package appview

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"html/template"
	"log/slog"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"github.com/distribution/distribution/v3/registry/api/errcode"
	"github.com/distribution/distribution/v3/registry/handlers"
	"github.com/go-chi/chi/v5"
	chimiddleware "github.com/go-chi/chi/v5/middleware"

	"atcr.io/pkg/appview/db"
	"atcr.io/pkg/appview/holdhealth"
	"atcr.io/pkg/appview/jetstream"
	"atcr.io/pkg/appview/middleware"
	"atcr.io/pkg/appview/readme"
	"atcr.io/pkg/appview/routes"
	"atcr.io/pkg/appview/storage"
	"atcr.io/pkg/appview/webhooks"
	"atcr.io/pkg/atproto"
	"atcr.io/pkg/auth"
	"atcr.io/pkg/auth/oauth"
	"atcr.io/pkg/auth/token"
	"atcr.io/pkg/billing"
	"atcr.io/pkg/logging"

	"github.com/bluesky-social/indigo/atproto/atcrypto"
	indigooauth "github.com/bluesky-social/indigo/atproto/auth/oauth"
)

// OAuthPostAuthHook is called after the default OAuth post-auth logic
// (profile creation, avatar fetch, crew registration). Hooks added after
// NewAppViewServer but before the first request work correctly.
type OAuthPostAuthHook func(ctx context.Context, did, handle, pdsEndpoint, sessionID string) error

// TokenPostAuthHook is called after the default token post-auth logic
// (profile creation). Hooks added after NewAppViewServer but before the
// first request work correctly.
type TokenPostAuthHook func(ctx context.Context, did, handle, pdsEndpoint, accessToken string) error

// AppViewServer is the AppView service with an exposed router for extensibility.
// Consumers can add routes to Router and hooks before calling Serve().
type AppViewServer struct {
	// Router is the chi router. Add routes before calling Serve().
	Router chi.Router

	// Config is the AppView configuration.
	Config *Config

	// Database is the read-write SQLite database.
	Database *sql.DB

	// ReadOnlyDB is the read-only SQLite database connection.
	ReadOnlyDB *sql.DB

	// SessionStore manages web UI sessions.
	SessionStore *db.SessionStore

	// DeviceStore manages device authorization flows.
	DeviceStore *db.DeviceStore

	// OAuthStore manages OAuth session persistence.
	OAuthStore *db.OAuthStore

	// OAuthServer handles OAuth authorization and callback endpoints.
	OAuthServer *oauth.Server

	// OAuthClientApp is the indigo OAuth client application.
	OAuthClientApp *indigooauth.ClientApp

	// Refresher manages OAuth session refresh and caching.
	Refresher *oauth.Refresher

	// Templates are the parsed HTML templates.
	Templates *template.Template

	// HealthChecker checks hold service health.
	HealthChecker *holdhealth.Checker

	// ReadmeFetcher fetches README content for repository pages.
	ReadmeFetcher *readme.Fetcher

	// TokenIssuer issues registry JWTs (nil if auth is not configured).
	TokenIssuer *token.Issuer

	// HoldAuthorizer checks hold access permissions.
	HoldAuthorizer auth.HoldAuthorizer

	// OAuthKey is the P-256 private key used for OAuth client auth and appview service identity.
	OAuthKey *atcrypto.PrivateKeyP256

	// BillingManager handles Stripe billing and tier updates (nil if billing disabled).
	BillingManager *billing.Manager

	// WebhookDispatcher dispatches scan webhooks (stored in appview DB).
	WebhookDispatcher *webhooks.Dispatcher

	// Private fields for lifecycle management
	oauthHooks   []OAuthPostAuthHook
	tokenHooks   []TokenPostAuthHook
	httpServer   *http.Server
	healthWorker *holdhealth.Worker
	workerCancel context.CancelFunc
	branding     *BrandingOverrides
}

// AddOAuthPostAuthHook registers a hook that runs after the default OAuth
// post-auth logic. Multiple hooks run in registration order.
func (s *AppViewServer) AddOAuthPostAuthHook(hook OAuthPostAuthHook) {
	s.oauthHooks = append(s.oauthHooks, hook)
}

// AddTokenPostAuthHook registers a hook that runs after the default token
// post-auth logic. Multiple hooks run in registration order.
func (s *AppViewServer) AddTokenPostAuthHook(hook TokenPostAuthHook) {
	s.tokenHooks = append(s.tokenHooks, hook)
}

// NewAppViewServer creates a fully-initialized AppView server ready for the
// consumer to add routes and hooks before calling Serve(). Pass nil for
// branding to use default atcr.io assets and templates.
func NewAppViewServer(cfg *Config, branding *BrandingOverrides) (*AppViewServer, error) {
	// Initialize structured logging with optional remote shipping
	logging.InitLoggerWithShipper(cfg.LogLevel, logging.ShipperConfig{
		Backend:       cfg.LogShipper.Backend,
		URL:           cfg.LogShipper.URL,
		BatchSize:     cfg.LogShipper.BatchSize,
		FlushInterval: cfg.LogShipper.FlushInterval,
		Service:       "appview",
		Username:      cfg.LogShipper.Username,
		Password:      cfg.LogShipper.Password,
	})

	slog.Info("Configuration loaded successfully from environment")
	if cfg.AI.APIKey != "" {
		slog.Info("AI Image Advisor enabled")
	}

	s := &AppViewServer{
		Config:   cfg,
		branding: branding,
	}

	// Initialize UI database (required for all stores)
	slog.Info("Initializing UI database", "path", cfg.UI.DatabasePath)
	libsqlCfg := db.LibsqlConfig{
		SyncURL:      cfg.UI.LibsqlSyncURL,
		AuthToken:    cfg.UI.LibsqlAuthToken,
		SyncInterval: cfg.UI.LibsqlSyncInterval,
	}
	s.Database, s.ReadOnlyDB, s.SessionStore = db.InitializeDatabase(cfg.UI.DatabasePath, libsqlCfg)
	if s.Database == nil {
		return nil, fmt.Errorf("failed to initialize UI database - required for session storage")
	}

	// Initialize hold health checker
	slog.Info("Initializing hold health checker", "cache_ttl", cfg.Health.CacheTTL)
	s.HealthChecker = holdhealth.NewChecker(cfg.Health.CacheTTL)

	// Initialize README fetcher for rendering repo page descriptions
	s.ReadmeFetcher = readme.NewFetcher()

	// Start background health check worker
	startupDelay := 5 * time.Second
	dbAdapter := holdhealth.NewDBAdapter(s.Database)
	s.healthWorker = holdhealth.NewWorkerWithStartupDelay(s.HealthChecker, dbAdapter, cfg.Health.CheckInterval, startupDelay)

	workerCtx, workerCancel := context.WithCancel(context.Background())
	s.workerCancel = workerCancel
	s.healthWorker.Start(workerCtx)
	slog.Info("Hold health worker started", "startup_delay", startupDelay, "refresh_interval", cfg.Health.CheckInterval, "cache_ttl", cfg.Health.CacheTTL)

	// Initialize OAuth components
	slog.Info("Initializing OAuth components")

	s.OAuthStore = db.NewOAuthStore(s.Database)
	slog.Info("Using SQLite for OAuth session storage")

	s.DeviceStore = db.NewDeviceStore(s.Database)
	slog.Info("Using SQLite for device storage")

	baseURL := cfg.Server.BaseURL
	defaultHoldDID := cfg.Server.DefaultHoldDID
	testMode := cfg.Server.TestMode

	slog.Debug("Base URL for OAuth", "base_url", baseURL)
	if testMode {
		slog.Info("TEST_MODE enabled - will use HTTP for local DID resolution")
		atproto.SetTestMode(true)
	}

	// Load crypto keys from database (with file fallback and migration)
	oauthKey, err := loadOAuthKey(s.Database, cfg.Server.OAuthKeyPath)
	if err != nil {
		return nil, fmt.Errorf("failed to load OAuth key: %w", err)
	}
	s.OAuthKey = oauthKey

	// Create OAuth client app
	desiredScopes := oauth.GetDefaultScopes(defaultHoldDID)
	s.OAuthClientApp, err = oauth.NewClientAppWithKey(baseURL, s.OAuthStore, desiredScopes, oauthKey, cfg.Server.ClientName)
	if err != nil {
		return nil, fmt.Errorf("failed to create OAuth client app: %w", err)
	}

	// Invalidate sessions with mismatched scopes on startup
	invalidatedCount, err := s.OAuthStore.InvalidateSessionsWithMismatchedScopes(context.Background(), desiredScopes)
	if err != nil {
		slog.Warn("Failed to invalidate sessions with mismatched scopes", "error", err)
	} else if invalidatedCount > 0 {
		slog.Info("Invalidated OAuth sessions due to scope changes", "count", invalidatedCount)
	}

	// Create oauth token refresher
	s.Refresher = oauth.NewRefresher(s.OAuthClientApp)

	// Wire up UI session store to refresher
	if s.SessionStore != nil {
		s.Refresher.SetUISessionStore(s.SessionStore)
	}

	// Set global refresher for middleware
	middleware.SetGlobalRefresher(s.Refresher)

	// Set global database for hold DID lookups and manifest reference checks
	holdDIDDB := db.NewHoldDIDDB(s.Database)
	middleware.SetGlobalDatabase(holdDIDDB)
	middleware.SetGlobalManifestRefChecker(holdDIDDB)

	// Create RemoteHoldAuthorizer for hold authorization with caching
	s.HoldAuthorizer = auth.NewRemoteHoldAuthorizer(s.Database, testMode)
	middleware.SetGlobalAuthorizer(s.HoldAuthorizer)
	slog.Info("Hold authorizer initialized with database caching")

	// Clear all denial caches on startup for a clean slate
	if remote, ok := s.HoldAuthorizer.(*auth.RemoteHoldAuthorizer); ok {
		go func() {
			if err := remote.ClearAllDenials(); err != nil {
				slog.Warn("Failed to clear denial caches on startup", "error", err)
			}
		}()
	}

	// Initialize billing manager
	appviewDID := DIDFromBaseURL(baseURL)
	s.BillingManager = billing.New(
		&cfg.Billing,
		oauthKey,
		appviewDID,
		cfg.Server.ManagedHolds,
		baseURL,
	)
	// Allow hold captains to bypass billing feature gates
	if len(cfg.Server.ManagedHolds) > 0 {
		managedHolds := cfg.Server.ManagedHolds
		roDB := s.ReadOnlyDB
		s.BillingManager.SetCaptainChecker(func(userDID string) bool {
			isCaptain, _ := db.IsHoldCaptain(roDB, userDID, managedHolds)
			return isCaptain
		})
	}
	if s.BillingManager.Enabled() {
		slog.Info("Billing enabled", "appview_did", appviewDID, "managed_holds", len(cfg.Server.ManagedHolds))
		go s.BillingManager.RefreshHoldTiers()
	}

	// Create webhook dispatcher
	appviewMeta := atproto.AppviewMetadata{
		ClientName:      cfg.Server.ClientName,
		ClientShortName: cfg.Server.ClientShortName,
		BaseURL:         cfg.Server.BaseURL,
		FaviconURL:      cfg.Server.BaseURL + "/favicon-96x96.png",
		RegistryDomains: cfg.Server.RegistryDomains,
	}
	s.WebhookDispatcher = webhooks.NewDispatcher(s.Database, appviewMeta)
	middleware.SetGlobalWebhookDispatcher(s.WebhookDispatcher)

	// Initialize Jetstream workers
	s.initializeJetstream()

	// Create main chi router
	mainRouter := chi.NewRouter()

	mainRouter.Use(chimiddleware.RealIP)
	mainRouter.Use(chimiddleware.Logger)
	mainRouter.Use(chimiddleware.Recoverer)
	mainRouter.Use(chimiddleware.GetHead)
	mainRouter.Use(routes.CORSMiddleware())

	// Domain routing middleware
	if len(cfg.Server.RegistryDomains) > 0 {
		mainRouter.Use(DomainRoutingMiddleware(cfg.Server.RegistryDomains, cfg.Server.BaseURL))
		slog.Info("Domain routing middleware enabled",
			"registry_domains", cfg.Server.RegistryDomains,
			"ui_base_url", cfg.Server.BaseURL)
	}

	// Load templates
	ComputeAssetHashes(branding)
	s.Templates, err = Templates(branding)
	if err != nil {
		return nil, fmt.Errorf("failed to load UI templates: %w", err)
	}

	// Register UI routes
	routes.RegisterUIRoutes(mainRouter, routes.UIDependencies{
		Database:          s.Database,
		ReadOnlyDB:        s.ReadOnlyDB,
		SessionStore:      s.SessionStore,
		OAuthClientApp:    s.OAuthClientApp,
		OAuthStore:        s.OAuthStore,
		Refresher:         s.Refresher,
		BaseURL:           baseURL,
		RegistryDomain:    primaryRegistryDomain(cfg.Server.RegistryDomains),
		DeviceStore:       s.DeviceStore,
		HealthChecker:     s.HealthChecker,
		ReadmeFetcher:     s.ReadmeFetcher,
		Templates:         s.Templates,
		DefaultHoldDID:    defaultHoldDID,
		ClientName:        cfg.Server.ClientName,
		ClientShortName:   cfg.Server.ClientShortName,
		BillingManager:    s.BillingManager,
		WebhookDispatcher: s.WebhookDispatcher,
		ClaudeAPIKey:      cfg.AI.APIKey,
		LegalConfig: routes.LegalConfig{
			CompanyName:  cfg.Legal.CompanyName,
			Jurisdiction: cfg.Legal.Jurisdiction,
		},
	})

	// Register Stripe webhook route (if billing enabled)
	s.BillingManager.RegisterRoutes(mainRouter)

	// Create OAuth server
	s.OAuthServer = oauth.NewServer(s.OAuthClientApp)
	s.OAuthServer.SetRefresher(s.Refresher)
	if s.SessionStore != nil {
		s.OAuthServer.SetUISessionStore(s.SessionStore)
	}

	// Register OAuth post-auth callback (closure captures s for hook dispatch)
	s.OAuthServer.SetPostAuthCallback(func(ctx context.Context, did, handle, pdsEndpoint, sessionID string) error {
		slog.Debug("OAuth post-auth callback", "component", "appview/callback", "did", did)

		// Create ATProto client with session provider
		client := atproto.NewClientWithSessionProvider(pdsEndpoint, did, s.Refresher)

		// Ensure sailor profile exists
		slog.Debug("Ensuring profile exists", "component", "appview/callback", "did", did, "default_hold_did", defaultHoldDID)
		if err := storage.EnsureProfile(ctx, client, defaultHoldDID); err != nil {
			slog.Warn("Failed to ensure profile", "component", "appview/callback", "did", did, "error", err)
		} else {
			slog.Debug("Profile ensured", "component", "appview/callback", "did", did)
		}

		// Fetch user's profile record from PDS
		profileRecord, err := client.GetProfileRecord(ctx, did)
		if err != nil {
			slog.Warn("Failed to fetch profile record", "component", "appview/callback", "did", did, "error", err)
			profileRecord = nil
		}

		// Construct avatar URL from blob CID
		avatarURL := ""
		if profileRecord != nil && profileRecord.Avatar != nil && profileRecord.Avatar.Ref.Link != "" {
			avatarURL = atproto.BlobCDNURL(did, profileRecord.Avatar.Ref.Link)
			slog.Debug("Constructed avatar URL", "component", "appview/callback", "avatar_url", avatarURL)
		}

		// Store user in database
		if avatarURL != "" {
			err = db.UpsertUser(s.Database, &db.User{
				DID:         did,
				Handle:      handle,
				PDSEndpoint: pdsEndpoint,
				Avatar:      avatarURL,
				LastSeen:    time.Now(),
			})
		} else {
			err = db.UpsertUserIgnoreAvatar(s.Database, &db.User{
				DID:         did,
				Handle:      handle,
				PDSEndpoint: pdsEndpoint,
				Avatar:      avatarURL,
				LastSeen:    time.Now(),
			})
		}
		if err != nil {
			slog.Warn("Failed to store user in database", "component", "appview/callback", "error", err)
			return nil
		}

		slog.Debug("Stored user", "component", "appview/callback", "did", did, "has_avatar", avatarURL != "")

		// Migrate profile URL→DID if needed
		profile, err := storage.GetProfile(ctx, client)
		if err != nil {
			slog.Warn("Failed to get profile", "component", "appview/callback", "did", did, "error", err)
			return nil
		}

		var holdDID string
		if profile != nil && profile.DefaultHold != "" {
			if strings.HasPrefix(profile.DefaultHold, "http://") || strings.HasPrefix(profile.DefaultHold, "https://") {
				slog.Debug("Migrating hold URL to DID", "component", "appview/callback", "did", did, "hold_url", profile.DefaultHold)

				if resolvedDID, resolveErr := atproto.ResolveHoldDID(ctx, profile.DefaultHold); resolveErr != nil {
					slog.Warn("Failed to resolve hold DID from URL", "component", "appview/callback", "did", did, "hold_url", profile.DefaultHold, "error", resolveErr)
				} else {
					holdDID = resolvedDID
					profile.DefaultHold = holdDID
					if err := storage.UpdateProfile(ctx, client, profile); err != nil {
						slog.Warn("Failed to update profile with hold DID", "component", "appview/callback", "did", did, "error", err)
					} else {
						slog.Debug("Updated profile with hold DID", "component", "appview/callback", "hold_did", holdDID)
					}
				}
			} else {
				holdDID = profile.DefaultHold
			}
			// Register crew in background
			slog.Debug("Attempting crew registration", "component", "appview/callback", "did", did, "hold_did", holdDID)
			go func(client *atproto.Client, refresher *oauth.Refresher, holdDID string, authorizer auth.HoldAuthorizer) {
				ctx := context.Background()
				storage.EnsureCrewMembership(ctx, client, refresher, holdDID, authorizer)
			}(client, s.Refresher, holdDID, s.HoldAuthorizer)
		}

		// Migrate old-format star records to AT URI format in background
		go func(client *atproto.Client, did string) {
			ctx := context.Background()
			migrated, err := atproto.MigrateStarRecords(ctx, client)
			if err != nil {
				slog.Warn("Star record migration failed", "component", "appview/callback", "did", did, "error", err, "migrated", migrated)
			} else if migrated > 0 {
				slog.Info("Migrated star records to AT URI format", "component", "appview/callback", "did", did, "count", migrated)
			}
		}(client, did)

		// Drain manifests from old hold to successor in background
		go func(client *atproto.Client, did string) {
			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
			defer cancel()
			storage.MigrateManifestsForSuccessor(ctx, client, s.HoldAuthorizer, db.NewHoldDIDDB(s.Database), did)
		}(client, did)

		// Run consumer hooks
		for _, hook := range s.oauthHooks {
			if err := hook(ctx, did, handle, pdsEndpoint, sessionID); err != nil {
				slog.Warn("OAuth post-auth hook error", "component", "appview/callback", "error", err)
			}
		}

		return nil
	})

	// Create token issuer
	if cfg.Distribution.Auth["token"] != nil {
		rsaKey, certDER, err := loadJWTKeyAndCert(s.Database, cfg.Auth.KeyPath, cfg.Auth.CertPath)
		if err != nil {
			return nil, fmt.Errorf("failed to load JWT key material: %w", err)
		}
		s.TokenIssuer = token.NewIssuerFromKey(rsaKey, certDER, cfg.Auth.ServiceName, cfg.Auth.ServiceName, cfg.Auth.TokenExpiration)
		slog.Info("Auth keys initialized")
	}

	// Create registry app (distribution library handler)
	ctx := context.Background()
	app := handlers.NewApp(ctx, cfg.Distribution)

	// Wrap with auth method extraction middleware
	wrappedApp := middleware.ExtractAuthMethod(app)

	// Mount registry at /v2/
	mainRouter.Handle("/v2/*", wrappedApp)

	// Mount static files
	if s.SessionStore != nil && s.Templates != nil {
		publicHandler := CacheMiddleware(PublicHandler(branding), 31536000)
		rootFiles, err := PublicRootFiles(branding)
		if err != nil {
			slog.Warn("Failed to scan static root files", "error", err)
		} else {
			for _, filename := range rootFiles {
				file := filename
				mainRouter.Get("/"+file, func(w http.ResponseWriter, r *http.Request) {
					r.URL.Path = "/" + file
					publicHandler.ServeHTTP(w, r)
				})
			}
			slog.Info("Registered dynamic root file routes", "count", len(rootFiles), "files", rootFiles)
		}

		mainRouter.Handle("/css/*", CacheMiddleware(http.StripPrefix("/css/", PublicSubdir("css", branding)), 31536000))
		mainRouter.Handle("/js/*", CacheMiddleware(http.StripPrefix("/js/", PublicSubdir("js", branding)), 31536000))
		mainRouter.Handle("/fonts/*", CacheMiddleware(http.StripPrefix("/fonts/", PublicSubdir("fonts", branding)), 31536000))
		mainRouter.Handle("/static/*", CacheMiddleware(http.StripPrefix("/static/", PublicSubdir("static", branding)), 31536000))

		slog.Info("UI enabled", "home", "/", "settings", "/settings")
	}

	// Mount OAuth endpoints
	mainRouter.Get("/auth/oauth/authorize", s.OAuthServer.ServeAuthorize)
	mainRouter.Get("/auth/oauth/callback", s.OAuthServer.ServeCallback)

	// OAuth client metadata endpoint
	mainRouter.Get("/oauth-client-metadata.json", func(w http.ResponseWriter, r *http.Request) {
		config := s.OAuthClientApp.Config
		logoURI := cfg.Server.BaseURL + "/web-app-manifest-192x192.png"
		policyURI := cfg.Server.BaseURL + "/privacy"
		tosURI := cfg.Server.BaseURL + "/terms"

		metadata := config.ClientMetadata()
		metadata.ClientName = &cfg.Server.ClientName
		metadata.ClientURI = &cfg.Server.BaseURL
		metadata.LogoURI = &logoURI
		metadata.PolicyURI = &policyURI
		metadata.TosURI = &tosURI

		if config.IsConfidential() && metadata.JWKS == nil {
			jwks := config.PublicJWKS()
			metadata.JWKS = &jwks
		}

		w.Header().Set("Content-Type", "application/json")
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Cache-Control", "public, max-age=300")
		if err := json.NewEncoder(w).Encode(metadata); err != nil {
			http.Error(w, "Failed to encode metadata", http.StatusInternalServerError)
		}
	})

	// Mount auth endpoints
	if s.TokenIssuer != nil {
		tokenHandler := token.NewHandler(s.TokenIssuer, s.DeviceStore)

		tokenHandler.SetOAuthSessionValidator(s.Refresher)

		// Token post-auth callback (closure captures s for hook dispatch)
		tokenHandler.SetPostAuthCallback(func(ctx context.Context, did, handle, pdsEndpoint, accessToken string) error {
			slog.Debug("Token post-auth callback", "component", "appview/callback", "did", did)

			atprotoClient := atproto.NewClient(pdsEndpoint, did, accessToken)

			if err := storage.EnsureProfile(ctx, atprotoClient, defaultHoldDID); err != nil {
				slog.Warn("Failed to ensure profile", "component", "appview/callback", "did", did, "error", err)
			} else {
				slog.Debug("Profile ensured with default hold", "component", "appview/callback", "did", did, "default_hold_did", defaultHoldDID)
			}

			// Run consumer hooks
			for _, hook := range s.tokenHooks {
				if err := hook(ctx, did, handle, pdsEndpoint, accessToken); err != nil {
					slog.Warn("Token post-auth hook error", "component", "appview/callback", "error", err)
				}
			}

			return nil
		})

		mainRouter.Get("/auth/token", tokenHandler.ServeHTTP)

		// Device authorization endpoints (public)
		routes.RegisterDeviceEndpoints(mainRouter, s.DeviceStore, baseURL)

		slog.Info("Auth endpoints enabled",
			"basic_auth", "/auth/token",
			"device_code", "/auth/device/code",
			"device_token", "/auth/device/token",
			"oauth_authorize", "/auth/oauth/authorize",
			"oauth_callback", "/auth/oauth/callback",
			"oauth_metadata", "/client-metadata.json")
	}

	// Health check endpoint (for Docker health checks / load balancers)
	mainRouter.Get("/health", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		if err := json.NewEncoder(w).Encode(map[string]string{"status": "ok"}); err != nil {
			http.Error(w, "encode error", http.StatusInternalServerError)
			return
		}
	})

	// Appview metadata endpoint (public, used by holds for branding)
	mainRouter.Get(atproto.AppviewGetMetadata, func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		w.Header().Set("Cache-Control", "public, max-age=3600")
		if err := json.NewEncoder(w).Encode(atproto.AppviewMetadata{
			ClientName:      cfg.Server.ClientName,
			ClientShortName: cfg.Server.ClientShortName,
			BaseURL:         cfg.Server.BaseURL,
			FaviconURL:      cfg.Server.BaseURL + "/favicon-96x96.png",
			RegistryDomains: cfg.Server.RegistryDomains,
		}); err != nil {
			http.Error(w, "encode error", http.StatusInternalServerError)
		}
	})

	// Appview DID document endpoint (service identity for key discovery)
	mainRouter.Get("/.well-known/did.json", s.handleDIDDocument)

	s.Router = mainRouter

	return s, nil
}

// Serve starts the HTTP server and blocks until shutdown signal.
func (s *AppViewServer) Serve() error {
	listener, err := net.Listen("tcp", s.Config.Server.Addr)
	if err != nil {
		return fmt.Errorf("failed to create listener: %w", err)
	}

	s.httpServer = &http.Server{
		Handler: s.Router,
	}

	stop := make(chan os.Signal, 1)
	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)

	errChan := make(chan error, 1)
	go func() {
		slog.Info("Starting registry server", "addr", s.Config.Server.Addr)
		if err := s.httpServer.Serve(listener); err != nil && err != http.ErrServerClosed {
			errChan <- err
		}
	}()

	select {
	case <-stop:
		slog.Info("Shutting down registry server")

		if s.Config.Server.TestMode {
			listener.Close()
		}

		slog.Info("Stopping hold health worker")
		s.healthWorker.Stop()

		if s.workerCancel != nil {
			s.workerCancel()
		}

		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()

		if err := s.httpServer.Shutdown(shutdownCtx); err != nil && err != http.ErrServerClosed {
			logging.Shutdown()
			return fmt.Errorf("server shutdown error: %w", err)
		}
	case err := <-errChan:
		s.healthWorker.Stop()
		if s.workerCancel != nil {
			s.workerCancel()
		}
		logging.Shutdown()
		return fmt.Errorf("server error: %w", err)
	}

	logging.Shutdown()
	return nil
}

// DomainRoutingMiddleware enforces three-tier domain routing:
//
//  1. UI domain (BaseURL hostname): serves web UI, auth, and static assets.
//     Blocks /v2/* with an OCI UNSUPPORTED error — registry API lives on
//     the dedicated registry domain(s).
//  2. Registry domains: allows /v2/* for Docker clients. Redirects everything
//     else to the UI domain with 307 Temporary Redirect.
//  3. Unknown domains (CDN origins, IPs, etc.): redirects all requests to the
//     UI domain with 307, except /health for load balancer probes.
func DomainRoutingMiddleware(registryDomains []string, uiBaseURL string) func(http.Handler) http.Handler {
	regDomains := make(map[string]bool, len(registryDomains))
	for _, d := range registryDomains {
		regDomains[d] = true
	}

	// Extract UI hostname from BaseURL (e.g., "https://seamark.dev" -> "seamark.dev")
	var uiHost string
	if parsed, err := url.Parse(uiBaseURL); err == nil {
		uiHost = parsed.Hostname()
	}

	primaryReg := primaryRegistryDomain(registryDomains)

	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			host := r.Host
			if idx := strings.LastIndex(host, ":"); idx != -1 {
				host = host[:idx]
			}

			path := r.URL.Path
			isV2 := path == "/v2" || path == "/v2/" || strings.HasPrefix(path, "/v2/")

			switch {
			case host == uiHost:
				// UI domain: block /v2/*, serve everything else
				if isV2 {
					if err := errcode.ServeJSON(w, errcode.ErrorCodeUnsupported.WithMessage(
						fmt.Sprintf("registry API is not available on this domain, use %s", primaryReg),
					)); err != nil {
						slog.Error("failed to write OCI error response", "error", err)
					}
					return
				}
				next.ServeHTTP(w, r)

			case regDomains[host]:
				// Registry domain: allow /v2/*, /auth/token, /auth/device/*, redirect everything else
				// Auth endpoints must be served directly to avoid 307 redirects that strip
				// the Authorization header on cross-host redirects (Go http.Client behavior).
				isAuth := path == "/auth/token" || strings.HasPrefix(path, "/auth/device/")
				if isV2 || isAuth {
					next.ServeHTTP(w, r)
					return
				}
				http.Redirect(w, r, uiBaseURL+r.URL.RequestURI(), http.StatusTemporaryRedirect)

			default:
				// Unknown domain: allow /health, redirect everything else
				if path == "/health" {
					next.ServeHTTP(w, r)
					return
				}
				http.Redirect(w, r, uiBaseURL+r.URL.RequestURI(), http.StatusTemporaryRedirect)
			}
		})
	}
}

// primaryRegistryDomain returns the first registry domain, or empty string if none.
func primaryRegistryDomain(domains []string) string {
	if len(domains) > 0 {
		return domains[0]
	}
	return ""
}

// DID returns the appview's did:web identity derived from its BaseURL.
func (s *AppViewServer) DID() string {
	return DIDFromBaseURL(s.Config.Server.BaseURL)
}

// DIDFromBaseURL derives a did:web identifier from a base URL.
// Per the did:web spec, non-standard ports are percent-encoded.
// Examples:
//
//	"https://atcr.io" → "did:web:atcr.io"
//	"http://localhost:5000" → "did:web:localhost%3A5000"
func DIDFromBaseURL(baseURL string) string {
	u, err := url.Parse(baseURL)
	if err != nil {
		return "did:web:localhost"
	}

	hostname := u.Hostname()
	if hostname == "" {
		hostname = "localhost"
	}

	port := u.Port()
	isStandardPort := (u.Scheme == "https" && port == "443") ||
		(u.Scheme == "http" && port == "80") ||
		port == ""

	if isStandardPort {
		return "did:web:" + hostname
	}
	return fmt.Sprintf("did:web:%s%%3A%s", hostname, port)
}

// handleDIDDocument serves the appview's DID document at /.well-known/did.json.
// This is a service identity for key discovery — no PDS, no repo, no firehose.
// Holds use this to discover the appview's P-256 public key for JWT verification.
func (s *AppViewServer) handleDIDDocument(w http.ResponseWriter, r *http.Request) {
	did := s.DID()

	pubKey, err := s.OAuthKey.PublicKey()
	if err != nil {
		slog.Error("Failed to get public key for DID document", "error", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	doc := map[string]any{
		"@context": []string{
			"https://www.w3.org/ns/did/v1",
			"https://w3id.org/security/multikey/v1",
		},
		"id": did,
		"verificationMethod": []map[string]any{
			{
				"id":                 did + "#appview",
				"type":               "Multikey",
				"controller":         did,
				"publicKeyMultibase": pubKey.Multibase(),
			},
		},
		"authentication": []string{
			did + "#appview",
		},
		"assertionMethod": []string{
			did + "#appview",
		},
		"service": []map[string]any{
			{
				"id":              "#atcr_appview",
				"type":            "AtcrAppView",
				"serviceEndpoint": s.Config.Server.BaseURL,
			},
		},
	}

	w.Header().Set("Content-Type", "application/did+ld+json")
	w.Header().Set("Cache-Control", "public, max-age=3600")
	w.Header().Set("Access-Control-Allow-Origin", "*")
	if err := json.NewEncoder(w).Encode(doc); err != nil {
		slog.Error("Failed to encode DID document", "error", err)
	}
}

// initializeJetstream initializes the Jetstream workers for real-time events and backfill.
func (s *AppViewServer) initializeJetstream() {
	jetstreamURLs := s.Config.Jetstream.URLs

	go func() {
		worker := jetstream.NewWorker(s.Database, jetstreamURLs, 0)
		// Set webhook dispatcher on live worker (backfill skips dispatch)
		if s.WebhookDispatcher != nil {
			worker.Processor().SetWebhookDispatcher(s.WebhookDispatcher)
		}
		worker.StartWithFailover(context.Background())
	}()
	slog.Info("Jetstream real-time worker started", "component", "jetstream", "endpoints", len(jetstreamURLs))

	if s.Config.Jetstream.BackfillEnabled {
		relayEndpoints := s.Config.Jetstream.RelayEndpoints
		defaultHoldDID := s.Config.Server.DefaultHoldDID
		testMode := s.Config.Server.TestMode

		backfillWorker, err := jetstream.NewBackfillWorker(s.Database, relayEndpoints, defaultHoldDID, testMode, s.Refresher)
		if err != nil {
			slog.Warn("Failed to create backfill worker", "component", "jetstream/backfill", "error", err)
		} else {
			go func() {
				startupDelay := 5 * time.Second
				slog.Info("Waiting for services to be ready", "component", "jetstream/backfill", "startup_delay", startupDelay)
				time.Sleep(startupDelay)

				slog.Info("Starting sync-based backfill", "component", "jetstream/backfill", "relay_endpoints", relayEndpoints)
				if err := backfillWorker.Start(context.Background()); err != nil {
					slog.Warn("Backfill finished with error", "component", "jetstream/backfill", "error", err)
				} else {
					slog.Info("Backfill completed successfully", "component", "jetstream/backfill")
				}
			}()

			interval := s.Config.Jetstream.BackfillInterval
			if interval > 0 {
				go func() {
					ticker := time.NewTicker(interval)
					defer ticker.Stop()

					for range ticker.C {
						slog.Info("Starting periodic backfill", "component", "jetstream/backfill", "interval", interval)
						if err := backfillWorker.Start(context.Background()); err != nil {
							slog.Warn("Periodic backfill finished with error", "component", "jetstream/backfill", "error", err)
						} else {
							slog.Info("Periodic backfill completed successfully", "component", "jetstream/backfill")
						}
					}
				}()
				slog.Info("Periodic backfill scheduler started", "component", "jetstream/backfill", "interval", interval)
			} else {
				slog.Info("Periodic backfill disabled (interval=0), only startup backfill will run", "component", "jetstream/backfill")
			}
		}
	}
}