package main

import (
	"bytes"
	"crypto/hmac"
	"crypto/md5"
	"encoding/base64"
	"encoding/binary"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"github.com/tinode/chat/server/store"
	"github.com/tinode/chat/server/store/types"
)

type testVerificationStore struct {
	active    *types.VerificationCode
	get       *types.VerificationCode
	err       error
	created   *types.VerificationCode
	failed    bool
	verified  bool
	consumed  bool
	tokenHash string
}

func (s *testVerificationStore) Create(_ types.TenantID, vc *types.VerificationCode) error {
	s.created = vc
	return s.err
}

func (s *testVerificationStore) Get(_ types.TenantID, _ string) (*types.VerificationCode, error) {
	if s.err != nil {
		return nil, s.err
	}
	if s.get == nil {
		return nil, types.ErrNotFound
	}
	return s.get, nil
}

func (s *testVerificationStore) GetActive(_ types.TenantID, _, _ string, _ time.Time) (*types.VerificationCode, error) {
	if s.err != nil {
		return nil, s.err
	}
	if s.active == nil {
		return nil, types.ErrNotFound
	}
	return s.active, nil
}

func (s *testVerificationStore) Fail(_ types.TenantID, _ string, _ types.VerificationState) error {
	s.failed = true
	return nil
}

func (s *testVerificationStore) MarkVerified(_ types.TenantID, _, tokenHash string, _ time.Time) error {
	s.verified = true
	s.tokenHash = tokenHash
	return nil
}

func (s *testVerificationStore) Consume(_ types.TenantID, _, tokenHash string, _ time.Time) error {
	s.consumed = true
	s.tokenHash = tokenHash
	return nil
}

func makeTestAPIKey(t *testing.T) string {
	t.Helper()
	globals.apiKeySalt = []byte("0123456789abcdef")
	data := make([]byte, apikeyLength)
	data[0] = 1
	binary.LittleEndian.PutUint32(data[apikeyVersion:], uint32(0))
	binary.LittleEndian.PutUint16(data[apikeyVersion+apikeyAppID:], uint16(1))
	data[apikeyVersion+apikeyAppID+apikeySequence] = uint8(0)

	hasher := hmac.New(md5.New, globals.apiKeySalt)
	hasher.Write(data[:apikeyVersion+apikeyAppID+apikeySequence+apikeyWho])
	copy(data[apikeyVersion+apikeyAppID+apikeySequence+apikeyWho:], hasher.Sum(nil))
	return base64.URLEncoding.EncodeToString(data)
}

func decodeIMHTTPResponse(t *testing.T, rec *httptest.ResponseRecorder) imHTTPResponse {
	t.Helper()
	var resp imHTTPResponse
	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
		t.Fatalf("failed to decode response: %v; body=%s", err, rec.Body.String())
	}
	return resp
}

func TestServeIMTenantResolveSuccessFromHeader(t *testing.T) {
	oldTenants := store.Tenants
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:         7,
		Code:       "acme",
		Name:       "Acme Corp",
		TenantDesc: ptrString("demo tenant"),
		State:      types.TenantStateActive,
	}}
	defer func() { store.Tenants = oldTenants }()
	globals.servingAt = "https://im.example.com/"

	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve", nil)
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	req.Header.Set("X-Tenant-Code", " acme ")
	req.Header.Set("X-Request-ID", "req-1")
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Code != 0 || resp.RequestID != "req-1" {
		t.Fatalf("unexpected response envelope: %#v", resp)
	}
	data := resp.Data.(map[string]any)
	tenant := data["tenant"].(map[string]any)
	if tenant["code"] != "acme" || tenant["name"] != "Acme Corp" {
		t.Fatalf("unexpected tenant payload: %#v", tenant)
	}
	if _, ok := tenant["id"]; ok {
		t.Fatalf("tenant payload must not expose internal id: %#v", tenant)
	}
	endpoints := data["endpoints"].(map[string]any)
	if endpoints["websocket"] != "https://im.example.com/v0/channels" {
		t.Fatalf("unexpected websocket endpoint: %#v", endpoints)
	}
}

func TestServeIMTenantResolveSuccessFromBody(t *testing.T) {
	oldTenants := store.Tenants
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateActive,
	}}
	defer func() { store.Tenants = oldTenants }()
	globals.servingAt = "http://127.0.0.1:6060/"

	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve",
		bytes.NewBufferString(`{"tenant_code":"acme","platform":"android","app_version":"1.0.0"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Code != 0 || resp.Reason != "" {
		t.Fatalf("unexpected response envelope: %#v", resp)
	}
}

func TestServeIMTenantResolveRequiresPost(t *testing.T) {
	req := httptest.NewRequest(http.MethodGet, "/v1/im/tenants/resolve", nil)
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusMethodNotAllowed {
		t.Fatalf("status: got %d, want %d", rec.Code, http.StatusMethodNotAllowed)
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonMethodNotAllowed {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonMethodNotAllowed)
	}
}

func TestServeIMTenantResolveRequiresAPIKey(t *testing.T) {
	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve",
		bytes.NewBufferString(`{"tenant_code":"acme"}`))
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusForbidden {
		t.Fatalf("status: got %d, want %d", rec.Code, http.StatusForbidden)
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonAPIKeyRequired {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonAPIKeyRequired)
	}
}

func TestServeIMTenantResolveRejectsMalformedTenantCode(t *testing.T) {
	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve",
		bytes.NewBufferString(`{"tenant_code":"`+strings.Repeat("a", 65)+`"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status: got %d, want %d", rec.Code, http.StatusBadRequest)
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonMalformedRequest {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonMalformedRequest)
	}
}

func TestServeIMTenantResolveHidesUnavailableTenantState(t *testing.T) {
	oldTenants := store.Tenants
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateSuspended,
	}}
	defer func() { store.Tenants = oldTenants }()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve",
		bytes.NewBufferString(`{"tenant_code":"acme"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusForbidden {
		t.Fatalf("status: got %d, want %d", rec.Code, http.StatusForbidden)
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonTenantUnavailable {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonTenantUnavailable)
	}
}

func TestServeIMTenantResolveHidesMissingTenant(t *testing.T) {
	oldTenants := store.Tenants
	store.Tenants = testTenantStore{err: types.ErrNotFound}
	defer func() { store.Tenants = oldTenants }()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/tenants/resolve",
		bytes.NewBufferString(`{"tenant_code":"acme"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	rec := httptest.NewRecorder()

	serveIMTenantResolve(rec, req)

	if rec.Code != http.StatusNotFound {
		t.Fatalf("status: got %d, want %d", rec.Code, http.StatusNotFound)
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonTenantUnavailable {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonTenantUnavailable)
	}
}

func TestServeIMVerificationCodesCreatesChallenge(t *testing.T) {
	oldTenants := store.Tenants
	oldVerifications := store.Verifications
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateActive,
	}}
	verifications := &testVerificationStore{}
	store.Verifications = verifications
	defer func() {
		store.Tenants = oldTenants
		store.Verifications = oldVerifications
	}()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/auth/verification-codes",
		bytes.NewBufferString(`{"scene":"register","phone":"+8613800138000"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	req.Header.Set("X-Tenant-Code", "acme")
	rec := httptest.NewRecorder()

	serveIMVerificationCodes(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
	}
	if verifications.created == nil {
		t.Fatal("expected challenge to be stored")
	}
	if verifications.created.TenantID != 7 || verifications.created.Scene != "register" {
		t.Fatalf("unexpected stored challenge: %#v", verifications.created)
	}
	if verifications.created.CodeHash == "" || strings.Contains(rec.Body.String(), verifications.created.CodeHash) {
		t.Fatalf("code hash missing or leaked: %#v body=%s", verifications.created, rec.Body.String())
	}
	resp := decodeIMHTTPResponse(t, rec)
	data := resp.Data.(map[string]any)
	if data["challenge_id"] == "" || data["expires_in_seconds"].(float64) == 0 {
		t.Fatalf("unexpected response data: %#v", data)
	}
}

func TestServeIMVerificationCodesRateLimited(t *testing.T) {
	oldTenants := store.Tenants
	oldVerifications := store.Verifications
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateActive,
	}}
	store.Verifications = &testVerificationStore{active: &types.VerificationCode{
		TenantID:    7,
		ChallengeID: "challenge-1",
		State:       types.VerificationStatePending,
		ResendAfter: time.Now().UTC().Add(time.Minute),
	}}
	defer func() {
		store.Tenants = oldTenants
		store.Verifications = oldVerifications
	}()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/auth/verification-codes",
		bytes.NewBufferString(`{"scene":"register","phone":"+8613800138000"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	req.Header.Set("X-Tenant-Code", "acme")
	rec := httptest.NewRecorder()

	serveIMVerificationCodes(rec, req)

	if rec.Code != http.StatusTooManyRequests {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusTooManyRequests, rec.Body.String())
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonVerificationRate {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonVerificationRate)
	}
}

func TestServeIMVerificationCodeVerifySuccess(t *testing.T) {
	oldTenants := store.Tenants
	oldVerifications := store.Verifications
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateActive,
	}}
	vc := &types.VerificationCode{
		TenantID:    7,
		ChallengeID: "challenge-1",
		Scene:       "register",
		PhoneHash:   "phone-hash",
		CodeHash:    hashIMSecret(7, "register", "challenge-1", "phone-hash", "123456"),
		State:       types.VerificationStatePending,
		MaxAttempts: 5,
		ExpiresAt:   time.Now().UTC().Add(time.Minute),
	}
	verifications := &testVerificationStore{get: vc}
	store.Verifications = verifications
	defer func() {
		store.Tenants = oldTenants
		store.Verifications = oldVerifications
	}()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/auth/verification-codes/challenge-1/verify",
		bytes.NewBufferString(`{"code":"123456"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	req.Header.Set("X-Tenant-Code", "acme")
	rec := httptest.NewRecorder()

	serveIMVerificationCodeVerify(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusOK, rec.Body.String())
	}
	if !verifications.verified || verifications.tokenHash == "" {
		t.Fatalf("expected challenge to be marked verified: %#v", verifications)
	}
	resp := decodeIMHTTPResponse(t, rec)
	data := resp.Data.(map[string]any)
	if data["verification_token"] == "" {
		t.Fatalf("missing verification token: %#v", data)
	}
}

func TestServeIMVerificationCodeVerifyInvalidCode(t *testing.T) {
	oldTenants := store.Tenants
	oldVerifications := store.Verifications
	store.Tenants = testTenantStore{tenant: &types.Tenant{
		ID:    7,
		Code:  "acme",
		Name:  "Acme Corp",
		State: types.TenantStateActive,
	}}
	store.Verifications = &testVerificationStore{get: &types.VerificationCode{
		TenantID:    7,
		ChallengeID: "challenge-1",
		Scene:       "register",
		PhoneHash:   "phone-hash",
		CodeHash:    hashIMSecret(7, "register", "challenge-1", "phone-hash", "123456"),
		State:       types.VerificationStatePending,
		MaxAttempts: 5,
		ExpiresAt:   time.Now().UTC().Add(time.Minute),
	}}
	defer func() {
		store.Tenants = oldTenants
		store.Verifications = oldVerifications
	}()

	req := httptest.NewRequest(http.MethodPost, "/v1/im/auth/verification-codes/challenge-1/verify",
		bytes.NewBufferString(`{"code":"654321"}`))
	req.Header.Set("X-Tinode-APIKey", makeTestAPIKey(t))
	req.Header.Set("X-Tenant-Code", "acme")
	rec := httptest.NewRecorder()

	serveIMVerificationCodeVerify(rec, req)

	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusUnauthorized, rec.Body.String())
	}
	resp := decodeIMHTTPResponse(t, rec)
	if resp.Reason != imReasonCodeInvalid {
		t.Fatalf("reason: got %q, want %q", resp.Reason, imReasonCodeInvalid)
	}
}

func ptrString(s string) *string {
	return &s
}