package clientapi_test

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

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

const registerPath = "/_matrix/client/v3/register"

// TestRegisterReturnsFlows covers the first half of the registration
// handshake: an empty body gets the flows and a session, not a complaint
// about the missing password.
func TestRegisterReturnsFlows(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{}})
	expectStatus(t, rec, http.StatusUnauthorized)
	if ct := rec.Header().Get("Content-Type"); ct != "application/json" {
		t.Errorf("Content-Type = %q, want application/json", ct)
	}

	body := jsonBody(t, rec)
	if _, ok := body["session"].(string); !ok {
		t.Error("the challenge must carry a session")
	}
	if _, ok := body["params"].(map[string]any); !ok {
		t.Error("the challenge must carry a params object, even an empty one")
	}
	flows, ok := body["flows"].([]any)
	if !ok || len(flows) == 0 {
		t.Fatalf("flows = %v, want a non-empty array", body["flows"])
	}
	for _, flow := range flows {
		stages, ok := flow.(map[string]any)["stages"].([]any)
		if !ok || len(stages) == 0 {
			t.Fatalf("every flow needs a non-empty stages array, got %v", flow)
		}
		if stages[0] != "m.login.dummy" {
			t.Errorf("first stage = %v, want m.login.dummy", stages[0])
		}
	}
}

func TestRegisterCreatesAccount(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("alice", "sUp3rs3kr1t")

	if acc.UserID != "@alice:warp.example" {
		t.Errorf("user_id = %q, want @alice:warp.example", acc.UserID)
	}

	// The token works straight away: a registration that needs a separate
	// login is a registration that half worked.
	rec := ts.get("/_matrix/client/v3/account/whoami", acc.AccessToken)
	expectStatus(t, rec, http.StatusOK)
	if got := jsonBody(t, rec)["user_id"]; got != acc.UserID {
		t.Errorf("whoami = %v, want %s", got, acc.UserID)
	}
}

// TestRegisterDowncasesUsername pins the behaviour clients rely on: a
// localpart is lowercase, so a capital in the request is normalised rather
// than rejected.
func TestRegisterDowncasesUsername(t *testing.T) {
	ts := newTestServer(t, nil)
	acc := ts.register("user-UPPER", "sUp3rs3kr1t")

	if acc.UserID != "@user-upper:warp.example" {
		t.Errorf("user_id = %q, want @user-upper:warp.example", acc.UserID)
	}
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	session := jsonBody(t, rec)["session"]

	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username":                    "alice",
		"password":                    "sUp3rs3kr1t",
		"device_id":                   "my_device_id",
		"initial_device_display_name": "a phone",
		"auth":                        map[string]any{"type": "m.login.dummy", "session": session},
	}})
	expectStatus(t, rec, http.StatusOK)
	if got := jsonBody(t, rec)["device_id"]; got != "my_device_id" {
		t.Errorf("device_id = %v, want my_device_id", got)
	}
}

// TestRegisterRejectsBadUsernamesBeforeUIA is the half of the ordering that
// is easy to get wrong: a username that can never work is rejected with a
// 400 straight away, rather than after the client has completed a flow.
func TestRegisterRejectsBadUsernamesBeforeUIA(t *testing.T) {
	ts := newTestServer(t, nil)

	for _, ch := range []string{"!", `"`, ":", "?", `\`, "@", "[", "]", "{", "|", "}", "£", "é", "\n", "'", ","} {
		rec := ts.do(request{method: http.MethodPost, path: registerPath,
			body: map[string]any{"username": "user-" + ch + "-reject", "password": "sUp3rs3kr1t"}})
		expectError(t, rec, http.StatusBadRequest, "M_INVALID_USERNAME")
	}

	// The characters the spec does allow must still get through.
	for _, ch := range []string{"q", "3", ".", "_", "=", "-", "/", "+"} {
		ts.register("chrtest"+ch, "sUp3rs3kr1t")
	}
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": strings.Repeat("a", 256),
		"password": "sUp3rs3kr1t",
	}})
	expectError(t, rec, http.StatusBadRequest, "M_INVALID_USERNAME")
}

// TestRegisterRejectsTakenUsernameBeforeUIA is the other half: the name is
// checked before the challenge, so a client is not asked to authenticate
// only to be told the name was gone all along.
func TestRegisterRejectsTakenUsernameBeforeUIA(t *testing.T) {
	ts := newTestServer(t, nil)
	ts.register("alice", "sUp3rs3kr1t")

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	expectError(t, rec, http.StatusBadRequest, "M_USER_IN_USE")

	// Capitalisation does not get around it, because the name is
	// normalised first.
	rec = ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "ALICE", "password": "sUp3rs3kr1t"}})
	expectError(t, rec, http.StatusBadRequest, "M_USER_IN_USE")
}

// TestRegisterRequiresTheSession covers the rule that makes the flow a flow:
// an `auth` without the session the server handed out starts again rather
// than completing.
func TestRegisterRequiresTheSession(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.dummy"},
	}})
	expectStatus(t, rec, http.StatusUnauthorized)

	// An unknown session is treated the same way, with a fresh one offered.
	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.dummy", "session": "not-a-session"},
	}})
	expectStatus(t, rec, http.StatusUnauthorized)
	if _, ok := jsonBody(t, rec)["session"].(string); !ok {
		t.Error("a rejected session must come with a new one to try")
	}
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	session := jsonBody(t, rec)["session"]

	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.recaptcha", "session": session},
	}})
	expectError(t, rec, http.StatusBadRequest, "M_UNRECOGNIZED")
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice"}})
	expectStatus(t, rec, http.StatusUnauthorized)
	session := jsonBody(t, rec)["session"]

	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"auth":     map[string]any{"type": "m.login.dummy", "session": session},
	}})
	expectError(t, rec, http.StatusBadRequest, "M_MISSING_PARAM")
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	session := jsonBody(t, rec)["session"]

	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username":      "alice",
		"password":      "sUp3rs3kr1t",
		"inhibit_login": true,
		"auth":          map[string]any{"type": "m.login.dummy", "session": session},
	}})
	expectStatus(t, rec, http.StatusOK)

	body := jsonBody(t, rec)
	if body["user_id"] != "@alice:warp.example" {
		t.Errorf("user_id = %v", body["user_id"])
	}
	for _, field := range []string{"access_token", "device_id"} {
		if _, present := body[field]; present {
			t.Errorf("inhibit_login must suppress %s", field)
		}
	}
}

// TestRegisterGeneratesUsername covers the case where the client leaves the
// choice of name to the server.
func TestRegisterGeneratesUsername(t *testing.T) {
	ts := newTestServer(t, nil)

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"password": "sUp3rs3kr1t"}})
	session := jsonBody(t, rec)["session"]

	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.dummy", "session": session},
	}})
	expectStatus(t, rec, http.StatusOK)

	userID, _ := jsonBody(t, rec)["user_id"].(string)
	if !strings.HasPrefix(userID, "@") || !strings.HasSuffix(userID, ":warp.example") {
		t.Errorf("generated user_id = %q, want @<something>:warp.example", userID)
	}
	if len(userID) <= len("@:warp.example") {
		t.Errorf("generated user_id %q has an empty localpart", userID)
	}
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	session := jsonBody(t, rec)["session"]

	complete := map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.dummy", "session": session},
	}
	expectStatus(t, ts.do(request{method: http.MethodPost, path: registerPath, body: complete}), http.StatusOK)

	// Replaying the identical request must not create a second account; the
	// name is taken now, and the session is gone either way.
	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: complete})
	expectError(t, rec, http.StatusBadRequest, "M_USER_IN_USE")
}

func TestRegisterRespectsTheRegistrationSwitch(t *testing.T) {
	ts := newTestServer(t, nil)
	if err := ts.settings.SetRegistrationEnabled(t.Context(), false); err != nil {
		t.Fatalf("SetRegistrationEnabled: %v", err)
	}

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	expectError(t, rec, http.StatusForbidden, "M_FORBIDDEN")

	// And comes back without a restart, which is the point of the switch.
	if err := ts.settings.SetRegistrationEnabled(t.Context(), true); err != nil {
		t.Fatalf("SetRegistrationEnabled: %v", err)
	}
	ts.register("alice", "sUp3rs3kr1t")
}

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

	rec := ts.do(request{method: http.MethodPost, path: registerPath + "?kind=guest",
		body: map[string]any{}})
	expectError(t, rec, http.StatusForbidden, "M_FORBIDDEN")
}

// TestRegisterWithRegistrationToken covers the second stage a server with
// invite-only sign-up adds to the flow.
func TestRegisterWithRegistrationToken(t *testing.T) {
	ts := newTestServer(t, func(o *clientapi.Options) {
		o.Registration = config.Registration{Enabled: true, Tokens: []string{"let-me-in"}}
	})

	rec := ts.do(request{method: http.MethodPost, path: registerPath,
		body: map[string]any{"username": "alice", "password": "sUp3rs3kr1t"}})
	expectStatus(t, rec, http.StatusUnauthorized)

	body := jsonBody(t, rec)
	flows, _ := body["flows"].([]any)
	stages, _ := flows[0].(map[string]any)["stages"].([]any)
	if len(stages) != 2 || stages[0] != "m.login.registration_token" {
		t.Fatalf("stages = %v, want the token stage first", stages)
	}
	session := body["session"]

	// A wrong token fails the stage: the client gets the error and the
	// flows together, so it can prompt again without starting over.
	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth": map[string]any{
			"type": "m.login.registration_token", "session": session, "token": "nope",
		},
	}})
	expectStatus(t, rec, http.StatusUnauthorized)
	body = jsonBody(t, rec)
	if body["errcode"] != "M_FORBIDDEN" {
		t.Errorf("a failed stage must say why, got %s", rec.Body.String())
	}
	if body["session"] != session {
		t.Error("a failed stage must keep the session alive")
	}

	// The right one advances the flow but does not finish it.
	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth": map[string]any{
			"type": "m.login.registration_token", "session": session, "token": "let-me-in",
		},
	}})
	expectStatus(t, rec, http.StatusUnauthorized)
	completed, _ := jsonBody(t, rec)["completed"].([]any)
	if len(completed) != 1 || completed[0] != "m.login.registration_token" {
		t.Fatalf("completed = %v, want the token stage", completed)
	}

	// And the dummy stage completes it.
	rec = ts.do(request{method: http.MethodPost, path: registerPath, body: map[string]any{
		"username": "alice",
		"password": "sUp3rs3kr1t",
		"auth":     map[string]any{"type": "m.login.dummy", "session": session},
	}})
	expectStatus(t, rec, http.StatusOK)
	if jsonBody(t, rec)["user_id"] != "@alice:warp.example" {
		t.Errorf("user_id = %v", jsonBody(t, rec)["user_id"])
	}
}

func TestRegisterAvailable(t *testing.T) {
	ts := newTestServer(t, nil)
	const path = "/_matrix/client/v3/register/available"

	rec := ts.get(path+"?username=free_name", "")
	expectStatus(t, rec, http.StatusOK)
	if jsonBody(t, rec)["available"] != true {
		t.Errorf("available = %v, want true", jsonBody(t, rec)["available"])
	}

	ts.register("taken", "sUp3rs3kr1t")
	expectError(t, ts.get(path+"?username=taken", ""), http.StatusBadRequest, "M_USER_IN_USE")
	expectError(t, ts.get(path+"?username=not,valid", ""), http.StatusBadRequest, "M_INVALID_USERNAME")
	expectError(t, ts.get(path, ""), http.StatusBadRequest, "M_MISSING_PARAM")
}

func TestRegistrationTokenValidity(t *testing.T) {
	ts := newTestServer(t, func(o *clientapi.Options) {
		o.Registration = config.Registration{Enabled: true, Tokens: []string{"let-me-in"}}
	})
	const path = "/_matrix/client/v1/register/m.login.registration_token/validity"

	rec := ts.get(path+"?token=let-me-in", "")
	expectStatus(t, rec, http.StatusOK)
	if jsonBody(t, rec)["valid"] != true {
		t.Errorf("valid = %v, want true", jsonBody(t, rec)["valid"])
	}

	rec = ts.get(path+"?token=nope", "")
	expectStatus(t, rec, http.StatusOK)
	if jsonBody(t, rec)["valid"] != false {
		t.Errorf("valid = %v, want false", jsonBody(t, rec)["valid"])
	}

	expectError(t, ts.get(path, ""), http.StatusBadRequest, "M_MISSING_PARAM")
}