// Command exod is the gRPC backend daemon for the exo system.
// It is the sole owner of the SQLite database and blob store.
package main

import (
	"flag"
	"log"
	"net"
	"os"
	"os/signal"
	"syscall"

	"google.golang.org/grpc"

	"git.wntrmute.dev/kyle/exo/blob"
	"git.wntrmute.dev/kyle/exo/config"
	"git.wntrmute.dev/kyle/exo/db"
	pb "git.wntrmute.dev/kyle/exo/proto/exo/v1"
	"git.wntrmute.dev/kyle/exo/server"
)

var version = "dev"

func main() {
	var (
		listenAddr = flag.String("listen", "", "gRPC listen address (default from config)")
		basePath   = flag.String("base", "", "base data directory (default $HOME/exo)")
		showVer    = flag.Bool("version", false, "print version and exit")
	)
	flag.Parse()

	if *showVer {
		log.Printf("exod %s", version)
		os.Exit(0)
	}

	cfg := config.Default()
	if *basePath != "" {
		cfg = config.FromBasePath(*basePath)
	}
	if *listenAddr != "" {
		cfg.GRPCListenAddr = *listenAddr
	}

	// Ensure data directories exist.
	if err := os.MkdirAll(cfg.BasePath, 0o750); err != nil {
		log.Fatalf("exod: failed to create base directory: %v", err)
	}
	if err := os.MkdirAll(cfg.BlobStorePath, 0o750); err != nil {
		log.Fatalf("exod: failed to create blob store directory: %v", err)
	}

	// Open and migrate the database.
	database, err := db.Open(cfg.DatabasePath)
	if err != nil {
		log.Fatalf("exod: failed to open database: %v", err)
	}
	defer func() { _ = database.Close() }()

	if err := db.Migrate(database); err != nil {
		log.Fatalf("exod: failed to migrate database: %v", err)
	}

	blobStore := blob.NewStore(cfg.BlobStorePath)

	// Start gRPC server.
	lis, err := net.Listen("tcp", cfg.GRPCListenAddr)
	if err != nil {
		log.Fatalf("exod: failed to listen on %s: %v", cfg.GRPCListenAddr, err)
	}

	grpcServer := grpc.NewServer()
	pb.RegisterArtifactServiceServer(grpcServer, server.NewArtifactServer(database, blobStore))

	// Graceful shutdown on SIGINT/SIGTERM.
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		sig := <-sigCh
		log.Printf("exod: received %s, shutting down", sig)
		grpcServer.GracefulStop()
	}()

	log.Printf("exod %s listening on %s", version, cfg.GRPCListenAddr)
	if err := grpcServer.Serve(lis); err != nil {
		log.Fatalf("exod: gRPC server error: %v", err)
	}
}