package cli

import (
	"io"
	"os"
)

// A Source is a method of extracting input from the user.
type Source interface {
	// Extract fetches data from this source.
	Extract() (string, error)
}

// A StringSource is defined by a string.
type StringSource struct{ Data string }

// Extract pulls input data from the internal string.
func (s StringSource) Extract() (string, error) { return s.Data, nil }

// A StdinSource pulls from standard input.
type StdinSource struct{}

// Extract pulls input data from standard input.
func (s StdinSource) Extract() (string, error) {
	data, err := io.ReadAll(os.Stdin)
	if err != nil {
		return "", err
	}

	return string(data), nil
}

// A FileSource reads from a file.
type FileSource struct{ Path string }

// Extract pulls input data from the file source.
func (s FileSource) Extract() (string, error) {
	data, err := os.ReadFile(s.Path)
	if err != nil {
		return "", err
	}

	return string(data), nil
}