// Package turngeneration implements the turn-generation orchestrator
// owned by Game Master. It is the single entry point through which the
// scheduler ticker (Stage 15 worker) and the admin force-next-turn flow
// (Stage 17) drive a turn through the engine container.
//
// Lifecycle and failure-mode semantics follow `gamemaster/README.md
// §Lifecycles → Turn generation` and §Force-next-turn. Design rationale
// is captured in
// `gamemaster/docs/stage15-scheduler-and-turn-generation.md`.
package turngeneration

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"sort"
	"strings"
	"time"

	"galaxy/gamemaster/internal/domain/operation"
	"galaxy/gamemaster/internal/domain/playermapping"
	"galaxy/gamemaster/internal/domain/runtime"
	"galaxy/gamemaster/internal/logging"
	"galaxy/gamemaster/internal/ports"
	"galaxy/gamemaster/internal/service/scheduler"
	"galaxy/gamemaster/internal/telemetry"
	"galaxy/notificationintent"
)

// Trigger classifies the caller of one turn-generation operation. The
// value flows into telemetry and structured logs only — it does not
// branch the orchestrator's persistence path. The skip-tick mechanic is
// driven exclusively by the runtime record's `skip_next_tick` column.
type Trigger string

const (
	// TriggerScheduler labels turn generations dispatched by the
	// `schedulerticker` worker.
	TriggerScheduler Trigger = "scheduler"

	// TriggerForce labels turn generations dispatched by the admin
	// force-next-turn flow (Stage 17 `service/adminforce`).
	TriggerForce Trigger = "force"
)

// IsKnown reports whether trigger belongs to the frozen trigger
// vocabulary.
func (trigger Trigger) IsKnown() bool {
	switch trigger {
	case TriggerScheduler, TriggerForce:
		return true
	default:
		return false
	}
}

// Input stores the per-call arguments for one turn-generation
// operation.
type Input struct {
	// GameID identifies the runtime to drive.
	GameID string

	// Trigger classifies the caller. Used for telemetry and logs only.
	Trigger Trigger

	// OpSource classifies how the request entered Game Master. Used to
	// stamp `operation_log.op_source`. Defaults to `admin_rest` when
	// missing or unrecognised.
	OpSource operation.OpSource

	// SourceRef stores the optional opaque per-source reference (REST
	// request id, scheduler tick id). Empty when the caller does not
	// provide one.
	SourceRef string
}

// Validate reports whether input carries the structural invariants the
// service requires before any store is touched.
func (input Input) Validate() error {
	if strings.TrimSpace(input.GameID) == "" {
		return fmt.Errorf("game id must not be empty")
	}
	if !input.Trigger.IsKnown() {
		return fmt.Errorf("trigger %q is unsupported", input.Trigger)
	}
	if !input.OpSource.IsKnown() {
		return fmt.Errorf("op source %q is unsupported", input.OpSource)
	}
	return nil
}

// Result stores the deterministic outcome of one Handle call.
type Result struct {
	// Record carries the post-mutation runtime record. Populated on
	// every success outcome and on `engine_*` failures (where the row
	// was moved to `generation_failed`); zero on early-rejection
	// outcomes (`invalid_request`, `runtime_not_found`,
	// `runtime_not_running`, `conflict` on initial CAS,
	// `service_unavailable` on initial Get).
	Record runtime.RuntimeRecord

	// Trigger echoes back Input.Trigger for log/telemetry consumers.
	Trigger Trigger

	// Finished is true when the engine reported `finished=true` on this
	// turn and the runtime transitioned to `finished`.
	Finished bool

	// Outcome reports whether the operation completed (success) or
	// produced a stable failure code.
	Outcome operation.Outcome

	// ErrorCode stores the stable error code on failure. Empty on
	// success.
	ErrorCode string

	// ErrorMessage stores the operator-readable detail on failure.
	// Empty on success.
	ErrorMessage string
}

// IsSuccess reports whether the result represents a successful
// operation.
func (result Result) IsSuccess() bool {
	return result.Outcome == operation.OutcomeSuccess
}

// Dependencies groups the collaborators required by Service.
type Dependencies struct {
	// RuntimeRecords drives every CAS and scheduling persistence step.
	RuntimeRecords ports.RuntimeRecordStore

	// PlayerMappings supplies the per-game roster used to project
	// engine player state to user-facing notification recipients and
	// `player_turn_stats`.
	PlayerMappings ports.PlayerMappingStore

	// OperationLogs records the audit entry for the operation.
	OperationLogs ports.OperationLogStore

	// Engine drives the engine /admin/turn call.
	Engine ports.EngineClient

	// LobbyEvents publishes `runtime_snapshot_update` and
	// `game_finished` to `gm:lobby_events`.
	LobbyEvents ports.LobbyEventsPublisher

	// Notifications publishes `game.turn.ready`, `game.finished`, and
	// `game.generation_failed` intents to `notification:intents`.
	Notifications ports.NotificationIntentPublisher

	// Lobby resolves the human-readable `game_name` consumed by
	// notification payloads. Failure is fail-soft: the orchestrator
	// falls back to `game_id`.
	Lobby ports.LobbyClient

	// Scheduler computes the post-success `next_generation_at` value.
	Scheduler *scheduler.Service

	// Telemetry records the turn-generation outcome counter, lobby
	// publication counter, and notification publish-attempt counter.
	Telemetry *telemetry.Runtime

	// Logger records structured service-level events. Defaults to
	// `slog.Default()` when nil.
	Logger *slog.Logger

	// Clock supplies the wall-clock used for operation timestamps.
	// Defaults to `time.Now` when nil.
	Clock func() time.Time
}

// Service executes the turn-generation lifecycle operation.
type Service struct {
	runtimeRecords ports.RuntimeRecordStore
	playerMappings ports.PlayerMappingStore
	operationLogs  ports.OperationLogStore
	engine         ports.EngineClient
	lobbyEvents    ports.LobbyEventsPublisher
	notifications  ports.NotificationIntentPublisher
	lobby          ports.LobbyClient
	scheduler      *scheduler.Service

	telemetry *telemetry.Runtime
	logger    *slog.Logger
	clock     func() time.Time
}

// NewService constructs one Service from deps.
func NewService(deps Dependencies) (*Service, error) {
	switch {
	case deps.RuntimeRecords == nil:
		return nil, errors.New("new turn generation service: nil runtime records")
	case deps.PlayerMappings == nil:
		return nil, errors.New("new turn generation service: nil player mappings")
	case deps.OperationLogs == nil:
		return nil, errors.New("new turn generation service: nil operation logs")
	case deps.Engine == nil:
		return nil, errors.New("new turn generation service: nil engine client")
	case deps.LobbyEvents == nil:
		return nil, errors.New("new turn generation service: nil lobby events publisher")
	case deps.Notifications == nil:
		return nil, errors.New("new turn generation service: nil notification publisher")
	case deps.Lobby == nil:
		return nil, errors.New("new turn generation service: nil lobby client")
	case deps.Scheduler == nil:
		return nil, errors.New("new turn generation service: nil scheduler")
	case deps.Telemetry == nil:
		return nil, errors.New("new turn generation service: nil telemetry runtime")
	}

	clock := deps.Clock
	if clock == nil {
		clock = time.Now
	}
	logger := deps.Logger
	if logger == nil {
		logger = slog.Default()
	}
	logger = logger.With("service", "gamemaster.turngeneration")

	return &Service{
		runtimeRecords: deps.RuntimeRecords,
		playerMappings: deps.PlayerMappings,
		operationLogs:  deps.OperationLogs,
		engine:         deps.Engine,
		lobbyEvents:    deps.LobbyEvents,
		notifications:  deps.Notifications,
		lobby:          deps.Lobby,
		scheduler:      deps.Scheduler,
		telemetry:      deps.Telemetry,
		logger:         logger,
		clock:          clock,
	}, nil
}

// Handle executes one turn-generation operation end-to-end. The
// Go-level error return is reserved for non-business failures (nil
// context, nil receiver). Every business outcome flows through Result.
func (service *Service) Handle(ctx context.Context, input Input) (Result, error) {
	if service == nil {
		return Result{}, errors.New("turn generation: nil service")
	}
	if ctx == nil {
		return Result{}, errors.New("turn generation: nil context")
	}

	opStartedAt := service.clock().UTC()

	if err := input.Validate(); err != nil {
		return service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeInvalidRequest, err.Error()), nil
	}

	record, outcome, ok := service.loadRecord(ctx, opStartedAt, input)
	if !ok {
		return outcome, nil
	}

	if record.Status != runtime.StatusRunning {
		return service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeRuntimeNotRunning,
			fmt.Sprintf("runtime status is %q, expected %q",
				record.Status, runtime.StatusRunning)), nil
	}

	if outcome, ok := service.casToInProgress(ctx, opStartedAt, input); !ok {
		return outcome, nil
	}

	state, engineOK, engineCode, engineMsg := service.callEngineTurn(ctx, record)
	mappings, listErr := service.playerMappings.ListByGame(ctx, input.GameID)
	if listErr != nil {
		// Without mappings we cannot project player_turn_stats; treat
		// as a service_unavailable failure but still try to roll the
		// runtime to generation_failed because the engine call may
		// have already mutated state.
		return service.failGeneration(ctx, opStartedAt, input, record,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("list player mappings: %s", listErr.Error())), nil
	}

	if !engineOK {
		return service.failGeneration(ctx, opStartedAt, input, record,
			engineCode, engineMsg), nil
	}

	if outcome, ok := service.validateRoster(ctx, opStartedAt, input, record, state, mappings); !ok {
		return outcome, nil
	}

	if state.Finished {
		return service.completeFinished(ctx, opStartedAt, input, record, state, mappings), nil
	}
	return service.completeRunning(ctx, opStartedAt, input, record, state, mappings), nil
}

// loadRecord reads the runtime record and maps store errors to
// orchestrator outcomes. ok=false means the flow stops with the
// returned Result.
func (service *Service) loadRecord(ctx context.Context, opStartedAt time.Time, input Input) (runtime.RuntimeRecord, Result, bool) {
	record, err := service.runtimeRecords.Get(ctx, input.GameID)
	switch {
	case err == nil:
		return record, Result{}, true
	case errors.Is(err, runtime.ErrNotFound):
		return runtime.RuntimeRecord{}, service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeRuntimeNotFound, "runtime record does not exist"), false
	default:
		return runtime.RuntimeRecord{}, service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable, fmt.Sprintf("get runtime record: %s", err.Error())), false
	}
}

// casToInProgress flips the runtime row from `running` to
// `generation_in_progress`. ok=false means the flow stops with the
// returned Result; the caller has not touched the engine yet.
func (service *Service) casToInProgress(ctx context.Context, opStartedAt time.Time, input Input) (Result, bool) {
	err := service.runtimeRecords.UpdateStatus(ctx, ports.UpdateStatusInput{
		GameID:       input.GameID,
		ExpectedFrom: runtime.StatusRunning,
		To:           runtime.StatusGenerationInProgress,
		Now:          opStartedAt,
	})
	switch {
	case err == nil:
		return Result{}, true
	case errors.Is(err, runtime.ErrConflict):
		return service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeConflict,
			fmt.Sprintf("cas runtime status to generation_in_progress: %s", err.Error())), false
	case errors.Is(err, runtime.ErrNotFound):
		return service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeRuntimeNotFound,
			fmt.Sprintf("cas runtime status to generation_in_progress: %s", err.Error())), false
	default:
		return service.recordEarlyFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("cas runtime status to generation_in_progress: %s", err.Error())), false
	}
}

// callEngineTurn dispatches the engine /admin/turn call and classifies
// the outcome. engineOK=true means the response is well-formed at the
// transport level; engineOK=false populates errorCode / errorMessage
// with a stable failure shape.
func (service *Service) callEngineTurn(ctx context.Context, record runtime.RuntimeRecord) (state ports.StateResponse, engineOK bool, errorCode string, errorMessage string) {
	state, err := service.engine.Turn(ctx, record.EngineEndpoint)
	if err == nil {
		return state, true, "", ""
	}
	return ports.StateResponse{}, false, classifyEngineError(err), fmt.Sprintf("engine turn: %s", err.Error())
}

// classifyEngineError maps the engine port sentinels to the
// turn-generation stable error codes.
func classifyEngineError(err error) string {
	switch {
	case errors.Is(err, ports.ErrEngineValidation):
		return ErrorCodeEngineValidationError
	case errors.Is(err, ports.ErrEngineProtocolViolation):
		return ErrorCodeEngineProtocolViolation
	case errors.Is(err, ports.ErrEngineUnreachable):
		return ErrorCodeEngineUnreachable
	default:
		return ErrorCodeEngineUnreachable
	}
}

// validateRoster checks that the engine response carries exactly the
// race set installed at register-runtime. ok=false means the flow stops
// (and the runtime row is moved to `generation_failed`).
func (service *Service) validateRoster(ctx context.Context, opStartedAt time.Time, input Input, record runtime.RuntimeRecord, state ports.StateResponse, mappings []playermapping.PlayerMapping) (Result, bool) {
	if len(state.Players) != len(mappings) {
		message := fmt.Sprintf("engine player count %d does not match roster size %d",
			len(state.Players), len(mappings))
		return service.failGeneration(ctx, opStartedAt, input, record,
			ErrorCodeEngineProtocolViolation, message), false
	}
	expected := make(map[string]struct{}, len(mappings))
	for _, mapping := range mappings {
		expected[mapping.RaceName] = struct{}{}
	}
	for _, player := range state.Players {
		if _, ok := expected[player.RaceName]; !ok {
			message := fmt.Sprintf("engine returned race %q not present in roster", player.RaceName)
			return service.failGeneration(ctx, opStartedAt, input, record,
				ErrorCodeEngineProtocolViolation, message), false
		}
	}
	return Result{}, true
}

// completeFinished handles the `finished=true` branch: CAS to finished,
// clear scheduling, publish game_finished, publish game.finished
// notification, audit success.
func (service *Service) completeFinished(ctx context.Context, opStartedAt time.Time, input Input, record runtime.RuntimeRecord, state ports.StateResponse, mappings []playermapping.PlayerMapping) Result {
	finishedAt := service.clock().UTC()

	err := service.runtimeRecords.UpdateStatus(ctx, ports.UpdateStatusInput{
		GameID:       input.GameID,
		ExpectedFrom: runtime.StatusGenerationInProgress,
		To:           runtime.StatusFinished,
		Now:          finishedAt,
	})
	if err != nil {
		return service.handlePostEngineCASFailure(ctx, opStartedAt, input, record, err)
	}

	if err := service.runtimeRecords.UpdateScheduling(ctx, ports.UpdateSchedulingInput{
		GameID:           input.GameID,
		NextGenerationAt: nil,
		SkipNextTick:     false,
		CurrentTurn:      state.Turn,
		Now:              finishedAt,
	}); err != nil {
		// The CAS to finished succeeded; the row is in the terminal
		// state. Surface a service_unavailable to the caller but keep
		// the audit and snapshot consistent.
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("update scheduling on finish: %s", err.Error()))
	}

	persisted, reloadErr := service.runtimeRecords.Get(ctx, input.GameID)
	if reloadErr != nil {
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("reload runtime record: %s", reloadErr.Error()))
	}

	stats := projectPlayerStats(state, mappings)

	finishedMsg := ports.GameFinished{
		GameID:          input.GameID,
		FinalTurnNumber: state.Turn,
		RuntimeStatus:   runtime.StatusFinished,
		PlayerTurnStats: stats,
		FinishedAt:      finishedAt,
	}
	if err := service.lobbyEvents.PublishGameFinished(ctx, finishedMsg); err != nil {
		service.logger.ErrorContext(ctx, "publish game finished",
			"game_id", input.GameID,
			"err", err.Error(),
		)
	} else {
		service.telemetry.RecordLobbyEventPublished(ctx, "game_finished")
	}

	gameName := service.resolveGameName(ctx, input.GameID)
	recipients := recipientUserIDs(mappings)
	service.publishGameFinishedIntent(ctx, input, gameName, state.Turn, recipients, finishedAt)

	service.appendSuccessLog(ctx, opStartedAt, input)
	service.telemetry.RecordTurnGenerationOutcome(ctx,
		string(operation.OutcomeSuccess), "", string(input.Trigger))

	logArgs := []any{
		"game_id", input.GameID,
		"trigger", string(input.Trigger),
		"final_turn", state.Turn,
		"finished", true,
	}
	logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
	service.logger.InfoContext(ctx, "turn generation finished game", logArgs...)

	return Result{
		Record:   persisted,
		Trigger:  input.Trigger,
		Finished: true,
		Outcome:  operation.OutcomeSuccess,
	}
}

// completeRunning handles the `finished=false` branch: recompute next
// tick, CAS back to running, publish snapshot, publish
// game.turn.ready notification, audit success.
func (service *Service) completeRunning(ctx context.Context, opStartedAt time.Time, input Input, record runtime.RuntimeRecord, state ports.StateResponse, mappings []playermapping.PlayerMapping) Result {
	completedAt := service.clock().UTC()

	next, _, err := service.scheduler.ComputeNext(record.TurnSchedule, completedAt, record.SkipNextTick)
	if err != nil {
		return service.failGeneration(ctx, opStartedAt, input, record,
			ErrorCodeInvalidRequest,
			fmt.Sprintf("recompute next tick: %s", err.Error()))
	}

	if err := service.runtimeRecords.UpdateStatus(ctx, ports.UpdateStatusInput{
		GameID:       input.GameID,
		ExpectedFrom: runtime.StatusGenerationInProgress,
		To:           runtime.StatusRunning,
		Now:          completedAt,
	}); err != nil {
		return service.handlePostEngineCASFailure(ctx, opStartedAt, input, record, err)
	}

	if err := service.runtimeRecords.UpdateScheduling(ctx, ports.UpdateSchedulingInput{
		GameID:           input.GameID,
		NextGenerationAt: &next,
		SkipNextTick:     false,
		CurrentTurn:      state.Turn,
		Now:              completedAt,
	}); err != nil {
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("update scheduling on running: %s", err.Error()))
	}

	persisted, reloadErr := service.runtimeRecords.Get(ctx, input.GameID)
	if reloadErr != nil {
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("reload runtime record: %s", reloadErr.Error()))
	}

	stats := projectPlayerStats(state, mappings)

	snapshot := ports.RuntimeSnapshotUpdate{
		GameID:              input.GameID,
		CurrentTurn:         state.Turn,
		RuntimeStatus:       runtime.StatusRunning,
		EngineHealthSummary: persisted.EngineHealth,
		PlayerTurnStats:     stats,
		OccurredAt:          completedAt,
	}
	if err := service.lobbyEvents.PublishSnapshotUpdate(ctx, snapshot); err != nil {
		service.logger.ErrorContext(ctx, "publish runtime snapshot update",
			"game_id", input.GameID,
			"err", err.Error(),
		)
	} else {
		service.telemetry.RecordLobbyEventPublished(ctx, "runtime_snapshot_update")
	}

	gameName := service.resolveGameName(ctx, input.GameID)
	recipients := recipientUserIDs(mappings)
	service.publishGameTurnReadyIntent(ctx, input, gameName, state.Turn, recipients, completedAt)

	service.appendSuccessLog(ctx, opStartedAt, input)
	service.telemetry.RecordTurnGenerationOutcome(ctx,
		string(operation.OutcomeSuccess), "", string(input.Trigger))

	logArgs := []any{
		"game_id", input.GameID,
		"trigger", string(input.Trigger),
		"current_turn", state.Turn,
		"next_generation_at", next.Format(time.RFC3339Nano),
	}
	logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
	service.logger.InfoContext(ctx, "turn generation succeeded", logArgs...)

	return Result{
		Record:  persisted,
		Trigger: input.Trigger,
		Outcome: operation.OutcomeSuccess,
	}
}

// failGeneration handles every post-CAS failure path: CAS to
// generation_failed, publish snapshot, publish game.generation_failed
// admin notification, audit failure.
func (service *Service) failGeneration(ctx context.Context, opStartedAt time.Time, input Input, _ runtime.RuntimeRecord, errorCode string, errorMessage string) Result {
	failedAt := service.clock().UTC()

	casErr := service.runtimeRecords.UpdateStatus(ctx, ports.UpdateStatusInput{
		GameID:       input.GameID,
		ExpectedFrom: runtime.StatusGenerationInProgress,
		To:           runtime.StatusGenerationFailed,
		Now:          failedAt,
	})
	if casErr != nil && !errors.Is(casErr, runtime.ErrConflict) {
		// Best-effort transition. The original error code remains the
		// caller-visible one; log the secondary failure.
		service.logger.ErrorContext(ctx, "cas runtime status to generation_failed",
			"game_id", input.GameID,
			"err", casErr.Error(),
		)
	}

	persisted, reloadErr := service.runtimeRecords.Get(ctx, input.GameID)
	publishedStatus := runtime.StatusGenerationFailed
	if reloadErr == nil {
		publishedStatus = persisted.Status
	}

	snapshot := ports.RuntimeSnapshotUpdate{
		GameID:              input.GameID,
		CurrentTurn:         persistedTurn(persisted, reloadErr),
		RuntimeStatus:       publishedStatus,
		EngineHealthSummary: persistedHealth(persisted, reloadErr),
		PlayerTurnStats:     nil,
		OccurredAt:          failedAt,
	}
	if err := service.lobbyEvents.PublishSnapshotUpdate(ctx, snapshot); err != nil {
		service.logger.ErrorContext(ctx, "publish runtime snapshot update on failure",
			"game_id", input.GameID,
			"err", err.Error(),
		)
	} else {
		service.telemetry.RecordLobbyEventPublished(ctx, "runtime_snapshot_update")
	}

	gameName := service.resolveGameName(ctx, input.GameID)
	service.publishGameGenerationFailedIntent(ctx, input, gameName, errorCode, errorMessage, failedAt)

	service.appendFailureLog(ctx, opStartedAt, input, errorCode, errorMessage)
	service.telemetry.RecordTurnGenerationOutcome(ctx,
		string(operation.OutcomeFailure), errorCode, string(input.Trigger))

	logArgs := []any{
		"game_id", input.GameID,
		"trigger", string(input.Trigger),
		"error_code", errorCode,
		"error_message", errorMessage,
	}
	logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
	service.logger.WarnContext(ctx, "turn generation failed", logArgs...)

	return Result{
		Record:       persisted,
		Trigger:      input.Trigger,
		Outcome:      operation.OutcomeFailure,
		ErrorCode:    errorCode,
		ErrorMessage: errorMessage,
	}
}

// handlePostEngineCASFailure maps a CAS error that surfaced after the
// engine call already succeeded. Conflict means an external actor (e.g.
// admin stop) won the race; other errors are treated as
// service_unavailable. No publication is issued — the external mutation
// owns its own snapshot.
func (service *Service) handlePostEngineCASFailure(ctx context.Context, opStartedAt time.Time, input Input, _ runtime.RuntimeRecord, casErr error) Result {
	switch {
	case errors.Is(casErr, runtime.ErrConflict):
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeConflict,
			fmt.Sprintf("cas runtime status post-engine: %s", casErr.Error()))
	case errors.Is(casErr, runtime.ErrNotFound):
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeRuntimeNotFound,
			fmt.Sprintf("cas runtime status post-engine: %s", casErr.Error()))
	default:
		return service.recordTerminalFailure(ctx, opStartedAt, input,
			ErrorCodeServiceUnavailable,
			fmt.Sprintf("cas runtime status post-engine: %s", casErr.Error()))
	}
}

// recordEarlyFailure handles failures that occur before the runtime row
// is in `generation_in_progress`. No status mutation, no publication;
// only audit and telemetry.
func (service *Service) recordEarlyFailure(ctx context.Context, opStartedAt time.Time, input Input, errorCode string, errorMessage string) Result {
	service.appendFailureLog(ctx, opStartedAt, input, errorCode, errorMessage)
	service.telemetry.RecordTurnGenerationOutcome(ctx,
		string(operation.OutcomeFailure), errorCode, string(input.Trigger))
	logArgs := []any{
		"game_id", input.GameID,
		"trigger", string(input.Trigger),
		"error_code", errorCode,
		"error_message", errorMessage,
	}
	logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
	service.logger.WarnContext(ctx, "turn generation rejected", logArgs...)
	return Result{
		Trigger:      input.Trigger,
		Outcome:      operation.OutcomeFailure,
		ErrorCode:    errorCode,
		ErrorMessage: errorMessage,
	}
}

// recordTerminalFailure handles failures after a post-engine CAS or a
// reload failed. The runtime row is in an undetermined state owned by
// whatever mutation won; we record the audit and surface the failure
// without further publication.
func (service *Service) recordTerminalFailure(ctx context.Context, opStartedAt time.Time, input Input, errorCode string, errorMessage string) Result {
	service.appendFailureLog(ctx, opStartedAt, input, errorCode, errorMessage)
	service.telemetry.RecordTurnGenerationOutcome(ctx,
		string(operation.OutcomeFailure), errorCode, string(input.Trigger))
	logArgs := []any{
		"game_id", input.GameID,
		"trigger", string(input.Trigger),
		"error_code", errorCode,
		"error_message", errorMessage,
	}
	logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
	service.logger.WarnContext(ctx, "turn generation post-engine failure", logArgs...)
	return Result{
		Trigger:      input.Trigger,
		Outcome:      operation.OutcomeFailure,
		ErrorCode:    errorCode,
		ErrorMessage: errorMessage,
	}
}

// resolveGameName fetches the human-readable game name from Lobby and
// falls back to the platform game id on any error per Stage 15 D1.
func (service *Service) resolveGameName(ctx context.Context, gameID string) string {
	summary, err := service.lobby.GetGameSummary(ctx, gameID)
	if err != nil {
		logArgs := []any{
			"game_id", gameID,
			"error_code", "lobby_unavailable",
			"err", err.Error(),
		}
		logArgs = append(logArgs, logging.ContextAttrs(ctx)...)
		service.logger.WarnContext(ctx, "resolve game name fell back to game id", logArgs...)
		return gameID
	}
	if strings.TrimSpace(summary.GameName) == "" {
		return gameID
	}
	return summary.GameName
}

// publishGameTurnReadyIntent publishes the user-targeted notification
// that announces a freshly generated turn. Empty recipient sets are
// dropped silently — the validator inside notificationintent rejects
// them outright, but the orchestrator should not break commit.
func (service *Service) publishGameTurnReadyIntent(ctx context.Context, input Input, gameName string, turnNumber int, recipients []string, occurredAt time.Time) {
	if len(recipients) == 0 {
		service.logger.WarnContext(ctx, "skip game.turn.ready notification: empty recipient set",
			"game_id", input.GameID,
		)
		return
	}
	intent, err := notificationintent.NewGameTurnReadyIntent(
		notificationintent.Metadata{
			IdempotencyKey: fmt.Sprintf("game.turn.ready:%s:%d", input.GameID, turnNumber),
			OccurredAt:     occurredAt,
			RequestID:      logging.RequestIDFromContext(ctx),
		},
		recipients,
		notificationintent.GameTurnReadyPayload{
			GameID:     input.GameID,
			GameName:   gameName,
			TurnNumber: int64(turnNumber),
		},
	)
	if err != nil {
		service.logger.ErrorContext(ctx, "build game.turn.ready intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameTurnReady), "error")
		return
	}
	if err := service.notifications.Publish(ctx, intent); err != nil {
		service.logger.ErrorContext(ctx, "publish game.turn.ready intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameTurnReady), "error")
		return
	}
	service.telemetry.RecordNotificationPublishAttempt(ctx,
		string(notificationintent.NotificationTypeGameTurnReady), "ok")
}

// publishGameFinishedIntent publishes the user-targeted notification
// that announces a finished game.
func (service *Service) publishGameFinishedIntent(ctx context.Context, input Input, gameName string, finalTurnNumber int, recipients []string, occurredAt time.Time) {
	if len(recipients) == 0 {
		service.logger.WarnContext(ctx, "skip game.finished notification: empty recipient set",
			"game_id", input.GameID,
		)
		return
	}
	intent, err := notificationintent.NewGameFinishedIntent(
		notificationintent.Metadata{
			IdempotencyKey: fmt.Sprintf("game.finished:%s:%d", input.GameID, finalTurnNumber),
			OccurredAt:     occurredAt,
			RequestID:      logging.RequestIDFromContext(ctx),
		},
		recipients,
		notificationintent.GameFinishedPayload{
			GameID:          input.GameID,
			GameName:        gameName,
			FinalTurnNumber: int64(finalTurnNumber),
		},
	)
	if err != nil {
		service.logger.ErrorContext(ctx, "build game.finished intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameFinished), "error")
		return
	}
	if err := service.notifications.Publish(ctx, intent); err != nil {
		service.logger.ErrorContext(ctx, "publish game.finished intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameFinished), "error")
		return
	}
	service.telemetry.RecordNotificationPublishAttempt(ctx,
		string(notificationintent.NotificationTypeGameFinished), "ok")
}

// publishGameGenerationFailedIntent publishes the admin-email
// notification that announces a failed turn generation.
func (service *Service) publishGameGenerationFailedIntent(ctx context.Context, input Input, gameName string, errorCode string, errorMessage string, occurredAt time.Time) {
	failureReason := errorCode
	if strings.TrimSpace(errorMessage) != "" {
		failureReason = fmt.Sprintf("%s: %s", errorCode, errorMessage)
	}
	intent, err := notificationintent.NewGameGenerationFailedIntent(
		notificationintent.Metadata{
			IdempotencyKey: fmt.Sprintf("game.generation_failed:%s:%d",
				input.GameID, occurredAt.UnixMilli()),
			OccurredAt: occurredAt,
			RequestID:  logging.RequestIDFromContext(ctx),
		},
		notificationintent.GameGenerationFailedPayload{
			GameID:        input.GameID,
			GameName:      gameName,
			FailureReason: failureReason,
		},
	)
	if err != nil {
		service.logger.ErrorContext(ctx, "build game.generation_failed intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameGenerationFailed), "error")
		return
	}
	if err := service.notifications.Publish(ctx, intent); err != nil {
		service.logger.ErrorContext(ctx, "publish game.generation_failed intent",
			"game_id", input.GameID,
			"err", err.Error(),
		)
		service.telemetry.RecordNotificationPublishAttempt(ctx,
			string(notificationintent.NotificationTypeGameGenerationFailed), "error")
		return
	}
	service.telemetry.RecordNotificationPublishAttempt(ctx,
		string(notificationintent.NotificationTypeGameGenerationFailed), "ok")
}

// projectPlayerStats joins the engine response on RaceName against the
// installed roster to build one PlayerTurnStats per active member.
// Result is sorted by UserID for a deterministic wire order.
func projectPlayerStats(state ports.StateResponse, mappings []playermapping.PlayerMapping) []ports.PlayerTurnStats {
	if len(state.Players) == 0 || len(mappings) == 0 {
		return nil
	}
	userByRace := make(map[string]string, len(mappings))
	for _, mapping := range mappings {
		userByRace[mapping.RaceName] = mapping.UserID
	}
	stats := make([]ports.PlayerTurnStats, 0, len(state.Players))
	for _, player := range state.Players {
		userID, ok := userByRace[player.RaceName]
		if !ok {
			continue
		}
		stats = append(stats, ports.PlayerTurnStats{
			UserID:     userID,
			Planets:    player.Planets,
			Population: player.Population,
		})
	}
	sort.Slice(stats, func(i, j int) bool { return stats[i].UserID < stats[j].UserID })
	return stats
}

// recipientUserIDs returns the deduplicated, sorted-ascending list of
// platform user ids derived from the roster. Mirrors the
// notificationintent validator's expectations.
func recipientUserIDs(mappings []playermapping.PlayerMapping) []string {
	if len(mappings) == 0 {
		return nil
	}
	seen := make(map[string]struct{}, len(mappings))
	result := make([]string, 0, len(mappings))
	for _, mapping := range mappings {
		userID := strings.TrimSpace(mapping.UserID)
		if userID == "" {
			continue
		}
		if _, ok := seen[userID]; ok {
			continue
		}
		seen[userID] = struct{}{}
		result = append(result, userID)
	}
	sort.Strings(result)
	return result
}

// persistedTurn returns the stored CurrentTurn when reloadErr is nil,
// or zero otherwise. Used to populate the failure-side snapshot
// without making a second DB read.
func persistedTurn(record runtime.RuntimeRecord, reloadErr error) int {
	if reloadErr != nil {
		return 0
	}
	return record.CurrentTurn
}

// persistedHealth returns the stored EngineHealth when reloadErr is
// nil, or empty string otherwise.
func persistedHealth(record runtime.RuntimeRecord, reloadErr error) string {
	if reloadErr != nil {
		return ""
	}
	return record.EngineHealth
}

// appendSuccessLog records the success operation_log entry.
func (service *Service) appendSuccessLog(ctx context.Context, opStartedAt time.Time, input Input) {
	finishedAt := service.clock().UTC()
	service.bestEffortAppend(ctx, operation.OperationEntry{
		GameID:     input.GameID,
		OpKind:     operation.OpKindTurnGeneration,
		OpSource:   fallbackOpSource(input.OpSource),
		SourceRef:  input.SourceRef,
		Outcome:    operation.OutcomeSuccess,
		StartedAt:  opStartedAt,
		FinishedAt: &finishedAt,
	})
}

// appendFailureLog records the failure operation_log entry.
func (service *Service) appendFailureLog(ctx context.Context, opStartedAt time.Time, input Input, errorCode string, errorMessage string) {
	finishedAt := service.clock().UTC()
	service.bestEffortAppend(ctx, operation.OperationEntry{
		GameID:       input.GameID,
		OpKind:       operation.OpKindTurnGeneration,
		OpSource:     fallbackOpSource(input.OpSource),
		SourceRef:    input.SourceRef,
		Outcome:      operation.OutcomeFailure,
		ErrorCode:    errorCode,
		ErrorMessage: errorMessage,
		StartedAt:    opStartedAt,
		FinishedAt:   &finishedAt,
	})
}

// bestEffortAppend writes one operation_log entry. A failure is logged
// and discarded; the runtime row is the source of truth.
func (service *Service) bestEffortAppend(ctx context.Context, entry operation.OperationEntry) {
	if _, err := service.operationLogs.Append(ctx, entry); err != nil {
		service.logger.ErrorContext(ctx, "append operation log",
			"game_id", entry.GameID,
			"op_kind", string(entry.OpKind),
			"outcome", string(entry.Outcome),
			"error_code", entry.ErrorCode,
			"err", err.Error(),
		)
	}
}

// fallbackOpSource defaults to admin_rest when source is missing or
// unrecognised. Mirrors `gamemaster/README.md §Trusted Surfaces`.
func fallbackOpSource(source operation.OpSource) operation.OpSource {
	if source.IsKnown() {
		return source
	}
	return operation.OpSourceAdminRest
}