// Command geniusrund is geniusrun's backend server: syncs runs from Garmin,
// classifies them into workout kinds, and serves the REST API the frontend
// talks to.
package main

import (
	"context"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"geniusrun/backend/internal/api"
	"geniusrun/backend/internal/auth"
	"geniusrun/backend/internal/config"
	"geniusrun/backend/internal/garmin"
	applog "geniusrun/backend/internal/log"
	"geniusrun/backend/internal/store"
)

// fatal logs through the application JSON logger and exits -- the
// structured replacement for log.Fatalf, so even startup failures come
// out as JSON lines.
func fatal(msg string, err error) {
	applog.App("main", "fatal").Error(msg, "error", err)
	os.Exit(1)
}

func main() {
	// Bootstrap logger at info so failures loading the env config itself
	// (which carries the real log level) are still emitted as JSON.
	slog.SetDefault(applog.NewLogger("warn", os.Stdout))

	envCfg, err := config.LoadEnv()
	if err != nil {
		fatal("load env config", err)
	}
	slog.SetDefault(applog.NewLogger(envCfg.LogLevel, os.Stdout))

	db, err := store.Open(envCfg.DBPath)
	if err != nil {
		fatal("open database", err)
	}
	defer db.Close()

	values, err := db.ConfigValues(context.Background())
	if err != nil {
		fatal("read app config", err)
	}
	// Every registry key is mandatory in the DB: seed missing ones with
	// their defaults so the config table is always fully populated (no
	// code-side fallbacks anywhere downstream).
	for _, k := range config.AppRegistry() {
		if _, ok := values[k.Key]; !ok {
			if err := db.SetConfigValue(context.Background(), k.Key, k.Default); err != nil {
				fatal("seed app config default", err)
			}
			values[k.Key] = k.Default
		}
	}
	appCfg, err := config.LoadApp(values)
	if err != nil {
		fatal("load app config", err)
	}

	authVerifier, err := auth.NewOIDCVerifier(context.Background(), auth.OIDCConfig{
		IssuerURL:    envCfg.OIDCIssuerURL,
		ClientID:     envCfg.OIDCClientID,
		ClientSecret: envCfg.OIDCClientSecret,
		RedirectURL:  envCfg.OIDCRedirectURL,
		RequiredRole: envCfg.OIDCRequiredRole,
	})
	if err != nil {
		fatal("oidc verifier setup", err)
	}

	server := api.NewServer(
		db,
		garmin.NewClient,
		garmin.ClientConfig{
			PythonPath:     envCfg.PythonPath,
			TokenStorePath: envCfg.TokenStoreRoot,
		},
		garmin.SyncConfig{},
		authVerifier,
		api.SessionConfig{
			Secret:       envCfg.SessionSecret,
			Duration:     appCfg.SessionDuration,
			SetupTimeout: appCfg.SetupTimeout,
			Secure:       envCfg.SessionSecure,
			BackendURL:   envCfg.BackendURL,
			FrontendURL:  envCfg.FrontendURL,
		})

	for _, e := range envCfg.DisplayEnv() {
		server.EnvVars = append(server.EnvVars, api.EnvVar{Name: e.Name, Value: e.Value})
	}

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

	httpServer := &http.Server{Addr: envCfg.BackendAddr, Handler: server.Router()}
	go func() {
		applog.App("main", "main").Info("geniusrund listening", "addr", envCfg.BackendAddr)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			fatal("http server", err)
		}
	}()

	<-ctx.Done()
	applog.App("main", "main").Info("shutting down")
	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := httpServer.Shutdown(shutdownCtx); err != nil {
		applog.App("main", "main").Error("http server shutdown", "error", err)
	}
}