package go_pgp

import (
	"bytes"
	"io"
	"os"

	// required in order to use the crypto.SHA256- and -SHA512-Hashes
	_ "crypto/sha256"
	_ "crypto/sha512"

	"github.com/ProtonMail/go-crypto/openpgp"
	"github.com/ProtonMail/go-crypto/openpgp/armor"
)

func writeKeyDataToFile(data []byte, filePath, dataType string, armored bool) error {
	out, err := os.Create(filePath)
	if nil != err {
		return err
	}
	defer out.Close()
	if !armored {
		_, err = out.Write(data)
		if nil == err {
			out.Sync()
		}
	} else {
		var armored io.WriteCloser
		armored, err = armor.Encode(out, dataType, nil)
		if nil != err {
			return err
		}

		_, err = armored.Write(data)
		if nil == err {
			armored.Close()
			out.Sync()
		}
	}
	return err
}

// WritePublicEntityData will write the entitys complete public data to a file
func WritePublicEntityData(entity *Entity, filePath string) error {
	data, err := ExtractPublicEntityData(entity)
	if nil != err {
		return err
	}

	return writeKeyDataToFile(data, filePath, openpgp.PublicKeyType, false)
}

// WriteArmoredPublicEntityData will write the entitys complete public data to an armored file
func WriteArmoredPublicEntityData(entity *Entity, filePath string) error {
	data, err := ExtractPublicEntityData(entity)
	if nil != err {
		return err
	}

	return writeKeyDataToFile(data, filePath, openpgp.PublicKeyType, true)
}

// WritePrivateEntityData will write the entitys public and private keys to a file
func WritePrivateEntityData(entity *Entity, filePath string) error {
	data, err := ExtractPrivateEntityData(entity)
	if nil != err {
		return err
	}

	return writeKeyDataToFile(data, filePath, openpgp.PrivateKeyType, false)
}

// WriteArmoredPrivateEntityData will write the entitys public and private keys to an armored file
func WriteArmoredPrivateEntityData(entity *Entity, filePath string) error {
	data, err := ExtractPrivateEntityData(entity)
	if nil != err {
		return err
	}

	return writeKeyDataToFile(data, filePath, openpgp.PrivateKeyType, true)
}

// ExtractPublicEntityData will write the entitys complete public data to a []byte
func ExtractPublicEntityData(entity *Entity) ([]byte, error) {
	if nil == entity {
		return nil, ErrUndefinedPGPEntity
	}
	out := new(bytes.Buffer)
	entity.Serialize(out)
	return out.Bytes(), nil
}

// ExtractPrivateEntityData will write the entitys public and private keys to a []byte
func ExtractPrivateEntityData(entity *Entity) ([]byte, error) {
	if nil == entity {
		return nil, ErrUndefinedPGPEntity
	}
	out := new(bytes.Buffer)
	entity.SerializePrivate(out, &defaultConfig)
	return out.Bytes(), nil
}