package server

import (
	"net/http"
	"time"

	sentryhttp "github.com/getsentry/sentry-go/http"
	"github.com/go-chi/chi"
	"github.com/go-chi/chi/middleware"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"sneak.berlin/go/webhooker/static"
)

// maxFormBodySize is the maximum allowed request body size (in
// bytes) for form POST endpoints. 1 MB is generous for any form
// submission while preventing abuse from oversized payloads.
//
// Every route group below installs MaxBodySize(maxFormBodySize) as
// its FIRST middleware, ahead of both CSRF and RequireAuth. Both
// orderings are deliberate.
//
// Ahead of CSRF because gorilla/csrf parses the form. The cap has to
// be installed before anything reads the body, or the parse runs
// under net/http's 10 MB default instead of this one.
//
// Ahead of RequireAuth because an oversize body should be refused
// before the request buys a cookie decrypt, a session load and the
// database read behind it. Rejecting first is the cheaper failure,
// and it is the ordering that keeps an unauthenticated flood from
// choosing how much session work the process does.
//
// What that ordering costs: the 413 branch is reachable
// unauthenticated, at a URL of the client's choosing and of the
// client's chosen length. So is the CSRF rejection, which sits in
// front of RequireAuth for the same reason. Both log that path, so
// both cap it — see the log calls in Middleware.MaxBodySize and
// Middleware.CSRF, which spend the same per-field budget as the
// access log.
const maxFormBodySize int64 = 1 * 1024 * 1024 // 1 MB

// requestTimeout is the maximum time allowed for a single HTTP
// request.
const requestTimeout = 60 * time.Second

// SetupRoutes configures all HTTP routes and middleware on the
// server's router.
func (s *Server) SetupRoutes() {
	s.router = chi.NewRouter()
	s.setupGlobalMiddleware()
	s.setupRoutes()
}

func (s *Server) setupGlobalMiddleware() {
	s.router.Use(middleware.Recoverer)
	s.router.Use(middleware.RequestID)
	s.router.Use(s.mw.SecurityHeaders())
	s.router.Use(s.mw.Logging())

	// Metrics middleware (only if credentials are configured)
	if s.params.Config.MetricsUsername != "" {
		s.router.Use(s.mw.Metrics())
	}

	s.router.Use(s.mw.CORS())
	s.router.Use(middleware.Timeout(requestTimeout))

	// Sentry error reporting (if SENTRY_DSN is set). Repanic is
	// true so panics still bubble up to the Recoverer middleware.
	if s.sentryEnabled {
		sentryHandler := sentryhttp.New(sentryhttp.Options{
			Repanic: true,
		})
		s.router.Use(sentryHandler.Handle)
	}
}

func (s *Server) setupRoutes() {
	s.router.Get("/", s.h.HandleIndex())

	s.router.Mount(
		"/s",
		http.StripPrefix("/s", http.FileServer(http.FS(static.Static))),
	)

	s.router.Route("/api/v1", func(_ chi.Router) {
		// API routes will be added here.
	})

	s.router.Get(
		"/.well-known/healthcheck",
		s.h.HandleHealthCheck(),
	)

	// set up authenticated /metrics route:
	if s.params.Config.MetricsUsername != "" {
		s.router.Group(func(r chi.Router) {
			r.Use(s.mw.MetricsAuth())
			r.Get(
				"/metrics",
				http.HandlerFunc(
					promhttp.Handler().ServeHTTP,
				),
			)
		})
	}

	s.setupPageRoutes()
	s.setupUserRoutes()
	s.setupSourceRoutes()
	s.setupWebhookRoutes()
}

func (s *Server) setupPageRoutes() {
	s.router.Route("/pages", func(r chi.Router) {
		// MaxBodySize precedes CSRF and RequireAuth deliberately;
		// see maxFormBodySize for why, and for what it costs.
		r.Use(s.mw.MaxBodySize(maxFormBodySize))
		r.Use(s.mw.CSRF())
		r.Use(s.mw.NoCache())

		r.Group(func(r chi.Router) {
			r.Use(s.mw.LoginRateLimit())
			r.Get("/login", s.h.HandleLoginPage())
			r.Post("/login", s.h.HandleLoginSubmit())
		})

		r.Post("/logout", s.h.HandleLogout())
	})
}

func (s *Server) setupUserRoutes() {
	s.router.Route("/user/{username}", func(r chi.Router) {
		// MaxBodySize precedes CSRF and RequireAuth deliberately;
		// see maxFormBodySize for why, and for what it costs.
		r.Use(s.mw.MaxBodySize(maxFormBodySize))
		r.Use(s.mw.CSRF())
		r.Use(s.mw.NoCache())
		r.Use(s.mw.RequireAuth())
		r.Get("/", s.h.HandleProfile())
		r.With(s.mw.PasswordChangeRateLimit()).Post(
			"/password", s.h.HandlePasswordChange(),
		)
	})
}

func (s *Server) setupSourceRoutes() {
	s.router.Route("/sources", func(r chi.Router) {
		// MaxBodySize precedes CSRF and RequireAuth deliberately;
		// see maxFormBodySize for why, and for what it costs.
		r.Use(s.mw.MaxBodySize(maxFormBodySize))
		r.Use(s.mw.CSRF())
		r.Use(s.mw.NoCache())
		r.Use(s.mw.RequireAuth())
		r.Get("/", s.h.HandleSourceList())
		r.Get("/new", s.h.HandleSourceCreate())
		r.Post("/new", s.h.HandleSourceCreateSubmit())
	})

	s.router.Route("/source/{sourceID}", func(r chi.Router) {
		// MaxBodySize precedes CSRF and RequireAuth deliberately;
		// see maxFormBodySize for why, and for what it costs.
		r.Use(s.mw.MaxBodySize(maxFormBodySize))
		r.Use(s.mw.CSRF())
		r.Use(s.mw.NoCache())
		r.Use(s.mw.RequireAuth())
		r.Get("/", s.h.HandleSourceDetail())
		r.Get("/edit", s.h.HandleSourceEdit())
		r.Post("/edit", s.h.HandleSourceEditSubmit())
		r.Post("/delete", s.h.HandleSourceDelete())
		r.Get("/logs", s.h.HandleSourceLogs())
		// The log page renders each body only up to its cap, so
		// this is the only route that serves a whole one. It
		// belongs to this group for its RequireAuth and
		// NoCache; see HandleEventBodyDownload for the headers
		// that keep the bytes it returns inert.
		r.Get(
			"/logs/{eventID}/body",
			s.h.HandleEventBodyDownload(),
		)
		r.Post(
			"/entrypoints",
			s.h.HandleEntrypointCreate(),
		)
		r.Post(
			"/entrypoints/{entrypointID}/delete",
			s.h.HandleEntrypointDelete(),
		)
		r.Post(
			"/entrypoints/{entrypointID}/toggle",
			s.h.HandleEntrypointToggle(),
		)
		r.Post("/targets", s.h.HandleTargetCreate())
		r.Post(
			"/targets/{targetID}/delete",
			s.h.HandleTargetDelete(),
		)
		r.Post(
			"/targets/{targetID}/toggle",
			s.h.HandleTargetToggle(),
		)
	})
}

func (s *Server) setupWebhookRoutes() {
	s.router.With(s.mw.ReceiverRateLimit()).HandleFunc(
		"/webhook/{uuid}",
		s.h.HandleWebhook(),
	)
}