package migrator

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"tangled.org/core/idresolver"
	"tangled.org/core/log"
	"tangled.org/core/migrator/api"
	"tangled.org/core/migrator/config"
	"tangled.org/core/migrator/db"
	"tangled.org/core/migrator/git"
	"tangled.org/core/migrator/gitserver"
	migratoroauth "tangled.org/core/migrator/oauth"
	"tangled.org/core/netutil"
	"tangled.org/core/migrator/worker"
	"tangled.org/core/xrpc/serviceauth"
)

func Run(ctx context.Context, cfg *config.Config) error {
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	logger := log.FromContext(ctx)

	database, err := db.Make(ctx, cfg.DbPath)
	if err != nil {
		return fmt.Errorf("initializing database: %w", err)
	}
	defer database.Close()
	database.MaxActivePerOwner = cfg.MaxActivePerOwner

	connectProxy := netutil.NewSafeConnectProxy(nil, nil)
	proxyAddr, err := connectProxy.Start()
	if err != nil {
		return fmt.Errorf("starting connect proxy: %w", err)
	}
	defer connectProxy.Close()
	logger.Info("started safe connect proxy", "addr", proxyAddr)

	signer, err := serviceauth.NewSigner(cfg.ServiceDid, cfg.PrivateKey)
	if err != nil {
		return fmt.Errorf("initializing signer: %w", err)
	}

	resolver := idresolver.DefaultResolver(cfg.PlcUrl)
	serviceAuth := serviceauth.NewServiceAuth(logger, resolver.Directory(), cfg.ServiceDid.String())

	oauthClient, err := migratoroauth.NewClient(cfg, database, resolver.Directory(), logger)
	if err != nil {
		return fmt.Errorf("initializing oauth client: %w", err)
	}

	workerPool, err := worker.NewWorkerPool(
		database,
		cfg,
		connectProxy,
		git.RealCommandRunner{
			MaxDiskBytes: cfg.MaxDiskBytes,
		},
		oauthClient,
		logger,
	)
	if err != nil {
		return fmt.Errorf("initializing worker pool: %w", err)
	}

	workerPool.Start(ctx)

	go func() {
		ticker := time.NewTicker(15 * time.Second)
		defer ticker.Stop()
		for {
			select {
			case <-ctx.Done():
				return
			case <-ticker.C:
				scrubbed, err := database.ScrubExpiredCredentials(ctx)
				if err != nil {
					logger.Error("error scrubbing expired credentials", "err", err)
				} else if scrubbed > 0 {
					logger.Info("scrubbed expired GitHub credentials past 1h window", "count", scrubbed)
				}
			}
		}
	}()

	apiServer := api.NewServer(database, cfg, signer, serviceAuth, oauthClient, logger, nil, proxyAddr)

	// short timeout on json routes so a hung knot or pds cannot pin connections
	short := func(h http.Handler) http.Handler {
		return http.TimeoutHandler(h, cfg.APITimeout, "api timeout")
	}

	mux := http.NewServeMux()
	mux.Handle("/git/", gitserver.New(database, cfg))
	mux.Handle("/oauth-client-metadata.json", short(oauthClient.Routes()))
	mux.Handle("/oauth/", short(oauthClient.Routes()))
	mux.Handle("/", short(apiServer.Routes()))

	srv := &http.Server{
		Addr:              cfg.ListenAddr,
		Handler:           mux,
		ReadHeaderTimeout: 5 * time.Second,
		ReadTimeout:       cfg.JobTimeout, // streaming budget for /git/
		WriteTimeout:      cfg.JobTimeout,
		IdleTimeout:       60 * time.Second,
	}

	go func() {
		logger.Info("starting migrator http server", "addr", cfg.ListenAddr, "serviceDid", cfg.ServiceDid)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			logger.Error("http server stopped with error", "err", err)
			cancel()
		}
	}()

	<-ctx.Done()
	logger.Info("shutting down migrator daemon")

	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer shutdownCancel()

	if err := srv.Shutdown(shutdownCtx); err != nil {
		logger.Error("error shutting down http server", "err", err)
	}

	workerPool.Wait()
	logger.Info("migrator shutdown complete")

	return nil
}