tercul-backend/cmd/api/main.go

package main

import (
	"context"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"tercul/internal/app"
	"tercul/internal/app/analytics"
	graph "tercul/internal/adapters/graphql"
	dbsql "tercul/internal/data/sql"
	"tercul/internal/jobs/linguistics"
	"tercul/internal/observability"
	"tercul/internal/platform/auth"
	"tercul/internal/platform/config"
	"tercul/internal/platform/db"
	app_log "tercul/internal/platform/log"
	"tercul/internal/platform/search"
	"time"

	"github.com/99designs/gqlgen/graphql/playground"
	"github.com/pressly/goose/v3"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/weaviate/weaviate-go-client/v5/weaviate"
	"gorm.io/gorm"
)

// runMigrations applies database migrations using goose.
func runMigrations(gormDB *gorm.DB, migrationPath string) error {
	sqlDB, err := gormDB.DB()
	if err != nil {
		return err
	}

	if err := goose.SetDialect("postgres"); err != nil {
		return err
	}

	app_log.Info(fmt.Sprintf("Applying database migrations from %s", migrationPath))
	if err := goose.Up(sqlDB, migrationPath); err != nil {
		return err
	}
	app_log.Info("Database migrations applied successfully")
	return nil
}

// main is the entry point for the Tercul application.
func main() {
	// Load configuration from environment variables
	cfg, err := config.LoadConfig()
	if err != nil {
		log.Fatalf("cannot load config: %v", err)
	}

	// Initialize logger
	app_log.Init("tercul-api", cfg.Environment)
	obsLogger := observability.NewLogger("tercul-api", cfg.Environment)

	// Initialize OpenTelemetry Tracer Provider
	tp, err := observability.TracerProvider("tercul-api", cfg.Environment)
	if err != nil {
		app_log.Fatal(err, "Failed to initialize OpenTelemetry tracer")
	}
	defer func() {
		if err := tp.Shutdown(context.Background()); err != nil {
			app_log.Error(err, "Error shutting down tracer provider")
		}
	}()

	// Initialize Prometheus metrics
	reg := prometheus.NewRegistry()
	metrics := observability.NewMetrics(reg) // Metrics are registered automatically

	app_log.Info(fmt.Sprintf("Starting Tercul application in %s environment, version 1.0.0", cfg.Environment))

	// Initialize database connection
	database, err := db.InitDB(cfg, metrics)
	if err != nil {
		app_log.Fatal(err, "Failed to initialize database")
	}
	defer db.Close(database)

	if err := runMigrations(database, cfg.MigrationPath); err != nil {
		app_log.Fatal(err, "Failed to apply database migrations")
	}

	// Initialize Weaviate client
	weaviateCfg := weaviate.Config{
		Host:   cfg.WeaviateHost,
		Scheme: cfg.WeaviateScheme,
	}
	weaviateClient, err := weaviate.NewClient(weaviateCfg)
	if err != nil {
		app_log.Fatal(err, "Failed to create weaviate client")
	}

	// Create search client
	searchClient := search.NewWeaviateWrapper(weaviateClient)

	// Create repositories
	repos := dbsql.NewRepositories(database, cfg)

	// Create linguistics dependencies
	analysisRepo := linguistics.NewGORMAnalysisRepository(database)
	sentimentProvider, err := linguistics.NewGoVADERSentimentProvider()
	if err != nil {
		app_log.Fatal(err, "Failed to create sentiment provider")
	}

	// Create platform components
	jwtManager := auth.NewJWTManager(cfg)

	// Create application services
	analyticsService := analytics.NewService(repos.Analytics, analysisRepo, repos.Translation, repos.Work, sentimentProvider)

	// Create application dependencies
	deps := app.Dependencies{
		WorkRepo:           repos.Work,
		UserRepo:           repos.User,
		AuthorRepo:         repos.Author,
		TranslationRepo:    repos.Translation,
		CommentRepo:        repos.Comment,
		LikeRepo:           repos.Like,
		BookmarkRepo:       repos.Bookmark,
		CollectionRepo:     repos.Collection,
		TagRepo:            repos.Tag,
		CategoryRepo:       repos.Category,
		BookRepo:           repos.Book,
		PublisherRepo:      repos.Publisher,
		SourceRepo:         repos.Source,
		CopyrightRepo:      repos.Copyright,
		MonetizationRepo:   repos.Monetization,
		ContributionRepo:   repos.Contribution,
		AnalyticsRepo:      repos.Analytics,
		AuthRepo:           repos.Auth,
		LocalizationRepo:   repos.Localization,
		SearchClient:       searchClient,
		AnalyticsService:   analyticsService,
		JWTManager:         jwtManager,
	}

	// Create application
	application := app.NewApplication(deps)

	// Create GraphQL server
	resolver := &graph.Resolver{
		App: application,
	}

	// Create the main API handler with all middleware.
	// NewServerWithAuth now returns the handler chain directly.
	apiHandler := NewServerWithAuth(resolver, jwtManager, metrics, obsLogger)

	// Create the main ServeMux and register all handlers.
	mux := http.NewServeMux()
	mux.Handle("/query", apiHandler)
	mux.Handle("/playground", playground.Handler("GraphQL Playground", "/query"))
	mux.Handle("/metrics", observability.PrometheusHandler(reg))

	// Create a single HTTP server with the main mux.
	mainServer := &http.Server{
		Addr:    cfg.ServerPort,
		Handler: mux,
	}
	app_log.Info(fmt.Sprintf("API server listening on port %s", cfg.ServerPort))

	// Start the main server in a goroutine
	go func() {
		if err := mainServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			app_log.Fatal(err, "Failed to start server")
		}
	}()

	// Wait for interrupt signal to gracefully shutdown the server
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	app_log.Info("Shutting down server...")

	// Graceful shutdown
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	if err := mainServer.Shutdown(ctx); err != nil {
		app_log.Error(err, "Server forced to shutdown")
	}

	app_log.Info("Server shut down successfully")
}