// SPDX-License-Identifier: MPL-2.0

package auth

import (
	"context"
	"errors"
	"strings"
	"time"
	"unicode"
	"unicode/utf8"
)

var (
	ErrProfileInput        = errors.New("auth: invalid profile change")
	ErrProfileAccess       = errors.New("auth: profile session is unavailable")
	ErrProfileConflict     = errors.New("auth: profile changed; reload before editing")
	ErrUsernameUnavailable = errors.New("auth: username is unavailable")
)

// OwnProfile contains mutable identity, not credentials or organization roles.
// Revision is independent of timestamps and increases for every profile edit.
type OwnProfile struct {
	UserID, Username, Email, DisplayName string
	Revision                             int64
}

// ProfileEdit is a trusted repository command, not an HTTP input model. The
// application must authenticate the session, validate CSRF/origin and rate-limit
// mutations. Username edits additionally require recent reauthentication (and
// any account-specific MFA). For password reauthentication, supply the verified
// hash so a concurrent password reset invalidates the write. After verified
// passkey approval, leave it empty. Do not log or serialize this command.
type ProfileEdit struct {
	UserID               string
	SessionDigest        [32]byte
	ExpectedRevision     int64
	Field, Value         string
	ExpectedPasswordHash string
}

// NormalizeProfileValue validates only supported fields. Email is deliberately
// absent: verified mailbox changes need a separate pending/confirmation flow.
func NormalizeProfileValue(field, value string) (string, error) {
	value = strings.TrimSpace(value)
	switch field {
	case "username":
		if !identifierPattern.MatchString(value) {
			return "", ErrProfileInput
		}
	case "display_name":
		if value == "" || len(value) > 128 || !utf8.ValidString(value) {
			return "", ErrProfileInput
		}
		for _, r := range value {
			if unicode.IsControl(r) {
				return "", ErrProfileInput
			}
		}
	default:
		return "", ErrProfileInput
	}
	return value, nil
}

// OwnProfileRepository is optional; no change to the authentication Repository
// interface is required. It derives access from the current session, never from
// a site-wide administrator flag. Implementations atomically recheck identity,
// session and revision, mutate one field, and append the audit. Username edits
// revoke other sessions but preserve the acting session. They never reassign
// stable IDs, memberships, passkeys, billing identities or historical records.
type OwnProfileRepository interface {
	OwnProfile(context.Context, [32]byte, time.Time) (OwnProfile, error)
	UpdateOwnProfile(context.Context, ProfileEdit, AuditEvent) (OwnProfile, error)
}