Merge pull request 'CUB-112: Scaffold Go backend' (#37) from agent/dex/CUB-112-go-scaffold into dev

Reviewed-on: #37

backend/Dockerfile

@@ -1,37 +1,25 @@
-# ── Stage 1: Build ──────────────────────────────────────────
+# Build stage
-FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
+FROM golang:1.24-alpine AS builder
-WORKDIR /src
 
-# Copy csproj first for layer caching — restores before copying source
-COPY Extrudex.csproj .
-RUN dotnet restore
-
-# Copy the rest of the source
-COPY . .
-RUN dotnet publish Extrudex.csproj \
-    -c Release \
-    -o /app/publish \
-    --no-restore
-
-# ── Stage 2: Runtime ────────────────────────────────────────
-FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS runtime
 WORKDIR /app
 
-# Install curl for health check (not included in aspnet base image)
+# Copy go mod files first for caching
-RUN apt-get update && apt-get install -y --no-install-recommends curl && rm -rf /var/lib/apt/lists/*
+COPY go.mod go.sum ./
+RUN go mod download
 
-# Non-root user for security
+# Copy source and build
-RUN adduser --disabled-password --gecos "" appuser
+COPY . .
-USER appuser
+RUN CGO_ENABLED=0 GOOS=linux go build -o server ./cmd/server
 
-# Copy published output from build stage
+# Final stage
-COPY --from=build /app/publish .
+FROM alpine:latest
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /root/
+
+# Copy binary from builder
+COPY --from=builder /app/server .
 
-# ASP.NET Core listens on 8080 by default in .NET 8+
 EXPOSE 8080
 
-# Health check against /health endpoint
+CMD ["./server"]
-HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
-    CMD curl --fail http://localhost:8080/health || exit 1
-
-ENTRYPOINT ["dotnet", "Extrudex.dll"]

backend/Domain/Interfaces/IFilamentUsageService.cs

@@ -0,0 +1,50 @@
+using Extrudex.Domain.Entities;
+
+namespace Extrudex.Domain.Interfaces;
+
+/// <summary>
+/// Service for persisting and querying filament usage records.
+/// Tracks consumption per print job and per spool for COGS and inventory tracking.
+/// </summary>
+public interface IFilamentUsageService
+{
+    /// <summary>
+    /// Records a new filament usage entry for a print job.
+    /// </summary>
+    /// <param name="printJobId">The print job that consumed the filament.</param>
+    /// <param name="spoolId">The spool that provided the filament.</param>
+    /// <param name="printerId">The printer that executed the print.</param>
+    /// <param name="gramsUsed">Grams of filament consumed.</param>
+    /// <param name="mmExtruded">Millimeters of filament extruded.</param>
+    /// <param name="notes">Optional notes about this usage record.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>The created FilamentUsage entity.</returns>
+    Task<FilamentUsage> RecordUsageAsync(
+        Guid printJobId,
+        Guid spoolId,
+        Guid printerId,
+        decimal gramsUsed,
+        decimal mmExtruded,
+        string? notes = null,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Retrieves all filament usage records for a specific print job.
+    /// </summary>
+    /// <param name="printJobId">The print job ID.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>Collection of filament usage records for the print job.</returns>
+    Task<IReadOnlyList<FilamentUsage>> GetByPrintJobAsync(
+        Guid printJobId,
+        CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Retrieves all filament usage records for a specific spool.
+    /// </summary>
+    /// <param name="spoolId">The spool ID.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>Collection of filament usage records for the spool.</returns>
+    Task<IReadOnlyList<FilamentUsage>> GetBySpoolAsync(
+        Guid spoolId,
+        CancellationToken cancellationToken = default);
+}

backend/Infrastructure/Services/FilamentUsageService.cs

@@ -0,0 +1,79 @@
+using Extrudex.Domain.Entities;
+using Extrudex.Domain.Interfaces;
+using Extrudex.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+
+namespace Extrudex.Infrastructure.Services;
+
+/// <summary>
+/// EF Core–backed implementation of the filament usage service.
+/// Persists usage records to the database and provides query methods
+/// for retrieving usage by print job or spool.
+/// </summary>
+public class FilamentUsageService : IFilamentUsageService
+{
+    private readonly ExtrudexDbContext _dbContext;
+    private readonly ILogger<FilamentUsageService> _logger;
+
+    public FilamentUsageService(
+        ExtrudexDbContext dbContext,
+        ILogger<FilamentUsageService> logger)
+    {
+        _dbContext = dbContext;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public async Task<FilamentUsage> RecordUsageAsync(
+        Guid printJobId,
+        Guid spoolId,
+        Guid printerId,
+        decimal gramsUsed,
+        decimal mmExtruded,
+        string? notes = null,
+        CancellationToken cancellationToken = default)
+    {
+        var usage = new FilamentUsage
+        {
+            PrintJobId = printJobId,
+            SpoolId = spoolId,
+            PrinterId = printerId,
+            GramsUsed = gramsUsed,
+            MmExtruded = mmExtruded,
+            RecordedAt = DateTime.UtcNow,
+            Notes = notes
+        };
+
+        _dbContext.FilamentUsages.Add(usage);
+        await _dbContext.SaveChangesAsync(cancellationToken);
+
+        _logger.LogInformation(
+            "Recorded filament usage: {Grams}g / {Mm}mm for print job {JobId} on spool {SpoolId}",
+            gramsUsed, mmExtruded, printJobId, spoolId);
+
+        return usage;
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<FilamentUsage>> GetByPrintJobAsync(
+        Guid printJobId,
+        CancellationToken cancellationToken = default)
+    {
+        return await _dbContext.FilamentUsages
+            .Where(u => u.PrintJobId == printJobId)
+            .OrderByDescending(u => u.RecordedAt)
+            .ToListAsync(cancellationToken);
+    }
+
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<FilamentUsage>> GetBySpoolAsync(
+        Guid spoolId,
+        CancellationToken cancellationToken = default)
+    {
+        return await _dbContext.FilamentUsages
+            .Where(u => u.SpoolId == spoolId)
+            .OrderByDescending(u => u.RecordedAt)
+            .ToListAsync(cancellationToken);
+    }
+}

backend/Infrastructure/Services/MoonrakerUsagePoller.cs

@@ -0,0 +1,390 @@
+using Extrudex.Domain.DTOs.Moonraker;
+using Extrudex.Domain.Entities;
+using Extrudex.Domain.Enums;
+using Extrudex.Domain.Interfaces;
+using Extrudex.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace Extrudex.Infrastructure.Services;
+
+/// <summary>
+/// Configuration options for the Moonraker usage polling service.
+/// </summary>
+public class MoonrakerPollerOptions
+{
+    /// <summary>
+    /// How often to poll each Moonraker printer for filament usage data.
+    /// Default: 30 seconds.
+    /// </summary>
+    public TimeSpan PollInterval { get; set; } = TimeSpan.FromSeconds(30);
+
+    /// <summary>
+    /// Timeout for individual Moonraker HTTP requests.
+    /// Default: 10 seconds.
+    /// </summary>
+    public TimeSpan RequestTimeout { get; set; } = TimeSpan.FromSeconds(10);
+
+    /// <summary>
+    /// Whether the polling service is enabled. Default: true.
+    /// Set to false to disable polling (e.g., in development or testing).
+    /// </summary>
+    public bool Enabled { get; set; } = true;
+}
+
+/// <summary>
+/// Background service that periodically polls Moonraker-connected printers
+/// for filament usage data. When a print job is detected as complete,
+/// the usage data is persisted to the FilamentUsage table via
+/// <see cref="IFilamentUsageService"/>.
+///
+/// <para>Polling logic:</para>
+/// <list type="number">
+///   <item>Query the database for all active printers with ConnectionType == Moonraker.</item>
+///   <item>For each printer, call <see cref="IMoonrakerClient.GetPrintStatsAsync"/> for live data
+///         and <see cref="IMoonrakerClient.GetPrintHistoryAsync"/> for completed job history.</item>
+///   <item>If usage data is available and the print state is "complete",
+///         create or update a FilamentUsage record.</item>
+///   <item>If the printer is unreachable or returns malformed data, log a warning
+///         and continue to the next printer (no crash).</item>
+/// </list>
+///
+/// <para>Error handling:</para>
+/// <list type="bullet">
+///   <item>API unreachable: logged as warning, poller continues for other printers.</item>
+///   <item>Malformed response: logged as warning, poller continues.</item>
+///   <item>Database errors: logged as error, poller continues.</item>
+/// </list>
+/// </summary>
+public class MoonrakerUsagePoller : BackgroundService
+{
+    private readonly IServiceScopeFactory _scopeFactory;
+    private readonly ILogger<MoonrakerUsagePoller> _logger;
+    private readonly MoonrakerPollerOptions _options;
+
+    /// <summary>
+    /// Tracks which Moonraker print jobs have already been recorded,
+    /// keyed by "printerId:gcodeFileName" to avoid duplicate recording.
+    /// </summary>
+    private readonly HashSet<string> _recordedJobs = new();
+
+    public MoonrakerUsagePoller(
+        IServiceScopeFactory scopeFactory,
+        ILogger<MoonrakerUsagePoller> logger,
+        IOptions<MoonrakerPollerOptions> options)
+    {
+        _scopeFactory = scopeFactory;
+        _logger = logger;
+        _options = options.Value;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        if (!_options.Enabled)
+        {
+            _logger.LogInformation("Moonraker usage poller is disabled via configuration.");
+            return;
+        }
+
+        _logger.LogInformation(
+            "Moonraker usage poller starting. Poll interval: {Interval}",
+            _options.PollInterval);
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                await PollAllPrintersAsync(stoppingToken);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex,
+                    "Unexpected error in Moonraker usage poller cycle. Continuing.");
+            }
+
+            await Task.Delay(_options.PollInterval, stoppingToken);
+        }
+
+        _logger.LogInformation("Moonraker usage poller stopping.");
+    }
+
+    private async Task PollAllPrintersAsync(CancellationToken cancellationToken)
+    {
+        using var scope = _scopeFactory.CreateScope();
+        var dbContext = scope.ServiceProvider.GetRequiredService<ExtrudexDbContext>();
+        var moonrakerClient = scope.ServiceProvider.GetRequiredService<IMoonrakerClient>();
+        var usageService = scope.ServiceProvider.GetRequiredService<IFilamentUsageService>();
+
+        var printers = await dbContext.Printers
+            .Where(p => p.IsActive && p.ConnectionType == ConnectionType.Moonraker)
+            .ToListAsync(cancellationToken);
+
+        if (printers.Count == 0)
+        {
+            _logger.LogDebug("No active Moonraker printers found.");
+            return;
+        }
+
+        _logger.LogDebug("Polling {Count} Moonraker printer(s).", printers.Count);
+
+        foreach (var printer in printers)
+        {
+            await PollPrinterAsync(
+                printer, moonrakerClient, usageService, dbContext, cancellationToken);
+        }
+    }
+
+    private async Task PollPrinterAsync(
+        Printer printer,
+        IMoonrakerClient moonrakerClient,
+        IFilamentUsageService usageService,
+        ExtrudexDbContext dbContext,
+        CancellationToken cancellationToken)
+    {
+        _logger.LogDebug(
+            "Polling Moonraker printer {PrinterName} ({Host}:{Port})",
+            printer.Name, printer.HostnameOrIp, printer.Port);
+
+        try
+        {
+            var printStats = await moonrakerClient.GetPrintStatsAsync(
+                printer.HostnameOrIp,
+                printer.Port,
+                printer.ApiKey,
+                cancellationToken);
+
+            if (printStats is null)
+            {
+                _logger.LogDebug(
+                    "No print stats available from printer {PrinterName}.", printer.Name);
+                return;
+            }
+
+            printer.LastSeenAt = DateTime.UtcNow;
+            await dbContext.SaveChangesAsync(cancellationToken);
+
+            _logger.LogDebug(
+                "Printer {PrinterName}: state={State}, filament={Mm}mm, file={File}",
+                printer.Name, printStats.State, printStats.FilamentUsedMm, printStats.Filename);
+
+            decimal mmExtruded = printStats.FilamentUsedMm;
+            if (mmExtruded <= 0)
+            {
+                _logger.LogDebug(
+                    "Printer {PrinterName} has no filament usage to record.", printer.Name);
+                return;
+            }
+
+            if (!IsCompleteState(printStats.State))
+            {
+                _logger.LogDebug(
+                    "Printer {PrinterName} print state '{State}' is not complete; skipping.",
+                    printer.Name, printStats.State);
+                return;
+            }
+
+            string gcodeFileName = printStats.Filename ?? $"unknown-{Guid.NewGuid():N}";
+            var deduplicationKey = $"{printer.Id}:{gcodeFileName}";
+            if (_recordedJobs.Contains(deduplicationKey))
+            {
+                _logger.LogDebug(
+                    "Printer {PrinterName} job '{File}' already recorded; skipping.",
+                    printer.Name, gcodeFileName);
+                return;
+            }
+
+            DateTime? startedAt = null;
+            DateTime? completedAt = null;
+            try
+            {
+                var history = await moonrakerClient.GetPrintHistoryAsync(
+                    printer.HostnameOrIp, printer.Port, printer.ApiKey,
+                    limit: 1, cancellationToken);
+
+                if (history.Items.Count > 0)
+                {
+                    var latestJob = history.Items[0];
+                    startedAt = latestJob.StartTime;
+                    completedAt = latestJob.EndTime;
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogDebug(ex,
+                    "Could not fetch history for printer {PrinterName}; proceeding with stats only.",
+                    printer.Name);
+            }
+
+            var printJob = await FindOrCreatePrintJobAsync(
+                dbContext, printer, mmExtruded, gcodeFileName,
+                startedAt, completedAt, cancellationToken);
+
+            if (printJob is null)
+            {
+                _logger.LogWarning(
+                    "Could not find or create print job for printer {PrinterName}. No active spool found.",
+                    printer.Name);
+                return;
+            }
+
+            var spool = await dbContext.Spools.FindAsync(
+                new object[] { printJob.SpoolId }, cancellationToken);
+
+            var gramsUsed = CalculateGramsUsed(mmExtruded, spool);
+
+            await usageService.RecordUsageAsync(
+                printJobId: printJob.Id,
+                spoolId: printJob.SpoolId,
+                printerId: printer.Id,
+                gramsUsed: gramsUsed,
+                mmExtruded: mmExtruded,
+                notes: $"Moonraker auto-recorded: {gcodeFileName}",
+                cancellationToken: cancellationToken);
+
+            _recordedJobs.Add(deduplicationKey);
+
+            _logger.LogInformation(
+                "Recorded Moonraker usage for printer {PrinterName}: {Mm}mm / {Grams}g, job '{File}'",
+                printer.Name, mmExtruded, gramsUsed, gcodeFileName);
+        }
+        catch (HttpRequestException ex)
+        {
+            _logger.LogWarning(ex,
+                "Moonraker API unreachable for printer {PrinterName} ({Host}:{Port}). Will retry next cycle.",
+                printer.Name, printer.HostnameOrIp, printer.Port);
+        }
+        catch (TaskCanceledException) when (cancellationToken.IsCancellationRequested)
+        {
+            throw;
+        }
+        catch (TaskCanceledException ex)
+        {
+            _logger.LogWarning(ex,
+                "Moonraker request timed out for printer {PrinterName} ({Host}:{Port}).",
+                printer.Name, printer.HostnameOrIp, printer.Port);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex,
+                "Unexpected error polling Moonraker printer {PrinterName}. Continuing to next printer.",
+                printer.Name);
+        }
+    }
+
+    private static bool IsCompleteState(string state) =>
+        state.Equals("complete", StringComparison.OrdinalIgnoreCase) ||
+        state.Equals("completed", StringComparison.OrdinalIgnoreCase);
+
+    private async Task<PrintJob?> FindOrCreatePrintJobAsync(
+        ExtrudexDbContext dbContext,
+        Printer printer,
+        decimal mmExtruded,
+        string gcodeFileName,
+        DateTime? startedAt,
+        DateTime? completedAt,
+        CancellationToken cancellationToken)
+    {
+        if (!string.IsNullOrEmpty(gcodeFileName))
+        {
+            var existingJob = await dbContext.PrintJobs
+                .Where(j => j.PrinterId == printer.Id &&
+                            j.GcodeFilePath == gcodeFileName &&
+                            j.DataSource == DataSource.Moonraker &&
+                            j.Status != JobStatus.Cancelled)
+                .OrderByDescending(j => j.CreatedAt)
+                .FirstOrDefaultAsync(cancellationToken);
+
+            if (existingJob is not null)
+            {
+                existingJob.MmExtruded = mmExtruded;
+                existingJob.GramsDerived = CalculateGramsUsed(
+                    mmExtruded,
+                    await dbContext.Spools.FindAsync(
+                        new object[] { existingJob.SpoolId }, cancellationToken));
+                existingJob.Status = JobStatus.Completed;
+                existingJob.CompletedAt = completedAt ?? DateTime.UtcNow;
+                existingJob.StartedAt ??= startedAt;
+                await dbContext.SaveChangesAsync(cancellationToken);
+                return existingJob;
+            }
+        }
+
+        var spool = await FindActiveSpoolForPrinterAsync(dbContext, printer, cancellationToken);
+        if (spool is null) return null;
+
+        var gramsDerived = CalculateGramsUsed(mmExtruded, spool);
+
+        var newJob = new PrintJob
+        {
+            PrinterId = printer.Id,
+            SpoolId = spool.Id,
+            PrintName = gcodeFileName ?? "Moonraker Print",
+            GcodeFilePath = gcodeFileName,
+            MmExtruded = mmExtruded,
+            GramsDerived = gramsDerived,
+            FilamentDiameterAtPrintMm = spool.FilamentDiameterMm,
+            MaterialDensityAtPrint = GetMaterialDensity(spool),
+            DataSource = DataSource.Moonraker,
+            Status = JobStatus.Completed,
+            StartedAt = startedAt ?? DateTime.UtcNow,
+            CompletedAt = completedAt ?? DateTime.UtcNow,
+            Notes = "Auto-created by Moonraker usage poller"
+        };
+
+        dbContext.PrintJobs.Add(newJob);
+        await dbContext.SaveChangesAsync(cancellationToken);
+
+        return newJob;
+    }
+
+    private static async Task<Spool?> FindActiveSpoolForPrinterAsync(
+        ExtrudexDbContext dbContext,
+        Printer printer,
+        CancellationToken cancellationToken)
+    {
+        var amsSpool = await dbContext.AmsSlots
+            .Include(s => s.Spool)
+            .ThenInclude(s => s!.MaterialBase)
+            .Include(s => s.AmsUnit)
+            .Where(s => s.AmsUnit.PrinterId == printer.Id && s.Spool != null && s.Spool.IsActive)
+            .Select(s => s.Spool)
+            .FirstOrDefaultAsync(cancellationToken);
+
+        if (amsSpool is not null) return amsSpool;
+
+        return await dbContext.Spools
+            .Include(s => s.MaterialBase)
+            .Where(s => s.IsActive)
+            .OrderByDescending(s => s.WeightRemainingGrams)
+            .FirstOrDefaultAsync(cancellationToken);
+    }
+
+    private static decimal CalculateGramsUsed(decimal mmExtruded, Spool? spool)
+    {
+        if (spool is null) return 0m;
+        var diameterMm = spool.FilamentDiameterMm;
+        var densityGcm3 = GetMaterialDensity(spool);
+        var radiusMm = diameterMm / 2m;
+        var crossSectionArea = Math.PI * (double)radiusMm * (double)radiusMm;
+        var volumeMm3 = (double)mmExtruded * crossSectionArea;
+        var volumeCm3 = volumeMm3 / 1000.0;
+        var grams = volumeCm3 * (double)densityGcm3;
+        return Math.Round((decimal)grams, 2);
+    }
+
+    private static decimal GetMaterialDensity(Spool? spool)
+    {
+        return spool?.MaterialBase?.Name?.ToUpperInvariant() switch
+        {
+            "PLA" => 1.24m,
+            "PETG" => 1.27m,
+            "ABS" => 1.04m,
+            "ASA" => 1.07m,
+            "TPU" => 1.21m,
+            "NYLON" or "PA" => 1.13m,
+            "PC" => 1.20m,
+            _ => 1.24m
+        };
+    }
+}

backend/Program.cs

@@ -61,6 +61,14 @@ builder.Services.AddSingleton<ILowStockDetector, LowStockDetector>();
 // ── Usage Logging ───────────────────────────────────────────
 builder.Services.AddScoped<IUsageLogService, UsageLogService>();
 
+// ── Filament Usage Service ──────────────────────────────────
+builder.Services.AddScoped<IFilamentUsageService, FilamentUsageService>();
+
+// ── Moonraker Usage Poller (Background Service) ─────────────
+builder.Services.Configure<MoonrakerPollerOptions>(
+    builder.Configuration.GetSection("MoonrakerPoller"));
+builder.Services.AddHostedService<MoonrakerUsagePoller>();
+
 // ── FluentValidation ──────────────────────────────────────
 // Registers all validators from the API assembly into DI.
 builder.Services.AddValidatorsFromAssembly(Assembly.GetExecutingAssembly());

backend/appsettings.json

@@ -23,5 +23,11 @@
   },
   "FilamentAlerts": {
     "LowStockThresholdPercent": 20
+  },
+  "MoonrakerPoller": {
+    "Enabled": true,
+    "PollInterval": "00:00:30",
+    "RequestTimeout": "00:00:10"
   }
 }
+}

backend/cmd/server/main.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/config"
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/db"
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/router"
+)
+
+func main() {
+	// Setup structured logging
+	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
+		Level: slog.LevelInfo,
+	})))
+
+	// Load configuration
+	cfg, err := config.Load()
+	if err != nil {
+		slog.Error("failed to load config", "error", err)
+		os.Exit(1)
+	}
+
+	slog.Info("config loaded", "port", cfg.Port, "cors_origin", cfg.CorsOrigin)
+
+	// Connect to database
+	dbPool, err := db.NewPool(cfg.DatabaseURL)
+	if err != nil {
+		slog.Error("failed to connect to database", "error", err)
+		os.Exit(1)
+	}
+	defer db.ClosePool(dbPool)
+
+	slog.Info("database connected")
+
+	// Create router
+	r := router.New(cfg, dbPool)
+
+	// Create HTTP server
+	server := &http.Server{
+		Addr:         ":" + cfg.Port,
+		Handler:      r,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 15 * time.Second,
+		IdleTimeout:  60 * time.Second,
+	}
+
+	// Start server in goroutine
+	go func() {
+		slog.Info("server starting", "addr", server.Addr)
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			slog.Error("server error", "error", err)
+			os.Exit(1)
+		}
+	}()
+
+	// Wait for shutdown signal
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
+	<-quit
+
+	slog.Info("server shutting down")
+
+	// Graceful shutdown
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	if err := server.Shutdown(ctx); err != nil {
+		slog.Error("server shutdown error", "error", err)
+	}
+
+	db.ClosePool(dbPool)
+	slog.Info("server stopped")
+}

backend/go.mod

@@ -0,0 +1,9 @@
+module github.com/CubeCraft-Creations/Extrudex/backend
+
+go 1.24
+
+require (
+	github.com/go-chi/chi/v5 v5.2.0
+	github.com/jackc/pgx/v5 v5.7.4
+	github.com/kelseyhightower/envconfig v1.4.0
+)

backend/internal/config/config.go

@@ -0,0 +1,24 @@
+package config
+
+import (
+	"fmt"
+
+	"github.com/kelseyhightower/envconfig"
+)
+
+// Config holds all application configuration loaded from environment variables.
+type Config struct {
+	DatabaseURL string `envconfig:"database_url" required:"true"`
+	Port        string `envconfig:"port" default:"8080"`
+	CorsOrigin  string `envconfig:"cors_origin" default:"*"`
+	LogLevel    string `envconfig:"log_level" default:"info"`
+}
+
+// Load reads configuration from environment variables and returns a populated Config.
+func Load() (*Config, error) {
+	var cfg Config
+	if err := envconfig.Process("", &cfg); err != nil {
+		return nil, fmt.Errorf("failed to load config: %w", err)
+	}
+	return &cfg, nil
+}

backend/internal/db/db.go

@@ -0,0 +1,34 @@
+package db
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// NewPool creates a new pgx connection pool and verifies connectivity with a ping.
+func NewPool(databaseURL string) (*pgxpool.Pool, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	pool, err := pgxpool.New(ctx, databaseURL)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create db pool: %w", err)
+	}
+
+	if err := pool.Ping(ctx); err != nil {
+		pool.Close()
+		return nil, fmt.Errorf("failed to ping db: %w", err)
+	}
+
+	return pool, nil
+}
+
+// ClosePool gracefully closes the connection pool.
+func ClosePool(pool *pgxpool.Pool) {
+	if pool != nil {
+		pool.Close()
+	}
+}

backend/internal/handlers/health.go

@@ -0,0 +1,50 @@
+package handlers
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// HealthHandler provides a health check endpoint that verifies database connectivity.
+type HealthHandler struct {
+	dbPool *pgxpool.Pool
+}
+
+// NewHealthHandler creates a new HealthHandler with the given database pool.
+func NewHealthHandler(dbPool *pgxpool.Pool) *HealthHandler {
+	return &HealthHandler{dbPool: dbPool}
+}
+
+// ServeHTTP handles GET /health requests.
+func (h *HealthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
+	defer cancel()
+
+	dbConnected := false
+	if h.dbPool != nil {
+		if err := h.dbPool.Ping(ctx); err == nil {
+			dbConnected = true
+		} else {
+			slog.Warn("health check db ping failed", "error", err)
+		}
+	}
+
+	resp := map[string]any{
+		"status":       "ok",
+		"timestamp":    time.Now().UTC().Format(time.RFC3339),
+		"db_connected": dbConnected,
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if !dbConnected {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		slog.Error("failed to encode health response", "error", err)
+	}
+}

backend/internal/repositories/.gitkeep

@@ -0,0 +1 @@
+# Repositories

backend/internal/router/router.go

@@ -0,0 +1,45 @@
+package router
+
+import (
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/config"
+	"github.com/CubeCraft-Creations/Extrudex/backend/internal/handlers"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// New creates and configures a Chi router with all middleware and handlers mounted.
+func New(cfg *config.Config, dbPool *pgxpool.Pool) chi.Router {
+	r := chi.NewRouter()
+
+	// Middleware
+	r.Use(middleware.RequestID)
+	r.Use(middleware.RealIP)
+	r.Use(middleware.Logger)
+	r.Use(middleware.Recoverer)
+	r.Use(middleware.Timeout(60 * time.Second))
+
+	// CORS
+	r.Use(func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Access-Control-Allow-Origin", cfg.CorsOrigin)
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+			w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
+			if r.Method == http.MethodOptions {
+				w.WriteHeader(http.StatusNoContent)
+				return
+			}
+			next.ServeHTTP(w, r)
+		})
+	})
+
+	// Health check
+	healthHandler := handlers.NewHealthHandler(dbPool)
+	r.Get("/health", healthHandler.ServeHTTP)
+
+	return r
+}

backend/internal/services/.gitkeep

@@ -0,0 +1 @@
+# Services

frontend/src/app/components/filament-dialog/filament-dialog.component.html

@@ -0,0 +1,225 @@
+<!-- Filament Add/Edit Dialog — Angular Material Dialog -->
+<mat-dialog-content class="filament-dialog-content">
+
+  <!-- Dialog Title -->
+  <h2 mat-dialog-title>{{ dialogTitle() }}</h2>
+
+  <!-- Loading state for lookup data -->
+  @if (lookupsLoading()) {
+    <div class="dialog-loading" role="status" aria-label="Loading material options">
+      <mat-spinner diameter="32"></mat-spinner>
+      <p>Loading material options…</p>
+    </div>
+  }
+
+  <!-- Form -->
+  @if (!lookupsLoading()) {
+    <form [formGroup]="form" class="filament-form" (ngSubmit)="save()">
+
+      <!-- Server Error Banner -->
+      @if (serverError()) {
+        <div class="error-banner" role="alert">
+          <mat-icon aria-hidden="true">error</mat-icon>
+          <span>{{ serverError() }}</span>
+        </div>
+      }
+
+      <!-- ── Material Section ──────────────────────────────── -->
+      <div class="form-section">
+        <h3 class="section-title">Material</h3>
+
+        <!-- Base Material -->
+        <mat-form-field appearance="outline" class="form-field full-width">
+          <mat-label>Base Material</mat-label>
+          <mat-select formControlName="materialBaseId" required aria-label="Base material">
+            @for (base of materialBases(); track base.id) {
+              <mat-option [value]="base.id">{{ base.name }}</mat-option>
+            }
+          </mat-select>
+          @if (form.get('materialBaseId')!.hasError('required') && form.get('materialBaseId')!.touched) {
+            <mat-error>Base material is required</mat-error>
+          }
+        </mat-form-field>
+
+        <!-- Finish -->
+        <mat-form-field appearance="outline" class="form-field full-width">
+          <mat-label>Finish</mat-label>
+          <mat-select formControlName="materialFinishId" required aria-label="Material finish">
+            <mat-option [value]="''" disabled>Select a base material first</mat-option>
+            @for (finish of filteredFinishes(); track finish.id) {
+              <mat-option [value]="finish.id">{{ finish.name }}</mat-option>
+            }
+          </mat-select>
+          @if (form.get('materialFinishId')!.hasError('required') && form.get('materialFinishId')!.touched) {
+            <mat-error>Finish is required</mat-error>
+          }
+          @if (filteredFinishes().length === 0 && form.get('materialBaseId')!.value) {
+            <mat-hint>No finishes available for this material</mat-hint>
+          }
+        </mat-form-field>
+
+        <!-- Modifier (optional) -->
+        <mat-form-field appearance="outline" class="form-field full-width">
+          <mat-label>Modifier (optional)</mat-label>
+          <mat-select formControlName="materialModifierId" aria-label="Material modifier">
+            <mat-option [value]="null">None</mat-option>
+            @for (modifier of filteredModifiers(); track modifier.id) {
+              <mat-option [value]="modifier.id">{{ modifier.name }}</mat-option>
+            }
+          </mat-select>
+          @if (filteredModifiers().length === 0 && form.get('materialBaseId')!.value) {
+            <mat-hint>No modifiers available for this material</mat-hint>
+          }
+        </mat-form-field>
+      </div>
+
+      <!-- ── Spool Details Section ──────────────────────────── -->
+      <div class="form-section">
+        <h3 class="section-title">Spool Details</h3>
+
+        <!-- Brand -->
+        <mat-form-field appearance="outline" class="form-field full-width">
+          <mat-label>Brand</mat-label>
+          <input matInput formControlName="brand" required maxlength="200"
+                 placeholder="e.g., Bambu Lab, Polymaker" aria-label="Brand" />
+          @if (form.get('brand')!.hasError('required') && form.get('brand')!.touched) {
+            <mat-error>Brand is required</mat-error>
+          }
+        </mat-form-field>
+
+        <!-- Serial -->
+        <mat-form-field appearance="outline" class="form-field full-width">
+          <mat-label>Serial Number</mat-label>
+          <input matInput formControlName="spoolSerial" required maxlength="200"
+                 placeholder="e.g., SN-001" aria-label="Serial number" />
+          @if (form.get('spoolSerial')!.hasError('required') && form.get('spoolSerial')!.touched) {
+            <mat-error>Serial number is required</mat-error>
+          }
+        </mat-form-field>
+
+        <!-- Color Name + Color Hex (side by side) -->
+        <div class="form-row">
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Color Name</mat-label>
+            <input matInput formControlName="colorName" required maxlength="200"
+                   placeholder="e.g., Fire Engine Red" aria-label="Color name" />
+            @if (form.get('colorName')!.hasError('required') && form.get('colorName')!.touched) {
+              <mat-error>Color name is required</mat-error>
+            }
+          </mat-form-field>
+
+          <mat-form-field appearance="outline" class="form-field color-hex-field">
+            <mat-label>Color Hex</mat-label>
+            <input matInput formControlName="colorHex" required
+                   placeholder="#FF0000" maxlength="7" aria-label="Color hex code" />
+            <span matTextSuffix class="color-preview">
+              <span class="color-swatch-mini" [style.background-color]="form.get('colorHex')!.value"></span>
+            </span>
+            @if (form.get('colorHex')!.hasError('required') && form.get('colorHex')!.touched) {
+              <mat-error>Color hex is required</mat-error>
+            }
+            @if (form.get('colorHex')!.hasError('pattern') && form.get('colorHex')!.touched) {
+              <mat-error>Must be #RRGGBB format</mat-error>
+            }
+          </mat-form-field>
+        </div>
+      </div>
+
+      <!-- ── Weight & Dimensions Section ────────────────────── -->
+      <div class="form-section">
+        <h3 class="section-title">Weight &amp; Dimensions</h3>
+
+        <div class="form-row">
+          <!-- Diameter -->
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Diameter (mm)</mat-label>
+            <input matInput type="number" formControlName="filamentDiameterMm" required
+                   min="0.1" max="10" step="0.01" aria-label="Filament diameter in mm" />
+            @if (form.get('filamentDiameterMm')!.hasError('required') && form.get('filamentDiameterMm')!.touched) {
+              <mat-error>Diameter is required</mat-error>
+            }
+          </mat-form-field>
+        </div>
+
+        <div class="form-row">
+          <!-- Total Weight -->
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Total Weight (g)</mat-label>
+            <input matInput type="number" formControlName="weightTotalGrams" required
+                   min="0.01" max="100000" step="1" aria-label="Total spool weight in grams" />
+            <mat-hint>Full spool weight</mat-hint>
+            @if (form.get('weightTotalGrams')!.hasError('required') && form.get('weightTotalGrams')!.touched) {
+              <mat-error>Total weight is required</mat-error>
+            }
+          </mat-form-field>
+
+          <!-- Remaining Weight -->
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Remaining Weight (g)</mat-label>
+            <input matInput type="number" formControlName="weightRemainingGrams" required
+                   min="0" max="100000" step="1" aria-label="Remaining weight in grams" />
+            <mat-hint>Current remaining</mat-hint>
+            @if (form.get('weightRemainingGrams')!.hasError('required') && form.get('weightRemainingGrams')!.touched) {
+              <mat-error>Remaining weight is required</mat-error>
+            }
+            @if (form.get('weightRemainingGrams')!.hasError('exceedsTotal')) {
+              <mat-error>Cannot exceed total weight</mat-error>
+            }
+          </mat-form-field>
+        </div>
+      </div>
+
+      <!-- ── Purchase & Status Section ──────────────────────── -->
+      <div class="form-section">
+        <h3 class="section-title">Purchase &amp; Status</h3>
+
+        <div class="form-row">
+          <!-- Purchase Price -->
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Price</mat-label>
+            <input matInput type="number" formControlName="purchasePrice"
+                   min="0" max="1000000" step="0.01"
+                   placeholder="e.g., 25.00" aria-label="Purchase price" />
+            <span matTextSuffix>$</span>
+            @if (form.get('purchasePrice')!.hasError('min') && form.get('purchasePrice')!.touched) {
+              <mat-error>Price must be non-negative</mat-error>
+            }
+          </mat-form-field>
+
+          <!-- Purchase Date -->
+          <mat-form-field appearance="outline" class="form-field">
+            <mat-label>Purchase Date</mat-label>
+            <input matInput [matDatepicker]="picker" formControlName="purchaseDate"
+                   aria-label="Purchase date" />
+            <mat-datepicker-toggle matIconSuffix [for]="picker"></mat-datepicker-toggle>
+            <mat-datepicker #picker></mat-datepicker>
+          </mat-form-field>
+        </div>
+
+        <!-- Active Status -->
+        <div class="checkbox-row">
+          <mat-checkbox formControlName="isActive" aria-label="Active status">
+            Spool is active and available for use
+          </mat-checkbox>
+        </div>
+      </div>
+
+    </form>
+  }
+
+</mat-dialog-content>
+
+<!-- Dialog Actions -->
+<mat-dialog-actions align="end">
+  <button mat-button type="button" (click)="cancel()" [disabled]="saving()"
+          aria-label="Cancel">
+    Cancel
+  </button>
+  <button mat-raised-button color="primary" type="button" (click)="save()"
+          [disabled]="saving() || form.invalid" aria-label="Save filament">
+    @if (saving()) {
+      <mat-spinner diameter="20" class="btn-spinner"></mat-spinner>
+    }
+    {{ isEditMode() ? 'Save Changes' : 'Add Filament' }}
+  </button>
+</mat-dialog-actions>

frontend/src/app/components/filament-dialog/filament-dialog.component.scss

@@ -0,0 +1,175 @@
+/**
+ * Filament Dialog Styles
+ * Touch-optimized for kiosk (Raspberry Pi 5) and mobile PWA
+ */
+
+$touch-target-min: 48px;
+$spacing-unit: 8px;
+$color-error: #ef4444;
+
+// ── Dialog Layout ──────────────────────────────────────────
+
+.filament-dialog-content {
+  overflow-y: auto;
+  max-height: 70vh;
+  padding: 0 $spacing-unit * 2;
+
+  @media (max-width: 480px) {
+    padding: 0 $spacing-unit;
+  }
+}
+
+[mat-dialog-title] {
+  margin: 0 0 $spacing-unit * 2 0;
+  padding: $spacing-unit * 2 0 0 0;
+  font-size: 20px;
+  font-weight: 600;
+}
+
+// ── Loading State ──────────────────────────────────────────
+
+.dialog-loading {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 48px $spacing-unit * 2;
+  color: var(--mat-sys-on-surface-variant);
+
+  p {
+    margin-top: $spacing-unit * 2;
+    font-size: 14px;
+  }
+}
+
+// ── Error Banner ───────────────────────────────────────────
+
+.error-banner {
+  display: flex;
+  align-items: center;
+  gap: $spacing-unit;
+  padding: $spacing-unit * 1.5 $spacing-unit * 2;
+  border-radius: 8px;
+  margin-bottom: $spacing-unit * 2;
+  background-color: rgba($color-error, 0.12);
+  color: $color-error;
+  border: 1px solid rgba($color-error, 0.3);
+  font-size: 14px;
+  font-weight: 500;
+
+  mat-icon {
+    font-size: 20px !important;
+    width: 20px !important;
+    height: 20px !important;
+  }
+}
+
+// ── Form Sections ──────────────────────────────────────────
+
+.form-section {
+  margin-bottom: $spacing-unit * 3;
+
+  .section-title {
+    font-size: 14px;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.04em;
+    color: var(--mat-sys-on-surface-variant);
+    margin: 0 0 $spacing-unit * 1.5 0;
+    padding-bottom: $spacing-unit * 0.5;
+    border-bottom: 1px solid var(--mat-sys-outline-variant);
+  }
+}
+
+.filament-form {
+  display: flex;
+  flex-direction: column;
+  gap: $spacing-unit;
+}
+
+// ── Form Fields ────────────────────────────────────────────
+
+.form-field {
+  width: 100%;
+
+  // Touch target sizing
+  .mat-mdc-form-field-subscript-wrapper {
+    min-height: 20px;
+  }
+}
+
+.form-row {
+  display: flex;
+  gap: $spacing-unit * 2;
+  width: 100%;
+
+  .form-field {
+    flex: 1;
+  }
+
+  @media (max-width: 480px) {
+    flex-direction: column;
+    gap: 0;
+  }
+}
+
+// ── Color Hex Preview ──────────────────────────────────────
+
+.color-hex-field {
+  max-width: 180px;
+
+  @media (max-width: 480px) {
+    max-width: 100%;
+  }
+}
+
+.color-preview {
+  display: inline-flex;
+  align-items: center;
+  margin-left: 4px;
+}
+
+.color-swatch-mini {
+  display: inline-block;
+  width: 20px;
+  height: 20px;
+  border-radius: 4px;
+  border: 1px solid rgba(0, 0, 0, 0.12);
+  vertical-align: middle;
+}
+
+// ── Checkbox Row ───────────────────────────────────────────
+
+.checkbox-row {
+  display: flex;
+  align-items: center;
+  padding: $spacing-unit 0;
+
+  mat-checkbox {
+    min-height: $touch-target-min;
+    display: flex;
+    align-items: center;
+  }
+}
+
+// ── Save Button Spinner ────────────────────────────────────
+
+mat-dialog-actions {
+  padding: $spacing-unit $spacing-unit * 2 $spacing-unit * 2;
+  gap: $spacing-unit;
+
+  button {
+    min-height: $touch-target-min;
+    min-width: 100px;
+  }
+}
+
+.btn-spinner {
+  display: inline-block;
+  margin-right: $spacing-unit;
+  vertical-align: middle;
+
+  circle {
+    stroke: currentColor;
+  }
+}

frontend/src/app/components/filament-dialog/filament-dialog.component.ts

@@ -0,0 +1,277 @@
+import {
+  ChangeDetectionStrategy,
+  Component,
+  inject,
+  signal,
+  computed,
+} from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { FormsModule, ReactiveFormsModule, FormBuilder, FormGroup, Validators } from '@angular/forms';
+import { MatDialogRef, MAT_DIALOG_DATA, MatDialogModule } from '@angular/material/dialog';
+import { MatFormFieldModule } from '@angular/material/form-field';
+import { MatInputModule } from '@angular/material/input';
+import { MatSelectModule } from '@angular/material/select';
+import { MatDatepickerModule } from '@angular/material/datepicker';
+import { MatNativeDateModule } from '@angular/material/core';
+import { MatCheckboxModule } from '@angular/material/checkbox';
+import { MatButtonModule } from '@angular/material/button';
+import { MatIconModule } from '@angular/material/icon';
+import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
+import { MatTooltipModule } from '@angular/material/tooltip';
+
+import { Filament } from '../../models/filament.model';
+import {
+  MaterialBase,
+  MaterialFinish,
+  MaterialModifier,
+} from '../../models/material.model';
+import {
+  FilamentService,
+  CreateFilamentRequest,
+  UpdateFilamentRequest,
+} from '../../services/filament.service';
+
+/** Data passed into the dialog from the opener. */
+export interface FilamentDialogData {
+  /** If provided, the dialog opens in edit mode with pre-populated fields. */
+  filament?: Filament;
+}
+
+@Component({
+  selector: 'app-filament-dialog',
+  standalone: true,
+  imports: [
+    CommonModule,
+    FormsModule,
+    ReactiveFormsModule,
+    MatDialogModule,
+    MatFormFieldModule,
+    MatInputModule,
+    MatSelectModule,
+    MatDatepickerModule,
+    MatNativeDateModule,
+    MatCheckboxModule,
+    MatButtonModule,
+    MatIconModule,
+    MatProgressSpinnerModule,
+    MatTooltipModule,
+  ],
+  templateUrl: './filament-dialog.component.html',
+  styleUrl: './filament-dialog.component.scss',
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class FilamentDialogComponent {
+  private readonly dialogRef = inject(MatDialogRef<FilamentDialogComponent>);
+  private readonly data = inject<FilamentDialogData>(MAT_DIALOG_DATA);
+  private readonly fb = inject(FormBuilder);
+  private readonly filamentService = inject(FilamentService);
+
+  /** Whether this dialog is in edit mode (has existing filament data). */
+  readonly isEditMode = computed(() => !!this.data.filament);
+
+  /** Dialog title based on mode. */
+  readonly dialogTitle = computed(() =>
+    this.isEditMode() ? 'Edit Filament' : 'Add Filament'
+  );
+
+  // ── Lookup data signals ──────────────────────────────────
+
+  /** All material bases for the base material dropdown. */
+  readonly materialBases = signal<MaterialBase[]>([]);
+
+  /** Material finishes filtered by selected base material. */
+  readonly filteredFinishes = signal<MaterialFinish[]>([]);
+
+  /** Material modifiers filtered by selected base material. */
+  readonly filteredModifiers = signal<MaterialModifier[]>([]);
+
+  /** Whether material lookups are loading. */
+  readonly lookupsLoading = signal(true);
+
+  /** Whether the save operation is in progress. */
+  readonly saving = signal(false);
+
+  /** Server error message, if any. */
+  readonly serverError = signal<string | null>(null);
+
+  // ── Form ─────────────────────────────────────────────────
+
+  readonly form: FormGroup = this.fb.group({
+    materialBaseId: ['', Validators.required],
+    materialFinishId: ['', Validators.required],
+    materialModifierId: [null],
+    brand: ['', [Validators.required, Validators.maxLength(200)]],
+    colorName: ['', [Validators.required, Validators.maxLength(200)]],
+    colorHex: ['#000000', [Validators.required, Validators.pattern(/^#[0-9A-Fa-f]{6}$/)]],
+    weightTotalGrams: [1000, [Validators.required, Validators.min(0.01), Validators.max(100000)]],
+    weightRemainingGrams: [1000, [Validators.required, Validators.min(0), Validators.max(100000)]],
+    filamentDiameterMm: [1.75, [Validators.required, Validators.min(0.1), Validators.max(10)]],
+    spoolSerial: ['', [Validators.required, Validators.maxLength(200)]],
+    purchasePrice: [null, [Validators.min(0), Validators.max(1000000)]],
+    purchaseDate: [null],
+    isActive: [true],
+  });
+
+  constructor() {
+    this.loadLookups();
+    this.patchFormIfEditing();
+    this.setupCascadingFilters();
+  }
+
+  // ── Data loading ─────────────────────────────────────────
+
+  /** Load material bases, finishes, and modifiers for dropdowns. */
+  private loadLookups(): void {
+    this.lookupsLoading.set(true);
+    this.filamentService.getMaterialBases().subscribe({
+      next: (bases) => {
+        this.materialBases.set(bases);
+        this.lookupsLoading.set(false);
+      },
+      error: () => {
+        this.lookupsLoading.set(false);
+        this.serverError.set('Failed to load material options. Please try again.');
+      },
+    });
+  }
+
+  /** Pre-populate form fields when editing an existing filament. */
+  private patchFormIfEditing(): void {
+    if (this.data.filament) {
+      const f = this.data.filament;
+      this.form.patchValue({
+        materialBaseId: f.materialBaseId,
+        materialFinishId: f.materialFinishId,
+        materialModifierId: f.materialModifierId,
+        brand: f.brand,
+        colorName: f.colorName,
+        colorHex: f.colorHex,
+        weightTotalGrams: f.weightTotalGrams,
+        weightRemainingGrams: f.weightRemainingGrams,
+        filamentDiameterMm: f.filamentDiameterMm,
+        spoolSerial: f.spoolSerial,
+        purchasePrice: f.purchasePrice,
+        purchaseDate: f.purchaseDate ? new Date(f.purchaseDate) : null,
+        isActive: f.isActive,
+      });
+    }
+  }
+
+  /** Set up cascading filter: when base material changes, reload finishes & modifiers. */
+  private setupCascadingFilters(): void {
+    this.form.get('materialBaseId')!.valueChanges.subscribe((baseId: string | null) => {
+      // Clear dependent selections when base changes
+      this.form.get('materialFinishId')!.setValue('');
+      this.form.get('materialModifierId')!.setValue(null);
+      this.filteredFinishes.set([]);
+      this.filteredModifiers.set([]);
+
+      if (!baseId) return;
+
+      this.filamentService.getMaterialFinishes(baseId).subscribe({
+        next: (finishes) => this.filteredFinishes.set(finishes),
+        error: () => this.filteredFinishes.set([]),
+      });
+
+      this.filamentService.getMaterialModifiers(baseId).subscribe({
+        next: (modifiers) => this.filteredModifiers.set(modifiers),
+        error: () => this.filteredModifiers.set([]),
+      });
+    });
+
+    // If editing, trigger the cascading load for the pre-selected base
+    if (this.data.filament) {
+      const baseId = this.data.filament.materialBaseId;
+      // We need to load finishes and modifiers for the pre-selected base
+      // but also re-select the original finish and modifier after loading
+      this.filamentService.getMaterialFinishes(baseId).subscribe({
+        next: (finishes) => {
+          this.filteredFinishes.set(finishes);
+          // Re-patch finish after load
+          this.form.get('materialFinishId')!.setValue(this.data.filament!.materialFinishId);
+        },
+      });
+      this.filamentService.getMaterialModifiers(baseId).subscribe({
+        next: (modifiers) => {
+          this.filteredModifiers.set(modifiers);
+          // Re-patch modifier after load
+          this.form.get('materialModifierId')!.setValue(this.data.filament!.materialModifierId);
+        },
+      });
+    }
+  }
+
+  // ── Actions ──────────────────────────────────────────────
+
+  /** Cancel and close the dialog without saving. */
+  cancel(): void {
+    this.dialogRef.close(false);
+  }
+
+  /** Submit the form — creates or updates the filament. */
+  save(): void {
+    if (this.form.invalid) {
+      this.form.markAllAsTouched();
+      return;
+    }
+
+    // Cross-field validation: remaining weight must not exceed total weight
+    const total = this.form.value.weightTotalGrams;
+    const remaining = this.form.value.weightRemainingGrams;
+    if (remaining > total) {
+      this.form.get('weightRemainingGrams')!.setErrors({ exceedsTotal: true });
+      return;
+    }
+
+    this.saving.set(true);
+    this.serverError.set(null);
+
+    const formValue = this.form.value;
+    const request: CreateFilamentRequest | UpdateFilamentRequest = {
+      materialBaseId: formValue.materialBaseId,
+      materialFinishId: formValue.materialFinishId,
+      materialModifierId: formValue.materialModifierId || null,
+      brand: formValue.brand.trim(),
+      colorName: formValue.colorName.trim(),
+      colorHex: formValue.colorHex,
+      weightTotalGrams: formValue.weightTotalGrams,
+      weightRemainingGrams: formValue.weightRemainingGrams,
+      filamentDiameterMm: formValue.filamentDiameterMm,
+      spoolSerial: formValue.spoolSerial.trim(),
+      purchasePrice: formValue.purchasePrice ?? null,
+      purchaseDate: formValue.purchaseDate
+        ? new Date(formValue.purchaseDate).toISOString()
+        : null,
+      isActive: formValue.isActive,
+    };
+
+    if (this.isEditMode()) {
+      const id = this.data.filament!.id;
+      this.filamentService.updateFilament(id, request).subscribe({
+        next: (updated) => {
+          this.saving.set(false);
+          this.dialogRef.close(true);
+        },
+        error: (err) => {
+          this.saving.set(false);
+          this.serverError.set(
+            err?.error?.error || err?.message || 'Failed to update filament. Please try again.'
+          );
+        },
+      });
+    } else {
+      this.filamentService.createFilament(request).subscribe({
+        next: (created) => {
+          this.saving.set(false);
+          this.dialogRef.close(true);
+        },
+        error: (err) => {
+          this.saving.set(false);
+          this.serverError.set(
+            err?.error?.error || err?.message || 'Failed to create filament. Please try again.'
+          );
+        },
+      });
+    }
+  }
+}

frontend/src/app/models/material.model.ts

@@ -0,0 +1,50 @@
+/**
+ * Material lookup models matching the Extrudex backend Material DTOs.
+ * Used for populating dropdowns in the filament add/edit form.
+ */
+
+/** Material base (e.g., PLA, PETG, ABS). */
+export interface MaterialBase {
+  /** Unique identifier. */
+  id: string;
+  /** Human-readable name (e.g., "PLA", "PETG"). */
+  name: string;
+  /** Density in g/cm³. */
+  densityGperCm3: number;
+  /** Created timestamp (UTC). */
+  createdAt: string;
+  /** Updated timestamp (UTC). */
+  updatedAt: string;
+}
+
+/** Material finish (e.g., Basic, Matte, Silk). */
+export interface MaterialFinish {
+  /** Unique identifier. */
+  id: string;
+  /** Human-readable name (e.g., "Basic", "Matte"). */
+  name: string;
+  /** Foreign key to the parent material base. */
+  materialBaseId: string;
+  /** Name of the parent material base (for display). */
+  materialBaseName: string;
+  /** Created timestamp (UTC). */
+  createdAt: string;
+  /** Updated timestamp (UTC). */
+  updatedAt: string;
+}
+
+/** Material modifier (e.g., Carbon Fiber, Wood Fill). Optional. */
+export interface MaterialModifier {
+  /** Unique identifier. */
+  id: string;
+  /** Human-readable name (e.g., "Carbon Fiber"). */
+  name: string;
+  /** Foreign key to the parent material base. */
+  materialBaseId: string;
+  /** Name of the parent material base (for display). */
+  materialBaseName: string;
+  /** Created timestamp (UTC). */
+  createdAt: string;
+  /** Updated timestamp (UTC). */
+  updatedAt: string;
+}

frontend/src/app/models/paged-response.model.ts

@@ -0,0 +1,13 @@
+/**
+ * Generic paged response wrapper matching the Extrudex backend PagedResponse<T>.
+ */
+export interface PagedResponse<T> {
+  /** The items in this page. */
+  items: T[];
+  /** Total number of items across all pages. */
+  totalCount: number;
+  /** The current page number (1-based). */
+  pageNumber: number;
+  /** The number of items per page. */
+  pageSize: number;
+}

frontend/src/environments/environment.prod.ts

@@ -0,0 +1,8 @@
+/**
+ * Environment configuration for the Extrudex frontend (production).
+ * Override API URL for deployed environments.
+ */
+export const environment = {
+  production: true,
+  apiBaseUrl: '/api',
+};

frontend/src/environments/environment.ts

@@ -0,0 +1,8 @@
+/**
+ * Environment configuration for the Extrudex frontend.
+ * Replace API URL with the actual backend endpoint in production.
+ */
+export const environment = {
+  production: false,
+  apiBaseUrl: 'http://localhost:5000',
+};