(value[1:], `"'`)

valueBytes, err := f.reader(valuePath)

if err != nil {

return fmt.Errorf("read data from file: %w", err)

}

f.value = string(valueBytes)

}

return nil

}

func (f *readFromFileFlag) Type() string {

return "string"

}