Add shared workspace API

OtthonApi/Program.cs

@@ -465,6 +465,76 @@ app.MapGet("/api/shopping/recommendations", async (
     });
 });
 
+app.MapGet("/api/workspace/state", async (
+    HttpContext context,
+    OtthonDbContext db) =>
+{
+    if (!HasApiToken(context))
+    {
+        return Results.Unauthorized();
+    }
+
+    var token = GetWorkspaceToken(context);
+    if (string.IsNullOrWhiteSpace(token))
+    {
+        return Results.BadRequest(new { message = "Missing X-Workspace-Token header." });
+    }
+
+    var workspace = await GetOrCreateWorkspace(db, token);
+    return Results.Ok(new WorkspaceStateResponse(
+        workspace.Token,
+        workspace.StateJson,
+        workspace.UpdatedUtc));
+});
+
+app.MapPut("/api/workspace/state", async (
+    HttpContext context,
+    OtthonDbContext db) =>
+{
+    if (!HasApiToken(context))
+    {
+        return Results.Unauthorized();
+    }
+
+    var token = GetWorkspaceToken(context);
+    if (string.IsNullOrWhiteSpace(token))
+    {
+        return Results.BadRequest(new { message = "Missing X-Workspace-Token header." });
+    }
+
+    string? stateJson;
+    try
+    {
+        using var bodyDocument = await JsonDocument.ParseAsync(context.Request.Body);
+        var root = bodyDocument.RootElement;
+        stateJson = root.TryGetProperty("stateJson", out var stateProperty)
+            && stateProperty.ValueKind == JsonValueKind.String
+            ? stateProperty.GetString()?.Trim()
+            : root.GetRawText();
+
+        if (string.IsNullOrWhiteSpace(stateJson))
+        {
+            return Results.BadRequest(new { message = "Workspace state cannot be empty." });
+        }
+
+        using var _ = JsonDocument.Parse(stateJson);
+    }
+    catch (Exception ex) when (ex is JsonException or InvalidOperationException)
+    {
+        return Results.BadRequest(new { message = "Invalid workspace state JSON. Send UTF-8 encoded JSON." });
+    }
+
+    var workspace = await GetOrCreateWorkspace(db, token);
+    workspace.StateJson = stateJson;
+    workspace.UpdatedUtc = DateTimeOffset.UtcNow;
+    await db.SaveChangesAsync();
+
+    return Results.Ok(new WorkspaceStateResponse(
+        workspace.Token,
+        workspace.StateJson,
+        workspace.UpdatedUtc));
+});
+
 app.Run();
 
 static bool HasApiToken(HttpContext context)
@@ -496,6 +566,43 @@ static string? Clean(string? value)
     return string.IsNullOrWhiteSpace(trimmed) ? null : trimmed;
 }
 
+static string? GetWorkspaceToken(HttpContext context)
+{
+    if (context.Request.Headers.TryGetValue("X-Workspace-Token", out var headerToken))
+    {
+        return Clean(headerToken.ToString());
+    }
+
+    if (context.Request.Query.TryGetValue("workspaceToken", out var queryToken))
+    {
+        return Clean(queryToken.ToString());
+    }
+
+    return null;
+}
+
+static async Task<WorkspaceState> GetOrCreateWorkspace(
+    OtthonDbContext db,
+    string token)
+{
+    var workspace = await db.Workspaces.FindAsync(token);
+    if (workspace is not null)
+    {
+        return workspace;
+    }
+
+    workspace = new WorkspaceState
+    {
+        Token = token,
+        StateJson = "{}",
+        CreatedUtc = DateTimeOffset.UtcNow,
+        UpdatedUtc = DateTimeOffset.UtcNow
+    };
+    db.Workspaces.Add(workspace);
+    await db.SaveChangesAsync();
+    return workspace;
+}
+
 static void ApplyProductLookup(Product target, Product lookup, string source)
 {
     target.Name = lookup.Name;
@@ -580,6 +687,7 @@ static async Task EnsureDatabaseReady(OtthonDbContext db, ILogger logger)
             await db.Database.EnsureCreatedAsync();
             await EnsureProductSchemaAsync(db);
             await EnsureFoodLearningSchemaAsync(db);
+            await EnsureWorkspaceSchemaAsync(db);
             return;
         }
         catch (Exception ex) when (attempt < maxAttempts)
@@ -596,6 +704,7 @@ static async Task EnsureDatabaseReady(OtthonDbContext db, ILogger logger)
     await db.Database.EnsureCreatedAsync();
     await EnsureProductSchemaAsync(db);
     await EnsureFoodLearningSchemaAsync(db);
+    await EnsureWorkspaceSchemaAsync(db);
 }
 
 static async Task EnsureProductSchemaAsync(OtthonDbContext db)
@@ -615,6 +724,22 @@ IF COL_LENGTH('Products', 'IngredientsText') IS NULL
     await db.Database.ExecuteSqlRawAsync(sql);
 }
 
+static async Task EnsureWorkspaceSchemaAsync(OtthonDbContext db)
+{
+    var sql = """
+IF OBJECT_ID('Workspaces', 'U') IS NULL
+BEGIN
+    CREATE TABLE Workspaces (
+        Token nvarchar(160) NOT NULL CONSTRAINT PK_Workspaces PRIMARY KEY,
+        StateJson nvarchar(max) NOT NULL,
+        CreatedUtc datetimeoffset NOT NULL,
+        UpdatedUtc datetimeoffset NOT NULL
+    );
+END
+""";
+    await db.Database.ExecuteSqlRawAsync(sql);
+}
+
 static async Task EnsureFoodLearningSchemaAsync(OtthonDbContext db)
 {
     var sql = """
@@ -843,9 +968,12 @@ public sealed class OtthonDbContext(DbContextOptions<OtthonDbContext> options)
     public DbSet<RegisteredDevice> Devices => Set<RegisteredDevice>();
     public DbSet<Product> Products => Set<Product>();
     public DbSet<FoodLearningEvent> FoodLearningEvents => Set<FoodLearningEvent>();
+    public DbSet<WorkspaceState> Workspaces => Set<WorkspaceState>();
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
+        modelBuilder.Entity<WorkspaceState>().HasKey(workspace => workspace.Token);
+        modelBuilder.Entity<WorkspaceState>().Property(workspace => workspace.Token).HasMaxLength(160);
         modelBuilder.Entity<Product>().HasKey(product => product.Barcode);
         modelBuilder.Entity<Product>().Property(product => product.Barcode).HasMaxLength(64);
         modelBuilder.Entity<Product>().Property(product => product.Name).HasMaxLength(300);
@@ -910,6 +1038,14 @@ public sealed class FoodLearningEvent
     public DateTimeOffset CreatedUtc { get; set; }
 }
 
+public sealed class WorkspaceState
+{
+    public required string Token { get; set; }
+    public required string StateJson { get; set; }
+    public DateTimeOffset CreatedUtc { get; set; }
+    public DateTimeOffset UpdatedUtc { get; set; }
+}
+
 public sealed record LoginForm(string Password);
 public sealed record DeviceRegistrationRequest(string? DeviceName, string? Platform);
 public sealed record ProductUpsertRequest(
@@ -973,6 +1109,13 @@ public sealed record ShoppingRecommendationResponse(
     DateTimeOffset LastSeenUtc,
     IReadOnlyList<string> Reasons);
 
+public sealed record WorkspaceStateRequest(string StateJson);
+
+public sealed record WorkspaceStateResponse(
+    string WorkspaceToken,
+    string StateJson,
+    DateTimeOffset UpdatedUtc);
+
 public sealed record ProductResponse(
     bool Found,
     string Barcode,