feat: game lobby service

lobby/internal/adapters/userservice/client.go

@@ -0,0 +1,183 @@
+// Package userservice provides the HTTP adapter for the
+// ports.UserService eligibility port. It wraps the trusted
+// User Service internal endpoint
+// `GET /api/v1/internal/users/{user_id}/eligibility` and decodes the
+// response into the lobby-side ports.Eligibility shape.
+package userservice
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"galaxy/lobby/internal/ports"
+
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+)
+
+// permanentBlockSanctionCode mirrors policy.SanctionCodePermanentBlock in
+// galaxy/user. The lobby adapter inspects the active_sanctions array for
+// this string to populate Eligibility.PermanentBlocked without taking a
+// build-time dependency on the user module.
+const permanentBlockSanctionCode = "permanent_block"
+
+// maxRegisteredRaceNamesLimitCode mirrors
+// policy.LimitCodeMaxRegisteredRaceNames in galaxy/user. A snapshot value
+// of 0 denotes unlimited per the lifetime tariff.
+const maxRegisteredRaceNamesLimitCode = "max_registered_race_names"
+
+// Client implements ports.UserService against the trusted internal HTTP
+// surface of User Service.
+type Client struct {
+	baseURL    string
+	httpClient *http.Client
+}
+
+// Config groups the construction parameters of Client.
+type Config struct {
+	// BaseURL is the absolute root URL of User Service (no trailing slash
+	// required). The eligibility path is appended on every call.
+	BaseURL string
+
+	// Timeout bounds one round trip including TLS handshake. It must be
+	// positive.
+	Timeout time.Duration
+}
+
+// Validate reports whether cfg stores a usable Client configuration.
+func (cfg Config) Validate() error {
+	switch {
+	case strings.TrimSpace(cfg.BaseURL) == "":
+		return errors.New("user service base url must not be empty")
+	case cfg.Timeout <= 0:
+		return errors.New("user service timeout must be positive")
+	default:
+		return nil
+	}
+}
+
+// NewClient constructs a Client from cfg. Transport is wrapped with
+// otelhttp.NewTransport so traces propagate to User Service.
+func NewClient(cfg Config) (*Client, error) {
+	if err := cfg.Validate(); err != nil {
+		return nil, fmt.Errorf("new user service client: %w", err)
+	}
+	httpClient := &http.Client{
+		Timeout:   cfg.Timeout,
+		Transport: otelhttp.NewTransport(http.DefaultTransport),
+	}
+	return &Client{
+		baseURL:    strings.TrimRight(cfg.BaseURL, "/"),
+		httpClient: httpClient,
+	}, nil
+}
+
+// rawEligibility mirrors the lobby-relevant subset of
+// lobbyeligibility.GetUserEligibilityResult. Unknown JSON fields are
+// ignored intentionally so future user-side additions do not break the
+// lobby decoder; see the decision record for context.
+type rawEligibility struct {
+	Exists          bool             `json:"exists"`
+	Markers         rawMarkers       `json:"markers"`
+	ActiveSanctions []rawSanction    `json:"active_sanctions"`
+	EffectiveLimits []rawLimit       `json:"effective_limits"`
+}
+
+type rawMarkers struct {
+	CanLogin             bool `json:"can_login"`
+	CanCreatePrivateGame bool `json:"can_create_private_game"`
+	CanManagePrivateGame bool `json:"can_manage_private_game"`
+	CanJoinGame          bool `json:"can_join_game"`
+	CanUpdateProfile     bool `json:"can_update_profile"`
+}
+
+type rawSanction struct {
+	SanctionCode string `json:"sanction_code"`
+}
+
+type rawLimit struct {
+	LimitCode string `json:"limit_code"`
+	Value     int    `json:"value"`
+}
+
+// GetEligibility issues GET /api/v1/internal/users/{user_id}/eligibility
+// and decodes the response into a ports.Eligibility value. HTTP 404 is
+// treated as a present-but-missing user (Exists=false). Transport errors,
+// timeouts, and unexpected statuses surface as ports.ErrUserServiceUnavailable.
+func (client *Client) GetEligibility(ctx context.Context, userID string) (ports.Eligibility, error) {
+	if client == nil || client.httpClient == nil {
+		return ports.Eligibility{}, errors.New("get eligibility: nil client")
+	}
+	if ctx == nil {
+		return ports.Eligibility{}, errors.New("get eligibility: nil context")
+	}
+	trimmed := strings.TrimSpace(userID)
+	if trimmed == "" {
+		return ports.Eligibility{}, errors.New("get eligibility: user id must not be empty")
+	}
+
+	endpoint := client.baseURL + "/api/v1/internal/users/" + url.PathEscape(trimmed) + "/eligibility"
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint, nil)
+	if err != nil {
+		return ports.Eligibility{}, fmt.Errorf("get eligibility: %w", err)
+	}
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := client.httpClient.Do(req)
+	if err != nil {
+		return ports.Eligibility{}, fmt.Errorf("get eligibility: %w", errors.Join(ports.ErrUserServiceUnavailable, err))
+	}
+	defer resp.Body.Close()
+
+	switch {
+	case resp.StatusCode == http.StatusNotFound:
+		return ports.Eligibility{Exists: false}, nil
+	case resp.StatusCode < 200 || resp.StatusCode >= 300:
+		return ports.Eligibility{}, fmt.Errorf(
+			"get eligibility: unexpected status %d: %w",
+			resp.StatusCode, ports.ErrUserServiceUnavailable,
+		)
+	}
+
+	var raw rawEligibility
+	if err := json.NewDecoder(resp.Body).Decode(&raw); err != nil {
+		return ports.Eligibility{}, fmt.Errorf("get eligibility: decode body: %w", err)
+	}
+
+	return ports.Eligibility{
+		Exists:                 raw.Exists,
+		CanLogin:               raw.Markers.CanLogin,
+		CanCreatePrivateGame:   raw.Markers.CanCreatePrivateGame,
+		CanManagePrivateGame:   raw.Markers.CanManagePrivateGame,
+		CanJoinGame:            raw.Markers.CanJoinGame,
+		CanUpdateProfile:       raw.Markers.CanUpdateProfile,
+		PermanentBlocked:       containsSanction(raw.ActiveSanctions, permanentBlockSanctionCode),
+		MaxRegisteredRaceNames: lookupLimit(raw.EffectiveLimits, maxRegisteredRaceNamesLimitCode),
+	}, nil
+}
+
+func containsSanction(records []rawSanction, code string) bool {
+	for _, record := range records {
+		if record.SanctionCode == code {
+			return true
+		}
+	}
+	return false
+}
+
+func lookupLimit(records []rawLimit, code string) int {
+	for _, record := range records {
+		if record.LimitCode == code {
+			return record.Value
+		}
+	}
+	return 0
+}
+
+// Compile-time interface assertion.
+var _ ports.UserService = (*Client)(nil)