feat(CUB-39): create background job for filament usage sync

backend/Infrastructure/Services/MoonrakerClient.cs

@@ -0,0 +1,130 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using Extrudex.Domain.Interfaces;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace Extrudex.Infrastructure.Configuration;
+
+/// <summary>
+/// HTTP client for communicating with Moonraker REST API endpoints
+/// on Klipper-based printers (e.g., Elegoo Centauri Carbon).
+/// Retrieves filament usage data and printer status information.
+/// </summary>
+public class MoonrakerClient : IMoonrakerClient
+{
+    private readonly HttpClient _httpClient;
+    private readonly ILogger<MoonrakerClient> _logger;
+
+    /// <summary>
+    /// Creates a new MoonrakerClient with the configured HTTP client and logger.
+    /// </summary>
+    /// <param name="httpClient">The HTTP client for making requests to Moonraker endpoints.</param>
+    /// <param name="logger">Logger for diagnostic output.</param>
+    public MoonrakerClient(HttpClient httpClient, ILogger<MoonrakerClient> logger)
+    {
+        _httpClient = httpClient;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public async Task<Dictionary<string, decimal>> GetFilamentUsageAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default)
+    {
+        var baseUrl = BuildBaseUrl(hostnameOrIp, port);
+        var result = new Dictionary<string, decimal>();
+
+        try
+        {
+            // Query Moonraker server info endpoint for filament usage data
+            using var request = new HttpRequestMessage(HttpMethod.Get, $"{baseUrl}/server/history/items?limit=1");
+            if (!string.IsNullOrEmpty(apiKey))
+            {
+                request.Headers.Add("X-Api-Key", apiKey);
+            }
+
+            using var response = await _httpClient.SendAsync(request, cancellationToken);
+            response.EnsureSuccessStatusCode();
+
+            var json = await response.Content.ReadFromJsonAsync<JsonElement>(cancellationToken: cancellationToken);
+
+            // Extract filament usage from the response
+            // Moonraker returns job history with filament_used and similar fields
+            if (json.TryGetProperty("result", out var resultElement))
+            {
+                if (resultElement.TryGetProperty("items", out var items) && items.GetArrayLength() > 0)
+                {
+                    var job = items[0];
+
+                    // Moonraker tracks filament_used in millimeters
+                    if (job.TryGetProperty("filament_used", out var filamentUsed))
+                    {
+                        result["mm_extruded"] = filamentUsed.GetDecimal();
+                    }
+
+                    // Total duration in seconds
+                    if (job.TryGetProperty("print_duration", out var duration))
+                    {
+                        result["print_duration_seconds"] = duration.GetDecimal();
+                    }
+                }
+            }
+
+            _logger.LogDebug(
+                "Retrieved filament usage from Moonraker at {Host}:{Port}: {MetricCount} metrics",
+                hostnameOrIp, port, result.Count);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogWarning(ex,
+                "Failed to retrieve filament usage from Moonraker at {Host}:{Port}",
+                hostnameOrIp, port);
+        }
+        catch (JsonException ex)
+        {
+            _logger.LogWarning(ex,
+                "Failed to parse Moonraker response from {Host}:{Port}",
+                hostnameOrIp, port);
+        }
+
+        return result;
+    }
+
+    /// <inheritdoc />
+    public async Task<bool> IsReachableAsync(
+        string hostnameOrIp,
+        int port,
+        string? apiKey,
+        CancellationToken cancellationToken = default)
+    {
+        var baseUrl = BuildBaseUrl(hostnameOrIp, port);
+
+        try
+        {
+            using var request = new HttpRequestMessage(HttpMethod.Get, $"{baseUrl}/server/info");
+            if (!string.IsNullOrEmpty(apiKey))
+            {
+                request.Headers.Add("X-Api-Key", apiKey);
+            }
+
+            using var response = await _httpClient.SendAsync(request, cancellationToken);
+            return response.IsSuccessStatusCode;
+        }
+        catch (HttpRequestException)
+        {
+            _logger.LogDebug("Moonraker at {Host}:{Port} is not reachable", hostnameOrIp, port);
+            return false;
+        }
+    }
+
+    /// <summary>
+    /// Builds the base URL for Moonraker API calls from hostname and port.
+    /// </summary>
+    private static string BuildBaseUrl(string hostnameOrIp, int port)
+    {
+        return $"http://{hostnameOrIp}:{port}";
+    }
+}