Design

handlers_test.go

@@ -0,0 +1,891 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/go-telegram/bot"
+	"github.com/go-telegram/bot/models"
+	"github.com/stretchr/testify/assert"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+func TestHandleUpdate_NewChat(t *testing.T) {
+	// Setup
+	db := setupTestDB(t)
+	mockClock := &MockClock{
+		currentTime: time.Now(),
+	}
+
+	config := BotConfig{
+		ID:              "test_bot",
+		OwnerTelegramID: 123, // owner's ID
+		TelegramToken:   "test_token",
+		MemorySize:      10,
+		MessagePerHour:  5,
+		MessagePerDay:   10,
+		TempBanDuration: "1h",
+		SystemPrompts:   make(map[string]string),
+		Active:          true,
+	}
+
+	mockTgClient := &MockTelegramClient{}
+
+	// Create bot model first
+	botModel := &BotModel{
+		Identifier: config.ID,
+		Name:       config.ID,
+	}
+	err := db.Create(botModel).Error
+	assert.NoError(t, err)
+
+	// Create bot config
+	configModel := &ConfigModel{
+		BotID:           botModel.ID,
+		MemorySize:      config.MemorySize,
+		MessagePerHour:  config.MessagePerHour,
+		MessagePerDay:   config.MessagePerDay,
+		TempBanDuration: config.TempBanDuration,
+		SystemPrompts:   "{}",
+		TelegramToken:   config.TelegramToken,
+		Active:          config.Active,
+	}
+	err = db.Create(configModel).Error
+	assert.NoError(t, err)
+
+	// Create bot instance
+	b, err := NewBot(db, config, mockClock, mockTgClient)
+	assert.NoError(t, err)
+
+	testCases := []struct {
+		name     string
+		userID   int64
+		isOwner  bool
+		wantResp string
+	}{
+		{
+			name:     "Owner First Message",
+			userID:   123, // owner's ID
+			isOwner:  true,
+			wantResp: "I'm sorry, I'm having trouble processing your request right now.",
+		},
+		{
+			name:     "Regular User First Message",
+			userID:   456,
+			isOwner:  false,
+			wantResp: "I'm sorry, I'm having trouble processing your request right now.",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Setup mock response expectations for error case to test fallback messages
+			mockTgClient.SendMessageFunc = func(ctx context.Context, params *bot.SendMessageParams) (*models.Message, error) {
+				assert.Equal(t, tc.userID, params.ChatID)
+				assert.Equal(t, tc.wantResp, params.Text)
+				return &models.Message{}, nil
+			}
+
+			// Create update with new message
+			update := &models.Update{
+				Message: &models.Message{
+					Chat: models.Chat{ID: tc.userID},
+					From: &models.User{
+						ID:       tc.userID,
+						Username: "testuser",
+					},
+					Text: "Hello",
+				},
+			}
+
+			// Handle the update
+			b.handleUpdate(context.Background(), nil, update)
+
+			// Verify message was stored
+			var storedMsg Message
+			err := db.Where("chat_id = ? AND user_id = ? AND text = ?", tc.userID, tc.userID, "Hello").First(&storedMsg).Error
+			assert.NoError(t, err)
+
+			// Verify response was stored
+			var respMsg Message
+			err = db.Where("chat_id = ? AND is_user = ? AND text = ?", tc.userID, false, tc.wantResp).First(&respMsg).Error
+			assert.NoError(t, err)
+		})
+	}
+}
+
+func TestClearChatHistory(t *testing.T) {
+	// Setup
+	db := setupTestDB(t)
+	mockClock := &MockClock{
+		currentTime: time.Now(),
+	}
+
+	config := BotConfig{
+		ID:              "test_bot",
+		OwnerTelegramID: 123, // owner's ID
+		TelegramToken:   "test_token",
+		MemorySize:      10,
+		MessagePerHour:  5,
+		MessagePerDay:   10,
+		TempBanDuration: "1h",
+		SystemPrompts:   make(map[string]string),
+		Active:          true,
+	}
+
+	mockTgClient := &MockTelegramClient{}
+
+	// Create bot model first
+	botModel := &BotModel{
+		Identifier: config.ID,
+		Name:       config.ID,
+	}
+	err := db.Create(botModel).Error
+	assert.NoError(t, err)
+
+	// Create bot config
+	configModel := &ConfigModel{
+		BotID:           botModel.ID,
+		MemorySize:      config.MemorySize,
+		MessagePerHour:  config.MessagePerHour,
+		MessagePerDay:   config.MessagePerDay,
+		TempBanDuration: config.TempBanDuration,
+		SystemPrompts:   "{}",
+		TelegramToken:   config.TelegramToken,
+		Active:          config.Active,
+	}
+	err = db.Create(configModel).Error
+	assert.NoError(t, err)
+
+	// Create bot instance
+	b, err := NewBot(db, config, mockClock, mockTgClient)
+	assert.NoError(t, err)
+
+	// Create test users
+	ownerID := int64(123)
+	adminID := int64(456)
+	regularUserID := int64(789)
+	nonExistentUserID := int64(999)
+	chatID := int64(1000)
+
+	// Create admin role
+	adminRole, err := b.getRoleByName("admin")
+	assert.NoError(t, err)
+
+	// Create admin user
+	adminUser := User{
+		BotID:      b.botID,
+		TelegramID: adminID,
+		Username:   "admin",
+		RoleID:     adminRole.ID,
+		Role:       adminRole,
+		IsOwner:    false,
+	}
+	err = db.Create(&adminUser).Error
+	assert.NoError(t, err)
+
+	// Create regular user
+	regularRole, err := b.getRoleByName("user")
+	assert.NoError(t, err)
+	regularUser := User{
+		BotID:      b.botID,
+		TelegramID: regularUserID,
+		Username:   "regular",
+		RoleID:     regularRole.ID,
+		Role:       regularRole,
+		IsOwner:    false,
+	}
+	err = db.Create(&regularUser).Error
+	assert.NoError(t, err)
+
+	// Create test messages for each user.
+	// Each user's messages are stored with chat_id == their own user_id, mirroring
+	// how Telegram private DMs work (chat_id == user_id in 1-on-1 bot conversations).
+	// Using a shared artificial chatID here would mask the cross-user delete bug.
+	for _, userID := range []int64{ownerID, adminID, regularUserID} {
+		for i := 0; i < 5; i++ {
+			message := Message{
+				BotID:     b.botID,
+				ChatID:    userID, // per-user chat, not a shared chatID
+				UserID:    userID,
+				Username:  "test",
+				UserRole:  "user",
+				Text:      "Test message",
+				Timestamp: time.Now(),
+				IsUser:    true,
+			}
+			err = db.Create(&message).Error
+			assert.NoError(t, err)
+		}
+	}
+
+	// Test cases
+	testCases := []struct {
+		name           string
+		currentUserID  int64
+		targetUserID   int64
+		hardDelete     bool
+		expectedError  bool
+		expectedCount  int64
+		expectedMsg    string
+		targetChatID   int64
+		businessConnID string
+	}{
+		{
+			name:          "Owner clears own history",
+			currentUserID: ownerID,
+			targetUserID:  ownerID,
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Your chat history has been cleared.",
+		},
+		{
+			name:          "Admin clears own history",
+			currentUserID: adminID,
+			targetUserID:  adminID,
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Your chat history has been cleared.",
+		},
+		{
+			name:          "Regular user clears own history",
+			currentUserID: regularUserID,
+			targetUserID:  regularUserID,
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Your chat history has been cleared.",
+		},
+		{
+			name:          "Owner clears admin's history",
+			currentUserID: ownerID,
+			targetUserID:  adminID,
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Chat history for user @admin (ID: 456) has been cleared.",
+		},
+		{
+			name:          "Admin clears regular user's history",
+			currentUserID: adminID,
+			targetUserID:  regularUserID,
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Chat history for user @regular (ID: 789) has been cleared.",
+		},
+		{
+			name:          "Regular user attempts to clear admin's history",
+			currentUserID: regularUserID,
+			targetUserID:  adminID,
+			hardDelete:    false,
+			expectedError: true,
+			expectedCount: 5, // Messages should remain
+			expectedMsg:   "Permission denied. Only admins and owners can clear other users' histories.",
+		},
+		{
+			name:          "Admin attempts to clear non-existent user's history",
+			currentUserID: adminID,
+			targetUserID:  nonExistentUserID,
+			hardDelete:    false,
+			expectedError: true,
+			expectedCount: 5, // Messages should remain for admin
+			expectedMsg:   "User with ID 999 not found.",
+		},
+		{
+			name:          "Owner hard deletes regular user's history",
+			currentUserID: ownerID,
+			targetUserID:  regularUserID,
+			hardDelete:    true,
+			expectedError: false,
+			expectedCount: 0,
+			expectedMsg:   "Chat history for user @regular (ID: 789) has been cleared.",
+		},
+		{
+			// targetChatID scopes the delete to a specific chat; messages in other chats survive.
+			// We seed messages with ChatID == userID (per-user DM), so targeting a different chatID
+			// should leave the user's messages untouched (expectedCount == 5).
+			name:          "Admin clears regular user's history scoped to non-matching chat",
+			currentUserID: adminID,
+			targetUserID:  regularUserID,
+			targetChatID:  int64(9999), // a chat the user has no messages in
+			hardDelete:    false,
+			expectedError: false,
+			expectedCount: 5, // messages in chat 789 are unaffected
+			expectedMsg:   "Chat history for user @regular (ID: 789) has been cleared.",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Reset messages for the test case
+			if tc.name != "Owner hard deletes regular user's history" {
+				// Delete all messages for the target user
+				err = db.Where("user_id = ?", tc.targetUserID).Delete(&Message{}).Error
+				assert.NoError(t, err)
+
+				// Recreate messages for the target user
+				for i := 0; i < 5; i++ {
+					message := Message{
+						BotID:     b.botID,
+						ChatID:    chatID,
+						UserID:    tc.targetUserID,
+						Username:  "test",
+						UserRole:  "user",
+						Text:      "Test message",
+						Timestamp: time.Now(),
+						IsUser:    true,
+					}
+					err = db.Create(&message).Error
+					assert.NoError(t, err)
+				}
+			}
+
+			// Setup mock response expectations
+			var sentMessage string
+			mockTgClient.SendMessageFunc = func(ctx context.Context, params *bot.SendMessageParams) (*models.Message, error) {
+				sentMessage = params.Text
+				return &models.Message{}, nil
+			}
+
+			// Call the clearChatHistory method
+			b.clearChatHistory(context.Background(), chatID, tc.currentUserID, tc.targetUserID, tc.targetChatID, tc.businessConnID, tc.hardDelete)
+
+			// Verify the response message
+			assert.Equal(t, tc.expectedMsg, sentMessage)
+
+			// Count remaining messages for the target user
+			var count int64
+			if tc.hardDelete {
+				db.Unscoped().Model(&Message{}).Where("user_id = ? AND chat_id = ?", tc.targetUserID, chatID).Count(&count)
+			} else {
+				db.Model(&Message{}).Where("user_id = ? AND chat_id = ?", tc.targetUserID, chatID).Count(&count)
+			}
+			assert.Equal(t, tc.expectedCount, count)
+		})
+	}
+}
+
+func TestStatsCommand(t *testing.T) {
+	// Setup
+	db := setupTestDB(t)
+	mockClock := &MockClock{
+		currentTime: time.Now(),
+	}
+
+	config := BotConfig{
+		ID:              "test_bot",
+		OwnerTelegramID: 123, // owner's ID
+		TelegramToken:   "test_token",
+		MemorySize:      10,
+		MessagePerHour:  5,
+		MessagePerDay:   10,
+		TempBanDuration: "1h",
+		SystemPrompts:   make(map[string]string),
+		Active:          true,
+	}
+
+	mockTgClient := &MockTelegramClient{}
+
+	// Create bot model first
+	botModel := &BotModel{
+		Identifier: config.ID,
+		Name:       config.ID,
+	}
+	err := db.Create(botModel).Error
+	assert.NoError(t, err)
+
+	// Create bot config
+	configModel := &ConfigModel{
+		BotID:           botModel.ID,
+		MemorySize:      config.MemorySize,
+		MessagePerHour:  config.MessagePerHour,
+		MessagePerDay:   config.MessagePerDay,
+		TempBanDuration: config.TempBanDuration,
+		SystemPrompts:   "{}",
+		TelegramToken:   config.TelegramToken,
+		Active:          config.Active,
+	}
+	err = db.Create(configModel).Error
+	assert.NoError(t, err)
+
+	// Create bot instance
+	b, err := NewBot(db, config, mockClock, mockTgClient)
+	assert.NoError(t, err)
+
+	// Create test users
+	ownerID := int64(123)
+	adminID := int64(456)
+	regularUserID := int64(789)
+	chatID := int64(1000)
+
+	// Create admin role
+	adminRole, err := b.getRoleByName("admin")
+	assert.NoError(t, err)
+
+	// Create admin user
+	adminUser := User{
+		BotID:      b.botID,
+		TelegramID: adminID,
+		Username:   "admin",
+		RoleID:     adminRole.ID,
+		Role:       adminRole,
+		IsOwner:    false,
+	}
+	err = db.Create(&adminUser).Error
+	assert.NoError(t, err)
+
+	// Create regular user
+	regularRole, err := b.getRoleByName("user")
+	assert.NoError(t, err)
+	regularUser := User{
+		BotID:      b.botID,
+		TelegramID: regularUserID,
+		Username:   "regular",
+		RoleID:     regularRole.ID,
+		Role:       regularRole,
+		IsOwner:    false,
+	}
+	err = db.Create(&regularUser).Error
+	assert.NoError(t, err)
+
+	// Create test messages for each user
+	for _, userID := range []int64{ownerID, adminID, regularUserID} {
+		for i := 0; i < 5; i++ {
+			// User message
+			userMessage := Message{
+				BotID:     b.botID,
+				ChatID:    chatID,
+				UserID:    userID,
+				Username:  "test",
+				UserRole:  "user",
+				Text:      "Test message",
+				Timestamp: time.Now(),
+				IsUser:    true,
+			}
+			err = db.Create(&userMessage).Error
+			assert.NoError(t, err)
+
+			// Bot response
+			botMessage := Message{
+				BotID:     b.botID,
+				ChatID:    chatID,
+				UserID:    0,
+				Username:  "AI Assistant",
+				UserRole:  "assistant",
+				Text:      "Test response",
+				Timestamp: time.Now(),
+				IsUser:    false,
+			}
+			err = db.Create(&botMessage).Error
+			assert.NoError(t, err)
+		}
+	}
+
+	// Test cases
+	testCases := []struct {
+		name           string
+		command        string
+		currentUserID  int64
+		expectedError  bool
+		expectedMsg    string
+		businessConnID string
+	}{
+		{
+			name:          "Global stats",
+			command:       "/stats",
+			currentUserID: regularUserID,
+			expectedError: false,
+			expectedMsg:   "📊 Bot Statistics:",
+		},
+		{
+			name:          "User requests own stats",
+			command:       "/stats user",
+			currentUserID: regularUserID,
+			expectedError: false,
+			expectedMsg:   "👤 User Statistics for @regular (ID: 789):",
+		},
+		{
+			name:          "Admin requests another user's stats",
+			command:       "/stats user 789",
+			currentUserID: adminID,
+			expectedError: false,
+			expectedMsg:   "👤 User Statistics for @regular (ID: 789):",
+		},
+		{
+			name:          "Owner requests another user's stats",
+			command:       "/stats user 456",
+			currentUserID: ownerID,
+			expectedError: false,
+			expectedMsg:   "👤 User Statistics for @admin (ID: 456):",
+		},
+		{
+			name:          "Regular user attempts to request another user's stats",
+			command:       "/stats user 456",
+			currentUserID: regularUserID,
+			expectedError: true,
+			expectedMsg:   "Permission denied. Only admins and owners can view other users' statistics.",
+		},
+		{
+			name:          "User provides invalid user ID format",
+			command:       "/stats user abc",
+			currentUserID: adminID,
+			expectedError: true,
+			expectedMsg:   "Invalid user ID format. Usage: /stats user [user_id]",
+		},
+		{
+			name:          "User provides invalid command format",
+			command:       "/stats invalid",
+			currentUserID: adminID,
+			expectedError: true,
+			expectedMsg:   "Invalid command format. Usage: /stats or /stats user [user_id]",
+		},
+		{
+			name:          "User requests non-existent user's stats",
+			command:       "/stats user 999",
+			currentUserID: adminID,
+			expectedError: true,
+			expectedMsg:   "Sorry, I couldn't retrieve statistics for user ID 999.",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Setup mock response expectations
+			var sentMessage string
+			mockTgClient.SendMessageFunc = func(ctx context.Context, params *bot.SendMessageParams) (*models.Message, error) {
+				sentMessage = params.Text
+				return &models.Message{}, nil
+			}
+
+			// Create update with command
+			update := &models.Update{
+				Message: &models.Message{
+					Chat: models.Chat{ID: chatID},
+					From: &models.User{
+						ID:       tc.currentUserID,
+						Username: getUsernameByID(tc.currentUserID),
+					},
+					Text: tc.command,
+					Entities: []models.MessageEntity{
+						{
+							Type:   "bot_command",
+							Offset: 0,
+							Length: 6, // Length of "/stats"
+						},
+					},
+				},
+			}
+
+			// Handle the update
+			b.handleUpdate(context.Background(), nil, update)
+
+			// Verify the response message contains the expected text
+			assert.Contains(t, sentMessage, tc.expectedMsg)
+		})
+	}
+}
+
+// Helper function to get username by ID for test
+func getUsernameByID(id int64) string {
+	switch id {
+	case 123:
+		return "owner"
+	case 456:
+		return "admin"
+	case 789:
+		return "regular"
+	default:
+		return "unknown"
+	}
+}
+
+func setupTestDB(t *testing.T) *gorm.DB {
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("Failed to open test database: %v", err)
+	}
+
+	// AutoMigrate the models
+	err = db.AutoMigrate(&BotModel{}, &ConfigModel{}, &Message{}, &User{}, &Role{}, &Scope{})
+	if err != nil {
+		t.Fatalf("Failed to migrate database schema: %v", err)
+	}
+
+	// Create default roles and scopes
+	err = createDefaultRoles(db)
+	if err != nil {
+		t.Fatalf("Failed to create default roles: %v", err)
+	}
+	if err := createDefaultScopes(db); err != nil {
+		t.Fatalf("Failed to create default scopes: %v", err)
+	}
+
+	return db
+}
+
+// setupBotForTest creates a minimal Bot instance backed by an in-memory DB.
+// It follows the same pattern as the existing handler tests to avoid duplication.
+func setupBotForTest(t *testing.T, ownerID int64) (*Bot, *MockTelegramClient) {
+	t.Helper()
+	db := setupTestDB(t)
+	mockClock := &MockClock{currentTime: time.Now()}
+	config := BotConfig{
+		ID:              "test_bot",
+		OwnerTelegramID: ownerID,
+		TelegramToken:   "test_token",
+		MemorySize:      10,
+		MessagePerHour:  5,
+		MessagePerDay:   10,
+		TempBanDuration: "1h",
+		Model:           "claude-3-5-haiku-latest",
+		SystemPrompts:   make(map[string]string),
+		Active:          true,
+	}
+	mockTgClient := &MockTelegramClient{}
+	botModel := &BotModel{Identifier: config.ID, Name: config.ID}
+	assert.NoError(t, db.Create(botModel).Error)
+	assert.NoError(t, db.Create(&ConfigModel{
+		BotID:           botModel.ID,
+		MemorySize:      config.MemorySize,
+		MessagePerHour:  config.MessagePerHour,
+		MessagePerDay:   config.MessagePerDay,
+		TempBanDuration: config.TempBanDuration,
+		SystemPrompts:   "{}",
+		TelegramToken:   config.TelegramToken,
+		Active:          config.Active,
+	}).Error)
+	b, err := NewBot(db, config, mockClock, mockTgClient)
+	assert.NoError(t, err)
+	return b, mockTgClient
+}
+
+// TestAnthropicErrorResponse verifies that model-deprecation errors surface actionable
+// details only to admin/owner, and that regular users and non-model errors always get
+// the generic fallback.
+func TestAnthropicErrorResponse(t *testing.T) { //NOSONAR go:S100 -- underscore separation is idiomatic in Go test names
+	b, _ := setupBotForTest(t, 123)
+
+	// Create admin user
+	adminRole, err := b.getRoleByName("admin")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 456, Username: "admin",
+		RoleID: adminRole.ID, Role: adminRole,
+	}).Error)
+
+	// Create regular user
+	userRole, err := b.getRoleByName("user")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 789, Username: "regular",
+		RoleID: userRole.ID, Role: userRole,
+	}).Error)
+
+	modelErr := fmt.Errorf("%w: claude-3-5-haiku-latest", ErrModelNotFound)
+	otherErr := errors.New("network error")
+
+	tests := []struct {
+		name        string
+		err         error
+		userID      int64
+		wantSubstr  string
+		wantMissing string
+	}{
+		{
+			name:       "owner receives actionable model-not-found message",
+			err:        modelErr,
+			userID:     123,
+			wantSubstr: "/set_model",
+		},
+		{
+			name:       "admin receives actionable model-not-found message",
+			err:        modelErr,
+			userID:     456,
+			wantSubstr: "/set_model",
+		},
+		{
+			name:        "regular user receives generic message for model-not-found",
+			err:         modelErr,
+			userID:      789,
+			wantSubstr:  "I'm sorry",
+			wantMissing: "/set_model",
+		},
+		{
+			name:        "owner receives generic message for non-model error",
+			err:         otherErr,
+			userID:      123,
+			wantSubstr:  "I'm sorry",
+			wantMissing: "/set_model",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			resp := b.anthropicErrorResponse(tc.err, tc.userID)
+			assert.Contains(t, resp, tc.wantSubstr)
+			if tc.wantMissing != "" {
+				assert.NotContains(t, resp, tc.wantMissing)
+			}
+		})
+	}
+}
+
+// TestSetModelCommand verifies that /set_model enforces permissions, validates input,
+// updates the model in memory, and persists the change to the config file on disk.
+func TestSetModelCommand(t *testing.T) { //NOSONAR go:S100 -- underscore separation is idiomatic in Go test names
+	b, mockTgClient := setupBotForTest(t, 123)
+
+	// Point the config at a temporary file so PersistModel can write to disk.
+	tempDir, err := os.MkdirTemp("", "set_model_cmd_test")
+	assert.NoError(t, err)
+	defer func() { _ = os.RemoveAll(tempDir) }()
+
+	configPath := filepath.Join(tempDir, "config.json")
+	initialJSON := `{"id":"test_bot","telegram_token":"test_token","model":"claude-3-5-haiku-latest","messages_per_hour":5,"messages_per_day":10}`
+	assert.NoError(t, os.WriteFile(configPath, []byte(initialJSON), 0600))
+	b.config.ConfigFilePath = configPath
+
+	// Create admin and regular users
+	adminRole, err := b.getRoleByName("admin")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 456, Username: "admin",
+		RoleID: adminRole.ID, Role: adminRole,
+	}).Error)
+	userRole, err := b.getRoleByName("user")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 789, Username: "regular",
+		RoleID: userRole.ID, Role: userRole,
+	}).Error)
+
+	chatID := int64(1000)
+
+	// Seed chat 1000 with a prior message so isNewChatFlag is false for all subtests.
+	// Commands are only processed in the non-new-chat branch of handleUpdate.
+	assert.NoError(t, b.db.Create(&Message{
+		BotID: b.botID, ChatID: chatID, UserID: 789, Username: "regular",
+		UserRole: "user", Text: "hello", IsUser: true,
+	}).Error)
+
+	makeUpdate := func(userID int64, text string, cmdLen int) *models.Update {
+		return &models.Update{
+			Message: &models.Message{
+				Chat: models.Chat{ID: chatID},
+				From: &models.User{ID: userID, Username: getUsernameByID(userID)},
+				Text: text,
+				Entities: []models.MessageEntity{
+					{Type: "bot_command", Offset: 0, Length: cmdLen},
+				},
+			},
+		}
+	}
+
+	tests := []struct {
+		name       string
+		userID     int64
+		text       string
+		wantSubstr string
+	}{
+		{
+			name:       "regular user is denied",
+			userID:     789,
+			text:       "/set_model claude-sonnet-4-6",
+			wantSubstr: "Permission denied",
+		},
+		{
+			name:       "admin missing argument shows usage",
+			userID:     456,
+			text:       "/set_model",
+			wantSubstr: "Usage:",
+		},
+		{
+			name:       "owner missing argument shows usage",
+			userID:     123,
+			text:       "/set_model",
+			wantSubstr: "Usage:",
+		},
+		{
+			name:       "admin sets model successfully",
+			userID:     456,
+			text:       "/set_model claude-sonnet-4-6",
+			wantSubstr: "✅",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var sentMessage string
+			mockTgClient.SendMessageFunc = func(ctx context.Context, params *bot.SendMessageParams) (*models.Message, error) {
+				sentMessage = params.Text
+				return &models.Message{}, nil
+			}
+			b.handleUpdate(context.Background(), nil, makeUpdate(tc.userID, tc.text, 10))
+			assert.Contains(t, sentMessage, tc.wantSubstr)
+		})
+	}
+
+	// Verify the successful update took effect in memory and on disk.
+	t.Run("model change persisted in memory and on disk", func(t *testing.T) {
+		assert.Equal(t, "claude-sonnet-4-6", string(b.config.Model))
+		data, err := os.ReadFile(configPath)
+		assert.NoError(t, err)
+		assert.Contains(t, string(data), `"claude-sonnet-4-6"`)
+	})
+}
+
+// TestHasScope verifies that scope checks honour role assignments and the owner bypass.
+func TestHasScope(t *testing.T) { //NOSONAR go:S100 -- underscore separation is idiomatic in Go test names
+	const ownerID int64 = 100
+	b, _ := setupBotForTest(t, ownerID)
+
+	// Admin user
+	adminRole, err := b.getRoleByName("admin")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 200, Username: "admin_user",
+		RoleID: adminRole.ID, Role: adminRole,
+	}).Error)
+
+	// Regular user
+	userRole, err := b.getRoleByName("user")
+	assert.NoError(t, err)
+	assert.NoError(t, b.db.Create(&User{
+		BotID: b.botID, TelegramID: 300, Username: "regular_user",
+		RoleID: userRole.ID, Role: userRole,
+	}).Error)
+
+	tests := []struct {
+		name   string
+		userID int64
+		scope  string
+		want   bool
+	}{
+		{"owner bypass: model:set", ownerID, ScopeModelSet, true},
+		{"owner bypass: stats:view:any", ownerID, ScopeStatsViewAny, true},
+		{"admin: model:set", 200, ScopeModelSet, true},
+		{"admin: stats:view:any", 200, ScopeStatsViewAny, true},
+		{"admin: history:clear:any", 200, ScopeHistoryClearAny, true},
+		{"user: model:set denied", 300, ScopeModelSet, false},
+		{"user: stats:view:any denied", 300, ScopeStatsViewAny, false},
+		{"user: history:clear:any denied", 300, ScopeHistoryClearAny, false},
+		{"user: stats:view:own allowed", 300, ScopeStatsViewOwn, true},
+		{"user: history:clear:own allowed", 300, ScopeHistoryClearOwn, true},
+		{"unknown telegram_id", 999, ScopeModelSet, false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			assert.Equal(t, tc.want, b.hasScope(tc.userID, tc.scope))
+		})
+	}
+}