package app

import (
	"context"
	"errors"
	"net"
	"sync"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
	gamev1 "hyapp.local/api/proto/game/v1"
	"hyapp/pkg/grpchealth"
	"hyapp/pkg/logx"
	"hyapp/services/game-service/internal/client"
	"hyapp/services/game-service/internal/config"
	gameservice "hyapp/services/game-service/internal/service/game"
	mysqlstorage "hyapp/services/game-service/internal/storage/mysql"
	grpcserver "hyapp/services/game-service/internal/transport/grpc"
)

// App 装配 game-service gRPC 入口和持久化依赖。
type App struct {
	server     *grpc.Server
	listener   net.Listener
	health     *grpchealth.ServingChecker
	repo       *mysqlstorage.Repository
	walletConn *grpc.ClientConn
	userConn   *grpc.ClientConn
	closeOnce  sync.Once
}

func New(cfg config.Config) (*App, error) {
	startupCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	repo, err := mysqlstorage.Open(startupCtx, cfg.MySQLDSN)
	if err != nil {
		return nil, err
	}
	walletConn, err := grpc.Dial(cfg.WalletServiceAddr, grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		_ = repo.Close()
		return nil, err
	}
	userConn, err := grpc.Dial(cfg.UserServiceAddr, grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		_ = walletConn.Close()
		_ = repo.Close()
		return nil, err
	}
	listener, err := net.Listen("tcp", cfg.GRPCAddr)
	if err != nil {
		_ = userConn.Close()
		_ = walletConn.Close()
		_ = repo.Close()
		return nil, err
	}

	server := grpc.NewServer(grpc.UnaryInterceptor(logx.UnaryServerInterceptor("game-service")))
	svc := gameservice.New(gameservice.Config{LaunchSessionTTL: cfg.LaunchSessionTTL}, repo, client.NewWalletClient(walletConn), client.NewUserClient(userConn))
	transport := grpcserver.NewServer(svc)
	gamev1.RegisterGameAppServiceServer(server, transport)
	gamev1.RegisterGameCallbackServiceServer(server, transport)
	gamev1.RegisterGameAdminServiceServer(server, transport)
	health := grpchealth.NewServingChecker("game-service")
	healthgrpc.RegisterHealthServer(server, grpchealth.NewServer(health))

	return &App{server: server, listener: listener, health: health, repo: repo, walletConn: walletConn, userConn: userConn}, nil
}

func (a *App) Run() error {
	a.health.MarkServing()
	err := a.server.Serve(a.listener)
	a.health.MarkStopped()
	if errors.Is(err, grpc.ErrServerStopped) {
		return nil
	}
	return err
}

func (a *App) Close() {
	a.closeOnce.Do(func() {
		a.health.MarkDraining()
		a.server.GracefulStop()
		if a.walletConn != nil {
			_ = a.walletConn.Close()
		}
		if a.userConn != nil {
			_ = a.userConn.Close()
		}
		if a.repo != nil {
			_ = a.repo.Close()
		}
	})
}