//////////////////////////////////////////////////////////////////////////

package libvault

//////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////

import (
	"errors"
	log "github.com/sirupsen/logrus"
	"os"
	"strings"
	"time"
)

//////////////////////////////////////////////////////////////////////////

type Token struct {
	Token   string
	expires time.Time
}

//////////////////////////////////////////////////////////////////////////
// read and save token to a file

func NewTokenFromFile(filename string) (*Token, error) {

	// default the filename if not passed as arg
	if filename == "" {
		filename = VAULT_TOKEN_FILE
	}

	// read the contents of the file
	b, err := os.ReadFile(filename)
	if err != nil {
		log.WithFields(log.Fields{
			"filename": filename,
			"error":    err,
		}).Error("libvault: failed to read vault token from file")
		return nil, err
	}

	// get first line and trim any whitespace
	ts, _, _ := strings.Cut(string(b), "\n")
	ts = strings.TrimSpace(ts)
	if ts == "" {
		log.WithFields(log.Fields{
			"filename": filename,
			"raw":      string(b),
		}).Error("libvault: failed to parse vault token from file")
		return nil, errors.New("libvault: failed to parse vault token from file")
	}

	log.WithFields(log.Fields{
		"filename": filename,
		"token":    ts,
	}).Debug("libvault: successfully read vault token")

	return &Token{Token: ts}, nil
}

func (t *Token) SaveToFile(filename string) error {

	if filename == "" {
		filename = VAULT_TOKEN_FILE
	}

	data := []byte(t.Token + "\n")
	if err := os.WriteFile(filename, data, 0600); err != nil {
		log.WithFields(log.Fields{
			"filename": filename,
			"error":    err,
		}).Error("libvault: failed to write token to file")
		return err
	}

	log.WithFields(log.Fields{
		"filename": filename,
	}).Debug("libvault: successfully saved vault token")

	return nil
}

//////////////////////////////////////////////////////////////////////////
// find token expiry date

func (t *Token) Expires() (time.Time, error) {

	if t.expires.IsZero() {

		resp := &struct {
			Data *struct {
				ExpireTime time.Time `json:"expire_time"`
			} `json:"data"`
		}{}

		if err := vault.GET(t, "/auth/token/lookup-self", resp); err != nil {
			log.WithFields(log.Fields{
				"token": t.Token,
			}).Error("libvault: failed to determine token expiry date")
			return t.expires, err
		}

		t.expires = resp.Data.ExpireTime
	}

	return t.expires, nil
}

//////////////////////////////////////////////////////////////////////////
// renew token

func (t *Token) Renew(increment time.Duration) error {
	expiry, err := t.Expires()
	if err != nil {
		return err
	}

	// check if token should be renewed
	ttl := expiry.Sub(time.Now())
	if ttl.Seconds() > (VAULT_RENEW_PERIOD.Seconds()) {
		log.WithFields(log.Fields{
			"expiry": expiry.String(),
			"ttl":    ttl.String(),
		}).Debug("Token renewal not required")
		return nil
	}

	// renew token

	if increment == 0 {
		increment = VAULT_TTL
	}

	req := &struct {
		Increment string `json:"increment"`
	}{Increment: increment.String()}

	if err := vault.POST(t, "/auth/token/renew-self", req, nil); err != nil {
		log.WithFields(log.Fields{
			"token":     t.Token,
			"expiry":    expiry.String(),
			"ttl":       ttl.String(),
			"increment": increment.String(),
		}).Error("libvault: failed to renew token")
		return err
	}

	// reset expiry
	t.expires = time.Time{}

	return nil
}

//////////////////////////////////////////////////////////////////////////
// end of file