package surf

import (
	"errors"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/bouncer"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
)

// Smoke test for the in-process dispatch tracer of phase 19.7 (D-17): a
// request carrying the bouncer dispatch marker runs a guarded route through
// surf's compiled chain as the pre-resolved principal, while nothing an HTTP
// request can carry is treated as one.

// refusingGuard never authenticates a request and writes its own 401.
type refusingGuard struct{}

func (refusingGuard) AuthenticateCredential(*http.Request) (*bouncer.Principal, any, error) {
	return nil, nil, errors.New("acme: no token")
}

func (refusingGuard) WriteUnauthorized(w http.ResponseWriter, err error) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusUnauthorized)
	_, _ = w.Write([]byte(`{"error":true,"message":"Unauthenticated"}`))
}

// dispatchPlugin registers bouncer guard "acme" as middleware "acme.auth"
// and one guarded route.
type dispatchPlugin struct{}

func (dispatchPlugin) ID() string                   { return "acme.items" }
func (dispatchPlugin) Requires() []string           { return nil }
func (dispatchPlugin) Register(*backpack.App) error { return nil }
func (dispatchPlugin) Boot(*backpack.App) error     { return nil }

func (p dispatchPlugin) Middlewares() map[string]pact.Middleware {
	guards := bouncer.NewRegistry()
	if err := guards.Register(p.ID(), "acme", refusingGuard{}); err != nil {
		panic(err)
	}
	auth, err := guards.Middleware("acme")
	if err != nil {
		panic(err)
	}
	return map[string]pact.Middleware{"acme.auth": auth}
}

func (dispatchPlugin) Routes(r pact.Router) error {
	r.Group("/acme", Use("acme.auth"), func(g pact.Router) {
		g.Get("/items/{id}", func(w http.ResponseWriter, req *http.Request) {
			user, _ := bouncer.User(req.Context())
			w.Header().Set("Content-Type", "application/json")
			_, _ = w.Write([]byte(`{"user":` + itoa(user.ID) + `,"item":"` + req.PathValue("id") + `"}`))
		})
	})
	return nil
}

func itoa(n uint) string {
	if n == 0 {
		return "0"
	}
	var b []byte
	for n > 0 {
		b = append([]byte{byte('0' + n%10)}, b...)
		n /= 10
	}
	return string(b)
}

func TestDispatchSmoke(t *testing.T) {
	app := transportApp(t, "development", map[string]string{"http.yaml": transportBodyLimits})
	router, err := BuildRouter(app, []party.Plugin{dispatchPlugin{}})
	if err != nil {
		t.Fatal(err)
	}
	if _, ok := router.Handler("GET", "/acme/items/{id}/missing"); ok {
		t.Fatal("Handler found an unregistered route")
	}
	h, ok := router.Handler("GET", "/acme/items/{id}")
	if !ok || h == nil {
		t.Fatal("Handler did not find GET /acme/items/{id} after BuildRouter")
	}
	var nilRouter *Router
	if _, ok := nilRouter.Handler("GET", "/acme/items/{id}"); ok {
		t.Fatal("nil router found a handler")
	}

	serve := func(set func(*http.Request) *http.Request) *httptest.ResponseRecorder {
		req := httptest.NewRequest(http.MethodGet, "/acme/items/7", nil)
		req.SetPathValue("id", "7")
		req.Pattern = "GET /acme/items/{id}"
		req = set(req)
		rec := httptest.NewRecorder()
		h.ServeHTTP(rec, req)
		return rec
	}
	marker := func(guards ...string) func(*http.Request) *http.Request {
		return func(req *http.Request) *http.Request {
			d := &bouncer.Dispatch{Guards: guards, Principal: &bouncer.Principal{ID: 42}}
			return req.WithContext(bouncer.WithDispatch(req.Context(), d))
		}
	}

	rec := serve(marker("acme"))
	if rec.Code != http.StatusOK || strings.TrimSpace(rec.Body.String()) != `{"user":42,"item":"7"}` {
		t.Fatalf("dispatch with the marker = %d %s", rec.Code, rec.Body.String())
	}
	if rec := serve(func(req *http.Request) *http.Request { return req }); rec.Code != http.StatusUnauthorized {
		t.Fatalf("request without the marker = %d %s", rec.Code, rec.Body.String())
	}
	forged := serve(func(req *http.Request) *http.Request {
		req.Header.Set("X-Summer-Dispatch", "42")
		req.Header.Set("Authorization", "Dispatch 42")
		req.AddCookie(&http.Cookie{Name: "summer_dispatch", Value: "42"})
		return req
	})
	if forged.Code != http.StatusUnauthorized {
		t.Fatalf("forged headers = %d %s", forged.Code, forged.Body.String())
	}
	if rec := serve(marker("other")); rec.Code != http.StatusUnauthorized {
		t.Fatalf("marker for another guard = %d %s", rec.Code, rec.Body.String())
	}

	// The assembled handler serves the same route over HTTP unchanged.
	full, err := router.compile()
	if err != nil {
		t.Fatal(err)
	}
	rec = httptest.NewRecorder()
	full.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/acme/items/7", nil))
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("HTTP request without a token = %d %s", rec.Code, rec.Body.String())
	}
}