package main

import (
	"bufio"
	"context"
	"errors"
	"io/fs"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	assets "galo"
	"galo/internal/app"
	"galo/internal/auth"
	"galo/internal/config"
	"galo/internal/db"
	"galo/internal/settings"
	"galo/internal/sse"
	"galo/internal/storage"
	"galo/internal/store"
)

// version is set at build time via -ldflags "-X main.version=..."
var version = "dev"

func main() {
	loadDotEnv(".env")
	loadDotEnv("../.env")

	logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo}))
	slog.SetDefault(logger)
	slog.Info("starting galo", "version", version)

	cfg, err := config.Load()
	if err != nil {
		slog.Error("config error", "error", err)
		os.Exit(1)
	}

	switch cfg.Database.Backend {
	case "sqlite":
		slog.Info("metadata backend", "backend", "sqlite", "path", cfg.Database.SQLitePath)
	default:
		slog.Info("metadata backend", "backend", "postgres",
			"host", cfg.Postgres.Host, "database", cfg.Postgres.Database)
	}
	switch cfg.Storage.Backend {
	case "fs":
		slog.Info("storage backend", "backend", "fs", "root", cfg.Storage.FSRoot)
	default:
		slog.Info("storage backend", "backend", "s3",
			"endpoint", cfg.S3.Endpoint, "bucket", cfg.S3.Bucket)
	}

	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	var (
		repos  store.Repos
		ping   func(ctx context.Context) error
		closer func()
	)
	switch cfg.Database.Backend {
	case "sqlite":
		migFS, err := fs.Sub(assets.Migrations, "migrations/sqlite")
		if err != nil {
			slog.Error("migrations fs", "error", err)
			os.Exit(1)
		}
		if err := db.MigrateSQLite(cfg.Database.SQLitePath, migFS); err != nil {
			slog.Error("migration failed", "error", err)
			os.Exit(1)
		}
		database, err := db.OpenSQLite(cfg.Database.SQLitePath)
		if err != nil {
			slog.Error("database open failed", "error", err)
			os.Exit(1)
		}
		repos = store.NewSQLite(database)
		ping = database.PingContext
		closer = func() { _ = database.Close() }
	default:
		migFS, err := fs.Sub(assets.Migrations, "migrations")
		if err != nil {
			slog.Error("migrations fs", "error", err)
			os.Exit(1)
		}
		if err := db.Migrate(cfg.Postgres.DSN(), migFS); err != nil {
			slog.Error("migration failed", "error", err)
			os.Exit(1)
		}
		pool, err := db.Connect(ctx, cfg.Postgres.DSN())
		if err != nil {
			slog.Error("database connect failed", "error", err)
			os.Exit(1)
		}
		repos = store.NewPostgres(pool)
		ping = pool.Ping
		closer = pool.Close
	}
	defer closer()
	slog.Info("migrations applied", "db_backend", cfg.Database.Backend)

	secret, err := repos.Settings.Ensure(ctx, settings.JWTSecretKey, settings.GenerateSecret)
	if err != nil {
		slog.Error("secret init failed", "error", err)
		os.Exit(1)
	}
	tm := auth.NewTokenManager(secret, cfg.Auth.AccessTTL, cfg.Auth.RefreshTTL)

	blob, err := storage.Open(ctx, cfg, secret)
	if err != nil {
		slog.Error("storage init failed", "error", err)
		os.Exit(1)
	}
	if err := blob.EnsureBucket(ctx); err != nil {
		slog.Warn("could not ensure bucket", "error", err)
	} else {
		slog.Info("storage ready", "location", blob.Bucket())
	}

	hub := sse.NewHub(cfg.SSE.ClientBuffer)
	server := app.New(cfg, repos, ping, tm, blob, hub)

	go server.StartWorker(ctx)

	httpServer := &http.Server{
		Addr:              cfg.Server.Addr,
		Handler:           server.Router(),
		ReadHeaderTimeout: 10 * time.Second,
	}

	go func() {
		slog.Info("listening", "addr", cfg.Server.Addr)
		if err := httpServer.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			slog.Error("server error", "error", err)
			stop()
		}
	}()

	<-ctx.Done()
	slog.Info("shutting down")
	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	_ = httpServer.Shutdown(shutdownCtx)
}

func loadDotEnv(path string) {
	f, err := os.Open(path)
	if err != nil {
		return
	}
	defer f.Close()
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		key, value, ok := strings.Cut(line, "=")
		if !ok {
			continue
		}
		key = strings.TrimSpace(key)
		value = strings.TrimSpace(value)
		if _, exists := os.LookupEnv(key); !exists {
			_ = os.Setenv(key, value)
		}
	}
}