package clientapi_test

import (
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/dariuszjaniak/warp/server/internal/clientapi"
	"github.com/dariuszjaniak/warp/server/internal/config"
)

const loginPath = "/_matrix/client/v3/login"

func TestLoginFlows(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.get(loginPath, "")
	expectStatus(t, rec, http.StatusOK)
	if ct := rec.Header().Get("Content-Type"); ct != "application/json" {
		t.Errorf("Content-Type = %q, want application/json", ct)
	}

	flows, _ := jsonBody(t, rec)["flows"].([]any)
	if len(flows) == 0 {
		t.Fatal("flows must not be empty")
	}
	// Clients read the flat `type`; a strict reading of the spec wants
	// `stages`. Both are sent, so both are checked.
	for _, flow := range flows {
		entry, _ := flow.(map[string]any)
		if entry["type"] != "m.login.password" {
			t.Errorf("flow type = %v, want m.login.password", entry["type"])
		}
		if stages, ok := entry["stages"].([]any); !ok || len(stages) == 0 {
			t.Errorf("flow %v has no stages", entry)
		}
	}
}

func TestLoginWithPassword(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":       "m.login.password",
		"identifier": map[string]any{"type": "m.id.user", "user": acc.UserID},
		"password":   "superuser",
	}})
	expectStatus(t, rec, http.StatusOK)

	body := jsonBody(t, rec)
	for _, field := range []string{"user_id", "access_token", "device_id"} {
		if value, _ := body[field].(string); value == "" {
			t.Errorf("login response is missing %s: %s", field, rec.Body.String())
		}
	}
	if body["user_id"] != acc.UserID {
		t.Errorf("user_id = %v, want %s", body["user_id"], acc.UserID)
	}
	// Logging in must not reuse the registration's device, or a second
	// client would silently take over the first one's session.
	if body["device_id"] == acc.DeviceID {
		t.Error("a login without a device_id must create a new device")
	}
}

// TestLoginAcceptsEveryIdentifierForm covers the three shapes clients send:
// the full user ID, the bare localpart, and the deprecated top-level `user`.
func TestLoginAcceptsEveryIdentifierForm(t *testing.T) {
	ts := newTestServer(t, nil)
	ts.register("alice", "superuser")

	for name, body := range map[string]map[string]any{
		"full user ID": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "@alice:warp.example"},
			"password":   "superuser",
		},
		"localpart only": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
			"password":   "superuser",
		},
		"deprecated user field": {
			"type":     "m.login.password",
			"user":     "alice",
			"password": "superuser",
		},
		"uppercase user ID": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "@ALICE:warp.example"},
			"password":   "superuser",
		},
		"uppercase server name": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "@alice:WARP.example"},
			"password":   "superuser",
		},
	} {
		t.Run(name, func(t *testing.T) {
			rec := ts.do(request{method: http.MethodPost, path: loginPath, body: body})
			expectStatus(t, rec, http.StatusOK)
			if got := jsonBody(t, rec)["user_id"]; got != "@alice:warp.example" {
				t.Errorf("user_id = %v, want @alice:warp.example", got)
			}
		})
	}
}

func TestLoginHonoursRequestedDeviceID(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":                        "m.login.password",
		"identifier":                  map[string]any{"type": "m.id.user", "user": acc.UserID},
		"password":                    "superuser",
		"device_id":                   "test_device_id",
		"initial_device_display_name": "device display",
	}})
	expectStatus(t, rec, http.StatusOK)
	if got := jsonBody(t, rec)["device_id"]; got != "test_device_id" {
		t.Errorf("device_id = %v, want test_device_id", got)
	}
}

// TestLoginOnExistingDeviceRevokesItsToken is the spec's rule for a login
// naming a device that already exists: the device stays, its old token does
// not.
func TestLoginOnExistingDeviceRevokesItsToken(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	first := ts.login(acc, "SHARED")
	second := ts.login(acc, "SHARED")
	if first.AccessToken == second.AccessToken {
		t.Fatal("the second login returned the same token")
	}

	expectError(t, ts.get("/_matrix/client/v3/account/whoami", first.AccessToken),
		http.StatusUnauthorized, "M_UNKNOWN_TOKEN")
	expectStatus(t, ts.get("/_matrix/client/v3/account/whoami", second.AccessToken), http.StatusOK)
}

// TestLoginRejectionsAreIndistinguishable keeps the login endpoint from
// becoming a user directory: every failure is the same answer.
func TestLoginRejectionsAreIndistinguishable(t *testing.T) {
	ts := newTestServer(t, nil)
	ts.register("alice", "superuser")

	for name, body := range map[string]map[string]any{
		"wrong password": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
			"password":   "wrong_password",
		},
		"unknown user": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "i-dont-exist"},
			"password":   "superuser",
		},
		"malformed user ID": {
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "@not-a-user-id"},
			"password":   "superuser",
		},
	} {
		t.Run(name, func(t *testing.T) {
			rec := ts.do(request{method: http.MethodPost, path: loginPath, body: body})
			expectError(t, rec, http.StatusForbidden, "M_FORBIDDEN")
		})
	}
}

func TestLoginRejectsForeignUser(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":       "m.login.password",
		"identifier": map[string]any{"type": "m.id.user", "user": "@bob:other.example"},
		"password":   "superuser",
	}})
	expectError(t, rec, http.StatusForbidden, "M_FORBIDDEN")
}

func TestLoginRejectsUnsupportedType(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":  "m.login.token",
		"token": "whatever",
	}})
	expectError(t, rec, http.StatusBadRequest, "M_UNKNOWN")
}

func TestLoginRequiresAnIdentifier(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":     "m.login.password",
		"password": "superuser",
	}})
	expectError(t, rec, http.StatusBadRequest, "M_MISSING_PARAM")
}

func TestLogout(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")
	second := ts.login(acc, "")

	rec := ts.get("/_matrix/client/v3/devices", acc.AccessToken)
	expectStatus(t, rec, http.StatusOK)
	if devices, _ := jsonBody(t, rec)["devices"].([]any); len(devices) != 2 {
		t.Fatalf("expected 2 devices before logging out, got %d", len(devices))
	}

	rec = ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/logout", token: second.AccessToken})
	expectStatus(t, rec, http.StatusOK)

	// The token is dead and the device is gone, not merely signed out.
	expectError(t, ts.get("/_matrix/client/v3/sync", second.AccessToken),
		http.StatusUnauthorized, "M_UNKNOWN_TOKEN")

	rec = ts.get("/_matrix/client/v3/devices", acc.AccessToken)
	expectStatus(t, rec, http.StatusOK)
	devices, _ := jsonBody(t, rec)["devices"].([]any)
	if len(devices) != 1 {
		t.Fatalf("expected 1 device after logging out, got %d", len(devices))
	}
	if devices[0].(map[string]any)["device_id"] != acc.DeviceID {
		t.Error("the wrong device was removed")
	}
}

func TestLogoutAll(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")
	second := ts.login(acc, "")

	rec := ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/logout/all", token: second.AccessToken})
	expectStatus(t, rec, http.StatusOK)

	for name, token := range map[string]string{"the caller": second.AccessToken, "the other session": acc.AccessToken} {
		t.Run(name, func(t *testing.T) {
			expectError(t, ts.get("/_matrix/client/v3/sync", token),
				http.StatusUnauthorized, "M_UNKNOWN_TOKEN")
		})
	}
}

func TestLogoutRequiresAToken(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/logout"})
	expectError(t, rec, http.StatusUnauthorized, "M_MISSING_TOKEN")

	rec = ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/logout", token: "invalidAccessToken"})
	expectError(t, rec, http.StatusUnauthorized, "M_UNKNOWN_TOKEN")
}

// TestRefreshToken covers the rotation: a refresh swaps both halves of the
// pair, and the spent ones stop working.
func TestRefreshToken(t *testing.T) {
	ts := newTestServer(t, nil)
	ts.register("alice", "superuser")

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":          "m.login.password",
		"identifier":    map[string]any{"type": "m.id.user", "user": "alice"},
		"password":      "superuser",
		"refresh_token": true,
	}})
	expectStatus(t, rec, http.StatusOK)

	body := jsonBody(t, rec)
	oldAccess, _ := body["access_token"].(string)
	refresh, _ := body["refresh_token"].(string)
	if refresh == "" {
		t.Fatalf("refresh_token: true produced no refresh token: %s", rec.Body.String())
	}

	rec = ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/refresh",
		body: map[string]any{"refresh_token": refresh}})
	expectStatus(t, rec, http.StatusOK)

	refreshed := jsonBody(t, rec)
	newAccess, _ := refreshed["access_token"].(string)
	newRefresh, _ := refreshed["refresh_token"].(string)
	if newAccess == "" || newRefresh == "" || newRefresh == refresh {
		t.Fatalf("refresh did not rotate the pair: %s", rec.Body.String())
	}

	expectStatus(t, ts.get("/_matrix/client/v3/account/whoami", newAccess), http.StatusOK)
	expectError(t, ts.get("/_matrix/client/v3/account/whoami", oldAccess),
		http.StatusUnauthorized, "M_UNKNOWN_TOKEN")

	// Replaying a spent refresh token is a soft logout, not a second
	// rotation.
	rec = ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/refresh",
		body: map[string]any{"refresh_token": refresh}})
	expectError(t, rec, http.StatusUnauthorized, "M_UNKNOWN_TOKEN")
	if jsonBody(t, rec)["soft_logout"] != true {
		t.Error("a dead refresh token should be reported as a soft logout")
	}
}

func TestRefreshRequiresAToken(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: "/_matrix/client/v3/refresh",
		body: map[string]any{}})
	expectError(t, rec, http.StatusBadRequest, "M_MISSING_PARAM")
}

// TestLoginWithoutRefreshTokenOmitsIt keeps the response honest for the
// clients that do not support rotation.
func TestLoginWithoutRefreshTokenOmitsIt(t *testing.T) {
	ts := newTestServer(t, nil)
	ts.register("alice", "superuser")

	rec := ts.do(request{method: http.MethodPost, path: loginPath, body: map[string]any{
		"type":       "m.login.password",
		"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
		"password":   "superuser",
	}})
	expectStatus(t, rec, http.StatusOK)

	body := jsonBody(t, rec)
	if _, present := body["refresh_token"]; present {
		t.Error("a login that did not ask for a refresh token must not get one")
	}
	if _, present := body["expires_in_ms"]; present {
		t.Error("a token that does not expire must not report a lifetime")
	}
}

func TestLoginIsRateLimited(t *testing.T) {
	ts := newTestServer(t, withRateLimit(config.RateLimit{
		Enabled:  true,
		Default:  config.RateLimitBucket{Burst: 100, Interval: time.Millisecond},
		Login:    config.RateLimitBucket{Burst: 2, Interval: time.Minute},
		Register: config.RateLimitBucket{Burst: 100, Interval: time.Millisecond},
	}))

	attempt := func() int {
		return ts.do(request{
			method: http.MethodPost,
			path:   loginPath,
			remote: "192.0.2.10:4321",
			body: map[string]any{
				"type":       "m.login.password",
				"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
				"password":   "wrong",
			},
		}).Code
	}

	for i := range 2 {
		if status := attempt(); status != http.StatusForbidden {
			t.Fatalf("attempt %d status = %d, want 403", i+1, status)
		}
	}

	rec := ts.do(request{
		method: http.MethodPost,
		path:   loginPath,
		remote: "192.0.2.10:4321",
		body: map[string]any{
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
			"password":   "wrong",
		},
	})
	expectError(t, rec, http.StatusTooManyRequests, "M_LIMIT_EXCEEDED")
	retryAfter, _ := jsonBody(t, rec)["retry_after_ms"].(float64)
	if retryAfter <= 0 {
		t.Errorf("retry_after_ms = %v, want a positive number", retryAfter)
	}

	// Another address has its own budget: one noisy client must not lock
	// everybody out.
	ts2 := ts.do(request{
		method: http.MethodPost,
		path:   loginPath,
		remote: "198.51.100.7:4321",
		body: map[string]any{
			"type":       "m.login.password",
			"identifier": map[string]any{"type": "m.id.user", "user": "alice"},
			"password":   "wrong",
		},
	})
	if ts2.Code == http.StatusTooManyRequests {
		t.Error("the limiter is keyed globally rather than per client")
	}

	// And the budget is per endpoint class, so /login running dry does not
	// take the rest of the API with it.
	if rec := ts.get("/_matrix/client/v3/login", ""); rec.Code != http.StatusOK {
		t.Errorf("GET /login status = %d; limiters must be per endpoint", rec.Code)
	}
}

// TestAccessTokenInQueryString covers the form older clients and media URLs
// still use.
func TestAccessTokenInQueryString(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	rec := ts.get("/_matrix/client/v3/account/whoami?access_token="+acc.AccessToken, "")
	expectStatus(t, rec, http.StatusOK)
	if jsonBody(t, rec)["user_id"] != acc.UserID {
		t.Errorf("whoami = %s", rec.Body.String())
	}
}

func TestMalformedAuthorizationHeaderIsRejected(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	req := request{method: http.MethodGet, path: "/_matrix/client/v3/account/whoami"}
	for name, header := range map[string]string{
		"no scheme":    acc.AccessToken,
		"wrong scheme": "Basic " + acc.AccessToken,
		"empty bearer": "Bearer ",
	} {
		t.Run(name, func(t *testing.T) {
			httpReq := requestWithRawAuth(t, req, header)
			rec := serve(ts, httpReq)
			expectError(t, rec, http.StatusUnauthorized, "M_MISSING_TOKEN")
		})
	}

	// The scheme itself is case-insensitive, per RFC 9110.
	rec := serve(ts, requestWithRawAuth(t, req, "bearer "+acc.AccessToken))
	expectStatus(t, rec, http.StatusOK)
}

func TestWhoami(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	rec := ts.get("/_matrix/client/v3/account/whoami", acc.AccessToken)
	expectStatus(t, rec, http.StatusOK)

	body := jsonBody(t, rec)
	if body["user_id"] != acc.UserID || body["device_id"] != acc.DeviceID {
		t.Errorf("whoami = %s", rec.Body.String())
	}
	if body["is_guest"] != false {
		t.Errorf("is_guest = %v, want false", body["is_guest"])
	}
}

func TestCapabilities(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "superuser")

	// The endpoint is authenticated: what a server lets you do depends on
	// who you are.
	expectError(t, ts.get("/_matrix/client/v3/capabilities", ""),
		http.StatusUnauthorized, "M_MISSING_TOKEN")

	rec := ts.get("/_matrix/client/v3/capabilities", acc.AccessToken)
	expectStatus(t, rec, http.StatusOK)

	caps, _ := jsonBody(t, rec)["capabilities"].(map[string]any)
	for _, key := range []string{"m.room_versions", "m.change_password", "m.set_displayname"} {
		if _, present := caps[key]; !present {
			t.Errorf("capabilities is missing %s: %s", key, rec.Body.String())
		}
	}
	versions, _ := caps["m.room_versions"].(map[string]any)
	if versions["default"] != clientapi.DefaultRoomVersion {
		t.Errorf("default room version = %v, want %s", versions["default"], clientapi.DefaultRoomVersion)
	}
	if available, _ := versions["available"].(map[string]any); len(available) == 0 {
		t.Error("m.room_versions.available must list at least the default")
	}
}

func TestUnknownClientEndpoint(t *testing.T) {
	ts := newTestServer(t, nil)

	// A real endpoint this build does not serve: third-party protocols
	// belong to the application service API of PLAN.md phase 9. The spec's
	// answer for an endpoint a server does not implement is
	// M_UNRECOGNIZED, and the router's catch-all is what gives it.
	rec := ts.get("/_matrix/client/v3/thirdparty/protocols", "")
	expectError(t, rec, http.StatusNotFound, "M_UNRECOGNIZED")
}

// serve runs a prepared request through the handler.
func serve(ts *testServer, req *http.Request) *httptest.ResponseRecorder {
	rec := httptest.NewRecorder()
	ts.handler.ServeHTTP(rec, req)
	return rec
}

// requestWithRawAuth builds a request carrying an Authorization header
// verbatim, so the parsing of the header itself can be tested.
func requestWithRawAuth(t *testing.T, req request, header string) *http.Request {
	t.Helper()
	httpReq := httptest.NewRequest(req.method, req.path, nil)
	httpReq.Header.Set("Authorization", header)
	return httpReq
}