mcias/internal/model/model.go

// Package model defines the shared data types used throughout MCIAS.
// These are pure data definitions with no external dependencies.
package model

import (
	"fmt"
	"time"
)

// AccountType distinguishes human interactive accounts from non-interactive
// service accounts.
type AccountType string

// AccountTypeHuman and AccountTypeSystem are the two valid account types.
const (
	AccountTypeHuman  AccountType = "human"
	AccountTypeSystem AccountType = "system"
)

// AccountStatus represents the lifecycle state of an account.
type AccountStatus string

// AccountStatusActive, AccountStatusInactive, and AccountStatusDeleted are
// the valid account lifecycle states.
const (
	AccountStatusActive   AccountStatus = "active"
	AccountStatusInactive AccountStatus = "inactive"
	AccountStatusDeleted  AccountStatus = "deleted"
)

// Account represents a user or service identity in MCIAS.
// Fields containing credential material (PasswordHash, TOTPSecretEnc) are
// never serialised into API responses — callers must explicitly omit them.
type Account struct {
	CreatedAt       time.Time     `json:"created_at"`
	UpdatedAt       time.Time     `json:"updated_at"`
	DeletedAt       *time.Time    `json:"deleted_at,omitempty"`
	UUID            string        `json:"id"`
	Username        string        `json:"username"`
	AccountType     AccountType   `json:"account_type"`
	Status          AccountStatus `json:"status"`
	PasswordHash    string        `json:"-"`
	TOTPSecretEnc   []byte        `json:"-"`
	TOTPSecretNonce []byte        `json:"-"`
	ID              int64         `json:"-"`
	TOTPRequired    bool          `json:"totp_required"`
}

// Allowlisted role names (DEF-10).
// Only these strings may be stored in account_roles.  Extending the set of
// valid roles requires a code change, ensuring that typos such as "admim"
// are caught at grant time rather than silently creating a useless role.
const (
	RoleAdmin     = "admin"
	RoleUser      = "user"
	RoleGuest     = "guest"
	RoleViewer    = "viewer"
	RoleEditor    = "editor"
	RoleCommenter = "commenter"
)

// allowedRoles is the compile-time set of recognised role names.
var allowedRoles = map[string]struct{}{
	RoleAdmin:     {},
	RoleUser:      {},
	RoleGuest:     {},
	RoleViewer:    {},
	RoleEditor:    {},
	RoleCommenter: {},
}

// ValidateRole returns nil if role is an allowlisted role name, or an error
// describing the problem.  Call this before writing to account_roles.
//
// Security (DEF-10): prevents admins from accidentally creating unmatchable
// roles (e.g. "admim") by enforcing a compile-time allowlist.
func ValidateRole(role string) error {
	if _, ok := allowedRoles[role]; !ok {
		return fmt.Errorf("model: unknown role %q; allowed roles: admin, user, guest, viewer, editor, commenter", role)
	}
	return nil
}

// Role is a string label assigned to an account to grant permissions.
type Role struct {
	GrantedAt time.Time `json:"granted_at"`
	GrantedBy *int64    `json:"-"`
	Role      string    `json:"role"`
	ID        int64     `json:"-"`
	AccountID int64     `json:"-"`
}

// TokenRecord tracks an issued JWT by its JTI for revocation purposes.
// The raw token string is never stored — only the JTI identifier.
type TokenRecord struct {
	ExpiresAt    time.Time  `json:"expires_at"`
	IssuedAt     time.Time  `json:"issued_at"`
	CreatedAt    time.Time  `json:"created_at"`
	RevokedAt    *time.Time `json:"revoked_at,omitempty"`
	JTI          string     `json:"jti"`
	RevokeReason string     `json:"revoke_reason,omitempty"`
	ID           int64      `json:"-"`
	AccountID    int64      `json:"-"`
}

// IsRevoked reports whether the token has been explicitly revoked.
func (t *TokenRecord) IsRevoked() bool {
	return t.RevokedAt != nil
}

// IsExpired reports whether the token is past its expiry time.
func (t *TokenRecord) IsExpired() bool {
	return time.Now().After(t.ExpiresAt)
}

// SystemToken represents the current active service token for a system account.
type SystemToken struct {
	ExpiresAt time.Time `json:"expires_at"`
	CreatedAt time.Time `json:"created_at"`
	JTI       string    `json:"jti"`
	ID        int64     `json:"-"`
	AccountID int64     `json:"-"`
}

// PGCredential holds Postgres connection details for a system account.
// The password is encrypted at rest; PGPassword is only populated after
// decryption and must never be logged or included in API responses.
//
// OwnerID identifies the account permitted to update, delete, and manage
// access grants for this credential set.  A nil OwnerID means the credential
// pre-dates ownership tracking; for backwards compatibility, nil is treated as
// unowned (only admins can manage it via the UI).
type PGCredential struct {
	CreatedAt          time.Time `json:"created_at"`
	UpdatedAt          time.Time `json:"updated_at"`
	OwnerID            *int64    `json:"-"`
	ServiceAccountUUID string    `json:"service_account_uuid,omitempty"`
	PGUsername         string    `json:"username"`
	PGPassword         string    `json:"-"`
	ServiceUsername    string    `json:"service_username,omitempty"`
	PGDatabase         string    `json:"database"`
	PGHost             string    `json:"host"`
	PGPasswordEnc      []byte    `json:"-"`
	PGPasswordNonce    []byte    `json:"-"`
	ID                 int64     `json:"-"`
	AccountID          int64     `json:"-"`
	PGPort             int       `json:"port"`
}

// AuditEvent represents a single entry in the append-only audit log.
// Details must never contain credential material (passwords, tokens, secrets).
type AuditEvent struct {
	EventTime time.Time `json:"event_time"`
	ActorID   *int64    `json:"-"`
	TargetID  *int64    `json:"-"`
	EventType string    `json:"event_type"`
	IPAddress string    `json:"ip_address,omitempty"`
	Details   string    `json:"details,omitempty"`
	ID        int64     `json:"id"`
}

// Audit event type constants — exhaustive list, enforced at write time.
const (
	EventLoginOK        = "login_ok"
	EventLoginFail      = "login_fail"
	EventLoginTOTPFail  = "login_totp_fail"
	EventTokenIssued    = "token_issued"
	EventTokenRenewed   = "token_renewed"
	EventTokenRevoked   = "token_revoked"
	EventTokenExpired   = "token_expired"
	EventAccountCreated = "account_created"
	EventAccountUpdated = "account_updated"
	EventAccountDeleted = "account_deleted"
	EventRoleGranted    = "role_granted"
	EventRoleRevoked    = "role_revoked"
	EventTOTPEnrolled   = "totp_enrolled"
	EventTOTPRemoved    = "totp_removed"
	EventPGCredAccessed = "pgcred_accessed"
	EventPGCredUpdated  = "pgcred_updated" //nolint:gosec // G101: audit event type string, not a credential

	EventVaultSealed   = "vault_sealed"
	EventVaultUnsealed = "vault_unsealed"

	EventTagAdded   = "tag_added"
	EventTagRemoved = "tag_removed"

	EventPolicyRuleCreated = "policy_rule_created"
	EventPolicyRuleUpdated = "policy_rule_updated"
	EventPolicyRuleDeleted = "policy_rule_deleted"
	EventPolicyDeny        = "policy_deny"
)

// PGCredAccessGrant records that a specific account has been granted read
// access to a pg_credentials set.  Only the credential owner can manage
// grants; grantees can view connection metadata but never the plaintext
// password, and they cannot update or delete the credential set.
type PGCredAccessGrant struct {
	GrantedAt    time.Time `json:"granted_at"`
	GrantedBy    *int64    `json:"-"`
	GranteeUUID  string    `json:"grantee_id"`
	GranteeName  string    `json:"grantee_username"`
	ID           int64     `json:"-"`
	CredentialID int64     `json:"-"`
	GranteeID    int64     `json:"-"`
}

// Audit event type for pg_credential_access changes.
const (
	EventPGCredAccessGranted = "pgcred_access_granted" //nolint:gosec // G101: audit event type, not a credential
	EventPGCredAccessRevoked = "pgcred_access_revoked" //nolint:gosec // G101: audit event type, not a credential

	EventPasswordChanged = "password_changed"

	EventTokenDelegateGranted = "token_delegate_granted"
	EventTokenDelegateRevoked = "token_delegate_revoked"
)

// ServiceAccountDelegate records that a specific account has been granted
// permission to issue tokens for a given system account.  Only admins can
// add or remove delegates; delegates can issue/rotate tokens for that specific
// system account and nothing else.
type ServiceAccountDelegate struct {
	GrantedAt   time.Time `json:"granted_at"`
	GrantedBy   *int64    `json:"-"`
	GranteeUUID string    `json:"grantee_id"`
	GranteeName string    `json:"grantee_username"`
	ID          int64     `json:"-"`
	AccountID   int64     `json:"-"`
	GranteeID   int64     `json:"-"`
}

// PolicyRuleRecord is the database representation of a policy rule.
// RuleJSON holds a JSON-encoded policy.RuleBody (all match and effect fields).
// The ID, Priority, and Description are stored as dedicated columns.
// NotBefore and ExpiresAt define an optional validity window; nil means no
// constraint (always active / never expires).
type PolicyRuleRecord struct {
	CreatedAt   time.Time  `json:"created_at"`
	UpdatedAt   time.Time  `json:"updated_at"`
	NotBefore   *time.Time `json:"not_before,omitempty"`
	ExpiresAt   *time.Time `json:"expires_at,omitempty"`
	CreatedBy   *int64     `json:"-"`
	Description string     `json:"description"`
	RuleJSON    string     `json:"rule_json"`
	ID          int64      `json:"id"`
	Priority    int        `json:"priority"`
	Enabled     bool       `json:"enabled"`
}