package api

import (
	"log/slog"
	"net/http"
	"time"

	"github.com/redis/go-redis/v9"

	"github.com/alchemistkay/guestguard/internal/auth"
	"github.com/alchemistkay/guestguard/internal/billing"
	"github.com/alchemistkay/guestguard/internal/notification"
	"github.com/alchemistkay/guestguard/internal/ratelimit"
	"github.com/alchemistkay/guestguard/internal/storage"
)

type Server struct {
	logger    *slog.Logger
	db        *storage.DB
	hub       *Hub
	authH     *authHandler
	me        *meHandler
	events    *eventHandler
	guests    *guestHandler
	tokens    *tokenHandler
	rsvps     *rsvpHandler
	activity  *activityHandler
	ws        *wsHandler
	wsTicket  *wsTicketHandler
	health    *healthHandler
	signer    *auth.JWTSigner
	limiter   *ratelimit.Limiter
	unsub     *unsubscribeHandler
	webhooks  *webhookHandler
	csv       *csvImportHandler
	billing   *billingHandler
	stripeWH  *stripeWebhookHandler
	privacy   *privacyHandler
	collabs   *collaboratorHandler
	analytics *analyticsHandler
}

type ServerDeps struct {
	Logger          *slog.Logger
	DB              *storage.DB
	Hub             *Hub
	AccessPublisher     accessPublisher
	RSVPPublisher       rsvpPublisher
	InvitationPublisher invitationPublisher
	FraudScorer         fraudScorer
	TokenTTL            time.Duration

	// Auth
	JWTSecret            string
	JWTIssuer            string
	AccessTokenTTL       time.Duration
	RefreshTokenTTL      time.Duration
	EmailVerificationTTL time.Duration
	PasswordResetTTL     time.Duration
	PublicBaseURL        string
	RefreshCookieDomain  string
	RefreshCookieSecure  bool
	EmailSender          auth.EmailSender
	WSTicketTTL          time.Duration

	// Rate limiting / abuse controls
	Redis           *redis.Client
	LoginLockoutMax int           // failed attempts before account lockout (default 5)
	LoginFailWindow time.Duration // counter TTL (default 15 min)

	// Notifications / unsubscribe
	NotificationRepo  *notification.Repo
	SuppressionRepo   *notification.SuppressionRepo
	UnsubscribeSigner *notification.UnsubscribeSigner

	// Billing (Block F). Nil StripeClient leaves billing disabled — the
	// system still boots and runs, all users sit on the free tier with
	// its limits enforced; /billing/* returns 503.
	StripeClient *billing.Client
}

func NewServer(deps ServerDeps) (*Server, error) {
	eventRepo := storage.NewEventRepo(deps.DB)
	guestRepo := storage.NewGuestRepo(deps.DB)
	tokenRepo := storage.NewTokenRepo(deps.DB)
	rsvpRepo := storage.NewRSVPRepo(deps.DB)
	accessRepo := storage.NewAccessLogRepo(deps.DB)
	userRepo := storage.NewUserRepo(deps.DB)
	collabRepo := storage.NewCollaboratorRepo(deps.DB)
	inviteRepo := storage.NewInviteRepo(deps.DB)
	analyticsRepo := storage.NewAnalyticsRepo(deps.DB)
	verifRepo := storage.NewEmailVerificationRepo(deps.DB)
	resetRepo := storage.NewPasswordResetRepo(deps.DB)
	refreshRepo := storage.NewRefreshTokenRepo(deps.DB)
	subRepo := storage.NewSubscriptionRepo(deps.DB)
	enforcer := newTierEnforcer(subRepo, deps.PublicBaseURL)

	signer, err := auth.NewJWTSigner(deps.JWTSecret, deps.AccessTokenTTL, deps.JWTIssuer)
	if err != nil {
		return nil, err
	}
	hasher := auth.NewPasswordHasher()

	emails := deps.EmailSender
	if emails == nil {
		emails = auth.LogEmailSender{Logger: deps.Logger}
	}

	hub := deps.Hub
	if hub == nil {
		hub = NewHub(deps.Logger)
	}

	wsTicketTTL := deps.WSTicketTTL
	if wsTicketTTL <= 0 {
		wsTicketTTL = 60 * time.Second
	}
	wsTickets := newWSTicketStore(wsTicketTTL)

	var limiter *ratelimit.Limiter
	var lockout *auth.LockoutTracker
	if deps.Redis != nil {
		limiter = ratelimit.New(deps.Redis, "gg:rl")
		lockoutMax := deps.LoginLockoutMax
		if lockoutMax <= 0 {
			lockoutMax = 5
		}
		failWindow := deps.LoginFailWindow
		if failWindow <= 0 {
			failWindow = 15 * time.Minute
		}
		lockout = auth.NewLockoutTracker(deps.Redis, lockoutMax, failWindow)
	}

	authH := newAuthHandler(authHandlerDeps{
		Logger:               deps.Logger,
		Users:                userRepo,
		Verifications:        verifRepo,
		Resets:               resetRepo,
		Refreshes:            refreshRepo,
		Hasher:               hasher,
		Signer:               signer,
		Emails:               emails,
		Lockout:              lockout,
		Limiter:              limiter,
		PublicBaseURL:        deps.PublicBaseURL,
		EmailVerificationTTL: deps.EmailVerificationTTL,
		PasswordResetTTL:     deps.PasswordResetTTL,
		RefreshTTL:           deps.RefreshTokenTTL,
		CookieDomain:         deps.RefreshCookieDomain,
		CookieSecure:         deps.RefreshCookieSecure,
	})

	return &Server{
		logger: deps.Logger,
		db:     deps.DB,
		hub:    hub,
		authH:  authH,
		me:     &meHandler{users: userRepo},
		events: &eventHandler{repo: eventRepo, collabs: collabRepo, enforcer: enforcer},
		guests: &guestHandler{guests: guestRepo, events: eventRepo, collabs: collabRepo, enforcer: enforcer},
		tokens: &tokenHandler{
			logger:        deps.Logger,
			guests:        guestRepo,
			tokens:        tokenRepo,
			events:        eventRepo,
			users:         userRepo,
			accessLogs:    accessRepo,
			rsvps:         rsvpRepo,
			collabs:       collabRepo,
			gen:           auth.NewGenerator(),
			ttl:           deps.TokenTTL,
			pub:           deps.AccessPublisher,
			invitations:   deps.InvitationPublisher,
			publicBaseURL: deps.PublicBaseURL,
		},
		rsvps: &rsvpHandler{
			logger:     deps.Logger,
			guests:     guestRepo,
			tokens:     tokenRepo,
			events:     eventRepo,
			rsvps:      rsvpRepo,
			accessLogs: accessRepo,
			scorer:     deps.FraudScorer,
			pub:        deps.RSVPPublisher,
		},
		activity: &activityHandler{
			events:     eventRepo,
			collabs:    collabRepo,
			rsvps:      rsvpRepo,
			accessLogs: accessRepo,
		},
		ws:       &wsHandler{logger: deps.Logger, hub: hub, tickets: wsTickets},
		wsTicket: &wsTicketHandler{tickets: wsTickets, events: eventRepo, collabs: collabRepo},
		health:  &healthHandler{pool: deps.DB.Pool},
		signer:  signer,
		limiter: limiter,
		unsub: &unsubscribeHandler{
			logger:     deps.Logger,
			signer:     deps.UnsubscribeSigner,
			suppress:   deps.SuppressionRepo,
		},
		webhooks: &webhookHandler{
			logger:    deps.Logger,
			notifs:    deps.NotificationRepo,
			suppress:  deps.SuppressionRepo,
		},
		csv: &csvImportHandler{guests: guestRepo, events: eventRepo, collabs: collabRepo, enforcer: enforcer},
		billing: &billingHandler{
			logger:        deps.Logger,
			stripe:        deps.StripeClient,
			users:         userRepo,
			subscriptions: subRepo,
			publicBaseURL: deps.PublicBaseURL,
		},
		stripeWH: &stripeWebhookHandler{
			logger: deps.Logger,
			stripe: deps.StripeClient,
			subs:   subRepo,
		},
		analytics: &analyticsHandler{
			logger:  deps.Logger,
			events:  eventRepo,
			collabs: collabRepo,
			repo:    analyticsRepo,
			redis:   deps.Redis,
		},
		collabs: &collaboratorHandler{
			logger:        deps.Logger,
			events:        eventRepo,
			users:         userRepo,
			collabs:       collabRepo,
			invites:       inviteRepo,
			emails:        emails,
			publicBaseURL: deps.PublicBaseURL,
		},
		privacy: &privacyHandler{
			logger:  deps.Logger,
			users:   userRepo,
			events:  eventRepo,
			guests:  guestRepo,
			tokens:  tokenRepo,
			rsvps:   rsvpRepo,
			access:  accessRepo,
			notifs:  deps.DB,
			refresh: refreshRepo,
		},
	}, nil
}

func (s *Server) Hub() *Hub { return s.hub }

func (s *Server) Handler() http.Handler {
	mux := http.NewServeMux()

	mux.HandleFunc("GET /health", s.health.live)
	mux.HandleFunc("GET /health/ready", s.health.ready)

	// Per-route rate limiters (no-op when Redis isn't wired).
	authed := requireAuth(s.signer)
	rl := func(name string, limit int, window time.Duration, keyFn KeyFunc, h http.Handler) http.Handler {
		if s.limiter == nil {
			return h
		}
		return s.limiter.Middleware(
			ratelimit.Rule{Name: name, Limit: limit, Window: window},
			keyFn,
			s.logger,
		)(h)
	}

	// Anonymous auth endpoints — POST /auth/login + /auth/forgot-password
	// rate-limit inside the handler (key includes the email body field).
	mux.Handle("POST /auth/signup",
		rl("auth_signup", 5, time.Hour, ipKey, http.HandlerFunc(s.authH.signup)))
	mux.HandleFunc("POST /auth/login", s.authH.login)
	mux.HandleFunc("POST /auth/refresh", s.authH.refresh)
	mux.HandleFunc("POST /auth/logout", s.authH.logout)
	mux.HandleFunc("POST /auth/verify-email", s.authH.verifyEmail)
	mux.HandleFunc("POST /auth/forgot-password", s.authH.forgotPassword)
	mux.HandleFunc("POST /auth/reset-password", s.authH.resetPassword)

	mux.Handle("GET /me", authed(http.HandlerFunc(s.me.get)))
	mux.Handle("POST /auth/ws-ticket", authed(http.HandlerFunc(s.wsTicket.issue)))

	// Privacy / GDPR-style endpoints — host can export their data,
	// delete their account, and record terms acceptance from the
	// onboarding gate.
	mux.Handle("GET /me/data-export", authed(http.HandlerFunc(s.privacy.dataExport)))
	mux.Handle("DELETE /me", authed(http.HandlerFunc(s.privacy.deleteMe)))
	mux.Handle("POST /me/accept-terms", authed(http.HandlerFunc(s.privacy.acceptTerms)))

	// Host-facing event/guest/token writes are limited by user_id.
	mux.Handle("POST /events",
		authed(rl("events_create", 20, 24*time.Hour, userIDKey, http.HandlerFunc(s.events.create))))
	mux.Handle("GET /events", authed(http.HandlerFunc(s.events.list)))
	mux.Handle("GET /events/{id}", authed(http.HandlerFunc(s.events.get)))
	mux.Handle("PATCH /events/{id}", authed(http.HandlerFunc(s.events.update)))
	mux.Handle("DELETE /events/{id}", authed(http.HandlerFunc(s.events.delete)))

	mux.Handle("POST /events/{id}/guests",
		authed(rl("guests_create", 1000, 24*time.Hour, userIDKey, http.HandlerFunc(s.guests.create))))
	mux.Handle("GET /events/{id}/guests", authed(http.HandlerFunc(s.guests.list)))
	mux.Handle("PATCH /events/{id}/guests/{guest_id}",
		authed(rl("guests_update", 500, 24*time.Hour, userIDKey, http.HandlerFunc(s.guests.update))))
	mux.Handle("DELETE /events/{id}/guests/{guest_id}",
		authed(rl("guests_delete", 200, 24*time.Hour, userIDKey, http.HandlerFunc(s.guests.delete))))

	// CSV import (Block E). Preview is cheap (no DB writes), so we keep
	// its budget separate from commit's daily-row-add limit.
	mux.Handle("POST /events/{id}/guests/import/preview",
		authed(rl("guests_import_preview", 30, time.Hour, userIDKey, http.HandlerFunc(s.csv.preview))))
	mux.Handle("POST /events/{id}/guests/import",
		authed(rl("guests_import_commit", 20, 24*time.Hour, userIDKey, http.HandlerFunc(s.csv.commit))))
	mux.Handle("GET /events/{id}/guests/import/template", authed(http.HandlerFunc(s.csv.template)))

	mux.Handle("GET /events/{id}/activity", authed(http.HandlerFunc(s.activity.list)))

	// Block E — host analytics. Viewer+ on both endpoints; the Redis
	// cache absorbs the dashboard's repeated visits.
	mux.Handle("GET /events/{id}/analytics", authed(http.HandlerFunc(s.analytics.get)))
	mux.Handle("GET /events/{id}/analytics/export.csv",
		authed(http.HandlerFunc(s.analytics.exportCSV)))

	// Block C — collaborators (multi-host). All under /events/{id}/collaborators.
	// requireRole inside each handler enforces the right minimum role.
	mux.Handle("GET /events/{id}/collaborators",
		authed(http.HandlerFunc(s.collabs.list)))
	mux.Handle("POST /events/{id}/collaborators",
		authed(rl("collab_invite", 50, 24*time.Hour, userIDKey, http.HandlerFunc(s.collabs.invite))))
	mux.Handle("PATCH /events/{id}/collaborators/{user_id}",
		authed(http.HandlerFunc(s.collabs.updateRole)))
	mux.Handle("DELETE /events/{id}/collaborators/{user_id}",
		authed(http.HandlerFunc(s.collabs.remove)))
	mux.Handle("DELETE /events/{id}/collaborators/pending",
		authed(http.HandlerFunc(s.collabs.cancelInvite)))

	// Invite acceptance — preview is unauthed (the invitee may not be
	// logged in yet); accept requires auth (the caller's account must
	// exist + match the invited email).
	mux.HandleFunc("GET /invites/{token}", s.collabs.previewInvite)
	mux.Handle("POST /invites/{token}/accept",
		authed(http.HandlerFunc(s.collabs.acceptInvite)))

	mux.Handle("POST /events/{id}/guests/{guest_id}/tokens",
		authed(rl("tokens_issue", 500, 24*time.Hour, userIDKey, http.HandlerFunc(s.tokens.issue))))
	mux.Handle("POST /events/{id}/guests/{guest_id}/tokens/rotate",
		authed(rl("tokens_rotate", 200, 24*time.Hour, userIDKey, http.HandlerFunc(s.tokens.rotate))))
	mux.Handle("POST /events/{id}/guests/invitations/bulk",
		authed(rl("tokens_bulk", 10, 24*time.Hour, userIDKey, http.HandlerFunc(s.tokens.bulkIssue))))

	// Guest-facing endpoints — rate-limited by the access token in the URL
	// path so an attacker hammering a single invitation is slowed regardless
	// of their source IP.
	mux.Handle("GET /access/{token}",
		rl("access", 60, time.Hour, pathKey("token"), http.HandlerFunc(s.tokens.access)))
	// Block B: .ics download. Same rate-limit class as /access since the
	// payload is similarly cheap and the abuse profile is identical (one
	// token per attacker).
	mux.Handle("GET /access/{token}/calendar.ics",
		rl("calendar_ics", 60, time.Hour, pathKey("token"), http.HandlerFunc(s.tokens.calendar)))
	mux.Handle("POST /rsvp/{token}",
		rl("rsvp", 10, time.Hour, pathKey("token"), http.HandlerFunc(s.rsvps.submit)))
	// Block A: edits are bounded by MaxRSVPEdits server-side. The redis
	// limiter is a coarser guard that also throttles attempts that hit the
	// edit-cap 429 path, so a hostile actor can't burn through fraud-engine
	// calls on the same token.
	mux.Handle("PATCH /rsvp/{token}",
		rl("rsvp_edit", 10, time.Hour, pathKey("token"), http.HandlerFunc(s.rsvps.edit)))

	// Host view of the edit trail for a single guest.
	mux.Handle("GET /events/{id}/guests/{guest_id}/rsvp/history",
		authed(http.HandlerFunc(s.rsvps.history)))

	// WebSocket endpoint authenticates via single-use ticket on the query
	// string (see POST /auth/ws-ticket).
	mux.HandleFunc("GET /ws/events/{id}", s.ws.handle)

	// Unsubscribe (signed token, no auth required — links live in emails).
	mux.HandleFunc("GET /unsubscribe/{token}", s.unsub.preview)
	mux.HandleFunc("POST /unsubscribe/{token}", s.unsub.confirm)

	// Provider webhooks. Signature verification is enforced in the handler
	// once GG_TWILIO_AUTH_TOKEN / GG_SES_WEBHOOK_SECRET are set.
	mux.HandleFunc("POST /webhooks/twilio/status", s.webhooks.twilio)
	mux.HandleFunc("POST /webhooks/ses/notifications", s.webhooks.ses)

	// Billing (Block F). /billing/status is safe for everyone — returns
	// free tier defaults when Stripe is unconfigured or the user has no
	// subscription, so the frontend's plan page always has something to
	// render. The action endpoints (checkout, portal) return 503 in dev
	// without Stripe credentials.
	mux.Handle("GET /billing/status", authed(http.HandlerFunc(s.billing.status)))
	mux.Handle("POST /billing/checkout-session", authed(http.HandlerFunc(s.billing.checkoutSession)))
	mux.Handle("POST /billing/portal", authed(http.HandlerFunc(s.billing.portalSession)))
	mux.HandleFunc("POST /webhooks/stripe", s.stripeWH.handle)

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		writeError(w, http.StatusNotFound, "not found")
	})

	var h http.Handler = mux
	h = corsMiddleware(h)
	h = loggingMiddleware(s.logger)(h)
	h = recoverMiddleware(s.logger)(h)
	return h
}

// Permissive CORS for the dev frontend on a different origin. In production
// the frontend is served from the same domain so this is largely a no-op.
func corsMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		origin := r.Header.Get("Origin")
		if origin != "" {
			w.Header().Set("Access-Control-Allow-Origin", origin)
			w.Header().Set("Access-Control-Allow-Credentials", "true")
			w.Header().Set("Vary", "Origin")
			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PATCH, DELETE, OPTIONS")
			w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Device-Fingerprint")
		}
		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		next.ServeHTTP(w, r)
	})
}