From 471c46201c33220c046925e964e24070d768fbc1 Mon Sep 17 00:00:00 2001
From: "Collin M. Barrett" <collinbarrett@users.noreply.github.com>
Date: Tue, 16 Nov 2021 16:06:36 -0600
Subject: [PATCH] =?UTF-8?q?feat(dir):=20=E2=9C=A8=20add=20computed=20Chang?=
 =?UTF-8?q?e=20col=20for=20TPH=20discriminator?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../ConfigurationExtensions.cs                |  1 +
 .../Persistence/Queries/Entities/Change.cs    | 35 ++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/services/Directory/FilterLists.Directory.Infrastructure/ConfigurationExtensions.cs b/services/Directory/FilterLists.Directory.Infrastructure/ConfigurationExtensions.cs
index f78ddcb1c..7e7531b1a 100644
--- a/services/Directory/FilterLists.Directory.Infrastructure/ConfigurationExtensions.cs
+++ b/services/Directory/FilterLists.Directory.Infrastructure/ConfigurationExtensions.cs
@@ -37,6 +37,7 @@ public static void AddInfrastructure(this IServiceCollection services, IConfigur
         services.AddDbContextPool<CommandDbContext>(o =>
         {
             o.UseNpgsql(configuration.GetConnectionString("DirectoryConnection"))
+                .UseSnakeCaseNamingConvention()
 #if DEBUG
                 .LogTo(Console.WriteLine, LogLevel.Information);
             o.EnableSensitiveDataLogging();
diff --git a/services/Directory/FilterLists.Directory.Infrastructure/Persistence/Queries/Entities/Change.cs b/services/Directory/FilterLists.Directory.Infrastructure/Persistence/Queries/Entities/Change.cs
index 05c682f61..79a4be35c 100644
--- a/services/Directory/FilterLists.Directory.Infrastructure/Persistence/Queries/Entities/Change.cs
+++ b/services/Directory/FilterLists.Directory.Infrastructure/Persistence/Queries/Entities/Change.cs
@@ -1,4 +1,6 @@
-using System.Text.Json;
+using System.Globalization;
+using System.Text.Json;
+using EFCore.NamingConventions.Internal;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Metadata.Builders;
 
@@ -14,6 +16,7 @@ public record Change
     public string? RejectedReason { get; private init; }
     public JsonDocument? AggregateBefore { get; private init; }
     public JsonDocument? AggregateAfter { get; private init; }
+    public string? AggregateType { get; private init; }
     public int? FilterListId { get; private init; }
     public FilterList? FilterList { get; }
     public string? LanguageIso6391 { get; private init; }
@@ -30,9 +33,39 @@ public record Change
     public Tag? Tag { get; }
 }
 
+internal enum AggregateType
+{
+    FilterList,
+    Language,
+    License,
+    Maintainer,
+    Software,
+    Syntax,
+    Tag
+}
+
 internal class UpdateConfiguration : IEntityTypeConfiguration<Change>
 {
     public virtual void Configure(EntityTypeBuilder<Change> builder)
     {
+        builder
+            .Property(c => c.AggregateType)
+            .HasComputedColumnSql(BuildComputedAggregateTypeSql(), true);
+
+        static string BuildComputedAggregateTypeSql()
+        {
+            var nameRewriter = new SnakeCaseNameRewriter(CultureInfo.InvariantCulture);
+            return $@"
+                CASE 
+                    WHEN {nameRewriter.RewriteName(nameof(Change.FilterListId))} IS NOT NULL THEN '{AggregateType.FilterList}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.LanguageIso6391))} IS NOT NULL THEN '{AggregateType.Language}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.LicenseId))} IS NOT NULL THEN '{AggregateType.License}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.MaintainerId))} IS NOT NULL THEN '{AggregateType.Maintainer}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.SoftwareId))} IS NOT NULL THEN '{AggregateType.Software}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.SyntaxId))} IS NOT NULL THEN '{AggregateType.Syntax}'
+                    WHEN {nameRewriter.RewriteName(nameof(Change.TagId))} IS NOT NULL THEN '{AggregateType.Tag}'
+                    ELSE NULL
+                END";
+        }
     }
 }