package blogposts

import (
	"bufio"
	"io"
	"io/fs"
	"strings"
)

type Post struct {
	Title, Description, Body string
	Tags                     []string
}

const (
	titleSeparator       = "Title: "
	descriptionSeparator = "Description: "
)

func getPost(fileSystem fs.FS, fileName string) (Post, error) {
	postFile, err := fileSystem.Open(fileName)
	if err != nil {
		return Post{}, err
	}
	defer postFile.Close()

	return newPost(postFile)
}

// NOTE: Does newPost have to be coupled to an fs.File ?
// Do we use all the methods and data from this type? What do we really need?
func newPost(postFile io.Reader) (Post, error) {
	scanner := bufio.NewScanner(postFile)

	readMetaLine := func(tagName string) string {
		scanner.Scan()
		return strings.TrimPrefix(scanner.Text(), tagName)
	}

	post := Post{
		Title:       readMetaLine(titleSeparator),
		Description: readMetaLine(descriptionSeparator),
	}
	return post, nil
}