FictionArchive/FictionArchive.Service.NovelService/Migrations/20251229203027_AddVolumes.cs

using System;
using Microsoft.EntityFrameworkCore.Migrations;
using NodaTime;
using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;

#nullable disable

namespace FictionArchive.Service.NovelService.Migrations
{
    /// <inheritdoc />
    public partial class AddVolumes : Migration
    {
        /// <inheritdoc />
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            // 1. Create the Volume table
            migrationBuilder.CreateTable(
                name: "Volume",
                columns: table => new
                {
                    Id = table.Column<long>(type: "bigint", nullable: false)
                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
                    Order = table.Column<int>(type: "integer", nullable: false),
                    NameId = table.Column<Guid>(type: "uuid", nullable: false),
                    NovelId = table.Column<long>(type: "bigint", nullable: false),
                    CreatedTime = table.Column<Instant>(type: "timestamp with time zone", nullable: false),
                    LastUpdatedTime = table.Column<Instant>(type: "timestamp with time zone", nullable: false)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Volume", x => x.Id);
                    table.ForeignKey(
                        name: "FK_Volume_LocalizationKeys_NameId",
                        column: x => x.NameId,
                        principalTable: "LocalizationKeys",
                        principalColumn: "Id",
                        onDelete: ReferentialAction.Cascade);
                    table.ForeignKey(
                        name: "FK_Volume_Novels_NovelId",
                        column: x => x.NovelId,
                        principalTable: "Novels",
                        principalColumn: "Id",
                        onDelete: ReferentialAction.Cascade);
                });

            migrationBuilder.CreateIndex(
                name: "IX_Volume_NameId",
                table: "Volume",
                column: "NameId");

            migrationBuilder.CreateIndex(
                name: "IX_Volume_NovelId_Order",
                table: "Volume",
                columns: new[] { "NovelId", "Order" },
                unique: true);

            // 2. Add nullable VolumeId column to Chapter (keep NovelId for now)
            migrationBuilder.AddColumn<long>(
                name: "VolumeId",
                table: "Chapter",
                type: "bigint",
                nullable: true);

            // 3. Data migration: Create volumes and link chapters for each novel
            migrationBuilder.Sql(@"
DO $$
DECLARE
    novel_rec RECORD;
    loc_key_id uuid;
    volume_id bigint;
BEGIN
    FOR novel_rec IN SELECT ""Id"", ""RawLanguage"" FROM ""Novels"" LOOP
        -- Create LocalizationKey for volume name
        loc_key_id := gen_random_uuid();
        INSERT INTO ""LocalizationKeys"" (""Id"", ""CreatedTime"", ""LastUpdatedTime"")
        VALUES (loc_key_id, NOW(), NOW());

        -- Create LocalizationText for 'Main Story' in novel's raw language
        INSERT INTO ""LocalizationText"" (""Id"", ""LocalizationKeyId"", ""Language"", ""Text"", ""CreatedTime"", ""LastUpdatedTime"")
        VALUES (gen_random_uuid(), loc_key_id, novel_rec.""RawLanguage"", 'Main Story', NOW(), NOW());

        -- Create Volume for this novel
        INSERT INTO ""Volume"" (""Order"", ""NameId"", ""NovelId"", ""CreatedTime"", ""LastUpdatedTime"")
        VALUES (1, loc_key_id, novel_rec.""Id"", NOW(), NOW())
        RETURNING ""Id"" INTO volume_id;

        -- Link all chapters of this novel to the new volume
        UPDATE ""Chapter"" SET ""VolumeId"" = volume_id WHERE ""NovelId"" = novel_rec.""Id"";
    END LOOP;
END $$;
            ");

            // 4. Drop old FK and index for NovelId
            migrationBuilder.DropForeignKey(
                name: "FK_Chapter_Novels_NovelId",
                table: "Chapter");

            migrationBuilder.DropIndex(
                name: "IX_Chapter_NovelId",
                table: "Chapter");

            // 5. Drop NovelId column from Chapter
            migrationBuilder.DropColumn(
                name: "NovelId",
                table: "Chapter");

            // 6. Make VolumeId non-nullable
            migrationBuilder.AlterColumn<long>(
                name: "VolumeId",
                table: "Chapter",
                type: "bigint",
                nullable: false,
                oldClrType: typeof(long),
                oldType: "bigint",
                oldNullable: true);

            // 7. Add unique index and FK for VolumeId
            migrationBuilder.CreateIndex(
                name: "IX_Chapter_VolumeId_Order",
                table: "Chapter",
                columns: new[] { "VolumeId", "Order" },
                unique: true);

            migrationBuilder.AddForeignKey(
                name: "FK_Chapter_Volume_VolumeId",
                table: "Chapter",
                column: "VolumeId",
                principalTable: "Volume",
                principalColumn: "Id",
                onDelete: ReferentialAction.Cascade);
        }

        /// <inheritdoc />
        protected override void Down(MigrationBuilder migrationBuilder)
        {
            // Add back NovelId column
            migrationBuilder.AddColumn<long>(
                name: "NovelId",
                table: "Chapter",
                type: "bigint",
                nullable: true);

            // Migrate data back: set NovelId from Volume
            migrationBuilder.Sql(@"
UPDATE ""Chapter"" c
SET ""NovelId"" = v.""NovelId""
FROM ""Volume"" v
WHERE c.""VolumeId"" = v.""Id"";
            ");

            // Make NovelId non-nullable
            migrationBuilder.AlterColumn<long>(
                name: "NovelId",
                table: "Chapter",
                type: "bigint",
                nullable: false,
                oldClrType: typeof(long),
                oldType: "bigint",
                oldNullable: true);

            // Drop VolumeId FK and index
            migrationBuilder.DropForeignKey(
                name: "FK_Chapter_Volume_VolumeId",
                table: "Chapter");

            migrationBuilder.DropIndex(
                name: "IX_Chapter_VolumeId_Order",
                table: "Chapter");

            // Drop VolumeId column
            migrationBuilder.DropColumn(
                name: "VolumeId",
                table: "Chapter");

            // Recreate NovelId index and FK
            migrationBuilder.CreateIndex(
                name: "IX_Chapter_NovelId",
                table: "Chapter",
                column: "NovelId");

            migrationBuilder.AddForeignKey(
                name: "FK_Chapter_Novels_NovelId",
                table: "Chapter",
                column: "NovelId",
                principalTable: "Novels",
                principalColumn: "Id",
                onDelete: ReferentialAction.Cascade);

            // Note: Volume LocalizationKeys are not cleaned up in Down migration
            // as they may have been modified. Manual cleanup may be needed.
            migrationBuilder.DropTable(
                name: "Volume");
        }
    }
}