package user

import (
	"errors"
	"strings"
	"time"
)

var ErrUserNotFound = errors.New("user not found")
var ErrInvalidCredentials = errors.New("invalid credentials")
var ErrRegistrationClosed = errors.New("registration closed")
var ErrInvalidVerificationCode = errors.New("invalid verification code")
var ErrVerificationCodeExpired = errors.New("verification code expired")
var ErrAlreadyVerified = errors.New("user already verified")
var ErrInvalidPasswordResetCode = errors.New("invalid password reset code")
var ErrPasswordResetCodeExpired = errors.New("password reset code expired")
var ErrInvalidDisplayName = errors.New("invalid display name")
var ErrUsernameTaken = errors.New("username taken")
var ErrInvalidLookup = errors.New("invalid user lookup")
var ErrVerificationEmailNotSent = errors.New("verification email not sent")
var ErrPasswordTooLong = errors.New("password too long")
var ErrRoleChanged = errors.New("user role changed concurrently")
var ErrInvalidTransfer = errors.New("invalid ownership transfer")
var ErrConfirmationMismatch = errors.New("confirmation email does not match")

const MaxLookupIDs = 100

const MaxPasswordBytes = 72

func ValidatePassword(password string) error {
	if len(password) > MaxPasswordBytes {
		return ErrPasswordTooLong
	}
	return nil
}

type User struct {
	ID                      uint32    `json:"id"`
	Username                string    `json:"username"`
	Password                string    `json:"password"`
	PasswordResetCode       string    `json:"password_reset_code"`
	Email                   string    `json:"email"`
	DisplayName             string    `json:"display_name"`
	IsVerified              bool      `json:"is_verified"`
	RoleID                  uint32    `json:"role_id"`
	VerificationCode        string    `json:"verification_code"`
	VerificationExpiration  time.Time `json:"verification_expiration"`
	PasswordResetExpiration time.Time `json:"password_reset_expiration"`
	TokenVersion            uint32    `json:"token_version"`
	CreatedAt               time.Time `json:"created_at"`
	UpdatedAt               time.Time `json:"updated_at"`
}

const UnverifiedRetention = 7 * 24 * time.Hour

func (u User) IsStaleUnverifiedAt(now time.Time) bool {
	if u.IsVerified {
		return false
	}
	deadline := u.VerificationExpiration
	if deadline.IsZero() {
		deadline = u.CreatedAt
	}
	if deadline.IsZero() {
		return false
	}
	return now.After(deadline.Add(UnverifiedRetention))
}

func (u User) NameOrUsername() string {
	if trimmed := strings.TrimSpace(u.DisplayName); trimmed != "" {
		return trimmed
	}
	return u.Username
}