Extrudex/backend/Infrastructure/Services/MoonrakerClient.cs

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}";
    }
}