package webui

import (
	"context"
	"crypto/tls"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"

	"cmroubao/backend-api/internal/transport/authcommon"

	"github.com/gin-gonic/gin"
)

func TestLoginPageIssuesCSRFAndRendersSafeNext(t *testing.T) {
	router, _ := newAuthTestRouter(t, &fakeAdminSessions{})

	response := performRequest(
		t,
		router,
		http.MethodGet,
		"/login?next=%2Ftasks%2Fnew",
		nil,
		"",
	)

	if response.Code != http.StatusOK {
		t.Fatalf("status = %d, body = %s", response.Code, response.Body)
	}
	cookie := csrfCookie(t, response)
	body := response.Body.String()
	for _, expected := range []string{
		`name="csrf_token" value="` + cookie.Value + `"`,
		`name="next" value="/tasks/new"`,
		`autocomplete="username"`,
		`autocomplete="current-password"`,
		`data-password-toggle`,
	} {
		if !strings.Contains(body, expected) {
			t.Fatalf("login body missing %q", expected)
		}
	}
	assertSecurityHeaders(t, response)
}

func TestLoginRejectsInvalidCredentialsWithoutLeakingPassword(t *testing.T) {
	sessions := &fakeAdminSessions{loginErr: ErrInvalidCredentials}
	router, _ := newAuthTestRouter(t, sessions)
	csrf := loginCSRF(t, router)
	form := url.Values{
		"csrf_token": {csrf.Value},
		"username":   {"admin"},
		"password":   {"private-password-value"},
		"next":       {"/tasks"},
	}
	request := httptest.NewRequest(
		http.MethodPost,
		"/login",
		strings.NewReader(form.Encode()),
	)
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	request.AddCookie(csrf)
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	if response.Code != http.StatusUnauthorized ||
		!strings.Contains(response.Body.String(), "账号或密码不正确") {
		t.Fatalf("status/body = %d / %s", response.Code, response.Body)
	}
	if strings.Contains(response.Body.String(), "private-password-value") {
		t.Fatal("login response contains submitted password")
	}
	if sessions.loginInput.Username != "admin" ||
		sessions.loginInput.Password != "private-password-value" {
		t.Fatalf("login input = %+v", sessions.loginInput)
	}
}

func TestLoginRateLimitBlocksBeforePasswordVerification(t *testing.T) {
	sessions := &fakeAdminSessions{loginErr: ErrInvalidCredentials}
	limiter, err := authcommon.NewAttemptLimiter(1, time.Minute, 10)
	if err != nil {
		t.Fatalf("NewAttemptLimiter() error = %v", err)
	}
	router, _ := newAuthTestRouterWithLimiter(t, sessions, limiter)
	csrf := loginCSRF(t, router)
	form := url.Values{
		"csrf_token": {csrf.Value},
		"username":   {"admin"},
		"password":   {"private-password-value"},
		"next":       {"/tasks"},
	}
	requestLogin := func() *httptest.ResponseRecorder {
		request := httptest.NewRequest(
			http.MethodPost,
			"/login",
			strings.NewReader(form.Encode()),
		)
		request.Header.Set(
			"Content-Type",
			"application/x-www-form-urlencoded",
		)
		request.AddCookie(csrf)
		response := httptest.NewRecorder()
		router.ServeHTTP(response, request)
		return response
	}

	if response := requestLogin(); response.Code != http.StatusUnauthorized {
		t.Fatalf("first status = %d", response.Code)
	}
	response := requestLogin()
	if response.Code != http.StatusTooManyRequests ||
		response.Header().Get("Retry-After") == "" ||
		!strings.Contains(response.Body.String(), "尝试次数过多") ||
		sessions.loginCalls != 1 {
		t.Fatalf(
			"second status/retry/calls = %d / %q / %d",
			response.Code,
			response.Header().Get("Retry-After"),
			sessions.loginCalls,
		)
	}
}

func TestLoginRotatesSessionAndCSRFThenUsesSafeRedirect(t *testing.T) {
	expiresAt := time.Now().UTC().Add(8 * time.Hour)
	sessions := &fakeAdminSessions{
		loginResult: AdminLoginResult{
			Token:     mustToken(t),
			ExpiresAt: expiresAt,
		},
	}
	router, _ := newAuthTestRouter(t, sessions)
	csrf := loginCSRF(t, router)
	form := url.Values{
		"csrf_token": {csrf.Value},
		"username":   {"admin"},
		"password":   {"valid-password"},
		"next":       {"https://attacker.invalid/private"},
	}
	request := httptest.NewRequest(
		http.MethodPost,
		"/login",
		strings.NewReader(form.Encode()),
	)
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	request.AddCookie(csrf)
	request.AddCookie(&http.Cookie{
		Name:  AdminSessionCookieName,
		Value: mustToken(t),
	})
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	if response.Code != http.StatusSeeOther ||
		response.Header().Get("Location") != "/tasks" {
		t.Fatalf(
			"status/location = %d / %q",
			response.Code,
			response.Header().Get("Location"),
		)
	}
	var sessionCookie, rotatedCSRF *http.Cookie
	for _, cookie := range response.Result().Cookies() {
		switch cookie.Name {
		case AdminSessionCookieName:
			sessionCookie = cookie
		case csrfCookieName:
			rotatedCSRF = cookie
		}
	}
	if sessionCookie == nil ||
		sessionCookie.Value != sessions.loginResult.Token ||
		!sessionCookie.HttpOnly ||
		sessionCookie.SameSite != http.SameSiteLaxMode ||
		sessionCookie.Path != "/" ||
		sessionCookie.Secure {
		t.Fatalf("session cookie = %+v", sessionCookie)
	}
	if rotatedCSRF == nil || rotatedCSRF.Value == csrf.Value {
		t.Fatalf("CSRF was not rotated: %+v", rotatedCSRF)
	}
	if sessions.logoutToken == "" ||
		sessions.logoutToken == sessions.loginResult.Token {
		t.Fatalf(
			"previous session was not revoked: %q",
			sessions.logoutToken,
		)
	}
}

func TestAdminSessionCookieIsSecureForTLSRequest(t *testing.T) {
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/secure-cookie", func(ctx *gin.Context) {
		setAdminSessionCookie(ctx, AdminLoginResult{
			Token:     mustToken(t),
			ExpiresAt: time.Now().UTC().Add(time.Hour),
		})
		ctx.Status(http.StatusNoContent)
	})
	request := httptest.NewRequest(http.MethodGet, "/secure-cookie", nil)
	request.TLS = &tls.ConnectionState{}
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	var sessionCookie *http.Cookie
	for _, cookie := range response.Result().Cookies() {
		if cookie.Name == AdminSessionCookieName {
			sessionCookie = cookie
			break
		}
	}
	if sessionCookie == nil || !sessionCookie.Secure {
		t.Fatalf("TLS session cookie = %+v", sessionCookie)
	}
}

func TestLoginFailsClosedWhenPreviousSessionCannotBeRevoked(
	t *testing.T,
) {
	newToken := mustToken(t)
	oldToken := mustToken(t)
	for oldToken == newToken {
		oldToken = mustToken(t)
	}
	sessions := &fakeAdminSessions{
		loginResult: AdminLoginResult{
			Token:     newToken,
			ExpiresAt: time.Now().UTC().Add(8 * time.Hour),
		},
		logoutErr: ErrUnavailable,
	}
	router, _ := newAuthTestRouter(t, sessions)
	csrf := loginCSRF(t, router)
	form := url.Values{
		"csrf_token": {csrf.Value},
		"username":   {"admin"},
		"password":   {"valid-password"},
		"next":       {"/tasks"},
	}
	request := httptest.NewRequest(
		http.MethodPost,
		"/login",
		strings.NewReader(form.Encode()),
	)
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	request.AddCookie(csrf)
	request.AddCookie(&http.Cookie{
		Name:  AdminSessionCookieName,
		Value: oldToken,
	})
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	if response.Code != http.StatusServiceUnavailable ||
		sessions.logoutToken != newToken {
		t.Fatalf(
			"status/last revoked token = %d / %q",
			response.Code,
			sessions.logoutToken,
		)
	}
	for _, cookie := range response.Result().Cookies() {
		if cookie.Name == AdminSessionCookieName &&
			cookie.Value == newToken {
			t.Fatal("new session cookie was returned after revoke failure")
		}
	}
}

func TestSafeNextRejectsExternalAndAmbiguousPaths(t *testing.T) {
	tests := []string{
		"https://attacker.invalid/tasks",
		"//attacker.invalid/tasks",
		`/tasks\redirect`,
		"/tasks/../admin",
		"/healthz",
		"tasks",
	}
	for _, candidate := range tests {
		if actual := safeNext(candidate); actual != "/tasks" {
			t.Fatalf("safeNext(%q) = %q", candidate, actual)
		}
	}
	if actual := safeNext("/tasks/item?id=1"); actual != "/tasks/item?id=1" {
		t.Fatalf("safeNext(valid) = %q", actual)
	}
}

func TestLogoutRequiresCSRFAndRevokesSession(t *testing.T) {
	sessions := &fakeAdminSessions{}
	router, _ := newAuthTestRouter(t, sessions)
	csrf := loginCSRF(t, router)
	sessionValue := mustToken(t)
	form := url.Values{"csrf_token": {csrf.Value}}
	request := httptest.NewRequest(
		http.MethodPost,
		"/logout",
		strings.NewReader(form.Encode()),
	)
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	request.AddCookie(csrf)
	request.AddCookie(&http.Cookie{
		Name:  AdminSessionCookieName,
		Value: sessionValue,
	})
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	if response.Code != http.StatusSeeOther ||
		response.Header().Get("Location") != "/login" ||
		sessions.logoutToken != sessionValue {
		t.Fatalf(
			"status/location/token = %d / %q / %q",
			response.Code,
			response.Header().Get("Location"),
			sessions.logoutToken,
		)
	}
	foundCleared := false
	for _, cookie := range response.Result().Cookies() {
		if cookie.Name == AdminSessionCookieName && cookie.MaxAge < 0 {
			foundCleared = true
		}
	}
	if !foundCleared {
		t.Fatal("logout did not clear the admin session cookie")
	}
}

func TestLogoutRejectsWrongCSRFWithoutRevoking(t *testing.T) {
	sessions := &fakeAdminSessions{}
	router, _ := newAuthTestRouter(t, sessions)
	request := httptest.NewRequest(
		http.MethodPost,
		"/logout",
		strings.NewReader("csrf_token=wrong"),
	)
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	request.AddCookie(&http.Cookie{
		Name:  csrfCookieName,
		Value: mustToken(t),
	})
	response := httptest.NewRecorder()

	router.ServeHTTP(response, request)

	if response.Code != http.StatusForbidden || sessions.logoutToken != "" {
		t.Fatalf(
			"status/logout token = %d / %q",
			response.Code,
			sessions.logoutToken,
		)
	}
}

type fakeAdminSessions struct {
	loginInput  AdminLoginInput
	loginResult AdminLoginResult
	loginErr    error
	loginCalls  int
	logoutToken string
	logoutErr   error
}

func (service *fakeAdminSessions) LoginAdmin(
	_ context.Context,
	input AdminLoginInput,
) (AdminLoginResult, error) {
	service.loginCalls++
	service.loginInput = input
	return service.loginResult, service.loginErr
}

func (service *fakeAdminSessions) LogoutAdmin(
	_ context.Context,
	token string,
) error {
	service.logoutToken = token
	return service.logoutErr
}

func newAuthTestRouter(
	t *testing.T,
	sessions AdminSessionService,
) (http.Handler, *AuthHandler) {
	t.Helper()
	limiter, err := authcommon.NewAttemptLimiter(
		100,
		time.Minute,
		100,
	)
	if err != nil {
		t.Fatalf("NewAttemptLimiter() error = %v", err)
	}
	return newAuthTestRouterWithLimiter(t, sessions, limiter)
}

func newAuthTestRouterWithLimiter(
	t *testing.T,
	sessions AdminSessionService,
	limiter authcommon.AttemptLimiter,
) (http.Handler, *AuthHandler) {
	t.Helper()
	gin.SetMode(gin.TestMode)
	renderer, err := NewRenderer()
	if err != nil {
		t.Fatalf("NewRenderer() error = %v", err)
	}
	handler, err := NewAuthHandler(sessions, renderer, limiter)
	if err != nil {
		t.Fatalf("NewAuthHandler() error = %v", err)
	}
	router := gin.New()
	handler.RegisterPublic(router)
	handler.RegisterProtected(router)
	return router, handler
}

func loginCSRF(t *testing.T, router http.Handler) *http.Cookie {
	t.Helper()
	response := performRequest(
		t,
		router,
		http.MethodGet,
		"/login",
		nil,
		"",
	)
	return csrfCookie(t, response)
}

var _ AdminSessionService = (*fakeAdminSessions)(nil)