Add initial implementation of *arr service client

- Created `client.go` for the main client structure and methods to interact with *arr services.
- Added `types.go` to define data structures for system status, movies, and series.
- Implemented `radarr.go` for Radarr-specific client methods including health checks and movie retrieval.
- Introduced `interfaces.go` to define service interfaces for common operations across *arr services.
- Established a basic `main.go` for application entry point.
- Included a tutorial markdown file to guide users through building the client and understanding Go concepts.
- Initialized `go.mod` for module management.
- Organized code into appropriate packages for better structure and maintainability.

radarr.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+type RadarrClient struct {
+	*Client
+}
+
+func NewRadarrClient(baseURL, apiKey string) *RadarrClient {
+	return &RadarrClient{
+		Client: NewClient(baseURL, apiKey),
+	}
+}
+
+func (r *RadarrClient) GetHealth() ([]HealthCheck, error) {
+
+	// Create the URL for the health endpoint.
+	url := fmt.Sprintf("%s/api/v3/health", r.BaseURL)
+
+	// Create a new GET request to the health endpoint.
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	// Set the API key and content type headers.
+	req.Header.Set("X-Api-Key", r.APIKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	// Send the request and get the response.
+	resp, err := r.HTTPClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Check if the response is successful.
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to get health: %s", resp.Status)
+	}
+
+	// Decode the response body into a slice of HealthCheck structs.
+	var health []HealthCheck
+	if err := json.NewDecoder(resp.Body).Decode(&health); err != nil {
+		return nil, fmt.Errorf("failed to decode response body: %w", err)
+	}
+
+	return health, nil
+}
+
+func (r *RadarrClient) GetMovies() ([]Movie, error) {
+	// Create the URL for the movies endpoint.
+	url := fmt.Sprintf("%s/api/v3/movie", r.BaseURL)
+
+	// Create a new GET request to the movies endpoint.
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	// Set the API key and content type headers.
+	req.Header.Set("X-Api-Key", r.APIKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	// Send the request and get the response.
+	resp, err := r.HTTPClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Check if the response is successful.
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to get movies: %s", resp.Status)
+	}
+
+	// Decode the response body into a slice of Movie structs.
+	var movies []Movie
+	if err := json.NewDecoder(resp.Body).Decode(&movies); err != nil {
+		return nil, fmt.Errorf("failed to decode response body: %w", err)
+	}
+
+	return movies, nil
+}
+
+// GetMovie retrieves a specific movie by ID.
+func (r *RadarrClient) GetMovie(id int) (*Movie, error) {
+	// Create the URL for the movie endpoint.
+	url := fmt.Sprintf("%s/api/v3/movie/%d", r.BaseURL, id)
+
+	// Create a new GET request to the movie endpoint.
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	// Set the API key and content type headers.
+	req.Header.Set("X-Api-Key", r.APIKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	// Send the request and get the response.
+	resp, err := r.HTTPClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Check if the response is successful.
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to get movie: %s", resp.Status)
+	}
+
+	// Decode the response body into a Movie struct.
+	var movie Movie
+	if err := json.NewDecoder(resp.Body).Decode(&movie); err != nil {
+		return nil, fmt.Errorf("failed to decode response body: %w", err)
+	}
+
+	return &movie, nil
+}