feat: game lobby service

lobby/internal/adapters/redisstate/codecs_gameturnstats.go

@@ -0,0 +1,87 @@
+package redisstate
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"galaxy/lobby/internal/ports"
+)
+
+// playerStatsRecord stores the strict Redis JSON shape used for one
+// per-game per-user stats aggregate. The shape mirrors the field set
+// documented in lobby/README.md §Runtime Snapshot.
+type playerStatsRecord struct {
+	UserID            string `json:"user_id"`
+	InitialPlanets    int64  `json:"initial_planets"`
+	InitialPopulation int64  `json:"initial_population"`
+	InitialShipsBuilt int64  `json:"initial_ships_built"`
+	MaxPlanets        int64  `json:"max_planets"`
+	MaxPopulation     int64  `json:"max_population"`
+	MaxShipsBuilt     int64  `json:"max_ships_built"`
+}
+
+// MarshalPlayerStats encodes aggregate into the strict Redis JSON shape.
+// Negative counters are rejected to match the validation surface of
+// ports.PlayerObservedStats.Validate.
+func MarshalPlayerStats(aggregate ports.PlayerStatsAggregate) ([]byte, error) {
+	if err := validatePlayerStatsAggregate(aggregate); err != nil {
+		return nil, fmt.Errorf("marshal player stats aggregate: %w", err)
+	}
+	return json.Marshal(playerStatsRecord{
+		UserID:            aggregate.UserID,
+		InitialPlanets:    aggregate.InitialPlanets,
+		InitialPopulation: aggregate.InitialPopulation,
+		InitialShipsBuilt: aggregate.InitialShipsBuilt,
+		MaxPlanets:        aggregate.MaxPlanets,
+		MaxPopulation:     aggregate.MaxPopulation,
+		MaxShipsBuilt:     aggregate.MaxShipsBuilt,
+	})
+}
+
+// UnmarshalPlayerStats decodes payload into a PlayerStatsAggregate. The
+// returned aggregate is re-validated to guarantee the Redis store never
+// surfaces malformed records.
+func UnmarshalPlayerStats(payload []byte) (ports.PlayerStatsAggregate, error) {
+	var stored playerStatsRecord
+	if err := json.Unmarshal(payload, &stored); err != nil {
+		return ports.PlayerStatsAggregate{}, fmt.Errorf("unmarshal player stats aggregate: %w", err)
+	}
+	aggregate := ports.PlayerStatsAggregate{
+		UserID:            stored.UserID,
+		InitialPlanets:    stored.InitialPlanets,
+		InitialPopulation: stored.InitialPopulation,
+		InitialShipsBuilt: stored.InitialShipsBuilt,
+		MaxPlanets:        stored.MaxPlanets,
+		MaxPopulation:     stored.MaxPopulation,
+		MaxShipsBuilt:     stored.MaxShipsBuilt,
+	}
+	if err := validatePlayerStatsAggregate(aggregate); err != nil {
+		return ports.PlayerStatsAggregate{}, fmt.Errorf("unmarshal player stats aggregate: %w", err)
+	}
+	return aggregate, nil
+}
+
+func validatePlayerStatsAggregate(aggregate ports.PlayerStatsAggregate) error {
+	if aggregate.UserID == "" {
+		return fmt.Errorf("user id must not be empty")
+	}
+	if aggregate.InitialPlanets < 0 {
+		return fmt.Errorf("initial planets must not be negative")
+	}
+	if aggregate.InitialPopulation < 0 {
+		return fmt.Errorf("initial population must not be negative")
+	}
+	if aggregate.InitialShipsBuilt < 0 {
+		return fmt.Errorf("initial ships built must not be negative")
+	}
+	if aggregate.MaxPlanets < aggregate.InitialPlanets {
+		return fmt.Errorf("max planets must not be below initial planets")
+	}
+	if aggregate.MaxPopulation < aggregate.InitialPopulation {
+		return fmt.Errorf("max population must not be below initial population")
+	}
+	if aggregate.MaxShipsBuilt < aggregate.InitialShipsBuilt {
+		return fmt.Errorf("max ships built must not be below initial ships built")
+	}
+	return nil
+}