// 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"
	"net/http"
	"os/signal"
	"syscall"
	"time"

	"geniusrun/backend/internal/api"
	"geniusrun/backend/internal/auth"
	"geniusrun/backend/internal/config"
	"geniusrun/backend/internal/garmin"
	"geniusrun/backend/internal/store"
	appsync "geniusrun/backend/internal/sync"
)

func main() {
	cfg, err := config.Load()
	if err != nil {
		log.Fatalf("config: %v", err)
	}

	db, err := store.Open(cfg.DBPath)
	if err != nil {
		log.Fatalf("open database: %v", err)
	}
	defer db.Close()

	authVerifier, err := auth.NewOIDCVerifier(context.Background(), auth.OIDCConfig{
		IssuerURL:    cfg.OIDCIssuerURL,
		ClientID:     cfg.OIDCClientID,
		ClientSecret: cfg.OIDCClientSecret,
		RedirectURL:  cfg.OIDCRedirectURL,
		RequiredRole: cfg.OIDCRequiredRole,
	})
	if err != nil {
		log.Fatalf("oidc: %v", err)
	}

	server := api.NewServer(db, garmin.NewClient, garmin.Config{
		PythonPath:     cfg.GarminPythonPath,
		TokenStorePath: cfg.GarminTokenStoreRoot,
	}, appsync.Config{
		MinConfidence: cfg.MinConfidence,
	}, authVerifier, api.SessionConfig{
		Secret:      cfg.SessionSecret,
		Duration:    cfg.SessionDuration,
		Secure:      cfg.SessionSecure,
		BackendURL:  cfg.BackendURL,
		FrontendURL: cfg.FrontendURL,
	})

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

	go runIncrementalSyncLoop(ctx, server, cfg.IncrementalSyncEvery)

	httpServer := &http.Server{Addr: cfg.Addr, Handler: server.Router()}
	go func() {
		log.Printf("geniusrund listening on %s", cfg.Addr)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatalf("http server: %v", err)
		}
	}()

	<-ctx.Done()
	log.Println("shutting down...")
	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := httpServer.Shutdown(shutdownCtx); err != nil {
		log.Printf("http server shutdown: %v", err)
	}
}

// runIncrementalSyncLoop periodically syncs new activities for every
// provisioned user in the background so the frontend doesn't need to
// trigger every sync manually.
func runIncrementalSyncLoop(ctx context.Context, server *api.Server, every time.Duration) {
	ticker := time.NewTicker(every)
	defer ticker.Stop()
	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			server.RunIncrementalSyncForAllUsers(ctx)
		}
	}
}