package gamestore

import (
	"encoding/json"
	"fmt"
	"time"

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

// runtimeSnapshotJSON is the on-disk JSONB shape used for the denormalised
// runtime snapshot column on `games`. Keys mirror the field names in
// `game.RuntimeSnapshot` so a round-trip remains naked-comparable.
type runtimeSnapshotJSON struct {
	CurrentTurn         int    `json:"current_turn"`
	RuntimeStatus       string `json:"runtime_status,omitempty"`
	EngineHealthSummary string `json:"engine_health_summary,omitempty"`
}

func marshalRuntimeSnapshot(snapshot game.RuntimeSnapshot) ([]byte, error) {
	payload := runtimeSnapshotJSON{
		CurrentTurn:         snapshot.CurrentTurn,
		RuntimeStatus:       snapshot.RuntimeStatus,
		EngineHealthSummary: snapshot.EngineHealthSummary,
	}
	encoded, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("marshal runtime snapshot: %w", err)
	}
	return encoded, nil
}

func unmarshalRuntimeSnapshot(payload []byte) (game.RuntimeSnapshot, error) {
	if len(payload) == 0 {
		return game.RuntimeSnapshot{}, nil
	}
	var stored runtimeSnapshotJSON
	if err := json.Unmarshal(payload, &stored); err != nil {
		return game.RuntimeSnapshot{}, fmt.Errorf("unmarshal runtime snapshot: %w", err)
	}
	return game.RuntimeSnapshot{
		CurrentTurn:         stored.CurrentTurn,
		RuntimeStatus:       stored.RuntimeStatus,
		EngineHealthSummary: stored.EngineHealthSummary,
	}, nil
}

// runtimeBindingJSON is the on-disk JSONB shape used for the optional
// runtime binding column on `games`. The `bound_at_ms` field stores Unix
// milliseconds so the JSON serialisation matches the previous Redis JSON
// shape and the timezone is irrelevant inside the JSON payload itself; the
// adapter still re-wraps the resulting time.Time with .UTC() before exposing
// it to callers.
type runtimeBindingJSON struct {
	ContainerID    string `json:"container_id"`
	EngineEndpoint string `json:"engine_endpoint"`
	RuntimeJobID   string `json:"runtime_job_id"`
	BoundAtMS      int64  `json:"bound_at_ms"`
}

// marshalRuntimeBinding returns nil bytes (SQL NULL) when binding is nil,
// otherwise the JSON encoding of the binding.
func marshalRuntimeBinding(binding *game.RuntimeBinding) ([]byte, error) {
	if binding == nil {
		return nil, nil
	}
	payload := runtimeBindingJSON{
		ContainerID:    binding.ContainerID,
		EngineEndpoint: binding.EngineEndpoint,
		RuntimeJobID:   binding.RuntimeJobID,
		BoundAtMS:      binding.BoundAt.UTC().UnixMilli(),
	}
	encoded, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("marshal runtime binding: %w", err)
	}
	return encoded, nil
}

func unmarshalRuntimeBinding(payload []byte) (*game.RuntimeBinding, error) {
	if len(payload) == 0 {
		return nil, nil
	}
	var stored runtimeBindingJSON
	if err := json.Unmarshal(payload, &stored); err != nil {
		return nil, fmt.Errorf("unmarshal runtime binding: %w", err)
	}
	return &game.RuntimeBinding{
		ContainerID:    stored.ContainerID,
		EngineEndpoint: stored.EngineEndpoint,
		RuntimeJobID:   stored.RuntimeJobID,
		BoundAt:        time.UnixMilli(stored.BoundAtMS).UTC(),
	}, nil
}