added contact suggestion route, code refactor

database/auth.go

@@ -11,13 +11,13 @@ import (
 func CheckUserExists(db *sql.DB, username string) (bool, error) {
 	query := `SELECT COUNT(1) FROM accounts WHERE username = $1`
 
-	var exist bool
-	err := db.QueryRow(query, username).Scan(&exist)
-	if !errors.Is(err, sql.ErrNoRows) {
-		return false, helpers.NewError(helpers.ErrInternal, "Failed to check username", err)
+	var count int
+	err := db.QueryRow(query, username).Scan(&count)
+	if err != nil {
+		return false, helpers.NewError(helpers.ErrInternal, "Failed to check user existence", err)
 	}
 
-	return exist, nil
+	return count > 0, nil
 }
 
 func InsertUser(db *sql.DB, username string, passwordHash string) (string, error) {

database/contacts.go

@@ -7,6 +7,7 @@ import (
 	"github.com/google/uuid"
 	"relay-server/helpers"
 	"relay-server/model"
+	"strings"
 )
 
 func DeleteContact(db *sql.DB, userID uuid.UUID, conversationID uuid.UUID) error {
@@ -317,3 +318,31 @@ func GetContacts(db *sql.DB, userID uuid.UUID) ([]*model.Contact, error) {
 
 	return contacts, nil
 }
+
+func ContactSuggestion(db *sql.DB, contactUsername string) ([]string, error) {
+	query := `
+  	  SELECT username FROM accounts
+  	  WHERE LOWER(username) LIKE $1
+  	  LIMIT 5;
+  	`
+
+	rows, err := db.Query(query, "%"+strings.ToLower(contactUsername)+"%")
+
+	if err != nil && !errors.Is(err, sql.ErrNoRows) {
+		return nil, helpers.NewError(helpers.ErrInternal, "Failed to get contact suggestions", err)
+	}
+
+	var suggestions []string
+	for rows.Next() {
+		var suggestion string
+		err := rows.Scan(&suggestion)
+		if err != nil {
+			return nil, helpers.NewError(helpers.ErrInternal, "internal server error", err)
+		}
+		suggestions = append(suggestions, suggestion)
+	}
+	if err = rows.Err(); err != nil {
+		return nil, helpers.NewError(helpers.ErrInternal, "Error processing suggestions", err)
+	}
+	return suggestions, nil
+}

handlers/auth.go

@@ -40,7 +40,7 @@ func Signup(c *fiber.Ctx) error {
 	// Check if user exists
 	exist, err := database.CheckUserExists(database.DB, u.Username)
 	if err != nil {
-		return helpers.NewError(helpers.ErrInternal, "internal server error", fmt.Errorf("failed to check user existance: %w", err))
+		return err
 	}
 	if exist {
 		return helpers.NewError(helpers.ErrInvalidInput, "User already exists", nil)
@@ -55,7 +55,7 @@ func Signup(c *fiber.Ctx) error {
 	// Insert user
 	userID, err := database.InsertUser(database.DB, u.Username, string(passwordHash))
 	if err != nil {
-		return helpers.NewError(helpers.ErrInternal, "Failed to create user", err)
+		return err
 	}
 
 	// Generate token

handlers/contacts.go

@@ -9,8 +9,8 @@ import (
 
 func DeleteContact(c *fiber.Ctx) error {
 	type params struct {
-		ContactID      uuid.UUID `params:"contact_id"`
-		ConversationID uuid.UUID `params:"conversation_id"`
+		ContactID      uuid.UUID `params:"contactID"`
+		ConversationID uuid.UUID `params:"conversationID"`
 	}
 
 	p := new(params)
@@ -27,7 +27,7 @@ func DeleteContact(c *fiber.Ctx) error {
 
 	err := database.DeleteContact(database.DB, p.ContactID, p.ConversationID)
 	if err != nil {
-		return helpers.NewError(helpers.ErrInternal, "Failed to delete contact", err)
+		return err
 	}
 
 	return c.Status(fiber.StatusOK).JSON(fiber.Map{"message": "Contact deleted"})
@@ -59,7 +59,7 @@ func InsertContact(c *fiber.Ctx) error {
 	}
 
 	if !helpers.IsValidUsername(p.ContactUsername) {
-		return helpers.NewError(helpers.ErrInvalidInput, "username is invalid", nil)
+		return helpers.NewError(helpers.ErrInvalidInput, "invalid username", nil)
 	}
 
 	contactID, err := database.GetUserID(database.DB, p.ContactUsername)
@@ -94,3 +94,23 @@ func GetContacts(c *fiber.Ctx) error {
 
 	return c.Status(fiber.StatusOK).JSON(contacts)
 }
+
+func GetContactSuggestions(c *fiber.Ctx) error {
+	type params struct {
+		ContactUsername string `params:"contactUsername"`
+	}
+
+	p := new(params)
+	if err := c.ParamsParser(p); err != nil {
+		return helpers.NewError(helpers.ErrInvalidInput, "Invalid params", err)
+	}
+	if p.ContactUsername == "" {
+		return helpers.NewError(helpers.ErrInvalidInput, "contact username is empty", nil)
+	}
+
+	suggestions, err := database.ContactSuggestion(database.DB, p.ContactUsername)
+	if err != nil {
+		return err
+	}
+	return c.Status(fiber.StatusOK).JSON(suggestions)
+}

model/model.go

@@ -21,3 +21,7 @@ type Contact struct {
 	LastMessageTime   string    `json:"last_message_time"`
 	LastMessageSender string    `json:"last_message_sender"`
 }
+
+type ContactSuggestion struct {
+	Username string `json:"username"`
+}

router/router.go

@@ -25,4 +25,5 @@ func SetupRoutes(app *fiber.App) {
 	contacts.Delete("/:contact_id/:conversation_id", handlers.DeleteContact)
 	contacts.Post("/:contact_username", handlers.InsertContact)
 	contacts.Get("/", handlers.GetContacts)
+	contacts.Get("/suggestions/:contactUsername", handlers.GetContactSuggestions)
 }