feat: authsession service

authsession/internal/domain/userresolution/model.go

@@ -0,0 +1,110 @@
+// Package userresolution defines the domain result returned by the user
+// resolution boundary before session creation.
+package userresolution
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"galaxy/authsession/internal/domain/common"
+)
+
+// Kind identifies the coarse user-resolution result for one normalized e-mail.
+type Kind string
+
+const (
+	// KindExisting reports that the e-mail belongs to an existing user.
+	KindExisting Kind = "existing"
+
+	// KindCreatable reports that the e-mail is free and user creation is
+	// allowed.
+	KindCreatable Kind = "creatable"
+
+	// KindBlocked reports that the e-mail or subject is blocked from login or
+	// registration.
+	KindBlocked Kind = "blocked"
+)
+
+// IsKnown reports whether Kind is one of the user-resolution kinds supported
+// by the current domain model.
+func (k Kind) IsKnown() bool {
+	switch k {
+	case KindExisting, KindCreatable, KindBlocked:
+		return true
+	default:
+		return false
+	}
+}
+
+// BlockReasonCode stores one machine-readable user-block reason.
+type BlockReasonCode string
+
+// String returns BlockReasonCode as its stored code value.
+func (code BlockReasonCode) String() string {
+	return string(code)
+}
+
+// IsZero reports whether BlockReasonCode is empty.
+func (code BlockReasonCode) IsZero() bool {
+	return strings.TrimSpace(string(code)) == ""
+}
+
+// Validate reports whether BlockReasonCode is non-empty and normalized for
+// domain use.
+func (code BlockReasonCode) Validate() error {
+	switch {
+	case code.IsZero():
+		return errors.New("block reason code must not be empty")
+	case strings.TrimSpace(string(code)) != string(code):
+		return errors.New("block reason code must not contain surrounding whitespace")
+	default:
+		return nil
+	}
+}
+
+// Result stores the coarse user-resolution outcome consumed by later auth
+// workflow stages.
+type Result struct {
+	// Kind reports the coarse resolution outcome.
+	Kind Kind
+
+	// UserID is set only when Kind is KindExisting.
+	UserID common.UserID
+
+	// BlockReasonCode is set only when Kind is KindBlocked.
+	BlockReasonCode BlockReasonCode
+}
+
+// Validate reports whether Result satisfies the Stage-2 structural invariants.
+func (r Result) Validate() error {
+	if !r.Kind.IsKnown() {
+		return fmt.Errorf("user resolution kind %q is unsupported", r.Kind)
+	}
+
+	switch r.Kind {
+	case KindExisting:
+		if err := r.UserID.Validate(); err != nil {
+			return fmt.Errorf("user resolution user id: %w", err)
+		}
+		if !r.BlockReasonCode.IsZero() {
+			return errors.New("existing user resolution must not contain block reason code")
+		}
+	case KindCreatable:
+		if !r.UserID.IsZero() {
+			return errors.New("creatable user resolution must not contain user id")
+		}
+		if !r.BlockReasonCode.IsZero() {
+			return errors.New("creatable user resolution must not contain block reason code")
+		}
+	case KindBlocked:
+		if !r.UserID.IsZero() {
+			return errors.New("blocked user resolution must not contain user id")
+		}
+		if err := r.BlockReasonCode.Validate(); err != nil {
+			return fmt.Errorf("user resolution block reason code: %w", err)
+		}
+	}
+
+	return nil
+}