Agent-System-Backend/internal/store/account_model.go

package store

import (
	"crypto/rand"
	"database/sql"
	"encoding/hex"
	"errors"
	"fmt"
	"net/mail"
	"sort"
	"strings"
	"unicode"
	"unicode/utf8"
)

var ErrAccountForbidden = errors.New("store: account action forbidden")
var ErrInvalidAccountProfile = errors.New("store: invalid account profile")

// CredentialOrigin describes persisted credential history, not the authority
// of the caller. Unknown values never supply owner proof.
type CredentialOrigin string

const (
	CredentialOriginLegacyUnknown       CredentialOrigin = "legacy_unknown"
	CredentialOriginAdminPassword       CredentialOrigin = "admin_password"
	CredentialOriginOwnerInitialization CredentialOrigin = "owner_initialization"
	CredentialOriginOwnerRecovery       CredentialOrigin = "owner_recovery"
	InitializationLegacy                                 = "legacy"
	InitializationPending                                = "pending"
	InitializationInitialized                            = "initialized"
	AuthMethodLegacyUnknown                              = "legacy_unknown"
	AuthMethodPassword                                   = "password"
	AuthMethodGrant                                      = "grant"
)

// TrustedForOwnerProof checks only lineage. The recovery boundary must also
// check the exact live password session, account/version and proposal binding.
func (origin CredentialOrigin) TrustedForOwnerProof() bool {
	return origin == CredentialOriginOwnerInitialization || origin == CredentialOriginOwnerRecovery
}

type AccountProfile struct {
	Name       string `json:"name"`
	Phone      string `json:"phone"`
	Email      string `json:"email"`
	StaffNo    string `json:"staffNo"`
	Department string `json:"department"`
	Notes      string `json:"notes"`
}

// Account is an internal account view without credential material. Handlers and
// directory providers must project only the fields authorized for their caller.
type Account struct {
	ID                       string
	Owner                    string
	Profile                  AccountProfile
	ProfileVersion           int64
	Enabled                  bool
	StateVersion             int64
	IsAdmin                  bool
	HasPassword              bool
	MustChangePassword       bool
	AuthVersion              int
	CredentialOrigin         CredentialOrigin
	InitializationState      string
	InitializationGeneration int64
}

type AccountDirectoryRevision struct {
	Public  string
	StaffNo string
	Private string
}

type AccountCursorKey struct {
	Version int
	Secret  [32]byte
}

const accountColumns = `id,owner,COALESCE(name,''),phone,email,staff_no,department,notes,
	profile_version,enabled,state_version,is_admin,password_hash<>'',must_change_password,
	auth_version,credential_origin,initialization_state,initialization_generation`

type accountQuerier interface {
	QueryRow(string, ...any) *sql.Row
}

type accountScanner interface{ Scan(...any) error }

func scanAccount(row accountScanner) (Account, error) {
	var a Account
	err := row.Scan(&a.ID, &a.Owner, &a.Profile.Name, &a.Profile.Phone, &a.Profile.Email,
		&a.Profile.StaffNo, &a.Profile.Department, &a.Profile.Notes, &a.ProfileVersion,
		&a.Enabled, &a.StateVersion, &a.IsAdmin, &a.HasPassword, &a.MustChangePassword,
		&a.AuthVersion, &a.CredentialOrigin, &a.InitializationState, &a.InitializationGeneration)
	if errors.Is(err, sql.ErrNoRows) {
		return Account{}, ErrNotFound
	}
	return a, err
}

// GetAccount uses the stable identity; it performs no caller authorization.
func (s *Store) GetAccount(userID string) (Account, error) {
	return scanAccount(s.db.QueryRow(s.q(`SELECT `+accountColumns+` FROM users WHERE id=?`), userID))
}

func (s *Store) GetAccountByOwner(owner string) (Account, error) {
	return s.accountByOwner(s.db, owner)
}

func (s *Store) accountByOwner(db accountQuerier, owner string) (Account, error) {
	return scanAccount(db.QueryRow(s.q(`SELECT `+accountColumns+` FROM users WHERE owner=?`), owner))
}

// lockAccountUsers is the common first lock for account transactions. Always
// acquire all participating users in owner order before proposal, grant and
// session locks. PG locks persist to commit; SQLite already holds its immediate
// transaction write lock. Never lock a second user later in an arbitrary order.
func (s *Store) lockAccountUsers(tx *sql.Tx, owners ...string) (map[string]Account, error) {
	ordered := append([]string(nil), owners...)
	sort.Strings(ordered)
	accounts := make(map[string]Account, len(ordered))
	query := s.q(`SELECT ` + accountColumns + ` FROM users WHERE owner=?`)
	if s.Dialect() == "postgres" {
		query += ` FOR UPDATE`
	}
	for _, owner := range ordered {
		if _, exists := accounts[owner]; exists {
			continue
		}
		if err := s.dialect.lockAccount(tx, owner); err != nil {
			return nil, err
		}
		a, err := scanAccount(tx.QueryRow(query, owner))
		if err != nil {
			return nil, err
		}
		accounts[owner] = a
	}
	return accounts, nil
}

func validateAccountProfilePatch(patch map[string]string) (map[string]string, error) {
	limits := map[string]int{"name": 128, "phone": 64, "email": 254, "staffNo": 64, "department": 128, "notes": 2000}
	normalized := make(map[string]string, len(patch))
	for field, value := range patch {
		limit, ok := limits[field]
		if !ok {
			return nil, fmt.Errorf("%w: unknown field", ErrInvalidAccountProfile)
		}
		if !utf8.ValidString(value) {
			return nil, fmt.Errorf("%w: %s is not UTF-8", ErrInvalidAccountProfile, field)
		}
		for _, r := range value {
			if unicode.IsControl(r) {
				return nil, fmt.Errorf("%w: %s contains control characters", ErrInvalidAccountProfile, field)
			}
		}
		value = strings.TrimSpace(value)
		if utf8.RuneCountInString(value) > limit {
			return nil, fmt.Errorf("%w: %s exceeds %d characters", ErrInvalidAccountProfile, field, limit)
		}
		if field == "email" && value != "" {
			address, err := mail.ParseAddress(value)
			if err != nil || address.Address != value || address.Name != "" {
				return nil, fmt.Errorf("%w: invalid email", ErrInvalidAccountProfile)
			}
		}
		normalized[field] = value
	}
	return normalized, nil
}

func applyAccountProfilePatch(profile AccountProfile, patch map[string]string) AccountProfile {
	for field, value := range patch {
		switch field {
		case "name":
			profile.Name = value
		case "phone":
			profile.Phone = value
		case "email":
			profile.Email = value
		case "staffNo":
			profile.StaffNo = value
		case "department":
			profile.Department = value
		case "notes":
			profile.Notes = value
		}
	}
	return profile
}

// PatchAccountProfile takes an actor from a trusted authentication boundary;
// callers must enforce its full password-session requirement. Current account
// status/admin authorization is rechecked under the same locks as the write.
func (s *Store) PatchAccountProfile(actorOwner, userID string, expectedProfileVersion int64, patch map[string]string) (Account, error) {
	if expectedProfileVersion < 1 {
		return Account{}, fmt.Errorf("%w: expectedProfileVersion is required", ErrInvalidAccountProfile)
	}
	normalized, err := validateAccountProfilePatch(patch)
	if err != nil {
		return Account{}, err
	}
	tx, err := s.db.Begin()
	if err != nil {
		return Account{}, err
	}
	defer tx.Rollback()
	actor, err := s.accountByOwner(tx, actorOwner)
	if errors.Is(err, ErrNotFound) || (err == nil && !actor.Enabled) {
		return Account{}, ErrAccountForbidden
	}
	if err != nil {
		return Account{}, err
	}
	target, err := scanAccount(tx.QueryRow(s.q(`SELECT `+accountColumns+` FROM users WHERE id=?`), userID))
	if errors.Is(err, ErrNotFound) && actor.ID != userID {
		return Account{}, ErrAccountForbidden
	}
	if err != nil {
		return Account{}, err
	}
	locked, err := s.lockAccountUsers(tx, actorOwner, target.Owner)
	if err != nil {
		return Account{}, err
	}
	actor, target = locked[actorOwner], locked[target.Owner]
	if !actor.Enabled {
		return Account{}, ErrAccountForbidden
	}
	if actor.ID != target.ID {
		if err := s.requireSystemActionTx(tx, actor, "system.users.edit"); err != nil {
			return Account{}, err
		}
	}
	if target.ID != userID || target.ProfileVersion != expectedProfileVersion {
		return Account{}, ErrConflict
	}
	profile := applyAccountProfilePatch(target.Profile, normalized)
	result, err := tx.Exec(s.q(`UPDATE users SET name=?,phone=?,email=?,staff_no=?,department=?,notes=?,profile_version=profile_version+1 WHERE id=? AND profile_version=?`),
		profile.Name, profile.Phone, profile.Email, profile.StaffNo, profile.Department, profile.Notes, userID, expectedProfileVersion)
	if err != nil {
		return Account{}, err
	}
	if n, err := result.RowsAffected(); err != nil {
		return Account{}, err
	} else if n != 1 {
		return Account{}, ErrConflict
	}
	if profile != target.Profile {
		if err := s.bumpAccountDirectoryRevision(tx, profile.Name != target.Profile.Name, profile.StaffNo != target.Profile.StaffNo); err != nil {
			return Account{}, err
		}
	}
	// Audit field names and versions only, never profile values.
	fields := make([]string, 0, len(normalized))
	for field := range normalized {
		fields = append(fields, field)
	}
	sort.Strings(fields)
	if err := s.insertAccountEvent(tx, actorOwner, "account-profile", target.Owner, "profile_updated", fmt.Sprintf("version=%d fields=%s", expectedProfileVersion+1, strings.Join(fields, ","))); err != nil {
		return Account{}, err
	}
	if err := s.auditAccountMutation(tx, target.Owner, actorOwner, "account.profile"); err != nil {
		return Account{}, err
	}
	if err := tx.Commit(); err != nil {
		return Account{}, err
	}
	target.Profile, target.ProfileVersion = profile, expectedProfileVersion+1
	return target, nil
}

// CreatePendingAccount is the ordinary account-management primitive. It cannot
// set passwords, administrator privileges or trusted credential provenance.
func (s *Store) CreatePendingAccount(actorOwner, owner string, profile AccountProfile) (Account, error) {
	tx, err := s.db.Begin()
	if err != nil {
		return Account{}, err
	}
	defer tx.Rollback()
	locked, err := s.lockAccountUsers(tx, actorOwner)
	if errors.Is(err, ErrNotFound) {
		return Account{}, ErrAccountForbidden
	}
	if err != nil {
		return Account{}, err
	}
	actor := locked[actorOwner]
	if err := s.requireSystemActionTx(tx, actor, "system.users.create"); err != nil {
		return Account{}, err
	}
	a, err := s.insertPendingAccountTx(tx, owner, profile)
	if err != nil {
		return Account{}, err
	}
	if err := s.insertAccountEvent(tx, actorOwner, "account-management", owner, "account_created_pending", a.ID); err != nil {
		return Account{}, err
	}
	if err := s.auditAccountMutation(tx, owner, actorOwner, "account.create_pending"); err != nil {
		return Account{}, err
	}
	if err := tx.Commit(); err != nil {
		return Account{}, err
	}
	return a, nil
}

// CreateAdminPasswordAccount creates an ordinary user with an administrator-
// supplied password hash. The account row, hash, and audit entries commit
// together so a failed write cannot leave a credential without its account.
func (s *Store) CreateAdminPasswordAccount(actorOwner, owner string, profile AccountProfile, passwordHash string) (Account, error) {
	if passwordHash == "" {
		return Account{}, ErrConflict
	}
	tx, err := s.db.Begin()
	if err != nil {
		return Account{}, err
	}
	defer tx.Rollback()
	locked, err := s.lockAccountUsers(tx, actorOwner)
	if errors.Is(err, ErrNotFound) {
		return Account{}, ErrAccountForbidden
	}
	if err != nil {
		return Account{}, err
	}
	actor := locked[actorOwner]
	if err := s.requireSystemActionTx(tx, actor, "system.users.create"); err != nil {
		return Account{}, err
	}
	a, err := s.insertPendingAccountTx(tx, owner, profile)
	if err != nil {
		return Account{}, err
	}
	if _, err := tx.Exec(s.q(`UPDATE users SET password_hash=?,password_set_at=?,must_change_password=?,credential_origin=?,initialization_state=? WHERE id=?`),
		passwordHash, nowISO(), true, CredentialOriginAdminPassword, InitializationInitialized, a.ID); err != nil {
		return Account{}, err
	}
	a, err = s.accountByOwner(tx, owner)
	if err != nil {
		return Account{}, err
	}
	if err := s.insertAccountEvent(tx, actorOwner, "account-management", owner, "account_created_password", a.ID); err != nil {
		return Account{}, err
	}
	if err := s.auditAccountMutation(tx, owner, actorOwner, "account.create_password"); err != nil {
		return Account{}, err
	}
	if err := tx.Commit(); err != nil {
		return Account{}, err
	}
	return a, nil
}

// insertPendingAccountTx lets the trusted local initializer create and grant in
// one transaction without impersonating an administrator. The caller owns its
// authorization, audit and commit; this helper always inserts an ordinary user.
func (s *Store) insertPendingAccountTx(tx *sql.Tx, owner string, profile AccountProfile) (Account, error) {
	if owner == "" || owner != strings.TrimSpace(owner) || !utf8.ValidString(owner) {
		return Account{}, fmt.Errorf("%w: invalid owner", ErrInvalidAccountProfile)
	}
	for _, r := range owner {
		if unicode.IsControl(r) {
			return Account{}, fmt.Errorf("%w: invalid owner", ErrInvalidAccountProfile)
		}
	}
	patch, err := validateAccountProfilePatch(map[string]string{"name": profile.Name, "phone": profile.Phone, "email": profile.Email, "staffNo": profile.StaffNo, "department": profile.Department, "notes": profile.Notes})
	if err != nil {
		return Account{}, err
	}
	profile = applyAccountProfilePatch(AccountProfile{}, patch)
	_, err = tx.Exec(s.q(`INSERT INTO users(id,owner,name,phone,email,staff_no,department,notes,created_at,initialization_state) VALUES(?,?,?,?,?,?,?,?,?,?)`),
		newID("usr"), owner, profile.Name, profile.Phone, profile.Email, profile.StaffNo, profile.Department, profile.Notes, nowISO(), InitializationPending)
	if isUniqueViolation(err) {
		return Account{}, ErrConflict
	}
	if err != nil {
		return Account{}, err
	}
	if err := s.bumpAccountDirectoryRevision(tx, true, true); err != nil {
		return Account{}, err
	}
	return s.accountByOwner(tx, owner)
}

func (s *Store) GetAccountDirectoryRevision() (AccountDirectoryRevision, error) {
	var revision AccountDirectoryRevision
	err := s.db.QueryRow(`SELECT public_revision,staff_no_revision,private_revision FROM account_directory_revision WHERE id=1`).Scan(&revision.Public, &revision.StaffNo, &revision.Private)
	return revision, err
}

// GetAccountCursorKey initializes one random signing key in the shared account
// database. The compare-and-set update lets concurrent Backend instances
// converge on the same key without exposing it through directory responses.
func (s *Store) GetAccountCursorKey() (AccountCursorKey, error) {
	var key AccountCursorKey
	var generated [32]byte
	if _, err := rand.Read(generated[:]); err != nil {
		return key, err
	}
	tx, err := s.db.Begin()
	if err != nil {
		return key, err
	}
	defer tx.Rollback()
	if _, err := tx.Exec(s.q(`UPDATE account_directory_revision SET cursor_secret=? WHERE id=1 AND cursor_secret=''`), hex.EncodeToString(generated[:])); err != nil {
		return key, err
	}
	var encoded string
	if err := tx.QueryRow(`SELECT cursor_key_version,cursor_secret FROM account_directory_revision WHERE id=1`).Scan(&key.Version, &encoded); err != nil {
		return key, err
	}
	decoded, err := hex.DecodeString(encoded)
	if err != nil || len(decoded) != len(key.Secret) || key.Version < 1 {
		return AccountCursorKey{}, ErrConflict
	}
	copy(key.Secret[:], decoded)
	if err := tx.Commit(); err != nil {
		return AccountCursorKey{}, err
	}
	return key, nil
}

func newAccountDirectoryRevision() (string, error) {
	var bytes [16]byte
	if _, err := rand.Read(bytes[:]); err != nil {
		return "", err
	}
	return hex.EncodeToString(bytes[:]), nil
}

// Call only after all user locks. Public covers name/identity/valid; StaffNo is
// composed into a directory version only when that field is authorized. Private
// changes on every profile edit, without exposing hidden-field edits to callers.
func (s *Store) bumpAccountDirectoryRevision(tx *sql.Tx, publicChanged, staffNoChanged bool) error {
	private, err := newAccountDirectoryRevision()
	if err != nil {
		return err
	}
	assignments := []string{`private_revision=?`}
	args := []any{private}
	if publicChanged {
		public, err := newAccountDirectoryRevision()
		if err != nil {
			return err
		}
		assignments = append(assignments, `public_revision=?`)
		args = append(args, public)
	}
	if staffNoChanged {
		staffNo, err := newAccountDirectoryRevision()
		if err != nil {
			return err
		}
		assignments = append(assignments, `staff_no_revision=?`)
		args = append(args, staffNo)
	}
	query := `UPDATE account_directory_revision SET ` + strings.Join(assignments, ",") + ` WHERE id=1`
	result, err := tx.Exec(s.q(query), args...)
	if err != nil {
		return err
	}
	if n, err := result.RowsAffected(); err != nil {
		return err
	} else if n != 1 {
		return errors.New("store: account directory revision missing")
	}
	return nil
}