// Package bootstrap deals with the creation of bootstrap files
package bootstrap

import (
	"cryptic-net/tarutil"
	"fmt"
	"io"
	"io/fs"
)

// GetHashFromFS returns the hash of the contents of the given bootstrap file.
// It may return nil if the bootstrap file doesn't have a hash.
func GetHashFromFS(bootstrapFS fs.FS) ([]byte, error) {

	b, err := fs.ReadFile(bootstrapFS, tarutil.HashBinPath)

	if err != nil {
		return nil, fmt.Errorf("reading file %q from bootstrap fs: %w", tarutil.HashBinPath, err)
	}

	return b, nil
}

// GetHashFromReader reads the given tgz file as an fs.FS, and passes that to
// GetHashFromFS.
func GetHashFromReader(r io.Reader) ([]byte, error) {

	bootstrapFS, err := tarutil.FSFromReader(r)
	if err != nil {
		return nil, fmt.Errorf("reading tar fs from reader: %w", err)
	}

	return GetHashFromFS(bootstrapFS)
}