// Package app wires notice-service modules, health endpoints and background workers.
package app

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

	"google.golang.org/grpc"
	healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
	"hyapp/pkg/grpchealth"
	"hyapp/pkg/grpcshutdown"
	"hyapp/pkg/healthhttp"
	"hyapp/pkg/logx"
	"hyapp/pkg/tencentim"
	"hyapp/services/notice-service/internal/config"
	"hyapp/services/notice-service/internal/modules/walletnotice"
	mysqlplatform "hyapp/services/notice-service/internal/platform/mysql"
)

// App owns the notice-service process lifecycle.
type App struct {
	server              *grpc.Server
	listener            net.Listener
	health              *grpchealth.ServingChecker
	healthHTTP          *healthhttp.Server
	store               *mysqlplatform.Store
	walletNoticeService *walletnotice.Service
	walletWorkerOptions walletnotice.WalletNoticeWorkerOptions
	walletWorkerEnabled bool
	workerCtx           context.Context
	workerCancel        context.CancelFunc
	workerWG            sync.WaitGroup
	closeOnce           sync.Once
}

// New initializes MySQL, module repositories and optional Tencent IM publisher.
func New(cfg config.Config) (*App, error) {
	startupCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	store, err := mysqlplatform.Open(startupCtx, cfg.MySQLDSN)
	if err != nil {
		return nil, err
	}
	listener, err := net.Listen("tcp", cfg.GRPCAddr)
	if err != nil {
		_ = store.Close()
		return nil, err
	}

	walletRepo, err := walletnotice.NewMySQLRepository(store.DB, cfg.WalletDatabase)
	if err != nil {
		_ = listener.Close()
		_ = store.Close()
		return nil, err
	}
	var publisher walletnotice.UserMessagePublisher
	if cfg.TencentIM.Enabled {
		tencentClient, err := tencentim.NewRESTClient(cfg.TencentIM.RESTConfig())
		if err != nil {
			_ = listener.Close()
			_ = store.Close()
			return nil, err
		}
		publisher = tencentClient
	}
	if cfg.WalletNoticeWorker.Enabled && publisher == nil {
		_ = listener.Close()
		_ = store.Close()
		return nil, errors.New("wallet notice worker requires tencent_im.enabled")
	}

	server := grpc.NewServer(grpc.UnaryInterceptor(logx.UnaryServerInterceptor("notice-service")))
	health := grpchealth.NewServingChecker("notice-service", grpchealth.Dependency{
		Name:  "mysql",
		Check: store.Ping,
	})
	healthgrpc.RegisterHealthServer(server, grpchealth.NewServer(health))
	healthHTTP, err := healthhttp.New(cfg.HealthHTTPAddr, cfg.NodeID, health)
	if err != nil {
		_ = listener.Close()
		_ = store.Close()
		return nil, err
	}

	workerCtx, workerCancel := context.WithCancel(context.Background())
	return &App{
		server:              server,
		listener:            listener,
		health:              health,
		healthHTTP:          healthHTTP,
		store:               store,
		walletNoticeService: walletnotice.New(walletnotice.Config{NodeID: cfg.NodeID}, walletRepo, publisher),
		walletWorkerOptions: walletNoticeWorkerOptions(cfg.WalletNoticeWorker),
		walletWorkerEnabled: cfg.WalletNoticeWorker.Enabled,
		workerCtx:           workerCtx,
		workerCancel:        workerCancel,
	}, nil
}

// Run starts health serving, optional workers and the gRPC health endpoint.
func (a *App) Run() error {
	a.runHealthHTTP()
	a.health.MarkServing()
	defer func() {
		if a.workerCancel != nil {
			a.workerCancel()
		}
		a.workerWG.Wait()
		a.health.MarkStopped()
	}()
	if a.walletWorkerEnabled && a.walletNoticeService != nil {
		a.workerWG.Go(func() {
			a.walletNoticeService.RunWalletBalanceWorker(a.workerCtx, a.walletWorkerOptions)
		})
	}
	err := a.server.Serve(a.listener)
	if errors.Is(err, grpc.ErrServerStopped) {
		return nil
	}
	return err
}

// Close drains workers before closing gRPC and MySQL resources.
func (a *App) Close() {
	a.closeOnce.Do(func() {
		a.health.MarkDraining()
		if a.workerCancel != nil {
			a.workerCancel()
		}
		a.workerWG.Wait()
		grpcshutdown.GracefulStop(a.server, 15*time.Second)
		a.closeHealthHTTP()
		if a.store != nil {
			_ = a.store.Close()
		}
	})
}

func (a *App) runHealthHTTP() {
	if a.healthHTTP == nil {
		return
	}
	go func() {
		if err := a.healthHTTP.Run(); err != nil {
			logx.Error(context.Background(), "health_http_run_failed", err)
		}
	}()
}

func (a *App) closeHealthHTTP() {
	if a.healthHTTP == nil {
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	_ = a.healthHTTP.Close(ctx)
}

func walletNoticeWorkerOptions(cfg config.WalletNoticeWorkerConfig) walletnotice.WalletNoticeWorkerOptions {
	return walletnotice.WalletNoticeWorkerOptions{
		PollInterval:   cfg.PollInterval,
		BatchSize:      cfg.BatchSize,
		LockTTL:        cfg.LockTTL,
		PublishTimeout: cfg.PublishTimeout,
		MaxRetryCount:  cfg.MaxRetryCount,
		InitialBackoff: cfg.InitialBackoff,
		MaxBackoff:     cfg.MaxBackoff,
	}
}