// Package ports defines the stable interfaces that connect Game Lobby
// Service use cases to external state and external services.
package ports

import (
	"context"
	"fmt"
	"time"

	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/game"
)

// GameStore stores game records and their secondary indexes. Adapters are
// responsible for maintaining the status index together with the record.
type GameStore interface {
	// Save upserts record. It is used for draft creation and for
	// field-only edits. The adapter must rewrite the status secondary
	// index when the status field changes. Save does not apply the
	// domain transition gate; callers that intend a status transition
	// must use UpdateStatus instead.
	Save(ctx context.Context, record game.Game) error

	// Get returns the record identified by gameID. It returns
	// game.ErrNotFound when no record exists.
	Get(ctx context.Context, gameID common.GameID) (game.Game, error)

	// GetByStatus returns every record currently indexed under status.
	// The slice is ordered by the created-at score ascending; callers
	// may reorder as needed.
	GetByStatus(ctx context.Context, status game.Status) ([]game.Game, error)

	// CountByStatus returns the number of game records indexed under
	// each known status. The map carries one entry per game.Status from
	// game.AllStatuses, with zero counts for empty buckets. Telemetry
	// uses the result to emit the `lobby.active_games` observable gauge
	// without scanning record payloads.
	CountByStatus(ctx context.Context) (map[game.Status]int, error)

	// GetByOwner returns every record whose OwnerUserID equals userID.
	// The order is adapter-defined; callers may reorder as needed. The
	// secondary index is maintained alongside the per-status index;
	// cascade-release callers consume it without touching the
	// status listings.
	GetByOwner(ctx context.Context, userID string) ([]game.Game, error)

	// UpdateStatus applies one status transition in a compare-and-swap
	// fashion. The adapter must first call game.Transition to reject
	// invalid triplets without touching the store; on success it must
	// verify that the current status equals input.ExpectedFrom, update
	// the primary record, and rewrite the status secondary index.
	// Adapters set StartedAt when transitioning to running and
	// FinishedAt when transitioning to finished.
	UpdateStatus(ctx context.Context, input UpdateStatusInput) error

	// UpdateRuntimeSnapshot overwrites the denormalized runtime snapshot
	// fields on the record identified by input.GameID. It does not
	// mutate the status field or the status secondary index.
	UpdateRuntimeSnapshot(ctx context.Context, input UpdateRuntimeSnapshotInput) error

	// UpdateRuntimeBinding overwrites the runtime binding metadata on the
	// record identified by input.GameID. It does not mutate the status
	// field or the status secondary index. The binding must satisfy the
	// domain invariants (see game.RuntimeBinding.Validate). The adapter
	// returns game.ErrNotFound when no record exists.
	UpdateRuntimeBinding(ctx context.Context, input UpdateRuntimeBindingInput) error
}

// UpdateStatusInput stores the arguments required to apply one status
// transition through a GameStore.
type UpdateStatusInput struct {
	// GameID identifies the record to mutate.
	GameID common.GameID

	// ExpectedFrom stores the status the caller believes the record
	// currently has. A mismatch results in game.ErrConflict.
	ExpectedFrom game.Status

	// To stores the destination status.
	To game.Status

	// Trigger stores the transition trigger used by the domain gate.
	Trigger game.Trigger

	// At stores the wall-clock used for UpdatedAt, and for StartedAt or
	// FinishedAt when the destination status requires it.
	At time.Time
}

// Validate reports whether input contains a structurally valid status
// transition request.
func (input UpdateStatusInput) Validate() error {
	if err := input.GameID.Validate(); err != nil {
		return fmt.Errorf("update status: game id: %w", err)
	}
	if !input.ExpectedFrom.IsKnown() {
		return fmt.Errorf("update status: expected from status %q is unsupported", input.ExpectedFrom)
	}
	if !input.To.IsKnown() {
		return fmt.Errorf("update status: to status %q is unsupported", input.To)
	}
	if !input.Trigger.IsKnown() {
		return fmt.Errorf("update status: trigger %q is unsupported", input.Trigger)
	}
	if input.At.IsZero() {
		return fmt.Errorf("update status: at must not be zero")
	}

	return nil
}

// UpdateRuntimeSnapshotInput stores the arguments required to update the
// denormalized runtime snapshot on one game record.
type UpdateRuntimeSnapshotInput struct {
	// GameID identifies the record to mutate.
	GameID common.GameID

	// Snapshot stores the new snapshot values to persist.
	Snapshot game.RuntimeSnapshot

	// At stores the wall-clock used for UpdatedAt.
	At time.Time
}

// Validate reports whether input contains a structurally valid runtime
// snapshot update request.
func (input UpdateRuntimeSnapshotInput) Validate() error {
	if err := input.GameID.Validate(); err != nil {
		return fmt.Errorf("update runtime snapshot: game id: %w", err)
	}
	if input.Snapshot.CurrentTurn < 0 {
		return fmt.Errorf("update runtime snapshot: current turn must not be negative")
	}
	if input.At.IsZero() {
		return fmt.Errorf("update runtime snapshot: at must not be zero")
	}

	return nil
}

// UpdateRuntimeBindingInput stores the arguments required to persist
// runtime binding metadata on one game record.
type UpdateRuntimeBindingInput struct {
	// GameID identifies the record to mutate.
	GameID common.GameID

	// Binding stores the runtime binding values to persist. The adapter
	// validates the binding before writing.
	Binding game.RuntimeBinding

	// At stores the wall-clock used for UpdatedAt.
	At time.Time
}

// Validate reports whether input contains a structurally valid runtime
// binding update request.
func (input UpdateRuntimeBindingInput) Validate() error {
	if err := input.GameID.Validate(); err != nil {
		return fmt.Errorf("update runtime binding: game id: %w", err)
	}
	if err := input.Binding.Validate(); err != nil {
		return fmt.Errorf("update runtime binding: %w", err)
	}
	if input.At.IsZero() {
		return fmt.Errorf("update runtime binding: at must not be zero")
	}

	return nil
}