package sessions

import (
	"encoding/base64"
	"encoding/json"
	"net/http"
	"net/url"
	"testing"

	"github.com/oauth2-proxy/mockoidc"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	xcfg "gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/app/cfg"
	"gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/app/domain"
	"gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/pkg/oidc"
	"gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/pkg/pls"
	"gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/pkg/test"
	"gitlab.com/gitlab-org/software-supply-chain-security/authorization/sparkled/pkg/web/cookie"
)

func TestSessions(t *testing.T) {
	srv := test.NewOIDCServer(t)
	defer srv.Close()

	clientID := srv.MockOIDC.Config().ClientID
	clientSecret := srv.MockOIDC.Config().ClientSecret
	cfg, err := oidc.New(
		t.Context(),
		srv.Issuer(),
		clientID,
		clientSecret,
		"callback_url",
	)
	require.NoError(t, err)
	controller := New(cfg, http.DefaultClient)
	mux := http.NewServeMux()
	controller.MountTo(mux)

	t.Run("GET /session/new", func(t *testing.T) {
		t.Run("without an authenticated session", func(t *testing.T) {
			r, w := test.RequestResponse("GET", "/session/new")

			mux.ServeHTTP(w, r)

			t.Run("redirect to the OIDC Provider", func(t *testing.T) {
				require.Equal(t, http.StatusFound, w.Code)
				require.NotEmpty(t, w.Header().Get("Location"))
				redirectURL, err := url.Parse(w.Header().Get("Location"))
				require.NoError(t, err)
				assert.Equal(t, srv.AuthorizationEndpoint(), redirectURL.Scheme+"://"+redirectURL.Host+redirectURL.Path)
				assert.NotEmpty(t, redirectURL.Query().Get("state"))
				assert.Equal(t, srv.MockOIDC.Config().ClientID, redirectURL.Query().Get("client_id"))
				assert.Equal(t, "openid profile email", redirectURL.Query().Get("scope"))
				assert.Equal(t, cfg.Config.ClientID, redirectURL.Query().Get("audience"))
				assert.Equal(t, cfg.Config.RedirectURL, redirectURL.Query().Get("redirect_uri"))
				assert.Equal(t, "code", redirectURL.Query().Get("response_type"))
			})

			t.Run("generates a CSRF token", func(t *testing.T) {
				cookieHeader := w.Header().Get("Set-Cookie")
				require.NotEmpty(t, cookieHeader)

				cookie, err := http.ParseSetCookie(w.Header().Get("Set-Cookie"))
				require.NoError(t, err)
				require.NotZero(t, cookie)
			})
		})

		t.Run("with an active authenicated session", func(t *testing.T) {
			t.Run("redirects to the dashboard", func(t *testing.T) {
				user := &domain.User{}
				r, w := test.RequestResponse(
					"GET",
					"/session/new",
					test.WithContextKeyValue(t.Context(), xcfg.CurrentUser, user),
				)

				mux.ServeHTTP(w, r)

				require.Equal(t, http.StatusFound, w.Code)
				assert.Equal(t, "/dashboard", w.Header().Get("Location"))
			})
		})
	})

	t.Run("GET /session/callback", func(t *testing.T) {
		t.Run("with an invalid csrf token", func(t *testing.T) {
			user := mockoidc.DefaultUser()
			code := srv.CreateAuthorizationCodeFor(user)
			nonce := pls.GenerateRandomHex(32)

			r, w := test.RequestResponse(
				"GET",
				"/session/callback?code="+code+"&state=invalid",
				test.WithCookie(cookie.New("oauth_state", nonce)),
			)

			mux.ServeHTTP(w, r)

			require.Equal(t, http.StatusBadRequest, w.Code)
		})

		t.Run("with an invalid authorization code grant", func(t *testing.T) {
			r, w := test.RequestResponse("GET", "/session/callback?code=invalid")

			mux.ServeHTTP(w, r)

			assert.Equal(t, http.StatusBadRequest, w.Code)
		})

		t.Run("with a valid authorization code grant", func(t *testing.T) {
			user := mockoidc.DefaultUser()
			code := srv.CreateAuthorizationCodeFor(user)
			nonce := pls.GenerateRandomHex(32)

			r, w := test.RequestResponse(
				"GET",
				"/session/callback?code="+code+"&state="+nonce,
				test.WithCookie(cookie.New("oauth_state", nonce)),
			)

			mux.ServeHTTP(w, r)

			cookie, err := http.ParseSetCookie(w.Header().Get("Set-Cookie"))
			require.NoError(t, err)
			require.NotZero(t, cookie)
			data, err := base64.URLEncoding.DecodeString(cookie.Value)
			require.NoError(t, err)
			tokens := map[string]interface{}{}
			require.NoError(t, json.Unmarshal(data, &tokens))

			t.Run("stores the id token in a session cookie", func(t *testing.T) {
				require.NotEmpty(t, tokens["id_token"])

				idToken := srv.Verify(tokens["id_token"].(string))
				assert.Equal(t, user.Subject, idToken.Subject)
			})

			t.Run("stores the access token in a session cookie", func(t *testing.T) {
				assert.NotEmpty(t, tokens["access_token"])
				assert.Equal(t, "bearer", tokens["token_type"])

				keypair, err := mockoidc.DefaultKeypair()
				require.NoError(t, err)

				token, err := keypair.VerifyJWT(tokens["access_token"].(string), nil)
				require.NoError(t, err)

				sub, err := token.Claims.GetSubject()
				require.NoError(t, err)
				assert.Equal(t, user.Subject, sub)
			})

			t.Run("stores the refresh token in a session cookie", func(t *testing.T) {
				assert.NotEmpty(t, tokens["refresh_token"])

				keypair, err := mockoidc.DefaultKeypair()
				require.NoError(t, err)

				token, err := keypair.VerifyJWT(tokens["refresh_token"].(string), nil)
				require.NoError(t, err)

				sub, err := token.Claims.GetSubject()
				require.NoError(t, err)
				assert.Equal(t, user.Subject, sub)
			})

			t.Run("redirects to the homepage", func(t *testing.T) {
				require.Equal(t, http.StatusFound, w.Code)
				assert.Equal(t, "/dashboard", w.Header().Get("Location"))
			})
		})
	})

	t.Run("POST /session/destroy", func(t *testing.T) {
		t.Run("clears the session cookie", func(t *testing.T) {
			cookie := cookie.New("session", "value")
			r, w := test.RequestResponse("POST", "/session/destroy", test.WithCookie(cookie))

			mux.ServeHTTP(w, r)

			require.Equal(t, http.StatusFound, w.Code)
			assert.Equal(t, "/", w.Header().Get("Location"))
			assert.Equal(t, "session=; Path=/; Domain=localhost; Expires=Thu, 01 Jan 1970 00:00:00 GMT; Max-Age=0; HttpOnly; Secure", w.Header().Get("Set-Cookie"))
		})
	})
}