package htpasswd

import (
	"errors"
	"strings"
)

var (
	// ErrExists indicates the specified user already exists
	ErrExists = errors.New("user already exists")
	// ErrNotExists indicates the specified user does not exist
	ErrNotExists = errors.New("user does not exist")
	// ErrInvalidAlgorithm indicates the htpasswd entry doesn't contain a
	// valid algorithm signature
	ErrInvalidAlgorithm = errors.New("invalid algorithm")
	// ErrInvalidPassword indicates the offered password doesn't match
	ErrInvalidPassword = errors.New("invalid password")
)

// UserError indicates an error associated to the specified user
type UserError struct {
	Name string
	Hint string
	Err  error
}

func (e *UserError) Error() string {
	var buf strings.Builder
	var reason string

	if e.Hint != "" {
		reason = e.Hint
	} else {
		reason = e.Err.Error()
	}

	if e.Name == "" {
		return reason
	}

	_, _ = buf.WriteString(e.Name)
	_, _ = buf.WriteString(": ")
	_, _ = buf.WriteString(reason)
	return buf.String()
}

func (e *UserError) Unwrap() error {
	return e.Err
}