Overview
The Question Service provides a clean abstraction layer over the trivia API client, implementing the service pattern for question and category management.
Package: internal/core/question/service.go
QuestionServiceApi Interface
Defines the contract for question service implementations.
Source: internal/core/question/interfaces.go
type QuestionServiceApi interface {
GetQuestions(amount int, category int) ([]entities.Question, error)
GetCategories() ([]Category, error)
}
Interface Methods
Retrieves trivia questions based on amount and category
Retrieves all available trivia categories
QuestionService Implementation
Structure
type QuestionService struct {
questionClient QuestionClientApi
}
QuestionClientApi implementation (typically the TriviaClient) to provide question retrieval functionality.
Constructor
func NewQuestionService(client QuestionClientApi) *QuestionService
client
QuestionClientApi
required
A client implementing the QuestionClientApi interface (e.g., TriviaClient)
import (
"github.com/Lafetz/showdown-trivia-game/internal/core/question"
"github.com/Lafetz/showdown-trivia-game/internal/trivia_api"
)
triviaClient := triviaapi.NewTriviaClient()
questionService := question.NewQuestionService(triviaClient)
Methods
GetQuestions
Retrieves trivia questions by delegating to the underlying client.
func (q *QuestionService) GetQuestions(amount int, category int) ([]entities.Question, error)
Number of questions to retrieve
Category ID for filtering questions
[]entities.Question: Array of Question entitieserror: Error if retrieval fails
Example:
// Get 5 questions from category 21 (Sports)
questions, err := questionService.GetQuestions(5, 21)
if err != nil {
return err
}
for _, q := range questions {
fmt.Println(q.Question)
for i, opt := range q.Options {
fmt.Printf("%d. %s\n", i+1, opt)
}
}
internal/core/question/service.go:9
GetCategories
Retrieves all available trivia categories.
func (q *QuestionService) GetCategories() ([]Category, error)
[]Category: Array of available categorieserror: Error if retrieval fails
Example:
categories, err := questionService.GetCategories()
if err != nil {
return err
}
for _, cat := range categories {
fmt.Printf("[%d] %s\n", cat.Id, cat.Name)
}
internal/core/question/service.go:12
Data Structures
Question Entity
Represents a trivia question with multiple-choice options.
Source: internal/core/entities/question.go
type Question struct {
Question string
Options []string
CorrectAnswer string
}
The question text to display to the user
Array of answer options (includes correct and incorrect answers, shuffled)
The correct answer (one of the options in the Options array)
func NewQuestion(question string, options []string, correctAnswer string) Question
question := entities.NewQuestion(
"What is the capital of France?",
[]string{"London", "Berlin", "Paris", "Madrid"},
"Paris",
)
Category
Represents a trivia category.
Source: internal/core/question/domain.go
type Category struct {
Id int
Name string
}
Unique identifier for the category
Human-readable category name
{Id: 9, Name: "General Knowledge"}{Id: 21, Name: "Sports"}{Id: 23, Name: "History"}
QuestionClientApi Interface
Defines the contract for question client implementations.
Source: internal/core/question/interfaces.go
type QuestionClientApi interface {
GetQuestions(amount int, category int) ([]entities.Question, error)
GetCategories() ([]Category, error)
}
triviaapi.triviaClient - Open Trivia Database client
Service Pattern Benefits
- Abstraction: Separates business logic from API implementation details
- Testability: Easy to mock the QuestionClientApi for unit testing
- Flexibility: Can swap different question sources without changing service consumers
- Single Responsibility: Service focuses on orchestration, client handles API communication
Usage in Application
Typical initialization flow:
func InitializeQuestionService() question.QuestionServiceApi {
// Create API client
triviaClient := triviaapi.NewTriviaClient()
// Create service with client
questionService := question.NewQuestionService(triviaClient)
return questionService
}
func StartGame(service question.QuestionServiceApi) error {
// Fetch questions for the game
questions, err := service.GetQuestions(10, 9)
if err != nil {
return fmt.Errorf("failed to load questions: %w", err)
}
// Use questions in game logic
for _, q := range questions {
// Display question and handle user input
answerCorrectly := AskQuestion(q)
// ... game logic
}
return nil
}